steam to electricity

STEAM TO ELECTRICITY

K.KRISHNAMOORTHYAEE/TECHNICAL SERVICES

MTPS

IS / ISO 9001:2008CERTIFIED POWER PLANT

Unit 1: 227daysUnit 2: 205daysUnit3: 272daysUnit4: 311daysStation: 71days

IS / ISO 9001:2008• Quality Policy: -Uninterrupted quality power to TNEB grid-Minimizing forced & planned outages-Quality excellence in all our activities Quality Objective:-Annual generation:>6500mu-Plant load factor :>88%-Aux. power consumption:>8.5%-Specific oil consumption :<1.25ml

THERMAL GENERATION

April 19, 2023 4

Fuel is fired in Boiler and

Super heatedsteam

Is produced

Energy in SH Steam from

Boiler is usedfor achieving

Rotational energyIn the Turbine.

Generator connected withTurbine rotatesand produces

Electricity.

Voltage is stepped up

Auxiliary Utility

(6.6KV & 415V)

Connected to Grid(110, 230, 400 & 785KV)

What is ‘Turbine’?

• Turbine is the prime mover for the Generator• It is a rotating machine.• Thermal energy is converted into rotational

energy by means of blades of Impulse and Reaction.

• This rotational energy is used in Generator to generate power

• LMW- Leningrade machine works, Russian deign,supplied by BHEL

HPT IPT LPT ~

Re heaterCondenser

Steam from FSH 130 ksc

Generator

CRH 26 kscHRH 24 ksc

1 ksc

Vacuum- 670mm Hg

CONDENSER VACUUM

TURBINE

HP TURBINE IP TURBINE LP TURBINES

HIGH PRESSURE TURBINE

• Impulse Reaction Turbine• No of stages :12(1+11)• Shaft out put:65MW• Inlet/outlet Steam flow :630/590 t/hr• Inlet/outlet Steam temp : 535/330 deg• Inlet/outlet Steam pr. : 130/26 ksc

HP ROTOR & CASING

INTERMEDIATE PRESSURE TURBINE

• Reaction Turbine• No of stages :11• Shaft out put:105MW• Inlet/outlet Steam flow :540/461 t/hr• Inlet/outlet Steam temp : 535/190 deg• Inlet/outlet Steam pr. : 24/1.32 ksc

LOW PRESSURE TURBINE

• No of stages :8(4+4)• Shaft out put:40MW• Inlet/outlet Steam flow :461/446 t/hr• Inlet/outlet Steam temp : 190/45 deg• Inlet/outlet Steam pr. : 1.32/0.06 ksc

The Main Equipments of Turbine

• 1. Main Turbine.• 2. Oil system.• 3. Condenser• 4. Cooling water system.• 5. Hot well & Condensate system • 6. HP Heaters & LP Heaters• 7. Feed Water system

OIL SYSTEM

• Supplies oil for lubricating all bearings in TG set(1ksc)

• Supplies oil for governing system(20ksc)• Generator seal oil system(10ksc)

COOLING WATER SYSTEM

• The clarified water used for condenser cooling and other coolers such as TLOC, seal oil cooler, stator water cooler, hydrogen gas cooler.

• To condense the LPT exhaust steam in the condenser and to create vacuum in it.

COMPRESED AIR SYSTEM

• Instrument Air: operation of pneumatic valves, BFP scoop, burner tilt, SADC, PA fan inlet damper operation, generator slip ring cleaning

• Service Air: Air pre heater air motor, LDO atomization, sky climber.

AIR EVACUATION SYSTEM

• Creates a vacuum in the condenser before the steam admission, evacuate air and non condensable gases during normal operation

• Starting Ejector: used to create vacuum during starting

• Main Ejector: Extracts non condensing gases from condenser and Regenerative heaters

HP LP B/P SYSTEM(30%)

• During startup of the unit, to raise the steam parameters and to match it with Turbine parameters.

• Bypass system is required to bypass the steam w/o entering the HPT from MSL to CRH and IPT from HRH to Condenser.

CONDENSATE SYSYEM

• The steam from the exhaust of the LPT, condenses into water and hence it is called as condensate

• Condensate water collected in the hotwell, at the bottom of the condenser

• CEP, Main Ejector, GSC1, LPH1, GSC2, LPH2,3,4 and Deaerator.

DEAERATOR

• Removes dissolved oxygen, from condensate water.

• To prevent internal corrosion of boiler tubes.

FEED WATER SYSTEM

• Feed water stored in the feed water storage tank (located at the bottom of the deaerator) is pumped th’ BFP, to boiler drum th’ HPH5,6 7 economiser.

• Re generative heaters: steam extracted from the Turbine is used to heat the feed water, flows th’ the spirals tube of the heaters

HEAT TRANSFER

1. CONDUCTION

2. RADIATION

3. CONVECTION

CONDUCTION

CONDUCTION IS THE TRANSFER OF HEAT FROM ONE PART OF THE MATERIAL TO ANOTHER OR ONE MATERIAL TO ANOTHER WHICH ARE IN CONTACT.

RADIATION

THE TRANSFER OF HEAT FROM THE HOT BODY TO THE COLD ONE BY MEANS OF ELECTROMAGNETIC HEAT WAVES OR RAYS WITHOUT HEATING THE MEDIUM THROUGH WHICH IT PASSES BETWEEN THE TWO BODIES INVOLVED.

CONVECTION

HEAT TRAVELS FROM ONE PARTICLE OF THE BODY TO ANOTHER PARTICLE BY ACTUAL MOTION OF HEATED PARTICLES DUE TO DIFFERENCE IN DENSITY.

TURBINE PROTECTIONS

1. CONDENSER VACUUM VERY LOW

2. LUBE OIL PRESSURE VERY LOW

3. AXIAL SHIFT HIGH

4. GENERATOR TO TURBINE THRO’ 86T

5. BOILER TO TURBINE THRO’ MFT

GENERATOR

• Voltage: 15.75 KV• Capacity: 210MW• Coolant: ROTOR- Hydrogen gas STATOR-DM WATER

GENERATOR DESCRIPTION : T H W 210 2 T TURBO GENERATOR

H H2 COOLED STATOR & ROTOR

W WATER COOLED STATOR

210 ACTIVE POWER

211 POLE

Capacity : 210 MW (247 MVA)Stator Voltage : 15.75 KVStator Current : 9050 Amps.Rotor Voltage :310 Volts.Rotor Current : 2600 Amps.

STATOR & ROTORMagnetic flux produced by a rotating magnetic field

passes across the air gap and through the stator core to generate three phase voltage in the stationary armature winding, also called the stator winding. The rotating magnetic field is created by passing current through the rotating field winding, also called the rotor field winding.

SEAL OIL SYSTEM

In order to prevent the escape of Hydrogen from the turbo-generator, it is essential to provide shaft seals at both end where the shaft extends through casing.

This is achieved by providing radial and axial oil films in the system

Supply of seal oil to shaft seal : During the operating condition of

the turbo-generator, the oil supply is taken from the governing system at 20 Kg/cm2 pressure. After APRV seal oil pressure is of 10-13 KSC. It is continuously supplied

A.C & D.C Seal oil pumps : In case of failure of governing oil or during a stand still condition of the generator, the oil is supplied to the seals by means of A.C. or D.C. pumps. The stand by pump is A.C operated and emergency pump is D.C. operated. These pumps are electrically inter locked.

The standby A.C. pump automatically starts in case the oil pressure (after filter) drops to 6.5 KSC and D.C. emergency pump auto start will be initiated at a seal oil pressure of 5.5 KSC.

Reasons for generator heating up1. I²R losses in stator/rotor coil(copper losses)2. Iron losses in core ( Hysteresis / Eddy current losses)3. Load on Rotor by the way of excitation power (DC V & I due to VAR loading on Generators)4.Other frictional loss in bearings (which are negligible)

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Reactive PowerInductors oppose the change in current by dropping voltage directly proportional to rate of change of currentInductive Load in the power system will produce the energy which transfers power to sourceEnergy, which returns to the source in each cycle, is known as reactive power. The loss of power in a system arising from the production of electric and magnetic fields. This the portion of power flow due to stored ” or “phantom power” is called Reactive power. It is measured in VAR. (Volt-Amps-Reactive)

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Reactive power(cont…)KW is the “real power” that actually does the work, KVAR is the “reactive power”. KVA is the “apparent power” KVA is the vector sum of both the reactive(KVAR) and the active power ( K.W.). Mathematically, power factor is the ratio between KW and KVA (PF = KW / KVA). In an inductive load, such as a motor, active power performs the work, and reactive power creates the electromagnetic fieldPower factor measures how efficiently the current is being converted into useful “real” work—with a low power factor, more electrical current will be required to provide the same amount of real power.

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STATOR WATER SYSTEM

STATOR WATER SYSTEM

•One of the efficient ways of taking away the losses from the windings of any electrical machine is by direct cooling using water.

•The 200 MW/210 MW/235 MW Turbo Generators employ a closed loop circulation of high quality demineralised water through the stator windings made of hollow and solid conductors.

• The Generator is capable of delivering its rated load only when the stator water cooling system is functioning properly.

FUNCTIONS OF STATOR WATER SYSTEM: • To cool down stator winding.• To supply polished DM water always• To supply dirt/dust free DM water.• To supply magnetic material free water.• To supply with adequate pressure temperature and flow of DM water to winding.• Draining facility if required.• To facilitate H2 gas sampling in stator water system.• To expel gas or air in the stator water to avoid contamination.• To makeup DM water if required.

Hydrogen cooling system of Turbogenerator

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Characteristics of HydrogenMolecular weight : 2.0156 Relative density : 0.06952 Boiling point : -252 °CCritical temperature/pr : - 239 °C /13.2 kg/cm²Ignition Temperature :510 °C

Combustion temperature : 2045 °C

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Hydrogen gas advantages Hydrogen is used for cooling medium primarily because of its superior cooling properties & low density. Thermal conductivity of hydrogen 7.3 times of air. It also has higher heat transfer co-efficient . Its ability to transfer heat through forced convection is about 75% better than air. Density of hydrogen is approx. 1/14 of the air at a given temperature and pressure. This reduces the windage & frictional losses in high speed machine like turbo-generator. Increasing the hydrogen pressure the machine improve its capacity to absorb & remove heat.

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Purity of HydrogenAt pressure 0.035 atm. of hydrogen heat carrying capacity is 1. But at 2.0atm. of hydrogen heat carrying capacity is 1.95 and there is serious possibility of hydrogen explosion with in the machine To ensure the safety of operation purity of hydrogen on the generator Casing must be maintained as high as possible. The purity of hydrogen should be 98% above but should not be less than 98% .

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The components of H₂ system H₂ cylinder bankCO₂ cylinder bank

Gas driers with reactivation cabinet.Gas panel. (not in service at present ).H ₂ circulation fans in the rotor @ both ends of exciter and turbine endsH ₂ coolers in the casing and its cooling water pumps

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SW system (Diagram)

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Synchronous generator operation & synchronizing

procedures

What is meant by synchronization?

• In a Power Station, it is the term used for the process of connecting the Generator to the Grid.

What are the requirements of synchronization?

• Matching of Machine Voltage, Frequency and Phase angle with the Grid parameters.

EVACUVATION OF POWER AT METTUR TPS

GOBI

INGUR

230 KV TUNNEL

DAM PH

SALEM 400 KV-I

SALEM 400 KV-II

METTUR AUTO SS

SINGARAPET

FEEDERS – 8 Nos.

15.75 KV

POWER TRANSFORMER

GENERATOR

230 KV

Circuit breakers • A circuit breaker is a switching and current

interrupting device. It serves two basic purposes• Switching during normal operating conditions

for the purpose of ,operation and maintenance• Switching during abnormal conditions such as

short circuits and interrupting fault currents.• There are several types of faults and abnormal

conditions. The fault current can damage the equipments if allowed to flow for a longer duration.

• Since the breaker is an fast acting device, the circuit breaker in association with the protection relay system opens and clears the fault

Circuit breakers

• Types: OCB OMCB ABCB SF6

Isolators • Isolators are Off load devices• Isolators are used for disconnecting the circuit

under no load conditions since it is operated under no load condition it does not have any making or breaking capacity

• To prevent mal operation of isolators it is interlocked with circuit breakers and earth switches.

• Isolators used in switchyards are normally three pole isolators

• Whereas in our 400KV yard the isolators are of individual pole

UNIT TRIP SEQUENCE

• When Trip initiated from Boiler, it goes to generator th’ Turbine only.

• When Trip initiated from Generator, it goes to Boiler th’ Turbine only.

• When Trip initiated from Turbine, it goes to Boiler and Generator simultaneously.

• Generator Trip: Class A,B.

POWER GRID

• A grid is a larger interconnected network of transmission lines linking different generating stations and load centers

OBJECTIVE OF GRID

• Continuity of service

• Economy of power production

LOAD DESPATCH CENTER

• Main LDC : Chennai• Sub LDC : Erode, Madurai.

GRID TYPES

• National Grid

• Regional Grid

• State Grid

Frequency control in the Grid

• Frequency is controlled and maintained in between 49.0 Hz. to 50.5 Hz. in the grid through ABT(Availability Based Tariff) system by scheduling and matching the Generation and the loads by Grid authority in coordination with Load dispatch centers/Generating Stations/State Electricity Boards in the Grid system continuously.

Voltage control in the Grid

• Voltage in the various points of the Grid are maintained in operating range by the Grid authority in coordination with Load dispatch centers/Generating Stations/State Electricity Boards/ Power grid by varying the MVAR generation, switching on/off capacitor banks, cutting in/out line reactors in the Grid system.

and Best Wishes for a happy long way in core engineering