genaux

BHEL, Hardwar

Generator Bearing

2.1-5001-0015/1

Turbo Generators

Description

BHEL, Hardwar 2.1-5003-0011/1

Measuring of Bearing TemperatureTurbo Generators

Description

BHEL, Hardwar 2.1-5005-0007/1

Generator Bearing Insulation

THDF, THFF Series

Turbo Generators

Description

BHEL, Hardwar

The rotor shaft ends are brought out of the

gastight enclosure through double-flow shaft seals.

With th is type of shaf t seal , the escape of

hydrogen between the rotating shaft and the housing

is prevented by maintaining a cdontinus film of oil

between the shaft and a non-rotating floating seal

ring. To accomplish this, seal oil from two separate

circuits, i.e. the air side and hydrogen side seal oil

circuit, is fed to the seal ring at a pressure slightly

higher than the hydrogen pressure. In addition,

higher pressure air side oil is supplied to the shaft

seal for thrust load compensation of the seal ring.

1 Seal ring carrier

2 Seal ring

Hydrogen side seal oil

Air side seal oil

Ring relief oil

Fig.1 Interchange of Oil in Annular Groove of Shaft

Seal

The double-flow shaft seal is characterized by its

shor t ax ia l length, i ts independence f rom the

respective axial and radial position of the shaft, and

low hydrogen losses due to absorption by the seal

oil.

The two halves of the babbitted seal ring float on

the shaft journal with a small clearance and are

guided in the axial direction by a seal ring carrier

resistant to distortion and bending. The seal ring is

Shaft Seal

2.1-6000-0006/1

relatively free to move in the radial direction, but is

restrained from rotating by use of a pin. The seal ring

carrier, bolted to the end shield, is insulated to prevent

the flow of shaft currents. The oil is supplied to the

shaft seal at three different pressures (air side and

hydrogen side seal oil pressures and higher pressure

oil for ring relief) over pipes and the mounting flange

of the seal ring carrier. The air side and hydrogen

side real oil is admitted into the air side and hydrogen

side annular grooves, respectively, of the seal ring

via passage in the seal ring carrier and seal ring. A

continuous film of oil is maintained between the shaft

and the seal ring. The clearance between shaft and

seal ring is such that friction losses are minimized

and an oil film of sufficient thickness is maintains

without an unnecessarily large oil flow. Temperature

rise of the seal oil is therefore small which contributes

to reliable sealing. The babsitt lining of the seal ring

ensure high reliability even in the event of boundary

friction.

The air side seal oil pump delivers the oil at a

pressure maintained at >1.4 bar above the generator

hydrogen gas pressure at the shaft seal by means of

a differential pressure valve ("A" valve)

On the hydrogen side, the hydrogen-saturated seal

oi l is c i rculated in a c losed circui t . A pressure

equalizing valve maintains the oil pressure on the

hydrogen side slightly blow that on the air side, thus

keeping the interchange of oil between the air and

hydrogen sides to a very small value.

Air side seal oil for ring relief is fed to the annular

groove in the air side seal ring carrier and forced

between the seal ring and the seal ring carrier. In this

way the oil and gas pressure acting on the seal ring

are balanced, and the friction between the seal and

seal ring carrier is reduced. The seal ring is thus free

to adjust its radial position, Which is important during

the starting and shutdown period. The seal ring will

adjust its position according to the shaft position as

dictated by the oil film thickness and the vibratory

condition.

The seal ring need follow the axial displacement

of the generator shaft, which is primarily caused by

turbine expansion. The dishing permits the shaft to

slide through the seal ring without impairing the

sealing effect.

Turbo Generators

Description

BHEL, Hardwar

Shaft Seal

2.1-6001-0004/1

Turbo Generators

Description

Air

Hydrogenb

Air side seal oil

H2 side seal oil

Pressure oil for seal ring relief

BHEL, Hardwar 2.1-7100-0025/1

Seal Oil System

Shaft seals supplied with pressurized seal oil are

provided to prevent hydrogen losses at the shaft and

the ingress of air into the hydrogen-cooled generator.

Details of the shaft seal are given in a separate

description in this manual.

As long as the seal oil pressure in the annular

gap exceeds the gas pressure in the generator, no

hydrogen will escape from the generator housing.

The shaft seal is supplied with seal oil by a separate

system consisting of a hydrogen side seal oil circuit

and an air side seal oil circuit. The oil in the seal oil

system is the same as that used in the turbine-

generator journal shown.

1 Air Side Seal Oil Circuit

During normal operation, the air side ac pump

draws the seal oil from the seal oil storage tank and

feeds it to the shaft seals via coolers and filters. The

seal oil supplied to the shaft seals which drains

towards the air s ide through the annular gaps

between the shaft and seal rings is returned to the

seal oil storage tank.

For the air side seal oil circuit, three seal oil

pumps are provided with one of the three pumps

always in operation. In the event of a failure of the

pump in service due to a mechanical or electrical

failure, the second pump automatically takes over. If

both pumps fail, the seal oil supply is taken over by

the stand-by pump without any interruption.

2 Hydrogen Side Seal Oil Circuit

During normal operation, the hydrogen side pump

draws the seal oil from the seal oil storage tank and

feeds it to the shaft seal via coolers and filters. The

seal oil supplied to the shaft seals which drains

towards the hydrogen side through the annular gaps

between the shaft and the seal rings is first collected

in the generater prechambers and then returned to

the seal oil tank.

By dividing the seal oil system into two separate

circuits, the hydrogen losses at the seals are kept to

a minimum. Since the hydrogen side seal oil comes

into contact with only the hydrogen gas, it is saturated

with hydrogen and contains no air. Vacuum treatment

of the seal oil and the resulting continuous hydrogen

losses are thus avoided. The air side seal oil, which

is only in contact with air, becomes saturated with

air. By separating the two seal oil circuits, entry of air

to the hydrogen compartment is kept to a minimum

thereby maintaining good hydrogen purity.

One seal oil pump is used for oil circulation in the

hydrogen side oil circuit. In the event of a failure of

this pump, the seal oil to the hydrogen side annular

Turbo Generators

Description

2.1-7100-0025/2

gap is derived from the air side oil supply circuit.

When opera t ing i s th is manner , a s low

deterioration of the hydrogen purity in the generator

will take place, since the oil f lowing towards the

hydrogen side will introduce air, which will come out

of the oil in the hydrogen atmoshere due to the change

in pressures. In case of prolonged operation, it may

eventually become necessary to improve the hydrogen

purity by gas scavenging.

3 Seal Oil Prsessure Regulation

The air side and the hydrogen side seal oil circuits

are, hower, in contact in the annular gaps between

the shaft seal. The seal oil pressures at the shaft seal

are set so that the air side seal oil pressure is slightly

higher than the hydrogen side seal oil pressure.

Accordingly, a very small quantity of oil flows from

the air side to the hydrogen side in the annular gap

resulting in a gradual increase in the amount of oil in

the hydrogen side oil circuit. A float valve in seal oil

tank returns the excess oil to the seal oil stroge tank.

The interchange of oil between the two circuit is so

small that the aforementioned advantages of two

separate circuit are not impaired.

Oil pressures which exceed the generator gas

pressure are required to ensure proper sealing of the

generator. With the seal oil pumps in operation, the

seal oil pressure is controlled by differential pressure

valves "A" ("A" valve). The first "A" valve controls the

seal oil pressure after two equal-priority ac air side

seal oil pumps. The pressure after the standby seal

oil pump is separately controlled by the second "A"

valve. Depending on the valve setting and the singnal

o i l p ressure preva i l l ing (sea l o i l p ressure and

hydrogen casing pressure), a larger or smaller amount

of oil is returned to the suction pipe so that the

required seal oil pressures is established at the shaft

seals.

The function of the "A" valves is illustrated in the

attached diagram. Since the gas pressure and the

signal oil pressure act in opposite directions, the valve

stem is moved upwards or downwards when these

pressure become unbalanced. The valve cone is

arranged so that the valve c loses further for a

downward movement of the valve stem (occurs at

rising gas pressure or falling seal oil pressure). This

oil flow throttling results in a rise of the air side seal

oil pressure at the shaft seals. Setting of the desired

differential pressure (set valve) to be maintainde by

the valve is done by a coresponding preloading of the

main bellows. The preloading is adjusted with a

compression spring, the upper end of which is rigidly

connected to the valve yoke, while its lower end is

linked to the valve stem by means of an adjusting nut.

As may be seen on the at tached d iagram,

differentaial pressure valve "C" ("C" valve) serves to

control the seal oil pressure in the hydrogen side seal

oil circuit and operates on the same principle, with

the only difference being that the air side seal oil

pressures are used as singals.

The constant differential pressure between the air

s ide and the hydrogen side oi l is control led by

separate pressure equalizing control valves for each

shaft seal. The function of the pressure equalizing

control valve is illustrated in the attached diagram.

Due to the fact that the air side and hydrogen side

seal oil pressures act in opposite directioins, the valve

stem is moved upwards or downwards when these

pressures are unbalanced. The valve opens further

with a downward movement of the valve stem (occours

at rising air side seal oil pressure), resulting in a reise

of the hydrogen side seal oil pressure. Setting of the

desired differential pressure to be maintained by the

valve is done by a corresponding preloading of the

control piston.

4 Seal Oil Drains

The oil drains from the air side of the shaft seals

discharges to the generator beadring space and is

returnde to the turbine oil tank via the seal oil storage

tank together with the bearign oil.

The oil drained from the hydrogen side of the shaft

seals is discharged into the generator prechambers.

The prechambers reduce the oil flow which permits

the escape of entrained gas bubbles and defoaming

of the oil. Down-stream of the prechambers the oil

flows are combined and returned into the seal oil tank.

Float valves keep the oi l level in the tank at a

predetermined level. If an excessive amount of oil is

supplied to the seal oil tank, a float valve allows some

oil to return to the seal oil storage tank.

The small amount of hydrogen escaping from the

generator together with the oil does not present a

danger to the generator surrounding since the oil

drained on the hydrogen side is returned to the turbine

oil tank only via the seal oil storage tank where the

majority of the entrained hydrogen is removed. The

seal oil storage tank is connected to the bearing vapor

exhaus te rs wh ich a lso ven t the genera to r

prechambers.

5 Seal Ring Relief

To ensure free movement of the seal ringl, the

shaft seals are provide with pressure oil for ring relief.

The oil supply for ring relief is obtainde from the air

side oil circuit. The required pressure setting for each

shaft seal is accomplished separately.

BHEL, Hardwar

BHEL, Hardwar 2.1-7104-0001/1

Pressure Equalizing Control ValveTurbo Generators

Description

BHEL, Hardwar 2.1-7101-0002/1

Differential Pressure Valve ATurbo Generators

Description

BHEL, Hardwar 2.1-7103-0002/1

Differential Pressure Valve CTurbo Generators

Description

BHEL, Hardwar 2.1-7111-7379/10197E

Seal Oil DiagramList of Valves For Seal Oil System

Turbo Generators

Description

SL. VLV TYPE OF VALVE NOM. NOM. BODY END FUNCTION LOCATIOIN REMARKNO.DESG BORE PRESS MATL CONN

MM MPA

1 MKW 01 Gate Vlave 80 2.5 CS FL Shut off Seal Oil Pumps Pipe LineAA 503

2. MKW 01 Needle Valve 15 2.5 CS SC Shut Off Valve For SOST Pipe LineAA 505 Drain

3. MKW 01 Needle Valve 15 2.5 CS SC Shut Off Valve in U Loop Pipe LineAA 505 Drain

4. MKW 03 Float Valve 50 1.6 CS FL Float Valve For Seal Oil Seal Oil UnitAA 001 Tank Drain

5. MKW 03 Float Valve 50 1.6 CS FL Float Valve For Seal Oil Seal Oil UnitAA 022 Tank, Supply From Air Side

Circuit

6. MKW 03 Gate Valve 50 4.0 CS FL Shut Off Valve in Drain Seal Oil UnitAA 501 Line of Seal Oil Tank Circuit

7. MKW03 Gate Valve 50 4.0 CS FL Shut Off Valve For Seal Seal Oil UnitAA 503 Seal Oil Drain Loop

8. MKW 03 Needle Vlave 15 2.5 CS SC Drain Valve For H2 Side Pipe LineAA 503 Seal Oil Drain Loop

9. MKW 03 Gate Valve 50 4.0 CS FL Shut Off Valve in Drain Seal Oil UnitAA 504 By Pass lIne at Seal Oil

Tank

10. MKW 03 Globe Valve 20 2.5 CS FL Shut Off Valve For Oil Seal Oil UnitAA 505 Level Indicator For Seal

Oil Tank

11. MKW 03 Globe Valve 20 2.5 CS FL Shut Off Valve For Oil Seal Oil UnitAA 506 Level Indicator, Bottom

12 MKW 11 Relief Valve 20 2.5 cs FL Relief Valve For AC Seal Oil Seal Oil UnitAA 001 Pump-1 (Air Side)

13 MKW 11 Diff. Pressure 25 1.6 CS FL For Maintaining Constant Seal Oil UnitAA 002 Regulating Valve Pressure Difference

14 MKW 11 Globe Valve 8 2.5 CS BW Seal Oil Impulse of DPRV Seal Oil UnitAA 507

15 MKW 11 Check Valve 50 4.0 CS FL Check Valve After AC Seal Seal Oil UnitAA 003 Oil Pump-1 (Air Side)

16 MKW 11 Gate Valve 50 4.0 CS FL Shut Off Valve in By Pass Seal Oil UnitAA 508 Line

17 MKW 11 Gate Valve 80 4.0 CS FL Inlet to Seal Oil Pump-1 S.O. Pump UnitAA 501 Air Side


MM MPA

18 MKW 11 Gate Vlave 50 4.0 CS BW Shut off Valve inOil Seal Oil UnitAA 505 DPRV

19 MKW 11 Gate Valve 10 2.5 CS BW Shut Off Valve in Oil Seal Oil UnitAA 506 Impule Line of DPRV

20 MKW 11 Shut Off Valve 50 2.5 CS FL Non Return Shut Off Valve Seal Oil UnitAA 004 After Air Side Seal Oil

Pump-1 & 2

21 MKW 11 Gate Valve 50 4.0 CS FL Shut Off Valve Before Seal Oil UnitAA 504 DPRV

22 MKW 13 Relief Valve 20 2.5 CS FL Relief Volve For Seal Seal Oil Pump UnitAA 001 Oil Pump (H2 Side)

23 MKW 13 Diff. Pressure 25 1.6 CS FL For Maintaining Constant Seal Oil UnitAA 002 Regulating Valve Pressure Difference

24 MKW 13 Check Valve 50 4.0 CS FL Check Valve After H2 Side Seal Oil UnitAA 003 Seal Oil Pump

25 MKW 13 Gate Valve 50 4.0 CS FL Shut Off Valve Before H2 Seal Oil UnitAA 501 Side Seal Oil Pump

26 MKw 13 Gate Valve 50 4.0 CS FL Shut Off Valcve For Seal Seal Oil UnitAA 503 Oil Before H2 Side Coolers

27 MKW 13 Globe Balve 10 2.5 CS BW Shut Off Valve in Air Side Seal Oil UnitAA 505 Impulse Line

28 MKW 13 Globe Valve 50 4.0 CS FL Shut Off Valve in H2 Side Seal Oil UnitAA 511 Seal Oil Drain Line

29 MKW 13 Globe Valve 10 2.5 CS BW Equalising Valve in Bypass Seal Oil UnitAA 507 of Impulse Line

30 MKW 13 Needle Valve 8 2.5 CS BW Seal Oil Vent Valve at Seal Oil UnitAA 508 DPRV (Air Side)

31 MKW 13 Globe Valve 8 2.5 CS BW Seal Oil Vent Valve at Seal Oil UnitAA 509 DPRV (H2 Side)

32 MKW 13 Gate Valve 25 4.0 CS FL Shut Off Valve in H2 Side Seal Oil UnitAA 510 DPRV Bypass Line to S.O.T.

33 MKW 13 Globe Valve 10 2.5 CS BW Shut of Vlave in H2 Side Seal Oil UnitAA 506 Impulse LIne

34 MKW 21 Relief Valve 20 0.0 CS FL Relief Valve For Seal Oil S.O. Pump UnitAA 001 Pump-2 (Air Side)

35 MKW 21 Check Valve 50 4.0 CS FL Check Valve After Seal Oil Seal Oil UnitAA 002 Pump-2 (Air Side)

36 MKW 21 Gate Valve 80 4.0 CS FL Inlet to Seal Oil Pump-2 S.O. Pump UnitAA 501 (Air Side)

2.1-7111-7379/20197E

BHEL, Hardwar


MM MPA

37 MKW 21 Gate Vlave 50 4.0 CS FL Air Side & H2 Side Oil Seal Oil UnitAA 503 Interconnection

38 MKW 23 Globe Valve 8 25.0 CS SC H2 Implulse to DPRV Seal Oil UnitAA 503

39 MKW 23 Globe Valve 8 25.0 CS SC H2 Impulse to DPRV Seal Oil UnitAA 504

40 MKW 31 Relief Valve 20 2.5 CS FL Relief Valve For Seal Oil S.O. Pump UnitAA 001 Pump-3 (Air Side)

41 MKW 31 Globe Valve 10 2.5 CS BW Shut Off Valve in Oil Seal Oil UnitAA 506 Impulse Line of DPRV

42 MKW 31 Diff. Pressure 25 1.6 CS FL For Mianitaining Constant Seal Oil UnitAA 002 Regulating Valve Pressure Difference

43 MKW 31 Globe Valve 8 2.5 CS BW Seal Oil IMpulse Vent of Seal Oil UnitAA 507 DPRV

44 MKW 31 N.R. Shut Off 50 2.5 CS FL Non Return shut Off Valve Seal Oil UnitAA 004 Valve After Air Side Seal Oil

45 MKW 31 Gate Valve 50 4.0 CS FL Shut Off Valve Before Seal Oil UnitAA 504 DPRV

46 MKW 31 Gate Valve 50 4.0 CS FL Shut Off Valve After DPRV Seal Oil UnitAA 505

47 MKW 31 Check Valve 50 4.0 CS FL Check Valve After Seal Oil Seal Oil UnitAA 003 Puni-3 (Air Side)

48 MKW 31 Gate Valve 80 4.0 CS FL Inlet to Seal Oil Pump-3 S.O. Pump UnitAA 501 (Air Side)

49 MKW 51 Double Change 50 1.6 CS FL Change Over Valve at Seal Oil UnitAA 501 Over Valve Seal Oil Cooler (Air Side)

50 MKW 51 Double Change 50 1.6 CS FL Change Over Valve at Seal Oil UnitAA 502 Over Valve Seal Oil Cooler (Air Side)

51 MKW 51 Globe Valve 8 2.5 CS BW Filler Valve For Air Side Seal Oil UnitAA 503 Seal Oil Cooler

52 MKW 51 Globe Valve 8 2.5 CS BW Seal Oil Drain Valve at Seal Oil UnitAA 504 Air Side Cooler-2

53 MKW 51 Globe Valve 8 2.5 CS BW Seal Oil Drain Valve at Seal Oil UnitAA 505 Air Side Cooler-1

54 MKW 51 Water Valve 8 2.5 CS BW Cooling Water Drain Valve Seal Oil UnitAA 506 at Cooler-2 (Air Side)

55 MKW 51 Double Change 50 1.6 CS FL Change Over Valve For Seal Seal Oil Unit With FiltyerAA 512 Over Valve Oil Filter-1 (Air Side)

2.1-7111-7379/30197E


MM MPA

56 MKW 51 Double Change 50 1.6 SC FL Change Over Valve For Seal Seal Oil Unit With FilterAA 513 Over Valve Oil Filter-2 (Air Side)

57 MKW 51 Globe Valve 8 2.5 CS BW Cooling Water Vant Valve Seal Oil UnitAA 508 at Cooler-2 (Air Side)

58 MKW 51 Globe Valve 8 2.5 CS BW Seal Oil Vent Valve From Seal Oil UnitAA 510 at Cooler-2 (Air Side)

59 MKW 51 Globe Valve 8 2.5 CS BW Seal Oil Vent Valve From Seal Oil UnitAA 511 at Cooler-1 (Air Side)

60 MKW 51 Globe Valve 8 2.5 CS BW Cooling Water Drain Valve Seal Oil UnitAA 507 at Cooler-1 (Air Side)

61 MKW 51 Globe Valve 8 2.5 CS BW Cooling Water Vent Valve Seal Oil UnitAA 509 at Cooler-1 (Air Side)

62 MKW 53 Double Change 50 1.6 CS FL Change Over Valve at Seal Oil UnitAA 501 Over Valve Seal Oil Cooler (H2 Side)

63 MKW 53 Globe Valve 8 2.5 CS BW Change Over Valve at Seal Oil UnitAA 502 Over Valve Seal Oil Cooler (H2 Side)

64 MKW 53 Globe Valve 8 2.5 CS BW Filler Valve For H2 Side Seal Oil UnitAA 503 Over Valve Seal Oil Cooler

65 MKW 53 Globe Valve 8 2.5 CS BW Seal Oil Drain Valve at H2 Seal Oil UnitAA 504 Side Cooler-2

66 MKW 53 Globe Valve 8 2.5 CS BW Seal Oil Drain Valve at H2 Seal Oil UnitAA 557 Side Cooler-1

67 MKW 53 Needle Valve 8 2.5 CS BW Cooling Water Drain Valve Seal Oil UnitAA 506 at Cooler-2 (H2 Side)

68 MKW 53 Double Change 50 1.6 CS FL Change Over Valve for Seal Seal Oil Unit With FilterAA 513 Over Valve Oil Filter-2 ( H2 Side)

69 MKW 53 Globe Valve 8 2.5 CS BW Cooling Water Drain Valve Seal Oil UnitAA 507 at Cooler-1 (H2 Side)

70 MKW 53 Globe Valve 8 2.5 CS BW Cooling Water Vent Valve Seal Oil UnitAA 509 at Cooler-1 (H2 Side)

71 MKW 53 Globe Valve 8 2.5 CS BW Seal Oil Vent Valve Seal Oil UnitAA 510 at Cooler-1 (H2 Side)

72 MKW 53 Globe Valve 8 2.5 CS BW Seal Oil Vent Valve Seal Oil UnitAA 511 at Cooler-1 (H2 Side)

73 MKW 53 Double Change 50 1.6 CS FL Change Over Valve for Seal Seal Oil UnitAA 512 Over Valve Oil Filter-1 ( H2 Side)

74 MKW 53 Globe Valve 8 2.5 CS BW Cooling Water Vent Valve Seal Oil UnitAA 508 at Cooler-2 (H2 Side)

2.1-7111-7379/40197E

BHEL, Hardwar


MM MPA

75 MKW 71 3-Way Valve 50 1.6 CS FL 3-Way Valve, TE (Air Side) S.O. Valve RackAA 511

76 MKW 71 Gate Valve 50 4.0 CS FL Shut Off Valve For Seal S.O. Valve RackAA 512 Oil, TE (Air Side)

77 MKW 71 Gate Valve 10 2.5 CS BW Shut Off Valve in Seal Oil S.O. Valve RackAA 512 Imppulse Line, TE (Air Side)

78 MKW 71 3-Way Valve 8 2.5 CS BW Vent For Equalising Valve S.O. Valve RackAA 514 TE (Air Side)

79 MKW 71 3-Way Valve 50 1.6 CS FL 3-Way Valve, EE (Air Side) S.O. Valve RackAA 521

80 MKW 71 Gate Valve 50 4.0 CS FL Shut Off Valve For Seal S.O. Valve RackAA 522 Oil, EE (Air Side) Thro’FM

81 MKW 71 Globe Valve 10 2.5 CS BW Sjit Pff Va;ve om Sea; Po; S.O. Valve RackAA 523 Impulse Line EE (Air Side)

82 MKW 71 Globe Valve 8 2.5 CS BW Vent For Equalising Valve S.O. Valve RackAA 524 EE (Air Side)

83 MKW 71 Needle Valve 15 2.5 CS SC First Shut Off Valve For Pipe LineAA 551 Pr. Measurement Before Air

Side Manifold

84 MKW 71 Needle Valve 15 2.5 CS SC First Shut Off Valve For Pipe LineAA 552 Air Side Seal Oil Pressure

Measurement, EE

85 MKW 71 Needle Valve 15 2.5 CS SC First Shut Off Valve For Pipe LineAA 553 Air Side Seal Oil Pressure

Measurement, EE

86 MKW 73 Equalising 50 2.5 CS FL Equalising Valve For Seal S.O. Valve RackAA 011 Valve Oil Pressure, TE (H2 Side)

87 MKW 73 Equalising 50 2.5 CS FL Equalising Valve For Seal S.O. Valve RackAA 021 Valve Oil Pressure, TE (H2 Side)

88 MKW 73 3-Way Valve 50 1.6 CS FL 3-Way Valve, TE (H2 Side) S.O. Valve RackAA 511

89 MKW 73 Gate Valve 50 4.0 CS FL Shut Off Valve For Seal S.O. Valve RackAA 512 Oil, TE (H2 Side)

90 MKW 73 Globe Valve 8 2.5 CS BW Vent For Equalising Valve S.O. Valve RackAA 513 Impulse Line, TE (H2 Side)

91 MKW 73 Globe Valve 8 2.5 CS BW Vent For Equalising Valve S.O. Valve RackAA 514 TE (H2 Side)

92 MKW 73 3-Way Valve 50 1.6 CS FL 3-Way Valve, EE (H2 Side) S.O. Valve RackAA 521

93 MKW 73 Gate Valve 50 4.0 CS FL Shut Off Valve For Seal S.O. Valve RackAA 522 Oil, EE (H2 Side)

2.1-7111-7379/50197E


MM MPA

94 MKW 73 Globe Valve 10 2.5 CS BW Shut Off Valve in Seal Oil S.O. Valve RackAA 523 Inpulse Line, EE (H2 Side)

95 MKW 73 Globe Valve 8 2.5 CS BW Vent For Equalising Valve S.O. Valve RackAA 524 EE (H2 Side)

96 MKW 76 3-Way Valve 25 1.6 CS FL Multiway Shut Off Valve S.O. Valve RackAA 511 For R.R. Flow Meters (TE)

97 MKW 76 Gate Valve 25 4.0 CS FL Shut Off Valve After S.O. Valve RackAA 512 R.R. Flow Meter (TE)

98 MKW 76 Regulating 25 4.0 CS FL Regulating Valve For S.O. Valve RackAA 513 Valve Ring Relief Oil, TE

99 MKW 76 3-Way Valve 25 1.6 CS FL Multiway Shut Off Valve S.O. Valve RackAA 521 For R.R. Flow Meters (EE)

100 MKW 76 Gate Valve 25 4.0 CS FL Shut Off Valve After S.O. Valve RackAA 522 R.R. Flow Meter (EE)

101 MKW 76 Regulating 25 4.0 CS FL Regulating Valve For S.O. Valve RackAA 523 Valve Ring Relief Oil, TE

102 PGB 51 3-Way Valve 65 1.6 CS FL 3-Way Valve f=For Cooling Seal Oil UnitAA 501 Water Inlet (H2 Side)

103 PGB 52 Regulating 65 1.6 CS FL Regulating Valve After Seal Oil UnitAA 501 Valve Seal Oil Cooler-1, H2 Side


105 PGB 61 3-Way Valve 65 1.6 CS FL 3-Way Valve f=For Cooling Seal Oil UnitAA 501 Water Inlet (H2 Side)



Legend

FL = FlangedSC = ScrewedCS = Carbon SteelSS = Stainless SteelCA = Cast Stell

2.1-7111-7379/60197E

BHEL, Hardwar 2.1-7120-0004/1

Bearing Vopor Exhauster

The bearing vapour exchauster establishes a

vacuum in the generator bearing compartments

which prevents the escape of oil from the bearing

compartments along the shaft . In addit ion, the

bearing vapour exhausted draws off any hydrogen

gas wh ich may be admi t ted in to the bear ing

compartments in the event of a shaft seal failure.

The bearing vapour exhauster embodies optimum

safeguards permitting it to be used for extracting

hydrogen gas from the bearing compartments.

The exchauser is driven by a three-phase motor

attached perpendicular to the exhauster housing.

Flanged connections are provided for the suction and

delivery pipes.

The fan impeller is directly mounted on the motor

shaft. The shaft is sealed with a double-acting

grease-lubricated axial seal which works via a

packing washer which is forced in the axial direction

against the seal collar. A spring provides for a highly

flexible seal.

1 Drive motor

2 Regressing device

3 Suction branch

4 Delivery branch

Fig.1 Bearing Vapour Exchauster

1 Packing washer

2 Seal collar

3 Motor shaft

4 Motor flange

5 Regressing device

6 Exhauster housing

7 Fan ampler

Fig.2 Bearing Vapour Exhauster

BHEL, Hardwar 2.1-7123-0005/1

Seal Oil Pumps

1 General

Oil lubricated radial seals at the rotor shaft ends

prevent the hydrogen gas from escaping from the

generator to the atmosphere.

Seal oil pumps are used to supply the seal oil to

the shaft seals in a closed circuit.

1 Idler screw

2 Driving rotor

3 Dummy pastor

4 Shaft seal (sliding ring gland)

Fig.1 Screw Pump With Relief Valve

2 Construction and Mode of Operation

The seal oil pumps are three-screw pumps. One

double-thread driving rotor and two driven idler screw

dare closely meshed and run with a close clearance

in the casing insert. The pump casing accommodates

the casing insert and is closed off by covers at the

drive end and nondriver end.

The crew pump is suitable for rigorous service and,

due to the absence of control parts sensitive to dirt,

a l lows for relat ively large var iat ions of seal oi l

viscosity.

High speeds are readily attainable because all

moving parts perform rotary movements only.

The main components of the pump are illustrated

in the sectional view of a screw pump.

By internalising, the helical passages in the rotors

are divided into compartments completely sealed

which, while rotating progress completely uniformly

and without undue stressing from the suction to the

discharge end, thus acting like a piston. Dummy

pistons compensate for the axial thrust on the thread

flank faces at the discharge end. Axial thrust on the

deep-groove ball bearing is thus eliminated.

The idler screw are hydraulically driven due to

suitable screw dimensioning. The thread f lanks

transmit only the torque resulting from fluid friction,

which ensures very quiet running.

The screw pumps are driven by electric motors

through a coupling. The motor speed and rating are

matched to the expected delivery flow and heads.

BHEL, Hardwar 2.1-7130-0003/1

Seal Oil Cooler and Seal Oil Filter

1 Seal Oil Coolers

The air side and hydrogen side oil coolers are

each fu l l - capac i t y coo le rs . One i s a lways in

operation, while the second one serves as a stand-

by. The seal oil flow can be changed over from one

cooler to the other by means of two interlocked three-

way rotary transfer valves.

2 Seal Oil Filters

The seal oil filters are arranged directly after the

seal oil coolers. The filters have a fine mesh screen

which serves to prevent damage to the shaft seals

by foreign particles entrained in the oil. By connecting

two separate filters in series, one if the two filters

can always be maintained in operation, supplying

filtered oil to the shaft seals. The changeover valve

assembly at the filters allows one filter to be out of

service for cleaning without interruption of the oil

flow.

1 Filter housing 5 Valve lever

2 Differential pressure 6 Transfer valve assembly

indicator

3 Valve assembly 7 P r e s s u r e

equalizing valve

4 Oil outlet flange 8 P o s i t i o n

indicator

Fig.1 Seal Oil Filter

BHEL, Hardwar

Seal Oil Filter

2.1-7132-0005/1

1 Position indicator 8 Drain plug2 Eyebolt 9 Changeover valve assembly3 Filter valve 10 Oil outlet flange4 Strainer 11 Valve lever5 Filter houshing 12 Oil inlet flange6 Support 13 Signal line for differential7 Vent plug Pressure

BHEL, Hardwar

1. General

The pressures of the hydrogen side and air side sealoil circuits are applied to dirrerential pressuremeasurement devices. A complete system formeasurement of the seal oil differential pressuresconsists of the following components.

Differential pressure transmission linesEqualizing valve assamblyDufferential pressure gauges

The seal oil pressurs are transmitted to the

Differential Pressure Meter SystemTurbo Generators

Description

2.1-7150-0012/1

diaphragms of the pressure gauges via the transmissionlines and equalizing valve assembly. Vents are providedat the pressure gauges.

2. Dirrerential Pressure Meters for Direct Indication

The two input pressures to be compared act on thediaphragms on bothe sides, With the force set up by thedifferential pressure producing a deflection of the elasticbody. The resulting movement is transmitted to thepointer mechanism for direct indication of the differentialpressure. The point has a deflection of 270 degrees.

BHEL, Hardwar

Gas SystemTurbo Generators

Description

2.1-7200-0027/10999E

1. GeneralThe gas system consists of the following

components :

CO2 bottle rack

H2 bottle rack

N2 bottle rack

Gas dryerGas valve rack

The design of the gas system complies withthe safety regulations according to VDE 0530.Part 3 and with the German pressure vesselcode.

2. Hydrogen SupplyThe hydrogen for the generator is supplied

from a hydrogen bottle rack. The hydrogenshould have a minimum purity of 99.7 %.

2.1 H2 Bottle Rack

The H2 bottles are connected to the manifoldon the bottle rack. Valves on the bottles andvalves on the manfold allow replacement ofindividual bottles during operation. The hydrogenis stored in the steel bottles at a very highpressure. The hydrogen gas available in themanifold at bottle pressure is passed to twoparal lel-connected pressure reducers forexpansion to the required intermediate pressureand is then passed to pressure reducers on thegas valve rack for expansion to the pressurerequired for generator operation. Relief valveson the low-pressure sides of all pressurereducers are connected to an outlet pipe systemthrough which any excess hydrogen is passedto the atmosphere. All pressure reducers are ofidentical design. Single-stage construction of thepressure reducers ensures a constant pressure,even under low or no flow conditions, and allowslarge volume flow quantities of hydrogen to bereduced in pressure during the hydrogen fillingprocedure.

3. Carbon Dioxide SupplyAs a precaution against explosive mixtures,

air must never be directly replaced with hydrogenduring generator filling not the hydrogen replaceddirectly with air during the emptying procedure.In both cases, the generator must be scavengedor purged with an inert gas, carbon dioxide(CO

2)

being used for this purpose.

3.1 CO2 Bottle Rack

The carbon dioxide is supplied in steel bottlesin the liquid state. The bottles should be providedwith risers to ensure complete emptying. Thearrangement of the CO

2 bottle rack corresponds

to that of the H2 bottle rack. The liquid CO

2, which

is stored under pressure, is fed to the gas valverack via a shutoff valve.

3.2 CO2 Flash Evaporator

At the gas valve rack the liquid CO2 is

evaporated and expanded in a CO2 f lash

evaporator. The heat for vaporization is suppliedto the flash evaporator electrically. A temperaturecontrol is provided so that freezing of the flashevaporator is prevented, and the CO

2 is admitted

into the generator at the proper temperature. Onesafety valve each on the high-pressure and low-pressure sides protects the pipe system againstinadmissible high pressure.

4 Compressed air SupplyTo remove the CO

2 from the generator, a

compressed air supply with compressed air filteris connected to the general air system of thepower plant.

Under all operating conditions, except forCO2 purging, the compressed air hose betweenthe filter and the generator pipe system shouldbe disconnected. This visible break is to ensurethat no air can be admitted into a hydrogen-filledgenerator.

5. Gas Valve Rack andGas Monitoring Equipment

5.1 Gas Valve RackTo aid in operation of the gas system, the

gas valve rack is furnished with a mini diagramon the face of the panel.

The valves used in the gas system haverubber/metal-sealed valve seats to ensure gastightness.

5.2 Casing Pressure MeasurementFor measuring and checking the gas pressure

in the generator, the gas rack is provided with apressure transmitter and pressure gauges forlocal measurement. For safety, the pressuretransmitter is of an explosion proof design.

2.1-7200-0027/20999E

5.3 Electrical Purity meter SystemThe transmitter for the CO

2/H

2 purity meter

system on the gas valve rack is also of anexplosion proof design. The meter systemoperates on the thermal conductivity method. Themeter system measures the H

2 content of the gas

in the generator as well as the composition ofgas mixtures (CO

2/air and H

2/CO

2) during filling

and emptying of the generator.

5.4 Mechanical Purity Meter SystemThe second puri ty meter system is a

mechanical type and uses the physicalrelationships between the hydrogen pressure, thespeed of the generator fan, and the specificgravity of the medium. This meter system,therefore, functions only at rated speed.

5.5 Gas AnalysisIn addition, facilities are provided for gas

sampling for chemical analysis of the gas in thegenerator.

6. Gas DryerA small amount of the hydrogen circulating

in the generator for cooling is passed through agas arier. The gas inlet and gas outlet pipes ofthe gas dryer are connected at points of thegenerator with different static heads(differentialfan pressure), so that the gas is forced throughthe dryer by the differential pressure only.

The gas dryer is a pressure- resistantchamber filled with moisture absorbent material.The absorbent material can be reactived at anytime when the generator is running by means ofa heater, a fan and changeover valves.

7. Nitrogen(N2 ) SupplyOn a water-cooled turbine generator an

additional nitrogen supply is required for:

* Removing the air above the water level in theprimary water tank during initial operation of

the primary water system.* Removing the oxygen dissolved in the

primary water during filling of the primarywater system.

* Removing the hydrogen gas above the waterlevel in the primary water tank duringshutdown of the primary water system

* Removing the hydrogen gas dissolved in theprimary water during shutdown of the primarywater system.

The N2 purge during initial operation ensures

a complete removal of the oxygen from theprimary water circuit, thus eliminating the risk ofcorrosion attack.

The N2 purge during shutdown prevents the

formation of an explosive hydrogen-air mixtureDuring operation hydrogen may enter into theprimary water tank by diffusion at the insulatinghoses.

The nitrogen available from a bottle is passedto a pressure reducer for expansion and admittedinto the primary water tank via the N

2 supply line.

BHEL, Hardwar

BHEL, Hardwar

Gas Diagram

List of Valves for Primary Water System

Turbo Generators

Description

2.1-7211-379/1 0197E


MM MPA

1 MKG 05 Globe Valve 15 4.0 CR SC To Mechnaical H2 Purity Pipe LineAA 501 Meter

2 MKG 05 Globe Valve 15 4.0 CR SC To Mechnaical H2 Purity Pipe LineAA 502 Meter

3 MKG 09 Globe Valve 15 4.0 CR SC To Core Monitor Pipe LineAA 520

4 MKG 09 Globe Valve 15 4.0 CR SC To Core Monitor Pipe LineAA 521

5 MKG 11 Globe Valve 8 25.0 CR SC Shut Off at Inlet to H2 DistributerAA 561 MKG 11/AA001

6 MKG 11 Monifold Valve 8 25.0 CR SC H2 Distributer Manifold H2 DistributerAA 531

7 MKG 12 Globe Valve 8 25.0 CR SC Shut Off at Inlet to H2 DistributerAA 501 MKG 12/AA001

8 MKG 15 Globe Valve 25 2.5 CR SC Shut Off at Inlet to Gas UnitAA 502 MKG 19/AA001

9 MKG 15 Globe Valve 25 2.5 CS SC For Connecting H2 Duistri Gas UnitAA 504 buter to Gas Unit

10 MKG 15 Globe Valve 25 2.5 CR SC Shut Off at Outlet From H2 DistributerAA 501 MKG 12/AA001

11 MKG 16 Globe Valve 25 2.5 CR SC Shut Off at Outlet From H2 DistributerAA 501 MKG 12/AA001

12 MKG 17 Globe Valve 25 2.5 CR SC For Connecting Gas Unit to Gas UnitAA 504 Station H2 Plant

13 MKG 17 Globe Valve 25 2.5 CR SC Shut Off at Inlet to Gas UnitAA 506 MKG 19/AA002

14 MKG 19 Globe Valve 25 2.5 CR SC Shut Off at Inlet From Gas UnitAA 501 MKG 19/AA001

15 MKG 19 Globe Valve 25 2.5 CR SC Shut Off at Inlet From Gas UnitAA 502 MKG 19/AA002

16 MKG 25 3-Way Valve 50 1.6 CR FL Shut Off to H2 Supply to Gas UnitAA 519

17 MKG 25 Globe Valve 50 2.5 CR FL Exhaust Gas UnitAA 502


MM MPA

18 MKG 25 Globe Valve 25 2.5 CR SC Shut Off at Inlet to AF Gas UnitAA 501

19 MKG 25 Globe Valve 8 25.0 CR SC Shut Off at Inlet to Gas Gas UnitAA 511 Analyser Cabinet

20 MKG 25 Globe Valve 8 25.0 CR SC For Taking Sample of Gas Gas UnitAA 512 Analyser Cabinet

21 MKG 25 3-Way Valve 50 1.6 CR FL Shut Off CO2 Supply to Gas UnitAA 518 Exhaust From TG

22 MKG 25 3-Way Valve 12 1.6 CR SC For Calibration of Gas Gas UnitAA 507 Analyser

23 MKG 25 Globe Valve 25 2.5 CS SC Shut Off at Outlet to AF Gas UnitAA 509

24 MKG 31 Gate Valve 8 25.0 CR SC Inlet to Pressure N2 DistributerAA 503 Regulator

25 MKG 31 Globe Valve 8 25.0 CR SC N2 Distributer Manifold N2 DistributerAA 502

26 MKG 35 Globe Valve 8 25.0 CR SC Outlet of Pressure N2 DistributerAA 501

27 MKG 31 Globe Valve 8 25.0 CR SC CO2 Distributer Manifold CO2 DistributerAA 531

28 MKG 51 Globe Valve 10 25.5 CR SC Shut Off at Inlet to CO2 CO2 VapouralserAA 561 Vapouralser

29 MKG 51 Sefety Relief 6 17.5 CS SC To Release Excess CO2 CO2 VapouralserAA 011 Valve Pressure at Inlet to

CO2 Vapouralser

30 MKG 59 Safety Relief 32 0.6 CS FL To Release Excess Co2 CO2 DistributerAA 001 Valve Pressure at CO2 Vapouriser

Outlet

31 MKG 69 Gas Valve 50 1.6 CS FL Shut Off at Inlet to Gas Pipe LineAA 501 Drier

32 MKG 69 Gas Valve 50 1.6 CS FL Shut Off at Intlet to Gas Pipe LineAA 504 Drier

33 MKG 69 Gas Valve 50 1.6 CS FL Shut Off at Outlet to Gas Pipe LineAA 505 Saparator in Gas Drier

Inlet Line

34 MKG 69 Gas Valve 15 1.6 CS SC Shut Off in Saparator Pipe LineAA 502 Drain

35 MKG 69 Globle Valve 8 25.0 CR SC Sampling Gas at Drier Gas UnitAA 503 Inlet Line

36 MKG 69 Non Return 50 1.6 CS FL Non Return in Air Line to Gas UnitAA 527 Valve Drying Tower

2.1-7211-379/2 0197E

BHEL, Hardwar


MM MPA

37 MKG 69 3-Way Double 50 1.6 CS FL Shut Off at Intlet to Gas Pipe LineAA 502 C/O Valve Drier

38 MKG 69 3-Way Double 50 1.6 CS FL Shut Off at Intlet to Gas Pipe LineAA 529 C/O Valve Drier

2.1-7211-379/3 0197E

Legend

FL = Flanged RT = Room TemperatureSC = ScrewedCS = Carbon SteelCR = Cromium SteelGM = Gun Metal

BHEL, Hardwar 2.1-7230-0011/1

C02 Flash Evaporator

1 General

C02 is used to displace air from the generator

before hydraogen filling and to displace hydrogen

from the generator before filling the generator with

air.

Since the C02 is available in the liquid state, it

must be expanded into a gas before use. The C02 is

expanded in a C02

flash evaporator located on the

gas va lve rack .To p reven t i c ing o f the f lash

evaporeator it is electrically heated.

2 Design features and mode of operation

The C02

flash evaporator consists of a tubular

housing closed by flanges at both ends. One flange

carr ies electreical heat ing elements which are

connected to terminals in the terminal box mounted

external to the flange. The opposite flange contains

the inlet and outlet to the cooled copper pipe of the

evaporator. The horizonntally arranged housing is

filled with heat transmitting liquid to ensure a better

heat trasfer to the copper pipe coil and thus to the

C02 flowing through the pipe coil.

The heat transmitting liquid is filled into the C02

f lash evaporator through the expansion vessel

mounted on top of the housing. For protection against

excessive heating a thermostat maintaining a constant

temperature is arranged in the housing holding the

heat t ransmit t ing l iquid. For protect ion against

excessive pressures in the C02

line, one relief valve

is arranged before and after the C02 flash evaporator.

The orifice at the C02

out let of the expansion

vessel provides for an expansioin of the C02 obtained

from the bottles to a pressure of 25 to 7 psig. Heating

of the C02 in the copper pipe coil is sufficient to prevent

icing of the expansion device at the prevailling flow

velocities.

2.1-7230-0011/1

C02 Flash Evaporator

1 Thermometer 8 Shutoff valve before C0 2 flash evaporator2 Vent for heat transmitting liquid 9 C0

2 inlet

3 Copper pipe coil 10 C02 outlet

4 Insulation 11 Housing5 Expansioin vessel 12 Heating element6 Relief valve before C02 flash evaporator 13 Drain for heat transmitting liquid7 Thermostat 14 Terminal box

Fig.1 C02 flash evaporator

BHEL, Hardwar 2.1-7260-0019/1

Gas Dryer

Any possible moisture contained in the hydrogen

in the generator is removed by a gas dryer. A gas

f low, set up by the dif ferential pressure of the

generator fan, circulates hydrogen through the gas

dryer chamber which is filled with absorbent material.

The absorben t mate r ia l i s p rov ided w i th a

humidicator. A change in color (blue/pink) as seen

through the sight glass tells the operator when it is

necessary to change over the cock from the drying

to the heating position. The absorbent material can

be reactivated at any time by heated air which is

supplied by a heater and fan. The changeover valves

are coupled so as to avoid incorrect operation and

provided with a limit switch which activates the heater

and fan.

To waste gas system

1 Multi-way valve

2 Pressure large

3 Gas dryer chamber

with absorbent material

4 Gas dryer heater

5 Gas dryer fan

6 Air filter

Fig.1 Gas Dryer Schematic

An in termediate pressure re l ie f pos i t ion is

provided for changeover from the drying position to

the heating position. When the changeover valve is

moved to the pressure relief position, the hydrogen

gauge pressure is allowed to go the zero. Via a

pressure re l ie f ho le commun ica t ing w i th the

atmosphere.

A pressure gauge shows when the gas dryer is

depessurized. The changeover valve should then be

moved to the heating position.

Position of four-way valve during drying

BHEL, Hardwar

Pressure Equalizing Control Valve

2.1-7262-0001/1

1 Gas dryer heater2 Gas dryer fan3 Temperature transmitter, heater4 Connectionto atmosphere5 Pessure garge6 Gas outlet7 Changeover lever8 Gas inlet9 Temperature gauge10 Gas inlet11 Filter for hot inlet air12 Fan motor13 Sight glass with cover

Gas Dryer Type: 8.70

BHEL, Hardwar

1 General

The losses occurring in the

stator winding,

terminal bushings and

phase connectors

are dissipated through direct water cooling. Since

the cooling water is the primary coolant to dissipate

the losses, it is designated as primary water.

The primary water is circulated in a closed circuit

by centrifugal pumps.

The primary water system basically consists of

the following components:

Primary water supply unit

Primary water coolers

Primary water valve rack

Primary water tank

The primary water supply unit combines the following

components fo r p r imary wate r supp ly to the

generator:

Primary water pumps

Primary water filters

Conductivity transmitter

Water treatment system

Volume flow, pressure and temperature transmitters.

The complete primary water system, its components and

their relationship are shown in the Primary Water Diagram.

2 Primary Water Quality

The primary water system may be fi l led with

oxygen free, mechanically clean

Primary Water System

2.1-7300-0009/1

distilled water

fully demineralized water from boiler feed water

treatment plant

condensate

Since the primary water comes into direct contact

with the high-voltage stator winding, it must have an

electrical conductivity of 0.5 to 1 µmho/cm. The water

in the primary water circuit is therefore treated in a

water treatment system. Fully demineralized water

f rom the boi ler feed water t reatment p lant and

condensate may only be used if no chemicals. Such

as ammonia, hydrazine, phosphate, etc. were added

to the water or condensate.

3 Primary Water Circuit

Fig. 1 shows a simplified schematic of the primary

water system. Note that the diagram shows that the

external port ion of the system may be operated

through a bypass line, with no primary water flowing

through the water-cooled generator components.

The primary water is circulated by one of the two

pumps on the primary water supply unit. Both primary

water pumps are of full-capacity type. The electric

control circuit of the pumps is arranged so that either

pump may be selected for normal service.

The primary water is drawn from the primary water

tank and passes to a primary water manifold (inlet)

via coolers and filters and from there to the stator

bars via teflon hoses. The primary water leaving the

stator winding is passed through similar teflon hoses

to another primary water manifold (outlet) and is then

returned to the primary water tank. A separate flow

path from a point before the stator winding inlet cools

the bushings and phase connectors.

4 Primary Water Tank

The primary water tank is mounted on the stator

frame on antivibration pads and is covered by the

generator lagging. The purpose of the primary water

water tank is to remove the hydrogen in the primary

water after is leaves the stator winding. The hydrogen

occurs in the primary water due to diffusion through

the telflon hoses which connect the stator winding to

inlet and outlet manifolds.

Since the primary water tank is the lowest pressure

point in the system, has a relat ively high water

temperature, a large water surface and sufficient

retention time, intensive degassing of the primary

water is ensured. The hydrogen gas in the primary

water tank is vesnted to atmosphere via the primary

water valve rack and a pressure regulator. The

pressure regulator can be adjusted to set the gas

pressure in the primary water tank.

The water level in the primary water tank can be

read a t a wate r leve l gauge. Add i t iona l l y , a

capatitance type measuring system is provide for

activating an alarm at minimum and maximum water

level.

BHEL, Hardwar

BHEL, Hardwar

Primary Water DiagramList of Valve for Primary System

2.1-7311-7422/1 0197 E

SL. VLV TYPE OF VALVE NOM. NOM. BODY END FUNCTION LOCATIOIN REMARKNO. DESG BORE PRESS MATL CONN

MM MPA

1 MKF 01 Water Vallve 20 1.6 SS FL Shut off Valve Before P.W.TankAA 321 Water Level Gauge, Top

2 MKF 01 Water Valve 20 1.6 SS FL Vent Valve at Level P.W.TankAA 251 Transmitter

3 MKF 01 Globe Valve 10 2.5 SS SC Drain Valve at Level P.W. TankAA 210 Trainsmitter

4 MkF 01 Water Valve 20 1.6 SS FL Shut off Valve Before P.W.TankAA 311 Water Level Gauge, Bottom

5 MKF 01 Water Valve 20 1.6 SS FL Shut off Valve Before P.W.TankAA 326 Level Transmitter, Top

6 MKF 01 Water Valve 20 1.6 SS FL Shutt off For Oulet From P.W.TankAA 301 Level Transmitter

7 MKF o1 Water Valve 20 1.6 SS FL Shutt off Valve For Inlet P.W. TankAA 316 Level Transmitter

8 MKF 01 Water Valve 20 1.6 SS FL Shutt off Valve For Inlet P.W.TankAA 306 tp Level Transmitter

9 MKF 12 Needle Valve 10 2.5 SS SC Drain Valve Before Pump-1 P&F UnitAA 502

10 MKF 12 Globe Valve 100 2.5 SS FL Outlet of Stator Water P&F UnitAA 504 Pump-1

11 MKF 12 Globe Valve 100 2.5 SS FL Inlet to Stator Water P&F UnitAA 501 Pump-1 MKF 12/AP001

12 MKF 12 Non Return 100 1.6 SS FL Non Return at Outlet of P&F UnitAA 001 Valve Stator Water Pump-1

13 MKF 22 Non Return 100 1.6 SS FL Non Return at Outlet of P&F UnitAA 001 Valve Stator Water Pump-2

14 MKF 22 Globe Valve 100 2.5 SS FL Inlet to Stator Water P&F UnitAA 501 Pump-2 MKF 22/AP001

15 MKF 22 Needle Valve 10 2.5 SS FL Drain Valve Before Pump-2 P&F UnitAA 502

16 MKF 22 Globe Valve 100 2.5 SS FL Outlet of Stator Water P&F UnitAA 504 Pump-2

17 MKF 52 Needle Valve 10 2.5 SS SC Primary Water Vent Valve Pipe LineAA 531 For Cooler-1

18 MKF 52 Needle Valve 15 2.5 SS SC Primary Water Vent Valve Pipe LineAA 541 Before Coolers


MM MPA

19 MKF 52 Needle Valve 15 2.5 SS SC Drain Valve at Filter-1 P&F UnitAA 581

20 MKF 52 Globe Valve 100 2.5 SS FL Primart Water Shut Off Pipe LineAA 512 Valve After Cooler-2

21 MKF 52 Needle Valve 10 2.5 SS SC Vent Valve at Filter-1 P&F UnitAA 582

22 MkF 52 Needle Valve 15 25.0 SS SC Cooleing Water Drain Valve Pipe LineAA 552 Cooler-2

23 MKF 52 Globe Valve 100 2.5 SS FL Primary Water Shut Off Pipe LineAA 502 Valve Before Cooler-2

24 MKF 52 Needle Valve 10 2.5 SS SC Cooleing Water Vent Valve Pipe LineAA 562 at Cooler-2

25 MKF 52 Needle Valve 15 2.5 SS SC Primary Water Drain Valve Pipe LineAA 544 (Manifold)

26 MKF 52 Globe Valve 100 2.5 SS FL Primary Water Shut Off Pipe LineAA 511 Valve Before Cooler-1

27 MKF 52 Needle Valve 10 2.5 SS SC Cooleing Water Vent Valve Pipe LineAA 561 at Cooler-1

28 MKF 52 Needle Valve 10 2.5 SS SC Primary Water Vent Valve Pipe LineAA 532 For Cooler-2

29 MKF 52 Globe Valve 100 2.5 SS FL Inlet to Water Filter-2 P&F UnitAA 590

30 MKF 52 Needle Valve 15 2.5 SS SC Drain Valve at Filter-2 P&F UnitAA 591

31 MKF 52 Needle Valve 10 2.5 SS SC Vent Valve at Filter-2 P&F UnitAA 592

32 MKF 52 Globe Valve 100 2.5 SS FL Outlet From Water Filter-2 P&F UnitAA 593

33 MKF 52 Globe Valve 100 2.5 SS FL Primary Water Shut Off Pipe LineAA 501 value Before Cooler -1

34 MKF 52 Needle Valve 15 2.5 SS SC Primary Water Drain Valve Pipe LineAA 522 For Cooler-2

35 MKF 52 Needle Valve 15 2.5 SS SC Primary Water Drain Valve Pipe LineAA 521 For Cooler-1

36 MKF 52 Needle Valve 15 2.5 SS SC Vent Valve After PW Pipe LineAA 578 Coolers

37 MKF 52 Globe Valve 100 2.5 SS FL Inlet to Water Filter-1 P&F UnitAA 580

38 MKF 52 Needle Valve 10 2.5 SS SC Primary Water Vent Valve Pipe LineAA 545 (Manifold)

39 MKF 52 Needle Valve 15 2.5 SS SC Cooling Water Drain Valve Pipe LineAA 551 at Cooler-1

2.1-7311-7422/2 0197 E

BHEL, Hardwar


MM MPA

40 MKF 52 Globe Vallve 100 2.5 SS FL Outlet From Water Filter-1 P&F UnitAA 583

41 MKF 60 Needle Valve 10 2.5 SS SC Drain Primary Water P&F UnitAA 522 Make UP Line

42 MKF 60 Needle Valve 10 2.5 SS SC Drain Valve After P&F UnitAA 510 ION-Exchanger

43 MkF 60 Globe Valve 25 2.5 SS FL Shut Off Valve in Make Up P&F UnitAA 506 Line

44 MKF 60 Needle Valve 10 2.5 SS SC Vent Valve at Fine Filter P&F UnitAA 512

45 MKF 60 Needle Valve 10 2.5 SS SC Vent Valve Before P&F UnitAA 503 ION-Exchanger

46 MKF 60 Needle Valve 10 2.5 SS SC Drain Valve For Water P&F UnitAA 517 Treatment System

47 MKF 60 Globe Valve 25 2.5 SS FL By Pass Valve in Make Up P&F UnitAA 520 Line

48 MKF 60 Needle Valve 10 2.5 SS SC Drain Velve After P&F UnitAA 511

49 MKF 60 Globe Valve 25 2.5 SS FL Shut Off Valve After P&F UnitAA 509 ION-Exchanger

50 MKF 60 Globe Valve 25 2.5 SS FL Shut Off Valve After Water P&F UnitAA 519 Treatment System

51 MKF 60 Regulating 25 2.5 SS SC Control Valve For Water P&F UnitAA 502 Valve Treatment System

52 MKF 60 Globe Valve 25 2.5 SS FL Make Up Drain Valve Pipe LineAA 201

53 MKF 60 Regulating 25 2.5 SS FL Make Up Drain Valve Pipe LineAA 501 Valve

54 MKF 60 Non Return 25 1.6 SS FL Check Valve in Make Up P&F UnitAA 003 Valve Line

55 MKF 60 Relief Valve 25 2.5 SS FL Relief Valve in Make Up P&F UnitAA 001 Line

56 MKF 60 Globe Valve 25 2.5 SS FL Shut Off Vavle After Fine P&F UnitAA 513 Filter

57 MKF 80 Globe Valve 100 2.5 SS FL Shut Off Vavle For Gen. P.W.TankAA 504 By Pass

58 MKF 80 Globe Valve 100 2.5 SS FL Shut Off in Main Circuit P.W.TankAA 503 Discharge Line

59 MKF 80 Globe Valve 100 2.5 SS FL Shut Off at Inlet to Gen. P.W.TankAA 121

2.1-7311-7422/3 0197 E


MM MPA

61 MKF 82 Globe Vallve 100 1.6 SS FL Shut Off Valve in Primary P.W.TankAA 001 Water Outlet of Stator

Winding62 MKF 82 Regulating 100 1.6 SS FL Regulating Valve Befofe Pipe Line

AA 501 Valve Stator Winding

63 MKF 82 Needle Valve 15 2.5 SS SC Shut Off Valve Before Flow Pipe LineAA 504 Transmitter at Stator Outlet

64 MKF 82 Needle Valve 15 2.5 SS SC Shut Off Valve After Flow Pipe LineAA 505 Transmitter at Stator Outlet

65 MKF 82 Needle Valve 15 2.5 SS SC Shut Off Valve For Press. Pipe LineAA 506 Measurement Before Stator

Outlet Winding

66 MKF 82 Needle Valve 15 2.5 SS SC Shut Off Valve Before Flow Pipe LineAA 507 Transmitter at Stator Outlet

67 MKF 82 Needle Valve 15 2.5 SS SC Shut Off Valve After Flow Pipe LineAA 508 Transmitter at Stator Outlet

68 MKF 82 Needle Valve 10 2.5 SS SC Isolation Valve For GeneratorAA 512 D.P. Gauge

69 MKF 82 Needle Valve 10 2.5 SS SC Isolation Valve For GeneratorAA 513 D.P. Gauge

70 MKF 83 Regulating 40 1.6 SS FL Regulating Valve Before Pipe LineAA 501 Valve Bushing

71 MKF 83 Globes Valve 40 1.6 SS SC Shut Off Valve After Pipe LineAA 502 Bushing

72 MKF 83 Needle Valve 15 2.5 SS SC Shut Off Valve Before Flow Pipe LineAA 503 Trainsmitter MKF83/CF001A

73 MKF 83 Needle Valve 15 2.5 SS SC Shut Off Valve Before Flow Pipe LineAA 515 Trainsmitter MKF83/CF001B

74 MKF 83 Needle Valve 15 2.5 SS SC Shut Off Valve After Flow Pipe LineAA 504 Trainsmitter MKF83/CF001A

75 MKF 83 Needle Valve 15 2.5 SS SC Shut Off Valve After Flow Pipe LineAA 516 Trainsmitter MKF83/CF011B


77 MKF 83 Needle Valve 15 2.5 SS SC Shut Off Valve Before Flow Pipe LineAA 517 Trainsmitter MKF83/CF021B


79 MKF 83 Needle Valve 15 2.5 SS SC Shut Off Valve After Flow Pipe LineAA 514 Trainsmitter MKF83/CF001B



2.1-7311-7422/4 0197 E

BHEL, Hardwar


MM MPA

82 MKF 83 Needle Vallve 15 2.5 SS SC Shut Off Valve Before Flow Pipe LineAA 513 Transmitter MK83/CF001B

83 MKF 83 Needle Vallve 15 2.5 SS SC Shut Off Valve After Flow Pipe LineAA 518 Transmitter MK83/CF021B

84 PGB 71 Gate Vallve 250 1.6 CS FL Cooling Water Inlet of Pipe LineAA 501 Cooler-1

85 PGB 71 Gate Vallve 250 1.6 CS FL Cooling Water Inlet of Pipe LineAA 502 Cooler-2

86 PGB 72 Gate Vallve 250 1.6 CS FL Cooling Water Outlet of Pipe LineAA 501 Cooler-1

87 PGB 72 Gate Vallve 250 1.6 CS FL Cooling Water Outlet of Pipe LineAA 502 Cooler-2

Legend

FL = FlangedSC = ScrewedCS = Carbon SteelSS = Stainless SteelSS = Stainless SteelCA = Cast Steel

2.1-7311-7422/5 0197 E

BHEL, Hardwar

Design Features of Primary Water Pumps

The primary water for cooling the stator winding,

phase connectors and terminal bushings circulated

in a closed system. To insure uninterrupted generator

operation, two full-capacity primary water pump sets

are provided. Either pump can be in service with

other acting as the standby. The state by pump is

ready for service and is automatically started without

interrupting the primary water circulat ion i f the

operating pump fails.

The primary water pumps are of a single-stage

centrifugal type with spiral and overhung implore.

Primary Water Pumps

2.1-7320-0009/1

Fig.1 Sliding-Ring Gland

The pump suction is arranged axially. While the

discharge is directed radially upwards. The spiral

casing is flanged to the bearing housing. The pump

imperil is provided with relief holes close to the hub

so that no axial thrust is carried by the bearings. The

point where the pump shaft passes through the pump

casing is sealed by means of a water-cooler sliding-

ring gland. The cooling water is supplied to the sliding-

ring gland through a by pass line from the pump

discharge. The pump shaft is supported in o i l -

lubricated antifrictioin bearings. The oil level in the

bearing housing can be checked at an oil sight glass.

The pump is connected to the three-phase ac motor

by a flexible coupling covered by a coupling guard.

The sliding-ring gland consists of a stationary part,

which is rigidly connected to the pump casing, and

rotating part attached to the shaft. The contact face

between the two parts is the seal ing face. The

stationary part is connected to the pump insert and is

composed of the seal ring and the Z-ring. The ceramic

Z-ring face toward the rotating part is lapped. The

sliding ring of the rotating part is made of resin-

impregnated graphite. The face of the sliding ring is

likewise lapped. The saft rotation is transmitted to the

sliding ring through a bellows connected to the sliding

ring. Shaft sealing is accomplished by the rear portion

of the bellow which is fitted tightly on the shaft. The

shaft rotation is transmitted to the sliding ring by the

bellows catch ring and catch sleeve. The bellows is

pressed against the sliding ring by the compression

ring, and the sliding ring is pressed against the Z-

ring through a spring supported on the shaft collar.

The design of this sliding-ring gland permits a free

movement of the rotating sliding ring relative to the

Z-ring.

BHEL, Hardwar 2.1-7330-0008/1

Primary Water Cooler

The primary water cooler is of a straight tube

type. One tubesheet is stationary, while the other

tubesheet is a floating type. The floating tubesheet

is sealed by O-Ring.

Tube bundle is free to move in response to

temperature change.

The water channel at glands can be removed

without draining the primary water.

The tube bund le cons is ts o f round tubes

expanded into the tubesheets. Baffles installed on

the tube bundle result in a transverse flow of cooling

water across the tubes. This achieves a more

efficient heat exchange and protects the tubes from

vibrations and bending.

The cooler shell is stainless steel with welded

flanges for connection to the flanges on the water

channels. The pipe nozzles for the primary water inlet

and outlet are welded to the shell. Each cooler shell

has vent and drain connection.

To vent and drain the tube side of the primary

water coolers, the water channels are equipped with

vent and drain connections.

Tube bundle, cooler shell and water channels are

bolted together. The larger tubesheet is mounted

between the shell flange and the water channel.

The p r imary wate r coo le r sec t ions a re

inlerconnected on their primary water sides via valves.

BHEL, Hardwar

Primary Water Treatment SystemTurbo Generators

Description

2.1-7340-0002/10999E

The water treatment system serves tomaintain a low electrical conductivity of theprimary water. The water treatment system isconnected in parallel to main circuit and containsa mixed-bed ion exchanger with series connectedfine filter, an integrating flow meter and aconductivity transmitter.

1. Mixed-Bed Ion ExchangerThe mixed-bed ion exchanger consists of a

tank filled with anion and cation exchanger tankprevent the escape of the resins into the pipingsystem. A fine filter after the ion exchangerretains any resin particles. An alarm is initiatedwhen the filter is contaminated.

The water flow passing through the ionexchanger is measured by means of anintegrating flow meter after the filter. After theion exchanger part of the flow is passed througha conductivity transmitter for checking the resinactivity.

2. Ion Exchanger ResinsThe ion exchangers consist of chemically and

highly active synthetic resins.The base substances of the exchanger resins

are polymers. The polymer in the cat ionexchanger contains highly acid groups, while thepolymer in the anion exchanger is composed ofhighly basic groups.

The exchanger resins are thus capable ofaccepting ions from the primary water whilesimultaneously releasing equivalent amounts ofother ions(hydrogen ions from the cationexchanger and hydroxyl ions from the exchanger)to the primary water. This process takes placethrough the ion exchanger.

The combination of highly acid cationexchangers and highly basic cation exchangersforms a multitude of small demineralization units,resulting in a high-purity deionate.

The capacity of the mixed- bed of the ionexchanger is limited by the number of ion it canexchange. This capacity is primarily determinedby the type of exchanger used, but also dependson the quantity of reactivating agent, the rate offlow and the water temperature.

When the resins are exhausted, they mustbe replaced by new resins.

After removal from the primary watertreatment system, the resins can be reactivated.

3. Adding Make-up Water to the PrimaryWater Circuit

Any loss of primary water in the total circuitcan be compensated for by introducing make-upwater upstream of the mixed-bed ion exchanger.The quantity of make -up water is totaled at avolumetric water meter and is indicative of thetightness of the primary water system.

BHEL, Hardwar

1 GeneralEven with the use of oxygen-poor water, copper

corrosion in the primary water circuit water circuit ofwater-cooled windings cannot be completely avoided;in isolated cases the corrosion products reduce thecross-sectional flow area of the water distributionsystem. Bes ides, the format ion of conduct ivedesposite can occur in the rotating water inlet andoutlet hoses of water-cooled rotor windings.

The severity of the corrosion attack can be largelyreduced by alkalizing the oxygen-poor water. Also,the system becomes less susceptible to disturbancesresulting from air in-leakage.

Operating the generator with alkaline water at pH8 to 9 improves its reliability land availability.

Operation at alkaline pH is ensured by a self-regulating alkalizer unit for feeding dilute sodiumhydroxide solution (NaOH).

2 Mode of OperationDilute sodium hydroxide solution is injected into

the low-conductivity primary water circuit where itremain as dissolved, dissociated sodium hydroxidesolution. OH ion connectration determines the pHvalue.

The ion exchanger in the water treatment system,i.e. mixedbed filters with H+ cation exchangers andO H – an ion exchangers , rema ins in se rv icecontinuously. It removes all copper, iron, chloringe,carbon dioxide ions, etc. from the water, However, italso removes the Na+ ions from the sodium hydroxidesolut ion. This e l iminat ion of sodium, which isproportional both to the volumetric flow rate throughthe ion exchanger and the NaOH concentration, mustbe compensated by continuous feeding of dilutesodium hydroxide solution.

Alkalizer Unitfor Primary Water Circuit

2.1-7341-0009/1

The alkalizer unit is arranged in the treatmentcircuit Sodium hydroxide solution is injected into thetreatment circuit where it is mixed with the water inthe treatment circuit and raises its conductivity. Thewater has the h ighest pur i ty a t the feed po in tdownstream of the ion exchangers. The conductivityo f the mixed water i s on ly de termined by theconcentration of the sodium hydroxide solution andprovides a reference quantity for the pH valve. Therelationship between pH and conductivity under idealconditions is illustrated in Fig.1

Following the admission on alkaline water, theconductivity in the treatment circuit is monitored.Conductivity must be maintained constant as requiredfor obtaining the specified alkalinity. Conductivity inprimary water circuit likewise approaches a constantvalue after several hours.3 Hydraulic Circuit

The hydraul ic circuit of the alkal izer units isillustrated in Fig.2

The diaphragm pump extracts the NaOH solutionfrom the NaOH tank and delivers it to the treatmentcircuit via a spring-loaded feed valve. The treatmentcircuit and especially the fine filter down steam of thetreatment circuit homogenize the concentration of thesolution injected into the circuit by shot feeding. Thevolume flow meter in the treatment circuit stops thediaphragm pump via a limit switch when the volumetricflow rate drops below a predetermined limit value. Avent on the diaphragm pump enables starting withoutback pressure and venting of the unit for activation.Low NaOH level in the tank is sensed with a leveldetector to activate an alarm. A soda lime filter in thetank vent binds the carbon dioxide contained in theinlet air and prevents the formation of carbonates inthe NaOH solution.

1 Diaphragm pump 4 Level detector2 NaOH tank 5 Soda lime filter in tank vent3 Feed valve 6 Vent

(check valve) 7 Treatment circuitFig.2 Schematic Diagram of Alkalizer Unit

The tank has a capacity to store the sodium

hydroxide solution required for a service period of several

months.

4 Control and Monitoring

An interlock using the volumetric flow rate in the

treatment circuit as a criterion prevents starting of the

diaphragm pump and NaOH feeding into the treatment

circuit under no-flow or empty conditions. The feed rate of

the diaphragm pump is controlled by changing the stroking

rate dependent on the conductivity in the treatment circuit

using a controller and stroking rate transducer.

The diaphragm pump is stopped as soon as the

conductivity in treatment circuit or

conductivity in primary water circuit

exceeds a predetermined maximum valve, or as soon as

the

conductivity in treatment circuit or

volumetric flow rate in treatment circuit drops below a

minimum valve.

This avoids over feeding due to faults or incorrect

operation of the alkalizer unit. After the pump has been

stopped the conductivity of the water is promptly decreased

by ion exchanger in the mixed-bed filter.

The alkalizer unit provides warning limits for

low conductivity in primary water circuit

low conductivity in leakage water circuit

low level in NaOH tank.

which are displayed in the control cabinet.

Via potential-isolated contacts the following alarm

conditions can be signalled to the control room either as

single alarm or as group alarm:

low conductivity in leakage water circuit

low conductivity in primary water circuit

low NaOH level in tank

loss of supply voltage.

1 NaOH tank

2 NaOH tank cap

3 Diaphragm pump

4 NaOH tank vent with lime filter

5 Feed valve (check valve)

6 Alarm and operating control

panel

7 Cable fracture is signalling

device

8 Analog/digital converter

9 Tale perm D con verger

10 Signal transmitter

Fig. 3 Alkalizer Unit

2.1-7341-0009/2

BHEL, Hardwar 2.1-7343-0002/1

Primary Water Filters

1 Main Filter

The primary water system includes a strainer-

type main filter with magnet bars. The filter screen

of the strainer has a mesh size of 75 µm (3 mils)

and is supported by a per forated sheet-meta l

cylinder. The magnet bars consist of a magnet carrier

and a number of permanent magnets. The high-grade

permanent magnets have an unlimited useful service

life. The magnet bars are arranged so that a strong

magnetic field is set up between them. The primary

water must pass through this magnetic field so that

al l i ron part ic les come within the range of the

magnetic bars, and are thus attracted and retained.

The magnet bar are protected by stainless steel

sleeves from which they can be removed with the

aid of eyebolts. On contamination of the strainer-type

filter, which is indicated by an alarm initiated at

excessive differential pressure, the filter should be

cleaned.

2 Fine Filter

A fine filed with one-way filter element giving a

degree of filtration of 5 µm (0.2 mils) is installed after

the mixed-bed ion exchanger in the primary water

treatment system.

The fi l ter element consist of cellulose fibbers

bonded with synthetic resin to achieve stability. The

fibres are distributed in the element in such a way

tha t the i r poros i t y i s h ighes t on the cu te r

c i rcumference o f the e lement and decreases

continuously towards the filer interior. Therefore,

filtration takes place in depth, and the solid matter is

his in the entire volume of the element. The coarser

particles are removed at the highly porous outer

surface, while the smaller particles are arrested in the

element body at varying depth, depending on their

size. On contamination of the filter, which is indicated

by an a larm in i t ia ted a t excess ive d i f fe rent ia l

pressure, the filter element should be removed and

replaced with new one.

BHEL, Hardwar 2.1-7131-0003/1

Seal Oil Cooler

1. Upper tubesheet2. Support plate3. Return water channel4. Partition ring5. Inspection port6. Tubel bundle7. Cooler shell

8. Cooling water connection9. Cooler base10. Water channel11. Lower tubesheet12. Oil outlet13. Oil inlet

BHEL, Hardwar 2.1-7344-0001/1

Primary Water Main Filter

BHEL, Hardwar 2.1-7345-0002/1

Primary Water Fine Filter

BHEL, Hardwar 2.1-7349-0003/1

Protective Screens atPrimary Water Inlet and OutletTHDF Series

BHEL, Hardwar

Coolant Temperature Control

2.1-8010-0002/1

Due to load variations during operation and the resulting

thermal expansions and contractions, the generator is

subjected to stresses.

In order to reduce these stresses, the hydrogen cooling

circuit and the primary water cooling are each provided

with a temperature control system to control the cooling

gas and primary water temperatures so that the active

generator components are maintained at the proper

temperature level.

The requirements for the temperature control systems

are described below :

ϑ cold = Cold gas temperature or cold primary water

temperature

ϑhot

= Hot gas temperature or hot primary water

temperature

ϑmean

= Mean temperature of hot and cold gas or of

hot and cold primary water

∆ϑ = hot - cold with generator carrying full load.

The temperature rise ∆ϑ at full load is the temperature

difference between the hot and cold hydrogen gas as given

in the hydrogen cooler design data or between the hot and

cold primary water as given in the design data of the primary

water cooler.

After startup and runup to rated speed, the cooling water

supply to the hydrogen coolers should be opened only when

the temperature of the hydrogen gas has reached the preset

cold gas reference. The temperature difference between

cold gas and hot gas is determined by the no-load losses.

The cooling water supply to the primary water coolers

should be opened only when the generator is carrying load,

since only then current-dependent heat losses will have to

be dissipated.

The temperature control systems are cold coolant

temperature control schemes with variable set point as a

function of the stator current. Set point adjustment is

selectable between I and I2 or with an exponent between

one and two. With rising stator current, the set point is

reduced, so that the mean value (ϑmean

) of hot and cold

coolant temperatures assumes a nearly constant value,

as shown in Fig. 1.

The difference between the setting values of the two

set points corresponds to half the temperature rise of the

hydrogen cooling gas at no-load, with 5-10 K (9-180F) to

be taken as a guiding value.

2.1-8010-0002/2

In order to maintain a low temperature level in the

generator, the reference should be set at the lowest

possible value, ensuring that the cold coolant temperature

will not drop the minimum level of 100 C (50

0F) even when

the generator is carrying full load.

Parallel shifting of the curves shown in Fig. 1 is possible

by adjustment of the cold coolant references. The

temperature of the cold primary water must, however,

always be higher than the temperature of the cold hydrogen

cooling has over the entire load range of the generator in

order to avoid any condensation of moisture contained in

the gas on the generator components carrying primary

water.

The control valve must be absolutely tight when in the

closed position to ensure that the coolant temperature will

not drop while the generator is being shut down.

For details on the operation and technical features of

this equipment, see equipment supplier’s operating

instructions.

The required temperatures for setting the coolant

temperature control system must be observed.

BHEL, Hardwar

Safety Equipment

for Hydrogen Operation

2.1-8310-0001/1

Turbo Generators

Operation

The use of hydrogen as coolant in the generator calls

for special safety equipment to ensure that hazardous

operating conditions which might endanger personnel or

the plant will not occur.

The safety and protective measures provided for the

generator are described in detail in this section. The

required measuring and alarm equipment is discussed

elsewhere in this manual [1].

During normal operation, leaks may develop which

result in a continuous escape of hydrogen. Long-time

experience has shown that no operational restrictions are

required as long as the hydrogen losses do not exceed 12

m3 (s.t.p.) during any 24-hour period. The surroundings of

the generator and the hydrogen supply system should not

be endangered if should engineering principles were

followed in plant design and provision is made for ample

ventilation of these areas so that the formation of localized

hydrogen pockets or explosive hydrogen-air mixtures is

precluded.

particular precautions are taken with respect to a failure

of the seal oil system. A special vapor exhauster creates a

slight vaccum in the generator bearing compartments to

prevent the escape of oil vapor from the bearing

compartments along the shaft. Any hydrogen collecting in

the bearing compartment will be drawn off by the exhauster

and vented.

Operation of the exhauster is monitored by a flow

transmitter with limit switch. If the exhauster fails, the

second exhauster on standby is automatically started.

To prevent the hydrogen which enters the bearing

compartment from escaping via the oil drain pipes, the drain

oil is returned to the turbine oil tank via the seal oil storage

tank and a loop seal. This loop seal is permanantly filled

with oil to prevent the escape of gas. The loop is designed

to withstand momentary pressure surges.

The bearing oil circuit and the seal oil circuit are

seperated from each other.

The seal oil drained from the seal oil tank (hydrogen

side circuit) passes into the seal oil storage tank. After

remaining in this tank for a predetermined time, the

degassed oil is admitted to the turbine oil tank together

with the bearing oil via a loop seal.

The measures outlined above have the following

effects:

The bearing compartments and the oil drain pipes are

vantilated continuously so that no explosive hazard will

arise during normal operation.

During normal operation, practically no hydrogen will

enter the turbine lube oil tank via the loop seal together

with the seal oil drained from the shaft seals, since the

hydrogen is already extracted in the seal oil storage

tank.

The isolating action of the loop seal prevents the

hydrogen escaping due to small leakages from flowing

into the turbine through the only partly filled oil drain

pipe.

The seal oil storage tank is continuously vented via the

vapor exhauster provided for the bearing compartments.

The exhauster creats a slight vaccum in the seal oil storage

tank so that the oil saturated with hydrogen is degassed.

After remaining in this tank for a predetermined time, the

degassed oil is admitted to the turbine oil tank together

with the bearing oil via a loop seal.

This continuous vantilation of the seal oil storage tank

prevents the formation of any explosive hydrogen-air-

mixture.

To avoid anydanger to the unit to the hydrogen supply,

only two hydrogen bottles should be opened if the bottle

supply is used.

BHEL, Hardwar

List of Valves

For vent Gas System

2.1-8311-7379/1

Turbo Generators

Operation

SL. VLV TYPE OF VALVE NOM. NOM BODY END FUNCTION LOCATION REMARKS

NO. DESG BORE PRESS MATL CONN

1 MKF 91 Safety Valve 6 2.5 CS SC Shut Off at PW Tank Pipe Line

AA 003

2 MKF 91 Globe Valve 20 2.5 CS SC PW Tank Gas Exhaust Pipe Line

AA 506


AA 513


AA 505

5 MKQ 31 Globe Valve 8 2.5 CS SC Isolating Valve Pipe Line

AA 301

6 MKQ 31 Disphragm valve 80 2.5 GM FL Shut Off at inlet of Pipe Line

AA 501 Vapour Exhauster

7 MKQ 32 Disphragm valve 80 2.5 GM FL Shut Off at inlet of Pipe Line


8 MKQ 31 Non-Return valve 80 2.5 CS FL Shut Off at Outlet of Pipe Line


9 MKQ 32 Non-Return valve 80 2.5 CS FL Shut Off at Outlet of Pipe Line


Legend

FL = Flanged

SC = Screwed

CS = Carbon Steel

CR = Cromium Steel

GM = Gun Metal

RT = Room Temperature

BHEL, Hardwar

Generator Mechanical Equipment

Protectoin

2.1-8320-0002/1

Turbo Generators

Operation

1 Tripping Criteria

Turbogenerators require comprehensive safety and

supervisory devices to prevent damage and long forced

outages.

The protective equipment detects dangerous operation

conditions at an early stage and prevents them from

developing into damaging conditions. The protection

relieves the operating personnel from making the necessary

fast decisions.

The following criteria are sensed by the generator

mechanical equipment protection and processed by the

generator protection circuits:

1.1 High Cold Gas Temperature in Generator

1.2 Liquid in Generator Terminal Box

1.3 High Hot Air Temperature in Exciser Unit

1.4 High Seal Oil Inlet Temperatures

1.5 High Primary Water Inlet Temeperature

1.6 Low Primary Water Flow Rate at Sector Outlet

1.7 Low Primary Water Flow Rate at Bushing Outlets

Each of these criteria activates a turbine trip. The

generator is disconnected from the system and de-excited

through the two-channel reverse power relay.

2 Protection Circuits

2.1 Generators Protection Against Overheating byHigh

Cold Gas Temperature

The protection circuit covering criterion 1.1 prevents

insufficient cooling and thus overheating of the hydrogen-

cooled components in case of high cooling gas

temperature.

2.2 Generator Protection Against Internal Ground Fault

or Terminal Short-Circuit

The generator may be damaged by loaks in

components through which primary or secondary cooling

water or seal oil flows inside the generator.

Primary water flows through the stator winding, terminal

bushing and phase connectors. Secondary cooling water

flows through the hydrogen coolers located in the stator

end shields. Generator operation will only be endangered

by these coolants in the event of large leakages. As a result

of the high hydrogen pressure. Little water will emerge from

a small leak. Hydrogen will, however, enter into the water

circuit. The hydrogen loss can be derived from the hydrogen

consumption of the generator.

Operation of the generator will be seriously endangered

in the event of a major ingress of water which will collect in

the generator terminal box. Due to the restricted volume of

the compartment the liquid ca rise quickly, resulting in a

terminal short-circuit or ground fault. In order to prevent

such a failure, two level detectors are conected to the

generator terminal box to activate the generator mechanical

equipment protection before a critical level is reached.

2.3 Exciter Unit Protection Against Overheating

The protection circuit covering criterion 1.3 prevents

overheating of the exciter in case of insufficient cooling

(failure of exciter coolers).

2.4 Shaft Seal protection Against High Seal Oil Inlet

Temperature

High seal oil inlet temperature endangers proper sealing

performance of the shaft seals. High seal oil temperature,

as may, for instance, be experienced on failure of the seal

oil coolers, results in a reduction of oil viscosity. The gas

may penetrate the seal oil film at the shaft seal contact

face and allow the hydrogen to enter the bearing

compartment.

2.5 Protecting of Water-Cooled Components Against

Overheating

The protection circuit covering criterian 1.5 prevents

insufficient cooling and thus overheating of the water-cooled

components in case of high primary water inlet temperature.

2.7/2.7 Protection of Water-Cooled Components

Against Insufficient primary Water Supply

The protection circuits covering criteria 1.6 to 1.7

prevent overheating and damage to the stator winding,

phase connectors and bushing in case of insufficient

primary water supply.

BHEL, Hardwar

Tripping Scheme for Generator

Mechanical Equipment Protection

2.1-8321-0002/1

Lequid in generator teminal box

High cold has temperature

High got air temperature

in main exciter

High seal oil temperature

downstream of cooler

High primary water flow rate

at stator outlet

Low primary water flow rate

at bushing outlet

Alarm is initiated when the electrical generator protection system is tripped. Individual alarms for each criterion are proveded.

BHEL, Hardwar 2.1-8323-0001/1

Generator Mechanical Equipemtn Protection

Two-out-or-Two Protection CircuitWith Functional Test

BHEL, Hardwar

Electrical Generators Protection

2.1-8330-0002/1

Turbo Generators

Operation

Generators are high-quality mechines for securing the

best possible continuity of power supply. In addition to a

suitable techinical design and responsible mode of

operation, provision must therefore be made for automatic

protection facilities. This protectron must ensure a fast and

selective detection of any faults in order to minimize their

dangerous effects.

The protective equipment must be designed so that

anyserious fault will result in an immediate disconection

and de-excitation of the generator. Faults which do not

cause any direct damage must be brought to the attention

of the operating staff, enabling them to operate the unit

ioutside the critical range or to take precautionary measures

for shutdown.

Generators may be endangered by short-circuits,

ground faults, overvoltages, underexcitation and excessive

thermal stresses.

The folliowing protective equipment is recommended:

1 Differential protection

Breakdown of insulation between different stator phase

windings results in an internal short-circuit. The fault is

detected by a differential relay which initiates immediate

isolation and de-excitation of the generator. In order to

obtain a high sensitivity, the protected area should include

the generator only.

Operaing value: 0.2-0.4/NRelay time: < 60 ms

In certain cases, the generator may also be included in

the differential protection for the main transformer and

station service feeder. Generator faults are then detected

by two differential protection devices.

2 Stator Ground Fault Protection

Breakdown of insulation between the stator winding and

frame results in a stator ground fault. If possible, the stator

ground fault protection should cover the complete winding.

including the neutral point of the generator. The protection

is to initiate immediate isolation and de-excitation of the

generator.

Relay time: <1 s

The load resistance of a fround transformer and any

required boost to raise the neutral point potential should

be selected so that ground current due to a fault will amount

to less than 15 A.

3 Rotor Ground Fault Protection

Rapid fault detectioon is required for the following

reasons:

An interruption of the field circuit with arcing releases

high amounts of energy in the form of heat which may

cause severe burning.

A one-line-to-ground fault may develop to a double

ground fault, resulting in dangerous magnetic

unbalances, especially on four-pole generators.

To minimize the consequential damage, it is

recommended to provide two=pole and four-pole

generators with a protection circuit featuring a delayed

response. In the core of four-pole generators, the rotor

ground fault protection must always operate of avoid the

hazard of sudden, esxtremely high vibrations due to

magnetic unbalances.

Relay time: approximately 1 s

4 Underexcitation Protection

Failure of the voltage regulator, maloperation of the

generator or transformer control system and generator

operation in a system with capacitive load may result in a

reduction of the excitation required to ensure system

stability below a predetermined minimum value. Short-

circuits or interruptions in the field circuit result in a complete

loss of field and thus in instability of the generator. This

causes higher temperature rises in the rotor and core end

end portions, rotor overvoltage, system swims and torisional

vibrations of the shaft.

A momentary excursion beyond the steady-state

stability limit must not necessarily result in a loss of stability.

Therefore it is advisable to design the under-excitation

protection so that a warning will be given when the steady-

state stability limit is reached. The generator will be shut

down after a few seconds only.

The protection must operate instantaneously if a loss

of field occurs when the steady-state stability limit is

reached.

If the loss of field cannot be detected directly (e.g.

exciters with rotating diodes), it is recommended to

introduce a second stator criterion covering the range of

the permeance values 1/xd and 1/x’d and to provide for

instantaneous tripping when this criterion is exceeded.

5 Overcurrent Protection

System faults may result in inadmissible thermal

stressing of the generator. For this reason, an overcurrent

protection should be provided which operates on failure of

the system protection.

A definite-time delay overcurrent relay may be used

for this purpose,however, its relay time should longer than

that of the system protection.

Operating value: 1.3/NRelay time: 6-8 s maximum

To avoid long relay times, it is recommended to equip

large generators with an inverse-time-delay (impedence0

relay. This relay is energized by overcurrent and operates

with long or short-time setting, dependent on the location

of the short-circuit.

If connected to the generator neutral point, the over-

current protection serves as back-up protection for the

differential protection.

6 Load Unbalance Protection

Generators operating in an interconected system are

normally subjected to small load unbalnced only. However,

all one-and two-line-to-ground faults occuring in the system,

phase breakages or circuit breaker failures are in fact load

unbalances which may result in unduly high thermal

stressing of the rotor.

It is recommended to provide a two-stage load

unbalance protection. When the continuously permissible

load unbalance is reached, an alarm is given, whereas a

time-dependent isolation from the system occurs when this

value is exceeded.

In case of large units, it is recommended to provide a

protection with unbalanced load/time characteristic.

Operating value and relay time should be matched to the

load unbalanced/time characteristic applicable to the

particular generator.

7 Rise-in-voltage Protection

Rejection of partial or complete system loads causes a

voltage rise, followed byan increase in the prime mover

speed. This may result in the generator and the apparatus

conected to it being endangered by undully high voltages.

Maloperation during manual voltage regulation of the

generator may also result in inadmissible voltage stressing

of these devices. Due ot the sudden voltage variations

resulting from switching operations, it is advisable, at least

in the case of large units, to provide a two-stage rise-in

voltageprotection,i.e.:

with high (1.45 × UN) operaing value and instaneous

tripping;

with low (1.2 × UN) operaing value and delayed tripping.

8 Under-Frequency Protection

Major disturbances in an interconected system may

result in operation of the generator at under-frequency. At

rated voltage, the generator can be continuously operated

at rated k VA up to 95% of rated frequency.

To avoid excessive magnetic and thermal stressing, it

is recommended to provide an under-frequency protection.

Since the frequency deviation due to a system

disturbance is normally accompanied by a voltage

deviation, the protection should be designed on the basis

of the permissible load characteristic of the generator on

frequency and voltage deviations.

9 Reverse Power Protection

A rise in system frequency for any reason whatsoever

result in closing of the control valves, and the turbine is

driven by the motoring generator. Since the turbine is then

no longer supplied with cooling steam, the unit must be

disconected from the system. The relay must be provided

with a time delay of approximately 20s to prevent undesired

response to system swings (long time setting).

Specific faults in the turbine-generator interior initiate

emergency tripping. The steam supply to the turbine is

interrupted. A reliable criterion og perfectly tight closure of

the emergency stop valves is the flow of power from the

system back into the generator.

Disconnection of the unit from the system by the

generator circuit breaker with a time delay of 4s is only

permissible after the reverse power has been drawn by

the generator (short-time setting).

Operating value: about 50-80& of revese power

Relay time: long-time setting: approximately 20 s

short-time setting: approximately 4s

10 Overvoltage Protection

The use of surge duverters on the high-voltage side of

the unit transformer is considered sufficient for protecting

the generator against stmospheric overvolatage and

switching surges in the system.

With a view to a possible flashover from the high-voltage

winding to the low-voltage winding inthe unit tranformer, it

is, however, advisable to proide surge diverters for the

generator too, which shoud be connected between the

phases and ground.

Normally, the surge diverters are installed inthe direct

vicinity of the unit transformer. It is assumed that switching

surges due to a load isolator or circuit breaker connected

between the generator and transformer will not endanger

the generator.

Care should be taken toprovide exlosion-proof suge

diverters or suitable constructional measures in order to

avoid danger to persons or nearby pnat components.

Design priciple:

Reseal voltage: approximately 1.2-1.4 × UN(allowing for power-frequency

overvoltage on load rejection)

Power-frequncy

sparkover voltage:approximately 2 × UN(<test voltage for stator winding,

e.g. VDE 0530,

UP = 2 UN + 1 kV)

Impulse sparkover

voltage <4 × UN

2.1-8320-0002/2

BHEL, Hardwar

Tripping Scheme for

Electrical Generator Protection

2.1-8331-0001/1

Differential protection

Stator ground fault protection

Rotor ground fault protection

inderexcitation protection

without loss of field

with loss of field

Overcurrent protection

Unbalance load protection

Rise-in-voltage protection

Under-frequency protection

Reverse power protection

Long time

Short time (operates only at TT)

TT = Turbine trip

GCB = Generator circuit breaker

FB = Field breaker

BHEL, Hardwar 2.1-8351-0002/1

Arrangement of Brush Holders for

Rotor Grounding System

BHEL, Hardwar

Measuring Devices andSupervisory EquipmentIntroduction

2.1-8400-0002/1

Turbo Generators

Operation

The supervisory equipment consists of alarms and

measuring devices. The measuring devices give a visual

indication of the system parameters, the alarm devices

initiate visual or sudible signals in the event of a controlled

quantity falling below or exceeding the predetermined limit

values. In many cases, the measuring and alarm devices

are combined to form one supervisory.

Closely associated with the supervisory equipment are

regulating systems, automatic controls and protective

devices which provide for a reduction of the manual

supervisory work.

BHEL, Hardwar

Temperature TranducersResistance Temperature Detectorsand Thermocouples

2.1-8410-0004/1

1 Resistance Temperature Detectors (RTD’s)

RTD’s are used for temperature measurements on the

generator, e.g. to measure the slot temperatures and the

cold gas and hot gas temperatures. Both RTD’s with four-

wire connection and double-element RTD’s with eight-wire

conection are used.

When making measurements with RTD’s the resistance

element is exposed to the temperature to be measured.

The RTS works on the change in electrical resistance of a

conductor by the following formula:

R = Ro. (1+a.T)

where

Ro = reference resistance at O0c

a = temperature coefficient and

T = tempreature in 0c

The standard reference resistance of the platinum

resistance element is 100 ohmsl. The temperature

coefficient amounts to a=3.85×10-3 deg-1. this mean value

for the range O -100 0c.

1.1Circuit Connections

The two-wire connections to far commonly used involes

errors in case of leads. Long leads are exposed to different

temperatures, and the lead resistances then reach values

in the order of the resistance of the RTD element.

1.1.1 Three-Wire Connection

If a third lead is connected to the element in addition to

the two element leads, automatic compensation for lead

wire resistance including its changes can be achieved by

resistance of the two leads forming the pair to the element

are always the same.

1.1.2 Four-Wire Connection

If the two element leads are not alike or if the three-

wire method of compensation would be too costly a foru-

wire circuit should be used. Fig.2 shows the circuit diagram

of the foru-wire method.

Leads RL 1

and RL2

form the pair of lead wires to the

RTD Pt 100, while the other set of lead wires RL3

and RL4

from the RTD are connected to amplifier V. Being a normal

differential amplifier, it amplifies only the voltage drop

across the RTD to the required output voltage level.

Due to the mostly very high input resistance of amplifier

V, the resistance of lead wires RL3 RL4 from the RTD to

the amplifier is negligible, even if it would be substantially

in-creased be the provision of a safety barrier (explosion

protection).

2 Thermocouples

Thermocouples are used for temperature

measurements on generator, e.g.to measure the generator

and exciter bearing temperatures. Thermocouples are

mainly employed where small constants require fast

temperature indication.

2.1 Principle

Temperature measurement with thermocouples is

carried out as follows:

Two conductors of dissimilar materials,i.e.the positive

and the negative conductor (thremoelectric elements) are

joined at one end (hot junction) so as to produce an

electromotive force (emf), i.e.a thermoelectric emf(inmV).

The magnitude of the emf is dependent upon the

temperature difference betweenthe temperature to be

measured and that of the other two ends of the conductors.

To use the thermoelectric emf for temperature

measurement the free ends of the conductors are exposed

to a constant temperature (cold juction temperature) and

connected to a millivoltemeter calibrated in 0c.

2.2 Compensating Leads

The compensating leads serve to extend the

thermocouple up to the cold junction. When exposed to a

temperature up to 200 0C they produce the same

jthermoelectric emf as the associated thermocouple.See

DIN 43710 for calibration data and limits of error of

compensating leads.

The compensating leads used for the different

thermocouples are identified by colors:

cu-cuNi brown

Fe-CuNi blue

NiCr-Ni green

PtRh-Pt white

NiCr-Constantan red

The insulating sleeve of the positive lead is provided

withe a red mark in addition to the color code.

2.3 Cold Junction

For measureing a temperature by mean of a

thermocouple, the cold junction temperature must be know.

A cold junction at a temperature of 00c can be very earily

proeuced by melting tures of 20 0C and 500C ia also

possible. Note that in these cases certain corrections must

be added to the calibration 00C.To do this, add the

thermoelectric emf due to the cold junction temperature to

the obtain the total thermoelectric emf.

2.1-8410-0004/2

BHEL, Hardwar 2.1-8410-0004/3

The cold junction can, however, also implemented by

using a Pt100 RTD for determination of the actual

temperature. The temperature is referred to the calibration

figure for o0C by electronic means. The electronic cold

junction also avoids the temperature error due to the

junction between the compensating leads and the copper

leads.

To obtain a simpler circuit, the large number of

thermocouples used on the generator can be connected

to a doublepole measuring point selector switch enabling

the resective thermocouple to be connected to a

compensator for measurement.

BHEL, Hardwar

Temperature Tranducers

Rod-Type Thermostats

2.1-8410-0005/1

TurboGenerators

Description

Rod-Type thermostats are used for detecting

temperature limits. These instruments utilize the coefficients

of thermal expansion of two dissimilar metals.

Whene exposed to a temperature rise a rod arranged

inside a tube and fitted to one of it feature a lliner expansion

different from that of the surrounding tube. As a result of

this, a movements initiated in a switching head at the other

end of the detector tube which in turn actuates a

changeover contact. This changeover contact operates on

rising and falling temperature when the set value is reached.

The contacts are connected to the detector tube through a

mechanism providing for sudden changeover. Since the

rod-type thermostats are employed for temperature

detection in pressurized surroundings, they must alwas be

used in connection with protective tubes.

BHEL, Hardwar

Supervision of Generator

2.1-842 0-0003/1

TurboGenerators

Description

The most essential measuring and supervisory devices

at the generator serve for:

temperature monitoring

detection of liquid in generator interior.

1 Temperature Monitoring

1.1 Stator Slot Monitoring

The slot tempreture are measure withe resistance

temperature detectors (RTD’S). This platinum measuring

wire is embedded in a molded plastic body which provides

for insulation and pressure relief.

The RTD’S are embedded directly in the stator slots

between the bottom and top bars at points where the

highest temperature are expected.

The RTD’S are characterized by a constant temperature

vs. resistance characteristic, high mechanical strengh and

insensitivity to electrical and magnetic fields.

1.2 Cold and Hot Gas Temperatures

The temperatue of the hot and cold gases are

measured by RTD’S upstream and downstream of the

hydrogen coolers, and the limit values are sinsed

downsteam of the coolers for use with the hydrogen

temperature control system.

Temperature detectors located in the generator interior

are mounted in gastight protective tubes welded to the

stator frame.

1.3 primary Water Temperatures

The temperature of the hot primary water in the turbine-

end water manifold of the stator winding is measured withe

manifold of the stator winding is measured with resistance

temperature detectors. The temperature detectors are

welded to the water manifold in protective tubes exposed

to the primary water.

2 Stator Liquid Detection

Liquid (cooling water from hydrogen coolers, primary

water or seal oil) entering the generator housing is sensed

by level detectors assembled in gastigh housing located

on the seal oil valve rack. See Figs.2 and 3.

When pipes from several low-level points of the generator

are connected to a common level detector, sight glasses

are provided in the inlet pipe to identify the source of the

liquid.

BHEL, Hardwar

The generator terminal box has two leakage detection

pipes acting on the generator protectors. The two pipes

extend serval inches above the bottom of the generator

terminal box and are interconnected so that both detectors

will respond if the box should be in an inclined position.

These detectors are utilized as tripping criteria for the

generator mechanical equipment protection, whereas all

other detectors initiate only alarms.

2.1-8420-0003/20984E

BHEL, Hardwar

List of Valves

For Generator system

2.1-8423-0001/1

Turbo Generators

Operation



1 MKA 24 Globe Valve 50 2.5 CS FL By-Pass of Valve Sela Oil Valve Rack

AA 511 MKA 24/AA 501

2 MKA 24 Globe Valve 15 25.0 CS SC Outlet of Sight Glass Sela Oil Valve Rack

AA 502 MKA 24/BR 506

3 MKA 24 Globe Valve 50 2.5 CS SC Inlet of Sight Glass Sela Oil Valve Rack

AA 501 MKA 24/BR 506


AA 512 MKA 23/BR 516

5 MKA 23 Globe Valve 50 2.5 CS FL Inlet of Sight Glass Sela Oil Valve Rack

AA 511 MKA 23/BR 516


AA 502 MKA 23/BR 506


AA 501 MKA 23/BR 506


AA 502 MKA 22/BR 506


AA 501 MKA 22/BR 506


AA 502 MKA 21/BR 506


AA 501 MKA 21/BR 506

12 PGB 31 Globe Valve 25 1.6 CS FL Cooler-D Inlet Pipe Line

AA 574 Ventilation

13 PGB 32 Globe Valve 25 1.6 CS FL Cooler-A Outlet Pipe Line

AA 571 Ventilation

14 PGB 32 Globe Valve 25 1.6 CS FL Cooler-B Outlet Pipe Line

AA 572 Ventilation

15 PGB 31 Globe Valve 25 1.6 CS FL Cooler-C Inlet Pipe Line

AA 572 Ventilation

16 PGB 31 Globe Valve 25 1.6 CS FL Cooler-C Outlet Pipe Line

AA 573 Ventilation

17 PGB 31 Globe Valve 10 2.5 CS SC Cooler-A Drain Pipe Line

AA 551

18 PGB 31 Needle Valve 10 2.5 CS SC Cooler-B Drain Pipe Line

AA 551



19 PGB 31 Needle Valve 10 2.5 CS SC Cooler-C Drain Pipe Line

AA 553

20 PGB 31 Needle Valve 10 2.5 CS SC Cooler-D Drain Pipe Line

AA 554

21 PGB 31 Globe Valve 25 1.6 CS FL Cooler-C Drain Pipe Line

AA 571

21 PGB 31 Globe Valve 25 1.6 CS FL Cooler-A Inlet Pipe Line

AA 571 Ventilation

22 PGB 32 Globe Valve 200 1.6 CS FL Shut off at Outlet of Pipe Line

AA 504 Cooler-D


AA 503 Cooler-C


AA 502 Cooler-B


AA 501 Cooler-A

26 PGB 31 Globe Valve 200 1.6 CS FL Shut off at Inlet of Pipe Line

AA 504 Cooler-D


AA 503 Cooler-C


AA 502 Cooler-B


AA 501 Cooler-A

30 PGB 32 Globe Valve 25 1.6 CS FL Cooler-C Outlet Pipe Line

AA 573 Ventilation

31 PGB 32 Globe Valve 25 1.6 CS FL Cooler-D Outlet Pipe Line

AA 574 Ventilation

Legend

FL = Flaged

SC = Screwed

CS = Carbon Steel

SS = Stainless Steel

CA = Cast Steel

2.1-8423-0001/2

BHEL, Hardwar

Supervision of Bearings

2.1-8440-0004/1

1 Generator Bearing Temperatures

The generator bearing temperatures are measured with

thermocouples located in the bearing lower hawer. The

actual measuring point is located at the babbitt/sleeve

interface. Measurement and recording of the temperatures

are performed in conjuction with the turbine supervision.

The overall turbine protection is tripped when the maximum

permissible temperature is exceeded.

2 Vibration Monitoring

The generator and exciter rotes are manufacured with

high precision and carefully balanced.

The unavoidable residual unbalance will, however,

result in vibrations during opertion, which are transmitted

to be stator frame and foundation via the bearings.

To permit a reliable assesment of the running condition,

vibration pickups are located at the bearubgs. Measurement

and recording of the vibrations are performed in conjunction

with the turbine supervision. The overall turbine protection

is tripped when a predetermined amplitude is exceeded.

Turbo Generators

Description

BHEL, Hardwar

Supervision of Seal Oil SystemTurbo Generators

Description

2.1-8450-0005/10999E

The location of the transmitters of the measuring

and supervisory equipment in the seal oil system is

shown in the seal oil Diagram[1].

The most essential measuring and supervisory

devices in the seal oil are:

Level detectors

Pressure and differential pressure gauges

Temperature detectors

Volume flow measuring devices

1 Level Detectors

Within the seal oil system

the oil levels in the TE and EE prechambers

the oil levels in the seal oil tank

the oil levels in the seal oil storage tank

are supervised.

A high oil level in the generator prechambers, due

to an increase in the amount of seal oil on the hydrogen

side of the shaft seal, results in an alarm is initiated when

the probe is immersed in oil.

A low oil level in the seal oil tank is monitored such

that an alarm takes place when the probe is no longer

covered with oil. This prevents dry running of the

hydrogen side seal oil pump.

A low oil level in the seal oil storage tank-only

feasible during the startup phase- results in an alarm for

protection of the air side pumps. The alarm is initiated

when the probe is no longer covered with oil.

2 Pressure and Differential Pressure Gauges

The following pressure measuring points are

provided:

Pressure downstream of air side seal oil pump 1

On failure of seal oil pump 1, a pressure switch

activates air side seal oil pump2, If the latter is not ready

for operation, air side oil pump 3 is automatically started.

Local indication is required for pressure setting of

the A1 valve and for valve and for visual examination.


On failure of seal oil pump2, a pressure switch

activates air side seal oil pump1. If the latter is not ready

for operation, air side seal oil pump 3 is automatically

started.

Local indication is required for pressure setting of

the A1 valve and for visual examination.


A pressure switch signals the takeover of the sealoil supply by seal oil pump 3.

Local indication is required for pressure setting ofthe A2 valve and for visual examination.

Pressure downstream of air side seal oil pumps

Readings from this pressure gauge are required forpressure setting of the A1 and A2 valves.

H2 casing pressure

This pressure gauge reading is required for settingthe pressure differential between the air side seal oilpressure and the H

2 casing pressure.

Seal oil pressure downstream of oil orifice

At this pressure gauge the seal oil pressure, set bymeans of the control orifice, can be observed.

Seal oil pump 3 is activated via a differentialpressure transducer, which detects the pressuredifferential between the generator casing pressure andthe air side seal oil, and a pressure switch when pressurefalls below the preset setpoint value. An additionalpressure switch initiates miscellaneous alarms and isused for Off control the hydrogen side seal oil pump.

TE and EE ring relief pressure

The pressure gauges indicate the relief pressure sitby means of the manual control valves.

In addition, pressure transmitters are provided forfurther processing of the pressure signals.

Pressure downstream of hydrogen side seal oil pump

A pressure switch signals a failure of the oil supply.The reading is required for setting of the C valve

and for visual examination.

Pressure in hydrogen side seal oil circuit of shaft seal

This pressure gauge serves for local observation ofthe set seal oil pressure at the shaft seal.

Pressure Differentials are Sensed at the Following Points:Pressure differential between the air side seal oil

before TE and EE shaft seals and the generator casingpressure is sensed by transducers which initiate an alarmon falling pressure differential, Local indication is providefor manual adjustment of the pressure regulating valvesand for visual examination.

2.1-8450-0005/20999E

Also refer to the following section[1] 2.1-7111 Seal Oil Diagram

Differential Pressure Indication at Air - Cooled

Hydrogen Side Seal Oil Filters

The indicators display the degree of f i l ter

contamination and activate an alarm at present pressure

differentials.

3. Temperature Detectors

The following temperatures are measured locally

with thermometers :

Seal oil temperature upstream and downstream of

air side seal oil coolers.


hydrogen side seal oil coolers.

Cool ing water temperature upstream and

downstream of air side and hydrogen side seal oil

coolers.

In addition, the following temperatures are measured

by means of resistance temperature detectors for

remotes indication :

Seal oil temperature in hydrogen side seal oil drain,

TE and EE.


air side and hydrogen side seal oil coolers.

The following temperature are also monitored with

rod type thermostats, which activate an alarm for high

seal oil temperature.

Seal oil temperature downstream of air side and

hydrogen side seal oil coolers.

4. Volume Flow Meter System

The following volume flows are measured for

comparison measurements :

Volume flow of EE sea ring relief oil

Volume flow of TE sea ring relief oil

Volume flow of air side seal oil, EE

Volume flow of air side seal oil, TE

Volume flow of hydrogen side seal oil, EE

Volume flow of hydrogen side seal oil, TE

BHEL, Hardwar

The location of the transmitters of the measuring and

wupervisory equipment in the gas system is shown in the

Gas Diagram [1].

The essential measuring and supervisory devices in

the gas system are :

Purity meter systems

Volume flow meter system

Pressure gauge

Temperature detectors

1 Electrical Gas Purity Meter System

The electrical gas purity meter system measures the

purity of the hydrogen gas in the generator as well as the

composition of the gas mixtures (CO2/air and H

2/CO

2)

during filling of the generator. The electrical gas purity meter

system is also used when removing the hydrogen from the

generator, where the hydrogen is replaced with carbon

dioxide and the carbon dioxide in turn with air. The gas

required for the measurement is taken from the generator

or from the filling lines, respectively, and, on completion of

the measurement, is discharged to the atmosphere through

a vent line.

For details on the electrical gas purity meter system,

see separate description [2].

The electrical gas purity meter system is equipped with

a limit switch which provides a signal to initiate an alarm

when the purity drops below a preset value.

2 Mechanical Gas Purity Meter System

A mechanical gas purity meter system is supplied to

operate independently of the electrical gas purity meter

system.

This meter system is a mechanical type and utilizes

the physical relationship between the H2 casing pressure

and the differential fan pressure, which in turn depends on

the fan speed (constant) and the density of the medium

handled the fan.

For details on the mechanical gas purity meter system

see separate description [3].

3 Volume Flow System

Measuring gas volume flow

For comparison measurement, a precisely defined

measuring gas flow must be admitted to the electrical gas

purity meter system. The measuring gas volume flow can

be read locally at the flow meter.

4 Pressure Gauges

The following measuring points are provided :

CO2 bottle pressure

The bottle pressure during CO2 filling can be obseved

at a local pressure gauge.

H2 bottle pressure

The bottle pressure can be read at the pressure gauge.

The pressure switch activates a signal at low H2 pressure.

In addition, the pressure is sensed with a pressure

transmitter, the electrical signal being used for remote

control and supervision.

N2 bottle pressure

The bottle pressure can be read at a local pressure

gauge.

H2 pressure at pressure reducers.

For observation of the pressure settings.

Defferential pressure at rotor fan

The differential pressure at the rotor fan can be

observed at a local pressure gauge.

H2 cssing pressure

The pressure is sensed by pressure transmitters, the

electrical signal of one pressure transmitter being used for

remote control and supervision. The signals of the

remaining two transmitters are converted into alarm and

control signals.

The H2 casing pressure dan be read at a local pressure

gauge.

Pressure in gas dryer chamber

The pressure in the gas dryer circuits can be observed

at local pressure gauges.

For aetails on the pressure transmitters, see separate

description [4].

5 Temperature detectors

Within the gas system, temperature detectors are used

for supervision of the gas dryer and CO2 flash evaporator.

The temperatures of the gas dryer heater and of the

heat transfer liquid in the CO2 flash evaporator are detected

by means of thermostats and used for control functions. In

addition, the temperature of the heat transfer liquid in the

CO2 flash evaporator is indicated locally by a thermometer.

For details of the thermostats, see separate description

[5].

Also refer to the following sections

[1] 2.1-7211Gas Diagram

[2] 2.1-7240Electrical Gas Purity Meter System

[3] 2.1-7250Mechanical Gas Purity Meter System

[4] 2.1-8412Pressure Transmitters

[5] 2.1-8410Temperature Detectors

Supervision of Gas System

2.1-8460-0009/1

TurboGenerators

Description

BHEL, Hardwar

Supervision of Primary Water SystemTurbo Generators

Description

2.1-8470-0003/10999E

The location of the transmitters of the measuringand supervisory equipment in the primary water systemis shown in the Primary Water Diagram[1].

The essential measuring and supervisory devicesin the primary water system are:

Conductivity meter systemLevel monitoring systemVolume flow metersPressure gaugesTemperature detectors

1 Conductivity Meter SystemThe conductivity of the primary water is monitored:

Downstream of ion exchangerUpstream of primary water inlet of generator

The measuring point downstream of the ionexchanger checks the ion exchanger for properperformance.

The measuring point in the primary water inlet ofthe generator permits the conductivity of the entirecooling system to be assessed.

Both measuring devices are equipped for indicationand alarm.

2 Level Monitoring SystemThe water level in the primary water tank by

capacitive method, a high or low water level initiating analarm.

A local water level gauge is located in parallel tothe electrical monitoring system.

3 Volume Flow Meter SystemThe primary water volume flows of the

stator winding andbushings

are measured and indicated by a differential pressureflow meter system. If the flow falls below a minimumvalue, an alarm is activated. If the flow continues to fall,the generator mechanical equipment protection istripped.

The amount of primary water flowing though the ionexchanger is monitored by a local flow meter. Theamount of water added to the system during operationis determined by of a water meter.

4 Pressure GaugesPressure or pressure differentials are sensed at the

following measuring point in the primary water coolingcircuit:

Pressure downstream of primary water pump 1Pressure downstream of primary water pump 2

The two pressure measuring points are equippedwith pressure switches and required for automatic controlof the two primary water pumps.

in addi t ion, a pressure gauge is provideddownstream of each pump for local observation of thepressure.

Pressure upstream of stator winding

This pressure measuring point is equipped withpressure switches and a local pressure gauge. Thepressure switches initiate an alarm at rising primary waterpressure.

The pressure gauge is provided for localobservation.

Gas pressure in primary water tank

A pressure switch activates an alarm at rising gaspressure in the primary water tank.

In addition, a pressure gauge is provided for localobservation of the tank gas pressure.

Differential pressure across main filterDifferential pressure across fine filter

Barton cells with switches display the degree of filtercontamination on a dial. In addition, contactsactivate an alarm on filter contamination at presetdifferential pressure.

5 Temperature DetectorsThe following temperatures are measured locally bymeans of thermometers:

Primary water temperature downstream of coolersCool ing water temperature upstream anddownstream of coolersPrimary water temperature downstream of bushings

Resistance temperature detectors are used tomeasure the followings temperatures for furtherprocessing according to different methods:

Pr imary water temperature upstream anddownstream of coolersPrimary water temperature downstream of statorwindingPrimary water temperature downstream of bushings

In addition, a rod-type thermostat monitors thefollowing temperature:

Primary water temperature downstream of coolers

Also refer to the following section[1] 2.1-7311 Primary Water Diagram

BHEL, Hardwar

Supervision of ExciterTurbo Generators

Description

The most essent ial measuring andsupervisory devices at the exciter are:

Temperature monitoring systemFuse monitoring systemGround fault detection systemExcitation current measuring device

1 Temperature Monitoring SystemThe exciter is provided with devices for

monitoring the temperatures of the cold air afterthe exciter cooler and the hot air leaving therectifier wheels and hot air leaving the rectifierwheels and main exciter.

2 Fuse Monitoring SystemThe indicator flags of the fuses on the

rectifier wheels may be checked during operation

with the built-in stroboscope.

3 Ground Fault Detection SystemTwo sliprings are installed on the shaft

between the main exciter and bearing. One isconnected to the star point of the three-phasewinding of the main exciter and the other to theframe. These sliprings permit ground faultdetection.

4 Excitation Current Measuring DeviceThe excitation current is measured indirectly

through a coil arranged between two poles of themain exciter. The voltage induced in this coil isproportional to the excitation current thusenabling a determination of the excitation current.

2.1-8490-0001/10999E

BHEL, Hardwar

BHEL, Hardwar

1 Design Feature

The exciter consists of

Rectifier wheels

Three-phase pilot exciter

Cooler

Metering and supervisory equipment

1 Automatic voltage regulator

2 Pemanent magnet pilot exciter

3 Sliprings for field groung fault detection

4 Qualdrature-axis measuring coil

5 Three-phse main exciter

6 Diode rectifier set

7 Three-phase lead

8 Multikontakt conector

9 Rotor winding of turbogenerator

10 Stator winding of tubogenerator

Fig. 1 Basic Arrangement of Brushless Excitation System

With Rotating Diodes

Exciter

2.1-9100-0021/1

Fig. 1 Shows the basic arrangement of the exciter. The

three-phase pilot exciter has a revolving held with

permanent magnet poles. The three-phase ac generated

by the permanent-magnet pilot exciter is rectified and

controlled by the TVR to provide a varable dc current for

exciting the main exciter The three-phase ac induced in

the rotor of the main exciter. The three-phase ac induced

in hte rotor of the main exciter is rectified by the rotating

rectifier bridge and fed to the field winding of the generator

rotor of the main exciter is rectified by the rotating rectifier

bridge and fed to the field winding of the generator rotor

through the dc leads in the rotor shaft.

Fig. 2 Exciter Rotor

The exciter shown in fig. 2 corresponds to ht basicarrangement described above.A common shaft carries the rectifier wheels, the rotor ofthe main exciter and the permanent-magnet rotor of thepilot exciter. The shaft is rigidly coupled to the genratorrotor. The exciter shaft is supported on a bearing betweenthe main and pilot exciters. The generator and exciter totorsare thus supported on total of three bearings.

Mechanical coupling of the two shaft assemblies resultsin simultaneous coupling of the dc leads in the central shaftbore through the Multikontakt electrical contact systemconsisting of plug-in bolts and sockets. This contact systemis also designed to compensate for length variations of theleads due to thermal expansion.

2 Rectifier WheelsThe main-components of the rectifier wheels are the

silicon diodes which are araanged in the rectifier wheels ina three-phase bridge circuit. The internal arrangement ofa diode is illustrated in Fig. 3. The contact pressure for thesilicon wafer is produced by a plate spring assembly. Thearrangement of the diods is such that this contact pressureiis increased by the cintrifugal force during rotation.

Fig. 3 Silicon Diods

Fig. 4 shows additional components contained in the

rectifier wheels. Two diodes each are mounted in each

aluminum alloy heat sink and thus connected in parallel.

Associated with each heat sink is a fuse which serves to

switch off the two diodes if one diods fails (loss of reverse

blocking capability).

Fig. 4 Rectifier Wheel

For suppression of the momentary voltage peaks arising

from commutation, each wheel is provided with six RC

network consisting of one capacitor and one damping

resistor each, which are combined in a single resin-

encapsulated unit.

The insulated and shrunken rectifier wheels seve as

dc buses for the negative and positive side of the rectifier

bridge. This arrangement ensures good accessibility to all

components and a minimum of circuit connections. The

two wheels are identical in their mechanical design and

dffer only in the forward direcitons of the diods.

The direct current from the rectifier wheels is fed to

these leads arrnaged in the center bore of the shaft via

radial bolts.

The three-phase alternating currents is obtained via

copper conductors arranged on the shaft circumference

between the rectifier wheels and the three-phase main

exiciter. The conductors are attached by means of banding

clips and equipped with screw-on lugs for the internal diode

connections. One three-phase conductor each is provided

for the four diodes of a heat sink set.

3 Three-Phase Main Exciter

Fig. 5 Main Exciter

The three-phase main exciter is a six-pole revolving-armature unit. Arranged in the stator frame are the poleseith the field and damper winding. The field winding isarranged on the laminated magnetic poles. At the pole shoebars are provided. Their ends being conected so as to forma damaper winding Between two poles a quadrature-axiscoil is fitted for inductive measurement of the exditercurrent.

The rotor consists of stacked laminations, which arecompressed by through bolts over compression rings. Thethree-phase winding is inserted in the slots of the laminatedrotor. The winding conductors are transposed within thecore lengt, and the end turns of the roteor winding aresecured with steal bands. The connections are made onthe side facing the rectifier wheels. The winding ends arerun to a bus ring system to which the three-phase leads tothe rectif ier wheels are also conected. After fullimpregnation with synthetic resin and curing, the completerotor is shrunk onto the shaft. A journal bearing is arrangedbetween main exciter and pilot exciter and has forced oillubrication from the turbine oil supply.

2.1-9100-0021/2

BHEL, Hardwar

4 Three-Phase Pilot Exciter

The three-phase pilotexciter is a 16 pole revolving-field

unit. The frame accommodates the laminated core with the

three-phase winding. The rotor consists of a hub with

mounted poles. Each pole consists of 12 separate

permanent magnets which are housed in a non-magnetic

metalic enclosure. The magnets are braced between the

hub and the external pole shoe with bolts. the rotor hub is

shrunk onto the free shaft end.

Fig. 6 Stator of Main Exciter

5 Cooling of Exciter

The is air cooled. The cooling air is cirvulated in a closed

circuit and recooled in two cooler sections arranged

alongside the exciter.

The complete exciter is housed in an enclosure draw

the cool air in at both ends and expel the warned air to the

compartment beneath the base plate.

The main exciter enclosure receives cool air from the

fan after it passes over the pilot exciter. The air enters the

main exciter from both ends and is passed into ducts below

the rotor body and discharged through radial slots in the

rotor core to the lower compartment. The wrm air is then

returned to the main enclosure via the cooler sections.

Fig. 7 Permanent-Magnet Pilot Exciter

6 Replacement of Air Inside Exciter Enclosure

When the generator is filled with hydrogen (operation

or standstill) an adequate replacement of the air inside the

exciter enclosure must be ensured. The air volume inside

the exciter enclosure requires an air change rate of 125m3/h.

While the generator is running, the air leving the exciter

enclosure via the bearing vapor exhaust system and the

leakage air outlet in the foundation provides for a pull-

through system. The volume of air extracted from the

cooling air circuit is replaced via the filters located at the

top of the enclosure.

When the generator is at rest, the air dryer of the exciter

unit discharges dry air inside the exciter enclosure. The air

leaves the exciter enclosure via the leakage air filter and

the leakage air oulet at the shaft as well as via the bearing

vapor exhaust system if this system is in sevice.

2.1-9100-0021/3

BHEL, Hardwar 2.1-9102-0002/1

Rectifier Wheels

ELR Series (More Than 60 Diodes)

BHEL, Hardwar 2.1-9103-0003/1

Rectifier Wheels and Coupling

ELR Series (Up to 120 Diodes)

BHEL, Hardwar 2.1-9104-0002/1

Permanent-Magnet

Pilot Exciter Rotor and Fan

BHEL, Hardwar 2.1-9110-0029/1

Exciter Cross Section

BHEL, Hardwar

BHEL, Hardwar 2.1-9140-0002/1

Stroboscope for Fuse Monitoring

The fuses on the rectifier wheels may be checked during

operation with the stroboscope. A separate flash tube is

provided for each wheel (A and B). The tubes, which are

supplied through a common control unit, are permanently

installed in the rectifier wheel enclosure. This permits easy

monitoring whithout any adjustment outside the exciter

enclosure being required.

Fig. 1 shows the basic arrangement of a fully

transistorized stroboscope The electronics required for

montrol of the light singals are contained in the control unit

and in the tubular lamps. The tubular lamps are connected

to the control unit by cables.

The stroboscope is located in the rectifier wheel and

exciter enclosure so that the fuses may be observed from

outside the exciter enclosure while controlling the

stroboscope.

To synchronize the sequence of flashes with the generator

rotation, the system frequency is utilized to activate the

flashes. A doyuble synchronous motor, controlled through

two pushbuttons and connected to two potentiometers and

IC's, causes the flash to be timed so that a slow-motion

observation of the fuse becomes possible.

The Observation period for one full revolution of the

rectifiier wheel (3600) is approximately 25 seconds. At

approximately 4500, the flash is reset to its initial rate, and

the observation can be repeated. The continuous sequence

of flshes can be interrupted at any time by actuating the

Feed of Return pushbutton. Following this, a stationry

image is obtained which ensures accurate checking of a

single fuse. After approximately two minutes, the

stroboscope is automatically switched off. If this period

should not be sufficient for fuse checking, switching on the

stroboscope for another two minutes without delay can be

repeated for any desired number of times by depressing

the On pushbutton.

The stroboscope contains four plug-in printed circuit

boards which can be readily replaced in order to remedy

any faults.

The capacitor and high-voltage transformer required

to produce the firing pulses for the flash tubes are located

on a printed circuit board which is accommodated in the

handle of the flash lamp.

The operating elements are located on the front panel

of the control unit for ease of operation. A depressed

pushbutton is indicated by an illuminated dot in the

pushbutton head.

Tthe line connector, the two connectors for the flash

lamps and the fuse are located on the back of the control

unit.

All connectors have a mechanical lock and are

protected agaist dust and splashwater. The cables are run

in flexible metal hoses for protection against mechanical

damage.

1 2 3 4 5 6 7 8 9 10

1 Flash tube 1 (A wheel)2 Control unit3 Pushbutton for flash tube 14 Pushbutton for flash tube 2

5 Feed pushbutton6 Pilot lamp for control voltage7 Return pushbutton

8 On pushbutton9 Off pushbutton10 Flash tube 2 (B wheel)

Fig.1 Components and Operating Elements of Stroboscope

BHEL, Hardwar

1 General

A dryer (dehumidifier) and an anicondensation heating

system are provided to avoid the formation of moisture

condensate inside the exciter with the turbine-generator at

rest or on turning gear.

Fig. 1 Exciter Dryer

2 Mode of Operation

The dryer dehumidifies the air within the exciter

enclosure. The dryer wheel is made of a nonflammable

material. On its inlet side, the wheel is provided with a

system of tubular ducts, the surfaces of which are

impregnated with a highly hygroscopic material.

The tubular ducts are dimensioned so that a laminar

flow with low pressure loss is obtained even at high air

velocity.

The moisture absorbed by the dryer wheel is removed

in a regeneration section by a stream of hot air derected

through the wheel in the opposite direction of the inlet air

and then discharged to the atmosphere.

After regeneration, the dryer wheel material is again

capable of absorbing moishture.

The adsorption of moisture and regeneration of the

dryer wheel material take place simultaneously, using

separate air streams, which ensures a continous drying of

the air.

Exciter Drying

2.1-9150-0003/1

TurboGenerators

Description

2.1 Operating Principle of Adsorption Dryer

The dehumidification takes place in a slowly rotating

dryer wheel (approximately 7 revolutions per hour). The

honeycomb dryer wheel consists of a magnesium silica

alloy containing crystalline lithium chloride. The inlet side

of the dryer wheel is subdivided so that 1/4 is available for

regeneration and 3/4 for the adsorption section.

2.1.1 Adsorption Section

The air to be dehumidified passes throungh the

adsorption section of the dryer wheel, with part of the

moisture contained in the air being removed by the

adsorbent material, i.e. lithium chloride. The moisture is

Fig. 2 Schematic Diagram

removed as a result of the pratial pressure drop existing

between the air and the adsorbent material.

2.1.2 Regeneration Section

In the regeneration section of the dryer wheel, the

accumulated moisture is removed from the dryer wheel by

the heated regeneratiion air.

Continuous rotation of the dryer wheel ensures

continuous dehumidification of the air within the exciter.

3 Anticondensation Heating System

An anticondensation heating system to support the

dryer is installed in the exciter baseframe. The heaters are

rated and arrgned so that the temperature in the exciter

interior.

BHEL, Hardwar

The field ground fault detection system detects high-

resistance and low-resistance ground faults in the exciter

field circuit. It is very important for safe operation of a

generatork, because a double fault causes magnetic

unbalances with very high currents flowing through the

faulted part, resulting in its destruction within a very short

time. It is therefore an essential requirement that even simle

ground faults should activate an alarm and protective

measures be initiated, if possible, before the fault can fully

Ground Fault Detection Systemfor Exciter Field Circuit

2.1-9180-0001/1

TurboGenerators

Description

develop. For this reason, the field ground fault detection

system consists of two stages and operates continuously.

Ifthe field ground fault detection system detects a

ground fault, an alarm is activated at RE < 80 kΩ (1st stage).

If the insulation resistance between the exciter field civuit

and ground either suddenly or slowly drops to RE < 5 kΩthe generator electrical protection is tripped (2nd stage).

The generator is thus automatically disconected from

the system and de-excited.

BHEL, Hardwar 2.1-9181-0002/1

Measuring Brush Holder for

Ground Fault Detection

BHEL, Hardwar 2.1-9182-0001/1

Brush Holders for

Ground-Fault Detection System

BHEL, Hardwar

Operating ans Setting Values

General

2.3-4000-0005/1

Turbo Generators

Operation

Strict observance of the operating and setting values

is a prerequiste for reliable operation of the turbogenerator.

Separate tables are provided for the various design

groups of the generator and its auxiliaries. They show the

transmitters activating the controls and alarms as well as

the transmitters acting on the generator protection circuits.

The Remark column contains additional information

on controls, temperatures and pressures.

All operating and setting values refer to rated output

of generator and maximum colling water temperatures

under steady-state conditions.

The operating ans setting values initially specified in

this manual are based on experience under due

consideration of the specific site conditions, such as static

head in case of pressure measuing points or thermal

characteristics in case of temperature measuring points.

These calculated values are intended as guiding values

for making the preliminary settings during init ial

commissionning of the unit.

These settings require certain corrections to account

for the actual conditions. The final settings obtained after

startup and initial load operation are to be entered in the

Operating Value column.

BHEL, Hardwar

Gas Quantities

2.3-4010-0001/11083E

Turbo Generators

Operation

BHEL, Hardwar

Measuring Point List of Generator

2.3-4030-0001/10197E

Turbo Generators

Operation

2.3-4030-0001/20197E

BHEL, Hardwar 2.3-4030-0001/30197E

2.3-4030-0001/40197E

BHEL, Hardwar 2.3-4030-0001/50197E

2.3-4030-0001/60197E

BHEL, Hardwar 2.3-4030-0001/70197E

2.3-4030-0001/80197E

BHEL, Hardwar 2.3-4030-0001/90197E

2.3-4030-0001/100197E

BHEL, Hardwar 2.3-4030-0001/110197E

2.3-4030-0001/120197E2.3-4030-0001/10

0197E

BHEL, Hardwar 2.3-4030-0001/130197E

2.3-4030-0001/140197E

BHEL, Hardwar 2.3-4030-0001/150197E

2.3-4030-0001/160197E

BHEL, Hardwar 2.3-4030-0001/170197E

2.3-4030-0001/180197E

BHEL, Hardwar 2.3-4030-0001/190197E

2.3-4030-0001/200197E

BHEL, Hardwar 2.3-4030-0001/210197E

2.3-4030-0001/220197E

BHEL, Hardwar 2.3-4030-0001/230197E

2.3-4030-0001/240197E

BHEL, Hardwar 2.3-4030-0001/250197E

2.3-4030-0001/260197E

BHEL, Hardwar

BHEL, Hardwar

1. Operating Log

During initial startup and during normal operation, the

hydrogen-colled turbogenerator, auxiliaries and all

instruments and controls should be monitored to assure

continuous reliable operation. The observations and

readings should be recorded. A typical operating log is

contained in these operating instructions.This table will, of

course, have to be adapted to the particular conditions of

the plant. The important requirement is that all checks and

readings be made at certain predetermined intervals and

preferably at the same load point. Any special conditions

regarding the operation of the hydrogen-cooled

Running Routine

General

2.3-4100-0002/1

Turbo Generators

Operation

turbogenerator should be noted separately. Such notes may

be useful in determining the cause of any subsequent

trouble and speeding up corrections.

2. Normal and Special Operating Conditions

The Generator should be continuously monitored from

startup ton shutdown. During initial startup, all checks

should be made at frequent intervals. Hourly readings may

be taken after completion of the initial period.

A generator at standstill is considered to have been

taken into service and must be continuously monitored after

one supply system was placed in operation.

BHEL, Hardwar

Operating values* Unit Tag Date

Number

Active power MW

Reactive power Mvar

Stator current kA

Stator voltage kV

Rotor current A

Speed s-1

Generator gas pressure kg/cm2

Slot 10C

20C

Slot temperature 30C

40C

50C

60C

Primary water Measuring point 10C

outlet temperature Measuring point 20C

TE water manifold measuring point 30C

Measuring point 10C

TE Measuring point 20C

Stator core Measuring point 30C

temperature Measuring point 10C

EE Measuring point 20C

Measuring point 30C

Coolers a/b cold0C

Coolers c/d cold0C

Gas temperature Coolers a/b hot0C

Coolers c/d hot0C

EE After coolers a/b0C

EE After coolers c/d0C

Inlet0C

Bearing oil TE0C

temperatureOutlet

EE0C

Generator bearing TE0C

temperatures EE0C

TE kg/cm2

Shaft lift oil pressureEE kg/cm

2

Generator bearing vibrationTE ahv µm

EE ahv µm

Job name ............................................................ Sl. No. ............................................ Remark .............................................

* Data should be recorded during steady-state conditions after constant operation for several hours.

2.3-4120-7347/1

Operating Log

Generator Supervision

Turbo Generators

Operation

BHEL, Hardwar


Number

Air side pressure after seal oil pumps kg/cm2

Hydrogen side pressure after seal oil pump kg/cm2

Air side seal oil pressure after orifice kg/cm2

TE kg/cm2

Air side seal oil pressureEE kg/cm

2

TE kg/cm2

Hydrogen side seal oil pressureEE kg/cm

2

TE mbarSeal oil differential pressure

EE mbar

TE kg/cm2

Ring relief oil pressureEE kg/cm

2

TE kg/sAir side seal oil volume flow

EE kg/s

TE kg/sHydrogen side seal oil volume flow

EE kg/s

TE kg/sRing relief oil volume flow

EE kg/s

Seal oil temperatures, Inlet0C

hydrogen side seal oil cooler Outlet0C

Hydrogen side seal TE0C

oil drain temperature EE0C

Seal oil temperatures, Inlet0C

air side seal oil coolers Outlet0C

Inlet0C

Outlet, H2 side cooler 10C

Cooling water Outlet, H2 side cooler 2

0C

temperaturesOutlet, air side cooler 1

0C

Outlet, air side cooler 20C


* Data should be recorded during steady-state conditions after constant operation for several hours.

2.3-4150-7347/1

Operation Log

Seal Oil System

Turbogenerators

Operation

BHEL, Hardwar

Operating values* Unit Tag. Date

Number

H2 boottle pressure kg/cm2

CO2 boottle pressure kg/cm2

N2 boottle pressure kg/cm2

H2 purity (elec. purity meter system) % H2

H2 purity (mech. purity meter system)** % H

2

Gas flow for measuring H2 purity I/h

H2 casing pressure kg/cm2

Temperature before gas dryer 0C

Pressure before gas dryer 0C


* Data should be recorded during steady-state conditions after constant operation several hours.

** To be recordced only on failure of electrical purity meter system.

2.3-4160-7347/1

Operation Log

Gas System

Turbogenerators

Operation

BHEL, Hardwar

Operating values* Unit Tag. Date

Number

Generator inlet 0C

Stator winding outlet 0C

Bushing outlet 0C

Before coolers 0C

After collers 0C

Stator winding oulet dm3/s

Bushing outlet U dm3/s

Prinary water flow Bushing outlet V dm3/s

Bushing outlet W dm3/s

Treated water dm3/s

Primary waterStator winding inlet kg/cm2

pressure After PW pumps 1/2 kg/cm2

Primary water After main filter µS/cm

conductivity After ion exchanges µS/cm

Primary water level in primary water tank %

Gas pressure in primary water tank kg/cm2

Job name ............................................................ Sl. No. ............................................ Remark .............................................Job name ............................................................ Sl. No. ............................................ Remark .............................................

2.3-4170-7347/1

Operation Log

Primary Water System

Turbogenerators

Operation

BHEL, Hardwar


Number

Cold air0C

Cooling air Main exciterHot air

0Ctemperature

Rectifier wheels Hot air0C

Cooling water Coolers e/f Inlet

0C

temperature Cooler e Outlet0C

Cooler f Outlet0C

Measuring Point 10C

Exciter bearing twmperatureMeasuring point 2

0C

Bearing oil outlet temperature0C

Exciter shaft vibration Relative µm

Exciter bearing vibration Absolute µm

Shaft lift oil pressure kg


* Data should be recorded during steady-state conditions after constant operation several hours.

2.3-4190-7347/1

Operation Log

Exciter Supervision

Turbogenerators

Operation

genaux

Documents

seal oil pressures

seal ring carrierresistant

seal oil pump

seal oilair

theshaft seal

seal ringare

seal oilcircuit

seal ringcarrier