sel700g part 2

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1

Introduction & Application of Generator Protection Relay Type

SEL700G Relay (Part2)

Kamin DaveBusiness Development Manager

[email protected] Engineering Laboratories, India

www.selinc.com

KNOWLEDGE IS POWER BUT IMMAGINATION IS MORE IMPORTANT THAN KNOWLEDGE

2

Generator Protections: Measuring Principal

Measuring Principals: Power System Protections:-

Current Based Protection:Current Based Protection:Current Based Protection:Current Based Protection:Three Phase Currents, Single Current Three Phase Currents, Single Current Three Phase Currents, Single Current Three Phase Currents, Single Current MeasurementMeasurementMeasurementMeasurement

Voltage Based Protection:Voltage Based Protection:Voltage Based Protection:Voltage Based Protection:Three Phase Voltages, Single Voltage Three Phase Voltages, Single Voltage Three Phase Voltages, Single Voltage Three Phase Voltages, Single Voltage MeasurementMeasurementMeasurementMeasurement

Frequency Based Protection:Frequency Based Protection:Frequency Based Protection:Frequency Based Protection:Three Phase Frequency Measurement Three Phase Frequency Measurement Three Phase Frequency Measurement Three Phase Frequency Measurement

Power Based Protection:Power Based Protection:Power Based Protection:Power Based Protection:Three or Single Phase Power MeasurementThree or Single Phase Power MeasurementThree or Single Phase Power MeasurementThree or Single Phase Power Measurement

Impedance Based Protection:Impedance Based Protection:Impedance Based Protection:Impedance Based Protection:PhPhPhPh----Ph, PhPh, PhPh, PhPh, Ph----G & 3G & 3G & 3G & 3----Ph Impedance MeasurementPh Impedance MeasurementPh Impedance MeasurementPh Impedance Measurement

Control Functions:Control Functions:Control Functions:Control Functions:

3


Measuring Principal: Power System Protections


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4


Measuring Principal; Power System ProtectionsImpedance (Z=V/I):Impedance (Z=V/I):Impedance (Z=V/I):Impedance (Z=V/I):Back up Impedance Back up Impedance Back up Impedance Back up Impedance ----21212121Voltage Controlled Voltage Controlled Voltage Controlled Voltage Controlled –––– 51VC51VC51VC51VCVoltage Restrain Voltage Restrain Voltage Restrain Voltage Restrain –––– 51VR51VR51VR51VRLoss of Excitation Loss of Excitation Loss of Excitation Loss of Excitation –––– 40G40G40G40GPole Slipping (dz/dt) Pole Slipping (dz/dt) Pole Slipping (dz/dt) Pole Slipping (dz/dt) ---- 78787878Line Distance Protection Line Distance Protection Line Distance Protection Line Distance Protection ---- 21 21 21 21

Resistance (R=V/I): Resistance (R=V/I): Resistance (R=V/I): Resistance (R=V/I): Rotor Earth Fault Rotor Earth Fault Rotor Earth Fault Rotor Earth Fault –––– 64R64R64R64R


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Generator Protections: Faults

G D Y GCB

Failed Prime-mover

E

SysSysSysSys


Exciter Failed

Rotor Ground Fault

RRRR

Stator Ground Fault

Stator Phase Fault

GT Phase fault

GT Ground fault

Grid Disturbances

Bus fault

Inadvertent energization

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• Stator Protections Stator Protections Stator Protections Stator Protections

• Rotor ProtectionsRotor ProtectionsRotor ProtectionsRotor Protections

• Exciter ProtectionsExciter ProtectionsExciter ProtectionsExciter Protections

• Backup ProtectionsBackup ProtectionsBackup ProtectionsBackup Protections

Generator Protections:


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7

• Stator Protections:Stator Protections:Stator Protections:Stator Protections:----

1.1.1.1. Generator differential Protection (87G)Generator differential Protection (87G)Generator differential Protection (87G)Generator differential Protection (87G)

2.2.2.2. Generator Split Phase differential Prot (50D)Generator Split Phase differential Prot (50D)Generator Split Phase differential Prot (50D)Generator Split Phase differential Prot (50D)

3.3.3.3. Over Voltage Protection (59)Over Voltage Protection (59)Over Voltage Protection (59)Over Voltage Protection (59)

4.4.4.4. Over all GeneratorOver all GeneratorOver all GeneratorOver all Generator----Transformer differential Transformer differential Transformer differential Transformer differential Protection (87GT)Protection (87GT)Protection (87GT)Protection (87GT)

5.5.5.5. 0 0 0 0 –––– 95% Stator E/F & 100% Stator E/F 95% Stator E/F & 100% Stator E/F 95% Stator E/F & 100% Stator E/F 95% Stator E/F & 100% Stator E/F Protection (59N/27TN)Protection (59N/27TN)Protection (59N/27TN)Protection (59N/27TN)

6.6.6.6. Protection against Stator winding over Protection against Stator winding over Protection against Stator winding over Protection against Stator winding over Heating & over loading (51O/L) Heating & over loading (51O/L) Heating & over loading (51O/L) Heating & over loading (51O/L)

Generator Protections: Stator Protections


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• Rotor Protections:Rotor Protections:Rotor Protections:Rotor Protections:----1.1.1.1. 1111stststst & 2& 2& 2& 2ndndndnd Rotor E/F Protection Rotor E/F Protection Rotor E/F Protection Rotor E/F Protection

(64F1/64F2)(64F1/64F2)(64F1/64F2)(64F1/64F2)

2.2.2.2. Stator Unbalanced current Stator Unbalanced current Stator Unbalanced current Stator Unbalanced current Protection Protection Protection Protection (NPS(NPS(NPS(NPS----46)46)46)46)

3.3.3.3. Loss of Excitation Protection (LOFLoss of Excitation Protection (LOFLoss of Excitation Protection (LOFLoss of Excitation Protection (LOF----40G)40G)40G)40G)

Generator Protections: Rotor Protections


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• Exciter Protections:Exciter Protections:Exciter Protections:Exciter Protections:----1.1.1.1. Under ExcitationUnder ExcitationUnder ExcitationUnder Excitation

2.2.2.2. Over ExcitationOver ExcitationOver ExcitationOver Excitation

3.3.3.3. Over VoltageOver VoltageOver VoltageOver Voltage

4.4.4.4. Rotating Diode failureRotating Diode failureRotating Diode failureRotating Diode failure

5.5.5.5. PT Fuse fail of Sensing TransformerPT Fuse fail of Sensing TransformerPT Fuse fail of Sensing TransformerPT Fuse fail of Sensing Transformer

Generator Protections: Exciter Protections


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• Abnormal Operating Conditions:Abnormal Operating Conditions:Abnormal Operating Conditions:Abnormal Operating Conditions:----

1.1.1.1. Reverse Power Protection (32R)Reverse Power Protection (32R)Reverse Power Protection (32R)Reverse Power Protection (32R)

2.2.2.2. Low forward Power Protection (37L/32L))Low forward Power Protection (37L/32L))Low forward Power Protection (37L/32L))Low forward Power Protection (37L/32L))

3.3.3.3. Under Frequency Protection (81U/F)Under Frequency Protection (81U/F)Under Frequency Protection (81U/F)Under Frequency Protection (81U/F)

4.4.4.4. Over Frequency Protection (81O/F)Over Frequency Protection (81O/F)Over Frequency Protection (81O/F)Over Frequency Protection (81O/F)

5.5.5.5. Out of Step or PoleOut of Step or PoleOut of Step or PoleOut of Step or Pole----Slip Protection (78)Slip Protection (78)Slip Protection (78)Slip Protection (78)

6.6.6.6. Generator Over Speeding ProtectionGenerator Over Speeding ProtectionGenerator Over Speeding ProtectionGenerator Over Speeding Protection

Generator Protections


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• Other Miscellaneous Protections:Other Miscellaneous Protections:Other Miscellaneous Protections:Other Miscellaneous Protections:----

1.1.1.1. Generator Generator Generator Generator –––– Transformer Over fluxing Transformer Over fluxing Transformer Over fluxing Transformer Over fluxing Protection (24)Protection (24)Protection (24)Protection (24)

2.2.2.2. Restricted E/F Protection if it required Restricted E/F Protection if it required Restricted E/F Protection if it required Restricted E/F Protection if it required

3.3.3.3. Back up Impedance Protection or Back up Back up Impedance Protection or Back up Back up Impedance Protection or Back up Back up Impedance Protection or Back up Protection using Voltage Dependent Protection using Voltage Dependent Protection using Voltage Dependent Protection using Voltage Dependent (Voltage restrain / Voltage controlled) over (Voltage restrain / Voltage controlled) over (Voltage restrain / Voltage controlled) over (Voltage restrain / Voltage controlled) over current unit (21/51V)current unit (21/51V)current unit (21/51V)current unit (21/51V)

4.4.4.4. Breaker Flash over ProtectionBreaker Flash over ProtectionBreaker Flash over ProtectionBreaker Flash over Protection

5.5.5.5. Voltage Balance Scheme (LOPVoltage Balance Scheme (LOPVoltage Balance Scheme (LOPVoltage Balance Scheme (LOP----60)60)60)60)

Generator Protections


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Protection schemes are recommended for Generator Prot based on Size:-

Less than 1MW

optional

YesYesYes87GGenerator differential

YesYesYes81UUnder frequency

YesYes-81OOver frequency

Only for alarmYesYes-27Under Voltage

YesYes-59 or 24

(99)

Over voltage or Over

fluxing

Required above

50MW &

GT unit

YesOptional either 21

or 51V

-21Under Impedance or Back

up Impedance

YesYesYes51VVoltage dependent O/C

Only for alarmYesYesYes51 O/LStator Over heat

REMARKSLARGE

(Above

10MW)

MEDIUM

(Up to 10MW)

SMALL

(Up to

10MW)

ANSI

CODE

PROTECTION

5

13


YesYes-37Low forward Power

YesYesYes32Reverse Power

Stage-1 for alarm &

Stage-2 for Trip

YesYes-64F1 & 64F2Rotor E/F-1st & 2nd

YesYesYes51N & 27N & 59GNStator E/F 0-95% &

100%

--Optional either

87G or 64R

64RRestricted earth fault

YesYes-46Negative Phase sequence

YesYes-87GTGenerator- Transformer

combined

differential


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Above 250MW

single unit

Yes--50/51Turn to Turn fault in

stator

YesYesYes12Over speed

Above 50MW

single unit

Yes--78Pole slipping

YesYes-40GField failure


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ROTOR AND BEARING PROTECTION:

YesYesYes26 or 38Bearing Insulation

YesYesYes26 or 38Bearing

temperature &

alarm trip

YesYesYes-Vibration

Indicator

REMARKSLARGE

(ABOVE

10MW)

MEDIUM

(UP TO

10MW)

SMALL (UP

TO 1MW)

ANSI CODEPROTECTION


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REQUIRED ALARMS:

Sp. For battery starting

engine

YesYesBattery voltage low

YesYesCooling water inlet

pressure low

Sp. For STGYesYesGovernor oil pressure

low

Sp. For diesel generatorYesYesLubricating oil

temperature low

YesYesStator winding

temperature high

YesYesBearing temperature high

YesYesBearing Oil pressure low

REMARKSHYDROGEN

COOLED

AIR COOLEDABNORMAL

CONDITION


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Tripping Criteria: Generator-Turbine Unit

• ClassClassClassClass----A TrippingA TrippingA TrippingA Tripping::::

– Turbine Trip + GCB Trip + Field Turbine Trip + GCB Trip + Field Turbine Trip + GCB Trip + Field Turbine Trip + GCB Trip + Field Breaker Trip Breaker Trip Breaker Trip Breaker Trip

• ClassClassClassClass----B TrippingB TrippingB TrippingB Tripping::::

– Turbine & Boiler Trip Turbine & Boiler Trip Turbine & Boiler Trip Turbine & Boiler Trip

• ClassClassClassClass----C TrippingC TrippingC TrippingC Tripping::::

– GCB Trip only or GCB & FB TripGCB Trip only or GCB & FB TripGCB Trip only or GCB & FB TripGCB Trip only or GCB & FB Trip

• GCB = Generator Circuit BreakerGCB = Generator Circuit BreakerGCB = Generator Circuit BreakerGCB = Generator Circuit Breaker

• FB = Field BreakerFB = Field BreakerFB = Field BreakerFB = Field Breaker


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Tripping Criteria: Generator – Turbine Unit

TRIP TYPE: TT GCB FBTRIP TYPE: TT GCB FBTRIP TYPE: TT GCB FBTRIP TYPE: TT GCB FB

• DIFFRENTIAL DIFFRENTIAL DIFFRENTIAL DIFFRENTIAL

• STATOR EARTH STATOR EARTH STATOR EARTH STATOR EARTH

• ROTOR EARTH ROTOR EARTH ROTOR EARTH ROTOR EARTH

• OVERVOLTAGEOVERVOLTAGEOVERVOLTAGEOVERVOLTAGE

• OVERCURRENT OVERCURRENT OVERCURRENT OVERCURRENT

• UNBALANCEUNBALANCEUNBALANCEUNBALANCE

• UNDERFREQUENCYUNDERFREQUENCYUNDERFREQUENCYUNDERFREQUENCY

Where; Where; Where; Where; TT: Turbine TripTT: Turbine TripTT: Turbine TripTT: Turbine TripGCB: Generator Control BreakerGCB: Generator Control BreakerGCB: Generator Control BreakerGCB: Generator Control BreakerFB: Field BreakerFB: Field BreakerFB: Field BreakerFB: Field Breaker


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• UNDEREXCITATION UNDEREXCITATION UNDEREXCITATION UNDEREXCITATION

W / O LOSS OF FIELD W / O LOSS OF FIELD W / O LOSS OF FIELD W / O LOSS OF FIELD

WITH LOSS OF FIELDWITH LOSS OF FIELDWITH LOSS OF FIELDWITH LOSS OF FIELD

• REVERSE POWER REVERSE POWER REVERSE POWER REVERSE POWER

LONG TIME (STAGELONG TIME (STAGELONG TIME (STAGELONG TIME (STAGE----1) 1) 1) 1)

SHORT TIME (STAGESHORT TIME (STAGESHORT TIME (STAGESHORT TIME (STAGE----2) 2) 2) 2)

(OPERATES ONLY AT TT)(OPERATES ONLY AT TT)(OPERATES ONLY AT TT)(OPERATES ONLY AT TT)

Tripping Criteria: Generator – Turbine Unit



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Tripping Criteria: Generator –Turbine Unit


• BACKUP IMPEDANCE BACKUP IMPEDANCE BACKUP IMPEDANCE BACKUP IMPEDANCE

• OVER EXCITATION OVER EXCITATION OVER EXCITATION OVER EXCITATION



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SEL700GSEL700GSEL700GSEL700G

Generating Station Protections:


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Relay Details: SEL700G

• Numerical Generator Protection Relay– Under & Over Voltage Protection

(27/59)

– Negative sequence Protection (46)

– Reverse & Low Forward Power Protection (32)

– Over Excitation Protection (24)

– Over & Under Freq. Protection (81O/81U)

– Under Impedance Protection (21)

– Loss of Excitation Protection (40G)

– 100% Stator E/F Protection (27TN/64G2)

– Rotor E/F Protection by using injection Principal

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Relay Details: SEL700G• Out of Step Protection (78)

• Voltage Restrained O/C Protection (51VR)

• Voltage Controlled O/C Protection (51VC)

• Over Current & E/F Protection (51/51N)

• Automatic Synchronizer Option

• Breaker Failure Protection

• Generator Differential Protection (87D)

• Over all Unit Differential Protection (87GT)

• 95% Stator E/F Protection (59GN/64G1)� Synchrophasor function. ANSI C37.118

message format allows up to 8 current & 8 voltages synchronized measurement

� Metering Parameters � Disturbance Recorder� Export file in COMTRADE format� 16 nos. of configurable LEDs� IEC61850 Station bus compliance� Compact device & less weight

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Generator Protection Scheme: Small Size Machine

G D Y

GTGen Set

333 3 3 3

51O/L51O/L51O/L51O/L

51V51V51V51V

32R & 32L32R & 32L32R & 32L32R & 32L87G87G87G87G

87GT87GT87GT87GT

46464646

YYYY

YYYY

81U/F & 81U/F & 81U/F & 81U/F & O/FO/FO/FO/F

60606060

3

87T87T87T87T

3

59GN59GN59GN59GN

NGT with NGRNGT with NGRNGT with NGRNGT with NGR

51G51G51G51G

3


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Generator Protection Scheme: Direct connected Small Size Machine

G

Gen Set

33 3 3


51V51V51V51V

32R & 32L32R & 32L32R & 32L32R & 32L87G87G87G87G

46464646

YYYY

YYYY

81U/F & O/F81U/F & O/F81U/F & O/F81U/F & O/F

60606060

59GN59GN59GN59GN

NGRNGRNGRNGR

51G51G51G51G

3


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Generator Protection Scheme: Medium Size Machine

G D Y

GTGen Set

333 3 3 351O/L51O/L51O/L51O/L

21212121

32R & 32L32R & 32L32R & 32L32R & 32L87G87G87G87G

87GT87GT87GT87GT

40G40G40G40G

46464646

YYYY

YYYY


27/5927/5927/5927/59

60606060

24242424

3

87T87T87T87T

359GN59GN59GN59GN


51G51G51G51G

3


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Generator Protection Scheme: Large Size Machine

G D Y

GTGen Set

333 3 3 3


21212121

32R & 32L32R & 32L32R & 32L32R & 32L87G87G87G87G

87GT87GT87GT87GT

40G40G40G40G

78787878

46464646

YYYY

YYYY


27/5927/5927/5927/59

60606060

24242424

3

87T87T87T87T

3

27N 27N 27N 27N & & & &

59GN59GN59GN59GN


51G51G51G51G

3


Rotor E/FRotor E/FRotor E/FRotor E/F

30



Front port communication

Push button for Trip/Close

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31



32

SEL700G: IEC61850 Certificate


KEMA Certificate for IEC61850

Protocol compliance

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SEL700G: IEC61850 Certificate


Interoperability Achieved between

ABB, AREVA, SCHNEIDER,

TOSHIBA, SIEMENS, OMICRON

& other devices…

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Protection Protection Protection Protection FunctionsFunctionsFunctionsFunctions

Generator Protection: SEL700G


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�Protection Functions require Protection Functions require Protection Functions require Protection Functions require to to to to set based on Machineset based on Machineset based on Machineset based on Machine & & & & Power system parametersPower system parametersPower system parametersPower system parameters

�Do notDo notDo notDo not follow thumb rule follow thumb rule follow thumb rule follow thumb rule blindly for settings of blindly for settings of blindly for settings of blindly for settings of Protection FunctionsProtection FunctionsProtection FunctionsProtection Functions

Generator Protection: General Terminology


36

Under Impedance Under Impedance Under Impedance Under Impedance Function (21)Function (21)Function (21)Function (21)



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Under Impedance Protection (21)

• Generally Offered as a Backup Protection of Generally Offered as a Backup Protection of Generally Offered as a Backup Protection of Generally Offered as a Backup Protection of MachineMachineMachineMachine

• Conceptually itConceptually itConceptually itConceptually it’’’’s a Impedance relay (i.e. s a Impedance relay (i.e. s a Impedance relay (i.e. s a Impedance relay (i.e. Z = V/IZ = V/IZ = V/IZ = V/I))))

• Easy to coEasy to coEasy to coEasy to co----ordinate with Transmission Line ordinate with Transmission Line ordinate with Transmission Line ordinate with Transmission Line Impedance relaysImpedance relaysImpedance relaysImpedance relays

• Impedance & Time CoImpedance & Time CoImpedance & Time CoImpedance & Time Co----ordination is require to ordination is require to ordination is require to ordination is require to check between Under Impedance & Loss of check between Under Impedance & Loss of check between Under Impedance & Loss of check between Under Impedance & Loss of Excitation functionsExcitation functionsExcitation functionsExcitation functions

• Coordination Concerns:Coordination Concerns:Coordination Concerns:Coordination Concerns: Must be coordinate with Transmission line Protection. Undesired operation for system conditions; especially stressed voltage situations and power swings.

38

Under Impedance Protection (21): (NERC)

• Coordination Concerns:Coordination Concerns:Coordination Concerns:Coordination Concerns: Must be coordinate with Transmission line Protection. Undesired operation for system conditions; especially stressed voltage situations and power swings.

39

Under Impedance Protection (21): (NERC)• Coordination Concerns:Coordination Concerns:Coordination Concerns:Coordination Concerns: Must be coordinate with

Transmission line Protection. Undesired operation for system conditions; especially stressed voltage situations and power swings.

14

40

• Protection measures Impedance (Z=V/I) at the generator end.



41

Impedance Function (21): Relay measures impedance via CT & PT inputs & will trips if impedance falls within pre-determined

characteristics. It is applicable for Line & Generator.


RRRR---- RRRR

XXXX

---- XXXX

ZZZZSetSetSetSet@Ang@Ang@Ang@AngOOOO

ZZZZMeas.Meas.Meas.Meas.@Ang@Ang@Ang@AngOOOO

Relay Stable: ZRelay Stable: ZRelay Stable: ZRelay Stable: ZMeas.Meas.Meas.Meas.>Z>Z>Z>ZSetSetSetSet


42

Impedance Function (21): Relay measures

impedance via CT & PT inputs & will trips if impedance falls within pre-determined characteristics. It is applicable for Line & Generator.


RRRR---- RRRR

XXXX

---- XXXX


ZZZZMeas.Meas.Meas.Meas.@Ang@Ang@Ang@AngOOOO

Relay issue Trip Relay issue Trip Relay issue Trip Relay issue Trip commandcommandcommandcommandZZZZMeas.Meas.Meas.Meas.<Z<Z<Z<ZSetSetSetSet


15

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Under Impedance Protection (21): Setting Criteria

RRRR---- RRRR

XXXX

---- XXXX


Note:Note:Note:Note:XXXXdddd’’’’: Generator Impedance: Generator Impedance: Generator Impedance: Generator ImpedanceZZZZTRTRTRTR: GT impedance: GT impedance: GT impedance: GT impedanceZZZZTLTLTLTL: Transmission Line : Transmission Line : Transmission Line : Transmission Line ImpedanceImpedanceImpedanceImpedance

XXXXdddd’’’’ZZZZTRTRTRTR

ZZZZTLTLTLTL

G D Y

ZZZZTRTRTRTR

ZZZZTLTLTLTL

AngAngAngAng

XXXXdddd’’’’


44

G D Y

GTGen Set

3 3 3

21212121

YYYY

YYYY

3 3

27N 27N 27N 27N & & & &

59GN59GN59GN59GN


51G51G51G51G

3

Under Impedance Protection (21): Circuit

VT Configurations VT Configurations VT Configurations VT Configurations –––– Start/StartStart/StartStart/StartStart/Start


IF

45

G D Y

GTGen Set

3 3 3

21212121

YYYY

YYYY

3 3

27N 27N 27N 27N & & & &

59GN59GN59GN59GN


51G51G51G51G

3

DDDD YYYY

IVT

Note: Interposing VT for Vector Matching


IVT Configurations to compensate 30 deg. Phase shiftIVT Configurations to compensate 30 deg. Phase shiftIVT Configurations to compensate 30 deg. Phase shiftIVT Configurations to compensate 30 deg. Phase shift–––– Delta/StartDelta/StartDelta/StartDelta/Start

YND1YND1YND1YND1


IF

16

46

G D Y

GTGen Set

3 3 3

21212121

YYYY

YYYY

3 327N 27N 27N 27N & & & &

59GN59GN59GN59GN


51G51G51G51G

3

DDDD YYYY

IVT



CT Location on Phase side & Fault in generator CT Location on Phase side & Fault in generator CT Location on Phase side & Fault in generator CT Location on Phase side & Fault in generator wdgwdgwdgwdg

YND1YND1YND1YND1


IF

IF

Example:-1

47


RRRR---- RRRR

XXXX

---- XXXX



XXXXdddd’’’’ZZZZTRTRTRTR

ZZZZTLTLTLTL

G D Y

ZZZZTRTRTRTR

ZZZZTLTLTLTL

AngAngAngAng

XXXXdddd’’’’


Require to set offset impedance in reverse direction also

Example:-1 for wound rotor machine

48

G D Y

GTGen Set

3 3 3

21212121

YYYY

YYYY

3 3

27N 27N 27N 27N & & & &

59GN59GN59GN59GN


51G51G51G51G

3

DDDD YYYY

IVT



YND1YND1YND1YND1


IF

CT Location on Neutral side & Fault in generator CT Location on Neutral side & Fault in generator CT Location on Neutral side & Fault in generator CT Location on Neutral side & Fault in generator wdgwdgwdgwdg

Example:-2

17

49


RRRR---- RRRR

XXXX

---- XXXX


X”d + ZTR + Z+ Z+ Z+ ZTLTLTLTL

AngAngAngAng


Do not Require to set offset impedance in reverse direction also


50


RRRR---- RRRR

XXXX

---- XXXX


Zone2: X”d + ZTR + Z+ Z+ Z+ ZTLTLTLTL

AngAngAngAng




Zone1: X”d + ZTR

51


RRRR---- RRRR

XXXX

---- XXXX

Note:Note:Note:Note:XXXXGGGG’’’’: (: (: (: (XXXX””””dddd + X+ X+ X+ X””””q)/2q)/2q)/2q)/2ZZZZTRTRTRTR: GT impedance: GT impedance: GT impedance: GT impedanceZZZZTLTLTLTL: Transmission Line : Transmission Line : Transmission Line : Transmission Line ImpedanceImpedanceImpedanceImpedance

Zone2: XG + ZTR + Z+ Z+ Z+ ZTLTLTLTL

AngAngAngAng



Example:-2 for salient pole machine

Zone1: XG + ZTR

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52

Generator Protection (SEL700G): Backup Impedance Function (21)


Impedance Function Range

53



Impedance Characteristic with Load Encroachment

54



Select function “DC”

19

55



Zone1 Threshold value

Zone1 Offset

Time Delay of Zone1


Zone2 Offset = 0 ohms

Time Delay of Zone1

56



Z1 & Z2 Circle Characteristic

57




Zone1 Offset

Time Delay of Zone1


Zone2 Offset = 5 Ohms

Time Delay of Zone1

20

58



Offset Mho

59



Relay Trip Logic for Backup Impedance Function

60

Over Excitation Function Over Excitation Function Over Excitation Function Over Excitation Function (24)(24)(24)(24)



21

61

Generator-Transformer Over Fluxing Protection (24)

Rotor Field current increasesRotor Field current increasesRotor Field current increasesRotor Field current increases

Stator current increasesStator current increasesStator current increasesStator current increases

Active Power Constant Active Power Constant Active Power Constant Active Power Constant (MW) due to Constant (MW) due to Constant (MW) due to Constant (MW) due to Constant speed of Turbinespeed of Turbinespeed of Turbinespeed of Turbine

Reactive Power Reactive Power Reactive Power Reactive Power (MVAR) Increases or (MVAR) Increases or (MVAR) Increases or (MVAR) Increases or DecreasesDecreasesDecreasesDecreases

� Generator will Overexcite due to Armature reactionGenerator will Overexcite due to Armature reactionGenerator will Overexcite due to Armature reactionGenerator will Overexcite due to Armature reaction


62


• Causes:Causes:Causes:Causes:

– Generator Regulator ProblemGenerator Regulator ProblemGenerator Regulator ProblemGenerator Regulator Problem

• AVR or Voltage Regulator FailsAVR or Voltage Regulator FailsAVR or Voltage Regulator FailsAVR or Voltage Regulator Fails

• Operating Error during off line manual Operating Error during off line manual Operating Error during off line manual Operating Error during off line manual regulator operationregulator operationregulator operationregulator operation

• Loss of VT supply of AVRLoss of VT supply of AVRLoss of VT supply of AVRLoss of VT supply of AVR

• Speed controller (Governor) fails or not Speed controller (Governor) fails or not Speed controller (Governor) fails or not Speed controller (Governor) fails or not functioning properlyfunctioning properlyfunctioning properlyfunctioning properly

– System ProblemSystem ProblemSystem ProblemSystem Problem

• Unit Load Rejection: Full Load or Unit Load Rejection: Full Load or Unit Load Rejection: Full Load or Unit Load Rejection: Full Load or –––– Partial Partial Partial Partial LoadLoadLoadLoad

• Power System Islanding during Major Power System Islanding during Major Power System Islanding during Major Power System Islanding during Major disturbances in Griddisturbances in Griddisturbances in Griddisturbances in Grid


63


• Excitation current increases to increase flux Excitation current increases to increase flux Excitation current increases to increase flux Excitation current increases to increase flux density. The increased excitation current is density. The increased excitation current is density. The increased excitation current is density. The increased excitation current is made up of higher harmonic. made up of higher harmonic. made up of higher harmonic. made up of higher harmonic.

• The fifth harmonic presence significantly.The fifth harmonic presence significantly.The fifth harmonic presence significantly.The fifth harmonic presence significantly.

Flux density (IEC60034):Flux density (IEC60034):Flux density (IEC60034):Flux density (IEC60034):

• The maximum flux density in any part of the The maximum flux density in any part of the The maximum flux density in any part of the The maximum flux density in any part of the core and yoke at normal voltage and frequency core and yoke at normal voltage and frequency core and yoke at normal voltage and frequency core and yoke at normal voltage and frequency should be such that the flux density in over should be such that the flux density in over should be such that the flux density in over should be such that the flux density in over voltage / flux conditions does not exceed 1.9 voltage / flux conditions does not exceed 1.9 voltage / flux conditions does not exceed 1.9 voltage / flux conditions does not exceed 1.9 Tesla / 19000 lines per cmTesla / 19000 lines per cmTesla / 19000 lines per cmTesla / 19000 lines per cm2222....

Flux = A*Flux = A*Flux = A*Flux = A*BBBBmaxmaxmaxmax


22

64


2222ndndndnd Harmonic components are Harmonic components are Harmonic components are Harmonic components are highhighhighhigh

IIIIARMSARMSARMSARMS = I= I= I= I50HZ50HZ50HZ50HZ + I+ I+ I+ I100HZ 100HZ 100HZ 100HZ + I+ I+ I+ I200Hz200Hz200Hz200Hz

5555thththth Harmonic components are highHarmonic components are highHarmonic components are highHarmonic components are high

IIIIARMSARMSARMSARMS = I= I= I= I50HZ50HZ50HZ50HZ + I+ I+ I+ I250HZ250HZ250HZ250HZ


65


• Fundamental Voltage & Flux relation:Fundamental Voltage & Flux relation:Fundamental Voltage & Flux relation:Fundamental Voltage & Flux relation:

EEEEAVEAVEAVEAVE ==== N*Flux*FrequencyN*Flux*FrequencyN*Flux*FrequencyN*Flux*Frequency

But, Foam Factor (EBut, Foam Factor (EBut, Foam Factor (EBut, Foam Factor (ERMSRMSRMSRMS/E/E/E/EAVEAVEAVEAVE) is 1.11;) is 1.11;) is 1.11;) is 1.11;

EEEERMSRMSRMSRMS ==== 1.11*N*Flux*Frequency1.11*N*Flux*Frequency1.11*N*Flux*Frequency1.11*N*Flux*Frequency

FluxFluxFluxFlux ==== (E(E(E(ERMSRMSRMSRMS) / (1.11*N*Frequency) ) / (1.11*N*Frequency) ) / (1.11*N*Frequency) ) / (1.11*N*Frequency)


66


• Flux = (VFlux = (VFlux = (VFlux = (VNNNN / F/ F/ F/ FNNNN))))------------�� (Volts/Hz)(Volts/Hz)(Volts/Hz)(Volts/Hz)

– Flux increases when System voltage rises at Flux increases when System voltage rises at Flux increases when System voltage rises at Flux increases when System voltage rises at Rated FrequencyRated FrequencyRated FrequencyRated Frequency

– Flux increases when System Frequency fall Flux increases when System Frequency fall Flux increases when System Frequency fall Flux increases when System Frequency fall at Rated Voltageat Rated Voltageat Rated Voltageat Rated Voltage

• Saturation of Magnetic Core of the GT due to Saturation of Magnetic Core of the GT due to Saturation of Magnetic Core of the GT due to Saturation of Magnetic Core of the GT due to exceeded the V/Hz ratiosexceeded the V/Hz ratiosexceeded the V/Hz ratiosexceeded the V/Hz ratios

• 5555thththth Harmonic current generate Negative seq. Harmonic current generate Negative seq. Harmonic current generate Negative seq. Harmonic current generate Negative seq. componentscomponentscomponentscomponents

• Serious Over heating will occur in bolts & Serious Over heating will occur in bolts & Serious Over heating will occur in bolts & Serious Over heating will occur in bolts & support structure of machine which destroys support structure of machine which destroys support structure of machine which destroys support structure of machine which destroys their own insulation as well as coil insulation if their own insulation as well as coil insulation if their own insulation as well as coil insulation if their own insulation as well as coil insulation if the phenomenon persist for longer duration the phenomenon persist for longer duration the phenomenon persist for longer duration the phenomenon persist for longer duration


23

67


Core Heating as a Function of Magnetic fluxCore Heating as a Function of Magnetic fluxCore Heating as a Function of Magnetic fluxCore Heating as a Function of Magnetic flux

Core losses increasesCore losses increasesCore losses increasesCore losses increases


68


Over fluxing withstand Over fluxing withstand Over fluxing withstand Over fluxing withstand curvescurvescurvescurves

69


• Protection measures a Ratio of Voltage to Frequency at the generator terminals.


24

70


• Phase to PhasePhase to PhasePhase to PhasePhase to Phase Voltage Voltage Voltage Voltage Measurement

• VLL = 110V

• FN = 50Hz

• V/Hz set value = 1.1PU

• V/Hz Measured = (VLL Measured in Volt) / (F Measured in Hz)

• V/Hz set value = {(VLL)/(FN)} * {1.1} = (2.2)*(1.1) = 2.422.422.422.42V/HzV/HzV/HzV/Hz


71


• Phase to GroundPhase to GroundPhase to GroundPhase to Ground Voltage Voltage Voltage Voltage Measurement

• VLL = 110/1.7325 = 63.5V

• FN = 50Hz

• V/Hz set value = 1.1PU

• V/Hz Measured = (VLN Measured in Volt) / (F Measured in Hz)

• V/Hz set value = {(VLN)/(FN)} * {1.1} = (1.1)*(1.1) = 1.21 V/Hz1.21 V/Hz1.21 V/Hz1.21 V/Hz


72


• Specific Over Fluxing Protection is Specific Over Fluxing Protection is Specific Over Fluxing Protection is Specific Over Fluxing Protection is not not not not MandatoryMandatoryMandatoryMandatory & It is generally offered as an & It is generally offered as an & It is generally offered as an & It is generally offered as an optional by other Protection like Over Voltage. optional by other Protection like Over Voltage. optional by other Protection like Over Voltage. optional by other Protection like Over Voltage. Protection should be in circuit whenever field Protection should be in circuit whenever field Protection should be in circuit whenever field Protection should be in circuit whenever field CB is closed CB is closed CB is closed CB is closed

• IEEE C50.13 Generator should continuous IEEE C50.13 Generator should continuous IEEE C50.13 Generator should continuous IEEE C50.13 Generator should continuous withstand withstand withstand withstand 105% of rated105% of rated105% of rated105% of rated excitation at full load excitation at full load excitation at full load excitation at full load

• Normally Inverse & DMT type relays are used Normally Inverse & DMT type relays are used Normally Inverse & DMT type relays are used Normally Inverse & DMT type relays are used for application for application for application for application


25

73

• Setting CriteriaSetting CriteriaSetting CriteriaSetting Criteria: Based on : Based on : Based on : Based on Generator V/Hz with stand Generator V/Hz with stand Generator V/Hz with stand Generator V/Hz with stand capability Curvecapability Curvecapability Curvecapability Curve

• Normally, Inverse Characteristic Normally, Inverse Characteristic Normally, Inverse Characteristic Normally, Inverse Characteristic element is used for element is used for element is used for element is used for StageStageStageStage----1111 (1.05 to (1.05 to (1.05 to (1.05 to 1.2 V/Hz for Alarm/Trip for 451.2 V/Hz for Alarm/Trip for 451.2 V/Hz for Alarm/Trip for 451.2 V/Hz for Alarm/Trip for 45----50s)50s)50s)50s)

• Definite Time element is used for Definite Time element is used for Definite Time element is used for Definite Time element is used for StageStageStageStage----2222 for Tripping (1.2 to 1.4 for Tripping (1.2 to 1.4 for Tripping (1.2 to 1.4 for Tripping (1.2 to 1.4 V/Hz for 2s V/Hz for 2s V/Hz for 2s V/Hz for 2s ---- 6s) 6s) 6s) 6s)



74


� IEC60076IEC60076IEC60076IEC60076----1 1 1 1 shows withstand capacity of GT for over shows withstand capacity of GT for over shows withstand capacity of GT for over shows withstand capacity of GT for over voltage shoot up should be 1.4 times for 5svoltage shoot up should be 1.4 times for 5svoltage shoot up should be 1.4 times for 5svoltage shoot up should be 1.4 times for 5s


75


� IS: 2026_1IS: 2026_1IS: 2026_1IS: 2026_1 shows withstand capacity of GT for over shows withstand capacity of GT for over shows withstand capacity of GT for over shows withstand capacity of GT for over voltage shoot up should be 1.4 times for 5svoltage shoot up should be 1.4 times for 5svoltage shoot up should be 1.4 times for 5svoltage shoot up should be 1.4 times for 5s

26

76

Generator Protection (SEL700G): Over Excitation Function (24)


Over Excitation Function Range

77



Select “DD” option for definite time trip

78



Definite time characteristic Mode (DD)

Stage1 Setting Stage2 Setting

27

79



Select “ID” option for Inverse definite time trip

80



Inverse Definite time characteristic Mode (ID)

Stage1 Setting in Definite time mode

Stage2 Setting in Inverse time mode

81



Select “I” option for Inverse time trip

28

82



Select Curve “0.5” option for Inverse time trip

83

Generator Protection SEL700G): Over Excitation Function (24)


Curves “0.5” on various time dial values

84

Generator Protection: Over Excitation Function (24)



29

85




86




87




30

88



Curve “0.5”, “1.0” & “2.0”on time dial value “1.0”

89

GGGG D Y CBCBCBCB

RYRYRYRY YBYBYBYB

Relay (Say; 1.15*VRelay (Say; 1.15*VRelay (Say; 1.15*VRelay (Say; 1.15*VNNNN/F/F/F/FNNNN))))

NGTNGTNGTNGT

Generator-Transformer Over Fluxing Protection (24): Circuit Diagram

86G86G86G86G

RelayRelayRelayRelay----1111

52T52T52T52T

86G86G86G86G----1111

24AX24AX24AX24AX

RelayRelayRelayRelay----2222

24AX24AX24AX24AX----1111

To Inhibit AVR RaiseTo Inhibit AVR RaiseTo Inhibit AVR RaiseTo Inhibit AVR Raise24AX24AX24AX24AX----2222

To Inhibit Manual RaiseTo Inhibit Manual RaiseTo Inhibit Manual RaiseTo Inhibit Manual Raise


90



Relay Trip Logic

31

91

Generator Synchronizing Generator Synchronizing Generator Synchronizing Generator Synchronizing Function (25)Function (25)Function (25)Function (25)



92

Check Synchronizing Function (25): SEL700G


G D Y

GTGen Set

333 3 3 3

YYYY

YYYY

3 3

27N 27N 27N 27N & & & &

59GN59GN59GN59GN


51G51G51G51G

3

Sys

YYYY

YYYY

25

GCB

93



G D Y

GTGen Set

333 3 3 3

YYYY

YYYY

3 3

27N 27N 27N 27N & & & &

59GN59GN59GN59GN


51G51G51G51G

3

Sys

YYYY

YYYY

25

30 deg. Vector compensation

GCB

32

94



G D Y

GTGen Set

333

YYYY

YYYY

3

27N 27N 27N 27N & & & &

59GN59GN59GN59GN


51G51G51G51G

3

Sys25

YYYY

YYYY

GCB

95



G D Y

GTGen Set

333

YYYY

YYYY

3

27N 27N 27N 27N & & & &

59GN59GN59GN59GN


51G51G51G51G

3

Sys25

30 deg. Vector compensation

GCB

YYYY

YYYY

96



G D Y

Gen Set1

333

YYYY

YYYY

3

25

YYYY

YYYY

GCB1

G

Gen Set2

333 3

GCB2

BC

D Y

D Y

D Y

33

97

Check Synchronizing Function (25): SEL700G (Connection Diagram)


98



Voltage difference (DV) setting

Slip frequency (DF) setting

Angle difference (DØ) setting

Advance CB closing angle setting

Vector Compensation setting

99



34

100



101

Generator Auto Generator Auto Generator Auto Generator Auto Synchronizing Function Synchronizing Function Synchronizing Function Synchronizing Function

(25)(25)(25)(25)



102

Auto Synchronizing Function (25): SEL700G


G D Y

GTGen Set

333 3 3 3

YYYY

YYYY

3 3

27N 27N 27N 27N & & & &

59GN59GN59GN59GN


51G51G51G51G

3

Sys

YYYY

YYYY

25

GCB

STG Speed Controller

Frequency – Raise/Low

RPM-Increase/Decrease

35

103



Steam flow control through Mechanical Governor

104



Steam flow control through Hydraulic Governor

105



Frequency ramp rate in Hz/s

Pulse Interval in s

Function ON

36

106



Freq pulse output

0

0.2

0.4

0.6

0.8

1

1.2

0 2 4 6 8 10 12

Time in s

Pulse width Pulse width Pulse width

Pulse interval Pulse interval

107



G D Y

GTGen Set

333 3 3 3

YYYY

YYYY

3 3

27N 27N 27N 27N & & & &

59GN59GN59GN59GN


51G51G51G51G

3

Sys

YYYY

YYYY

25

GCB

AVR Controller

Voltage – Raise/Low

Field voltage Increase/Decrease

E

108



Voltage ramp rate in Volt/s

Pulse Interval in s

37

109



Voltage pulse output

0

0.2

0.4

0.6

0.8

1

1.2

0 2 4 6 8 10 12

Time in s

Pulse width Pulse width Pulse width

Pulse interval Pulse interval

110

Under Voltage Function (27)Under Voltage Function (27)Under Voltage Function (27)Under Voltage Function (27)



111

Under Voltage Protection (27):

• Typically Provides Typically Provides Typically Provides Typically Provides alarm and supervision for other alarm and supervision for other alarm and supervision for other alarm and supervision for other protection using generator terminal voltage. protection using generator terminal voltage. protection using generator terminal voltage. protection using generator terminal voltage. Rarely used to trip the generator directly.Rarely used to trip the generator directly.Rarely used to trip the generator directly.Rarely used to trip the generator directly.

• Provides detection of low voltage that may result Provides detection of low voltage that may result Provides detection of low voltage that may result Provides detection of low voltage that may result in reduction in stability limit, excessive reactive in reduction in stability limit, excessive reactive in reduction in stability limit, excessive reactive in reduction in stability limit, excessive reactive power drawn from the system, and malfunction of power drawn from the system, and malfunction of power drawn from the system, and malfunction of power drawn from the system, and malfunction of voltage sensitive devices and equipment.voltage sensitive devices and equipment.voltage sensitive devices and equipment.voltage sensitive devices and equipment.

• GeneratorGeneratorGeneratorGenerator----Turbine Auxiliaries are effected by low Turbine Auxiliaries are effected by low Turbine Auxiliaries are effected by low Turbine Auxiliaries are effected by low voltagevoltagevoltagevoltage– Motor Tripping (BFP, CWP etc.) on Low voltage Motor Tripping (BFP, CWP etc.) on Low voltage Motor Tripping (BFP, CWP etc.) on Low voltage Motor Tripping (BFP, CWP etc.) on Low voltage

can Shutdown Machine can Shutdown Machine can Shutdown Machine can Shutdown Machine • Coordination Concerns:Coordination Concerns:Coordination Concerns:Coordination Concerns: Coordinate with any Coordinate with any Coordinate with any Coordinate with any

system undersystem undersystem undersystem under----voltage protection, system fault voltage protection, system fault voltage protection, system fault voltage protection, system fault conditions, and stressed system voltage situations conditions, and stressed system voltage situations conditions, and stressed system voltage situations conditions, and stressed system voltage situations for which the system is designed to survive.for which the system is designed to survive.for which the system is designed to survive.for which the system is designed to survive.


38

112

• Protection measures Voltage at the generator terminals.

Under Voltage Protection (27)


113

Under Voltage Protection (27)

• Normally, Inverse Characteristic Normally, Inverse Characteristic Normally, Inverse Characteristic Normally, Inverse Characteristic element is used for element is used for element is used for element is used for StageStageStageStage----1 1 1 1 for for for for Alarm/delayed Trip (Say: 80% to 70% Alarm/delayed Trip (Say: 80% to 70% Alarm/delayed Trip (Say: 80% to 70% Alarm/delayed Trip (Say: 80% to 70% of Un for 5s to 10s)of Un for 5s to 10s)of Un for 5s to 10s)of Un for 5s to 10s)

• Definite Time / Instantaneous element Definite Time / Instantaneous element Definite Time / Instantaneous element Definite Time / Instantaneous element is used for is used for is used for is used for StageStageStageStage----2222 for Tripping (30% for Tripping (30% for Tripping (30% for Tripping (30% to 25% for Inst. / 500ms ). to 25% for Inst. / 500ms ). to 25% for Inst. / 500ms ). to 25% for Inst. / 500ms ).


114

Generator Protection (SEL700G): Under Voltage Function (27)


Under Voltage Function Range

39

115

Generator Protection (SEL700G): Under Voltage Function (27)


Under Voltage Tripping Logic

116

Under Voltage Protection (27): SEL700G


Stage1 Settings Under VStage1 Settings Under VStage1 Settings Under VStage1 Settings Under VLNLNLNLN

Stage1 Settings Under VStage1 Settings Under VStage1 Settings Under VStage1 Settings Under VLLLLLLLL

Stage2 Settings Under VStage2 Settings Under VStage2 Settings Under VStage2 Settings Under VLNLNLNLN

Stage2 Settings Under VStage2 Settings Under VStage2 Settings Under VStage2 Settings Under VLLLLLLLL

117

Under Voltage Protection (27): Generator Auxiliary Power Systems

• PPPProtection rotection rotection rotection measures auxiliary system voltage.

• Provides Provides Provides Provides alarming or tripping, automatic transfer to backup supply, starting emergency generation.

• Coordination Concerns:Coordination Concerns:Coordination Concerns:Coordination Concerns: Coordinate with

– Any system under-voltage protection,

– System fault conditions and stressed system voltage situations for which the system is designed to survive.


40

118

Reverse Power (Reverse Power (Reverse Power (Reverse Power (ActiveActiveActiveActive) Protection ) Protection ) Protection ) Protection (32R)(32R)(32R)(32R)



119

What is Reverse Power???What is Reverse Power???What is Reverse Power???What is Reverse Power???



120

MW

MVARMVARMVARMVAR

----MVARMVARMVARMVAR

-MW

DDDD YYYYGGGG

MVARMVARMVARMVAR

MWMWMWMW

Reverse Active Power Protection (32R)

Relay setting ThresholdRelay setting ThresholdRelay setting ThresholdRelay setting Threshold

FFFFMachineMachineMachineMachine < F< F< F< FSystemSystemSystemSystem

Machine Act as a Synchronous MotorMachine Act as a Synchronous MotorMachine Act as a Synchronous MotorMachine Act as a Synchronous Motor


41

121

MW

MVARMVARMVARMVAR


-MW

DDDD YYYYGGGG

MVARMVARMVARMVAR

MWMWMWMW



VVVVMachine Machine Machine Machine < V< V< V< VSystemSystemSystemSystem


Machine Act as a Induction MotorMachine Act as a Induction MotorMachine Act as a Induction MotorMachine Act as a Induction Motor


122

• Causes:Causes:Causes:Causes:

– Two or more machines are Two or more machines are Two or more machines are Two or more machines are running running running running in parallel & Primein parallel & Primein parallel & Primein parallel & Prime----movermovermovermover of one of of one of of one of of one of the machine fails. Turbine has the machine fails. Turbine has the machine fails. Turbine has the machine fails. Turbine has Problems; exhaust hood Problems; exhaust hood Problems; exhaust hood Problems; exhaust hood temperature on steam turbinestemperature on steam turbinestemperature on steam turbinestemperature on steam turbines

– Sometimes the condition appear Sometimes the condition appear Sometimes the condition appear Sometimes the condition appear during synchronizationduring synchronizationduring synchronizationduring synchronization of machine, of machine, of machine, of machine, if incoming machine frequency is if incoming machine frequency is if incoming machine frequency is if incoming machine frequency is lesser than bus frequency lesser than bus frequency lesser than bus frequency lesser than bus frequency



123


Fails

Fails


42

124

Reverse Active Power Protection (32R): Example1

G D Y

GT

GCB

Gen Set

G D Y

GT

GCB

Gen Set

CB1

CB2

CB3

CB4

CB

5

TL Line

TL Line

MW

MW

Healthy Prime-mover

Failed Prime-mover

MVAR

MVAR

E

E


125


G D Y

GT

GCB

Gen Set

G D Y

GT

GCB

Gen Set

CB1

CB2

CB3

CB4

CB

5

TL Line

TL Line

MW

MW

Healthy Prime-mover

Failed Prime-mover

MVAR

MVAR

E

E


126


G D Y

GT

GCB

Gen Set

CB1 CB3

CB

5

TL Line

MW

Failed Prime-mover

MVAR

E

Active Power Import from Grid sourcesActive Power Import from Grid sourcesActive Power Import from Grid sourcesActive Power Import from Grid sources

GridGridGridGrid

GridGridGridGridMW

MW

MW


43

127


G

D Y

TR1

GCB

Gen Set

Failed Prime-mover

MVAR

E

Only Reactive Power Export to LoadsOnly Reactive Power Export to LoadsOnly Reactive Power Export to LoadsOnly Reactive Power Export to Loads

CB1CB1CB1CB1 CB2CB2CB2CB2

D Y

TR2

CB3CB3CB3CB3 CB4CB4CB4CB4

MMMM

CB

5C

B5

CB

5C

B5

CB6CB6CB6CB6

Loads

Loads

Loads

Loads

Loads

Loads

Loads

Loads


128

• Protection against the Protection against the Protection against the Protection against the motoring actionmotoring actionmotoring actionmotoring action of of of of the generator while the generator looses the generator while the generator looses the generator while the generator looses the generator while the generator looses itititit’’’’s Primes Primes Primes Prime----mover inputmover inputmover inputmover input

• Protection is applied for Protection is applied for Protection is applied for Protection is applied for PrimePrimePrimePrime----movermovermovermover

• Normally, Protection is applied only when Normally, Protection is applied only when Normally, Protection is applied only when Normally, Protection is applied only when machines are operating in parallel with machines are operating in parallel with machines are operating in parallel with machines are operating in parallel with each other as well as Power Grideach other as well as Power Grideach other as well as Power Grideach other as well as Power Grid

• Generator unaffected by reverse power, Generator unaffected by reverse power, Generator unaffected by reverse power, Generator unaffected by reverse power, but act as a but act as a but act as a but act as a Synchronous MotorSynchronous MotorSynchronous MotorSynchronous Motor(Exporting Reactive Power & Importing (Exporting Reactive Power & Importing (Exporting Reactive Power & Importing (Exporting Reactive Power & Importing Active Power) as long as field on Active Power) as long as field on Active Power) as long as field on Active Power) as long as field on



129

• Effect:Effect:Effect:Effect:

– Steam Turbine:Steam Turbine:Steam Turbine:Steam Turbine:----

• Steam turbine tends to overheat, when Steam turbine tends to overheat, when Steam turbine tends to overheat, when Steam turbine tends to overheat, when steam supply is cut off and the turbine still steam supply is cut off and the turbine still steam supply is cut off and the turbine still steam supply is cut off and the turbine still rotates as the generator runs as motor. rotates as the generator runs as motor. rotates as the generator runs as motor. rotates as the generator runs as motor. Steam turbine, act as a pump and the Steam turbine, act as a pump and the Steam turbine, act as a pump and the Steam turbine, act as a pump and the steam is trapped. The turbulence losses in steam is trapped. The turbulence losses in steam is trapped. The turbulence losses in steam is trapped. The turbulence losses in the trapped steam may then built up a high the trapped steam may then built up a high the trapped steam may then built up a high the trapped steam may then built up a high temperature in lowtemperature in lowtemperature in lowtemperature in low----pressure stage. pressure stage. pressure stage. pressure stage. Hence, the turbine blades are overheated Hence, the turbine blades are overheated Hence, the turbine blades are overheated Hence, the turbine blades are overheated due to due to due to due to windagewindagewindagewindage or air friction. However, or air friction. However, or air friction. However, or air friction. However, the heat caused by turbulence of the the heat caused by turbulence of the the heat caused by turbulence of the the heat caused by turbulence of the trapped steam can detrapped steam can detrapped steam can detrapped steam can de----temper turbine temper turbine temper turbine temper turbine runner. runner. runner. runner.



44

130

• Effect:Effect:Effect:Effect:

– Hydro Turbine:Hydro Turbine:Hydro Turbine:Hydro Turbine:----

• In case of hydro turbine, the flow of water In case of hydro turbine, the flow of water In case of hydro turbine, the flow of water In case of hydro turbine, the flow of water starts reducing or complete cut off and starts reducing or complete cut off and starts reducing or complete cut off and starts reducing or complete cut off and hence bubbles are formed causing hence bubbles are formed causing hence bubbles are formed causing hence bubbles are formed causing cavitations in the turbine resulting to cavitations in the turbine resulting to cavitations in the turbine resulting to cavitations in the turbine resulting to damage turbine runner.damage turbine runner.damage turbine runner.damage turbine runner.

– Diesel Engine:Diesel Engine:Diesel Engine:Diesel Engine:----

• In case of diesel driven set, loss of motive In case of diesel driven set, loss of motive In case of diesel driven set, loss of motive In case of diesel driven set, loss of motive power is likely to be cause by some power is likely to be cause by some power is likely to be cause by some power is likely to be cause by some mechanical failure, such as bearing over mechanical failure, such as bearing over mechanical failure, such as bearing over mechanical failure, such as bearing over heating leading to closure of fuel valves, heating leading to closure of fuel valves, heating leading to closure of fuel valves, heating leading to closure of fuel valves, and continued running is likely to cause and continued running is likely to cause and continued running is likely to cause and continued running is likely to cause several damages in engine.several damages in engine.several damages in engine.several damages in engine.



131

Reverse Power Active Protection (32R): Allowable limit

1% to 3% of rated power1% to 3% of rated power1% to 3% of rated power1% to 3% of rated powerHydro turbine

0.5% to 7.5% of rated power0.5% to 7.5% of rated power0.5% to 7.5% of rated power0.5% to 7.5% of rated powerSteam turbine

10% to 15% of rated power10% to 15% of rated power10% to 15% of rated power10% to 15% of rated powerGas turbine (Double shaft)

100% of rated powerGas turbine (Single shaft)

15% of rated powerDiesel (Four cycle-4

25% of rated powerDiesel (Two cycle-2 stroke) stroke)

Allowable limit of %P of Reverse Power

Prime Mover


132

• Protection measures Reverse Power (-PRW)at the generator end.



45

133


G D Y

GT

GCB

Gen Set

MW

Failed Prime-mover

MVAR

EYYYY

YYYY

3

32R32R32R32R

PPPPSet Set Set Set = 1.7325*V= 1.7325*V= 1.7325*V= 1.7325*VLLLLLLLL*I*I*I*ILLLL****COSphiCOSphiCOSphiCOSphiOperate: Operate: Operate: Operate: ----PPPPMeasureMeasureMeasureMeasure > > > > ----PPPPSetSetSetSet

SysSysSysSys

MVARMW


134

• Setting Criteria:Setting Criteria:Setting Criteria:Setting Criteria: As the overheating of the As the overheating of the As the overheating of the As the overheating of the turbine blade does not occur instantaneously turbine blade does not occur instantaneously turbine blade does not occur instantaneously turbine blade does not occur instantaneously while the generator starts motoring, so it is not while the generator starts motoring, so it is not while the generator starts motoring, so it is not while the generator starts motoring, so it is not required to trip instantaneously. required to trip instantaneously. required to trip instantaneously. required to trip instantaneously.

– Set Point 1:Set Point 1:Set Point 1:Set Point 1:

• ----P<0.5% for Steam Turbine GeneratorP<0.5% for Steam Turbine GeneratorP<0.5% for Steam Turbine GeneratorP<0.5% for Steam Turbine Generator

• Operating Time 10sOperating Time 10sOperating Time 10sOperating Time 10s

– Set Point 2:Set Point 2:Set Point 2:Set Point 2:

• ----P<0.5% for Steam Turbine GeneratorP<0.5% for Steam Turbine GeneratorP<0.5% for Steam Turbine GeneratorP<0.5% for Steam Turbine Generator


• Class1 CT can use for Accurate PowerClass1 CT can use for Accurate PowerClass1 CT can use for Accurate PowerClass1 CT can use for Accurate Powermeasurement for Reverse Power operationmeasurement for Reverse Power operationmeasurement for Reverse Power operationmeasurement for Reverse Power operation



135

• Reverse Power is Three Balanced Reverse Power is Three Balanced Reverse Power is Three Balanced Reverse Power is Three Balanced Phenomena so Phenomena so Phenomena so Phenomena so single phase single phase single phase single phase measurement can be Adequatemeasurement can be Adequatemeasurement can be Adequatemeasurement can be Adequate

• Three Phase measurement Three Phase measurement Three Phase measurement Three Phase measurement preferred preferred preferred preferred to watch power phenomenon in each to watch power phenomenon in each to watch power phenomenon in each to watch power phenomenon in each phase.phase.phase.phase.

• Connect current coil/circuit of relay Connect current coil/circuit of relay Connect current coil/circuit of relay Connect current coil/circuit of relay through Metering core of CT to get through Metering core of CT to get through Metering core of CT to get through Metering core of CT to get accurate measurementaccurate measurementaccurate measurementaccurate measurement of Power (i.e. of Power (i.e. of Power (i.e. of Power (i.e. CL1.5, CL1.0 etc.). CL1.5, CL1.0 etc.). CL1.5, CL1.0 etc.). CL1.5, CL1.0 etc.).



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• Directional Power relay will work effectively Directional Power relay will work effectively Directional Power relay will work effectively Directional Power relay will work effectively for larger machine. for larger machine. for larger machine. for larger machine. Power setting is Power setting is Power setting is Power setting is constantconstantconstantconstant


MWMWMWMW---- MWMWMWMW

MVARMVARMVARMVAR

---- MVARMVARMVARMVAR

Opera

ting R

egio

nO

pera

ting R

egio

nO

pera

ting R

egio

nO

pera

ting R

egio

n

---- PPPPSet Set Set Set >>>>


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• Calculation:Calculation:Calculation:Calculation:– MVA = 588MVAMVA = 588MVAMVA = 588MVAMVA = 588MVA

– MW = 500MWMW = 500MWMW = 500MWMW = 500MW

– PF = 0.85PF = 0.85PF = 0.85PF = 0.85

– KV = 21KVKV = 21KVKV = 21KVKV = 21KV

– %P%P%P%PSetSetSetSet = 0.5% of P= 0.5% of P= 0.5% of P= 0.5% of PNGNGNGNG

– IIIIFLCFLCFLCFLC = 16.2kA= 16.2kA= 16.2kA= 16.2kA

– CTR = 20000/5ACTR = 20000/5ACTR = 20000/5ACTR = 20000/5A

– PTR = 21/0.11kVPTR = 21/0.11kVPTR = 21/0.11kVPTR = 21/0.11kV



138

• Calculation:Calculation:Calculation:Calculation:

– PPPPRWPRWPRWPRWP = {(0.5)/100}*{500} = 2.5MW at primary side= {(0.5)/100}*{500} = 2.5MW at primary side= {(0.5)/100}*{500} = 2.5MW at primary side= {(0.5)/100}*{500} = 2.5MW at primary side

– IIIIRWPRWPRWPRWP = {(2.5)*(10= {(2.5)*(10= {(2.5)*(10= {(2.5)*(103333)}/{(1.7235)*(21)*(0.85)})}/{(1.7235)*(21)*(0.85)})}/{(1.7235)*(21)*(0.85)})}/{(1.7235)*(21)*(0.85)}

= 81A at primary side= 81A at primary side= 81A at primary side= 81A at primary side

– IIIIPWSPWSPWSPWS = (81)/(4000) = 0.02A at secondary side= (81)/(4000) = 0.02A at secondary side= (81)/(4000) = 0.02A at secondary side= (81)/(4000) = 0.02A at secondary side

– PPPPNSNSNSNS = (1.7325)*(110)*(5) = 952.87watts at secondary= (1.7325)*(110)*(5) = 952.87watts at secondary= (1.7325)*(110)*(5) = 952.87watts at secondary= (1.7325)*(110)*(5) = 952.87watts at secondary

– PPPPRWSRWSRWSRWS = (1.7325)*(110)*(0.02) = 3.8115watts= (1.7325)*(110)*(0.02) = 3.8115watts= (1.7325)*(110)*(0.02) = 3.8115watts= (1.7325)*(110)*(0.02) = 3.8115watts

– %P%P%P%PSetSetSetSet based on CT sec = (3.81) / (952.87) = 0.4%based on CT sec = (3.81) / (952.87) = 0.4%based on CT sec = (3.81) / (952.87) = 0.4%based on CT sec = (3.81) / (952.87) = 0.4%

– Setting is 0.4% of PSetting is 0.4% of PSetting is 0.4% of PSetting is 0.4% of PNSNSNSNS

– Where; PWhere; PWhere; PWhere; PNGNGNGNG = Rated Power of Machine= Rated Power of Machine= Rated Power of Machine= Rated Power of Machine

PPPPNSNSNSNS = Rated Power based on CT rating= Rated Power based on CT rating= Rated Power based on CT rating= Rated Power based on CT rating



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139

• Sequential Tripping:Sequential Tripping:Sequential Tripping:Sequential Tripping:

– In Sequential Tripping Mode; Turbine In Sequential Tripping Mode; Turbine In Sequential Tripping Mode; Turbine In Sequential Tripping Mode; Turbine Valves are tripped First Valves are tripped First Valves are tripped First Valves are tripped First

– Used on Steam Turbine Generator to Used on Steam Turbine Generator to Used on Steam Turbine Generator to Used on Steam Turbine Generator to Prevent OverspeedPrevent OverspeedPrevent OverspeedPrevent Overspeed

– This trip mode only used for This trip mode only used for This trip mode only used for This trip mode only used for boiler/reactor or turbine mechanical boiler/reactor or turbine mechanical boiler/reactor or turbine mechanical boiler/reactor or turbine mechanical problemsproblemsproblemsproblems

– This trip mode primarily used for steam This trip mode primarily used for steam This trip mode primarily used for steam This trip mode primarily used for steam turbineturbineturbineturbine



140

• Sequential Tripping:Sequential Tripping:Sequential Tripping:Sequential Tripping:– Step 1:Step 1:Step 1:Step 1:

• Abnormal Turbine/Boiler/Reactor condition is Abnormal Turbine/Boiler/Reactor condition is Abnormal Turbine/Boiler/Reactor condition is Abnormal Turbine/Boiler/Reactor condition is detecteddetecteddetecteddetected

– Step 2:Step 2:Step 2:Step 2:• Turbine Valves closed; Generator allowed to Turbine Valves closed; Generator allowed to Turbine Valves closed; Generator allowed to Turbine Valves closed; Generator allowed to

briefly briefly briefly briefly ““““MotorMotorMotorMotor”””” (i.e. Importing Active Power (i.e. Importing Active Power (i.e. Importing Active Power (i.e. Importing Active Power from Grid)from Grid)from Grid)from Grid)

– Step 3:Step 3:Step 3:Step 3:• A Reverse Power relay in Series with Turbine A Reverse Power relay in Series with Turbine A Reverse Power relay in Series with Turbine A Reverse Power relay in Series with Turbine

Valves position switches confirms all Valves Valves position switches confirms all Valves Valves position switches confirms all Valves Valves position switches confirms all Valves have closedhave closedhave closedhave closed



141

• Sequential Tripping:Sequential Tripping:Sequential Tripping:Sequential Tripping:

– Step 4:Step 4:Step 4:Step 4:• Generator is required to Isolate from Generator is required to Isolate from Generator is required to Isolate from Generator is required to Isolate from

Power SystemPower SystemPower SystemPower System

– ConsiderConsiderConsiderConsider

• Export High MVARsExport High MVARsExport High MVARsExport High MVARs

• Import Low MWImport Low MWImport Low MWImport Low MW


GGGGMWMWMWMW

DDDD YYYY

MVARsMVARsMVARsMVARsGCBGCBGCBGCB


48

142

Generator Protection (SEL700G): Power Function Function (32)


Power Function Range

143

Reverse Active Power Protection (32R): SEL700G


Stage1 SettingsStage1 SettingsStage1 SettingsStage1 Settings


144

Reverse Power (Reactive) Protection Reverse Power (Reactive) Protection Reverse Power (Reactive) Protection Reverse Power (Reactive) Protection (32R)(32R)(32R)(32R)



49

145

MW

MVARMVARMVARMVAR


-MW

DDDD YYYYGGGG

MVARMVARMVARMVAR

MWMWMWMW

Reverse Reactive Power Protection (32R)


VVVVMachine Machine Machine Machine < V< V< V< VSystemSystemSystemSystem


Machine Act as a Induction MotorMachine Act as a Induction MotorMachine Act as a Induction MotorMachine Act as a Induction Motor


146

Reverse Reactive Power Protection (32R): SEL700G




147

Low forward Power (Active) Low forward Power (Active) Low forward Power (Active) Low forward Power (Active) Protection (32L)Protection (32L)Protection (32L)Protection (32L)



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148

What is Low forward Power???What is Low forward Power???What is Low forward Power???What is Low forward Power???



149

MW

MVARMVARMVARMVAR


-MW

DDDD YYYYGGGG

MVARMVARMVARMVAR

MWMWMWMW

Low Forward Active Power Protection (32L)



150

MW

MVARMVARMVARMVAR


-MW

DDDD YYYYGGGG

MVARMVARMVARMVAR

MWMWMWMW




51

151

MW

MVARMVARMVARMVAR


-MW

DDDD YYYYGGGG

MVARMVARMVARMVAR

MWMWMWMW




152

• Protection measures Low forward Power (PFW) at the generator end.

Low forward Active Power Protection (32L)


153

G D Y

GT

GCB

Gen Set

MW

Less Load or during shutdown

MVAR

EYYYY

YYYY

3

32L32L32L32L

PPPPSetSetSetSet = 1.7325*V= 1.7325*V= 1.7325*V= 1.7325*VLLLLLLLL*I*I*I*ILLLL****COSphiCOSphiCOSphiCOSphiOperate: POperate: POperate: POperate: PMeasureMeasureMeasureMeasure > P> P> P> PSetSetSetSet

SysSysSysSys

MVARMW

Low forward Active Power Protection (32L)


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154

Generator Protection (SEL700G): Power Function Function (32)


Power Function Range

155

Low forward Active Power Protection (32L): SEL700G




156

• Setting Criteria:Setting Criteria:Setting Criteria:Setting Criteria:

– Set Point 1:Set Point 1:Set Point 1:Set Point 1:• ----P<5% for Steam Turbine GeneratorP<5% for Steam Turbine GeneratorP<5% for Steam Turbine GeneratorP<5% for Steam Turbine Generator


– Set Point 2:Set Point 2:Set Point 2:Set Point 2:• ----P<0.5% for Steam Turbine GeneratorP<0.5% for Steam Turbine GeneratorP<0.5% for Steam Turbine GeneratorP<0.5% for Steam Turbine Generator


• Class1 CT can useClass1 CT can useClass1 CT can useClass1 CT can use for Accurate Power for Accurate Power for Accurate Power for Accurate Power measurement for Reverse Power operationmeasurement for Reverse Power operationmeasurement for Reverse Power operationmeasurement for Reverse Power operation

Low forward Power Protection (32L)


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157

Power Protection (32L): SEL700G


Select number of stages (Max. 4 nos.)Select number of stages (Max. 4 nos.)Select number of stages (Max. 4 nos.)Select number of stages (Max. 4 nos.)

Two stages can be used for Reverse Two stages can be used for Reverse Two stages can be used for Reverse Two stages can be used for Reverse Power (Active) ProtectionsPower (Active) ProtectionsPower (Active) ProtectionsPower (Active) Protections

Two stages can be used for Two stages can be used for Two stages can be used for Two stages can be used for LowforwardLowforwardLowforwardLowforward Power (Active) Power (Active) Power (Active) Power (Active) ProtectionsProtectionsProtectionsProtections

158

•Ask Q???Ask Q???Ask Q???Ask [email protected][email protected][email protected][email protected]

SCHWEITZER ENGINEERING LABORATORIES


sel700g part 2

Documents

current based protection

phase currents

phase voltages

resistance r

dzdt pole

principalmeasuring principals

engineering laboratories