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GENERATOR

AUXILIARY SYSTEM

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GENERATORS AND ITS AUXILIARY CAN BE BROADLYDEVIDED INTO THREE SYSTEMS

A) Stator water system

B) Seal oil system

C) Gas system

D) Generator

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POLISH UNIT

FILTERS

COOLERS

PUMPS

GAS TRAP

FLOWMETERS

CONDUCTIVITY

EXPANSIONTANK

MAKEUP

FSI

IDIFF PRESS.

MAGNETFILTER

STATOR WATER SYSTEM

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VINDHYACHAL

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STATOR WATER SYSTEM

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TEFLON

TUBES

PW HEADER

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Stator Water System

Stator water cooling is a closed loop system

There are two full capacity single stagecentrifugal pumps with change over facility

The pumps are driven by 3Ph. 415V A.C. motors

The stator water cooler is shell and tube typeheat exchanger

DM water flows through shell

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Stator Water System

There are two mechanical filters and one

magnetic filters

Mechanical filters are of wire mesh type

Magnetic filter is having permanent magnet

The expansion tank is a hermetically sealed

container made of S.S.

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Stator Water System

Float valve is there in the expansion tank to

maintain water level in the tank which act as

suction storage tank for stator water pumps

Polishing unit (mixed bed ion exchanger) is there

to maintain conductivity of stator water to

desired level

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SEAL OIL SYSTEM

Generator shaft seals are supplied with

pressurized seal oil to prevent hydrogen escape

at the shaft

Oil pressure is kept higher than the gas pressure

There are one AC seal oil pp. and one DC seal oil

pp. which feed oil to the seal through cooler and

filter

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VINDHYACHAL

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BEARG

DRAINS

TG

1 2

EEBEARING

TEBEARING

GASEXHAUST

FROM GAS

SYSTEM

IOT

VACUUM

TANK

SOST

SOP

SOP-3

DC

DPSW

TS ES

FR

FLOW M.PS PG

SEAL OIL SYSTEM

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VINDHYACHAL

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SEAL OIL SYSTEM

Both the seal oil pumps are 100% capacity screwtype pump

A vacuum pump is provided to maintain vacuum

in seal oil tank

There is a additional facility to supply seal oilfrom governing oil

The seal oil pressure to the seal is controlled byDPR which maintain specified DP between oiland hydrogen

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SEAL OIL SYSTEM

Thrust oil is there to hold the seal ring in position

against gas pressure

Two seal oil coolers having 100% capacity isprovided to cool the oil

Duplex filter is provided in the oil line

Vacuum pump evacuates gases from SOT

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H2DISTRIB

HYDROGEN

CO2VAPOURIZER

H2 DRIER

CO2

ANALYZER

DRAIN

AIR

FILTER

OP

DPI

GAS SYSTEM

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VINDHYACHAL

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AXIAL FAN

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ABOUT HYDROGEN

H2 and O2 combine slowly at 180C or inbright sunlight. Explosion occurs with moist

gases at 550 - 700C.

Ignition temp. of H2 in air is 538C.

Calorific value of H2 is 136 k Cal / gm.

For filling in TGs, 99.9% v/v purity gas is

used. Traces of SO2 and NH3 shall not bedetectable by analysis.

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ABOUT HYDROGEN

H2 is lightest gas with 0.09 gm / litre whileairs 1.3 i.e. 14.4 times.

Thermal capacity of H2 as gas is high.

Thermal conductivity of H2 is 5 times that ofair. Its specific heat is 3.42 at 0C, as compared

to 0.237 of air.

2 H2 + O2 mixture ignites on adiabaticcompression at 526C, 3H2 + O2 at 544C.

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H2 FILLING

Check availability of adequate no of Hydrogen

filling points and cylinders

Functionally check the LLD system

Check whether the relief valves in the high

pressure valves are alright

Check the generator is completely boxed up

Check the seal oil system is in service

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Check generator air tightness test is successfully

completed

Start purging air with CO2

till the purity of CO2

inside casing reaches above 95%

After CO2 purity reaches as desired start purging

CO2

with Hydrogen

Continue purging till hydrogen purity reaches

above 98%

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Pressurise generator casing with hydrogen up to

its design value

Recheck hydrogen leakages by detector

Take drier into service

Take gas coolers into service

Vent the coolers and establish flow

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