600 mw stator bar training report

7/22/2019 600 mw stator bar training report

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MANUFACTURING PROCESS OF 500 MW

TURBO GENERTOR STATOR WINDING

BAR

HARSHIT AGARWAL

08070105022

AT BHEL HARIDWAR


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INTRODUCTIONIn 1956 India took a major step towards the establishment of itsheavy engineering industry when BHEL, the first heavy electrical

Manufacturing unit of the country was set up at Bhopal.

BHEL's Heavy Electrical Equipment Plant (HEEP) was set up

in technical collaboration with USSR, for the manufacturing of

power plant equipment.

In 1976, BHEL entered into a collaboration agreement with

M/s Kraftwerk Union, AG of Germany for design,

manufacturing, erection and commissioning of large size

steam turbines.

More than 40 percent of the country's electrical energy is

generated from the power equipment supplied by BHEL,

Haridwar.


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MANUFACTURING BLOCKS:

.

BLOCK I: ELECTRICAL MACHINE BLOCK, IS DESIGNED TO

MANUFACTURING OF TURBOGENERATORS

BLOCK II: FABRICATION BLOCK

BLOCK III: TURBINE BLADE BLOCK

BLOCK IV: COIL & INSULATION MANUFACTURING &

APPARATUS & CONTROL GEAR MANUFACTURINGBLOCK

BLOCK V: FEEDER BLOCK AND KNOWN AS FABRICATION

AND FORGE BLOCK

BLOCK VI: STAMPING AND DIES MANUFACTURING BLOCKBLOCK VII: WOODWORKING BLOCK

BLOCK VIII: HEAT EXCHANGER BLOCK, IS DESIGNED TO

MANUFACTURE HEAT EXCHANGER UNIT FOR

STEAM TURBINES.


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COIL & INSULATION MANUFACTURINGSHOP (BLOCK-IV)Block-4 is a feeder block for insulating items,

winding with class-B Bituminous insulation and sheet

metal components for all the products of Block-1 i.e.

Turbo-generators, Hydro-generators, A.C. and D.C.machines

There are three BAYS in this block each bay

manufactures stator bars and coils for differentmachines


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BAY-I: Bar winding shop: manufacturing of stator winding

bars of generator

BAY-II: Manufacturing of heavy duty generator stator bars

with New CNC M/c

BAY-III: Insulation detail shop: Manufacturing of hard

insulation & machining of hares insulation part (Glass Textolite)

such as packing, washer, insulation box, wedges etc

Bar Shop: This shop is meant for manufacturing of stator

winding coils of turbo-generator and hydro generator


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Layout of CIM, Block-IV


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Sections in Block IV1) Assembly Section

It is equipped with small size

Drilling machines

Welding sets

Hydraulic testing equipmentfor manufacturing turbo-

generator mechanical

assemblies.

2) Stator Bar Winding SectionIt is equipped with

Conductor cutting, insulation and

transposition section.

Stack consolidation section,forming and lug brazing sections.

Insulation taping sections with

automatic taping facilities in air-

conditioned

3) Impregnation Section

It is equipped with

Impregnation tank

Ovens for impregnation of DC pole coils.


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4) Armature Winding, Rotor coil and Stator bar Section

It is equipped with

Conductors cutting.

U- bending and terminal conductor cutting machines.

Semi-automatic winding machine.

Planking, boat pulling and diamond pulling machine. Insulation and pressing of AC coils.

5) Insulation Section

It is equipped with

Small size lathes. Milling and radial drilling machines.

Jet cutting saw.

Electrical ovens & Hydraulic presses.

Plastic Molding Section


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Types of GeneratorsThe generator may be classified based upon the cooling

system used in the generators such as: THRI, TARI, THDI,

THDD, THDF, THFF, and THW

Standsfortypeofgenerator

T-TurboGenerator

H-HydroGenerator

Standsforthecoolingmedia

forRotor

H-Hydrogengas

A-Air

Standsforthetypeofcooling

forRotor

R-Radial

D-Direct

F-Forced I-Indirect

Standsfortypeofcoolingfor

Stator

I-Indirect

D-Direct

F-Forced

StandsforcoolingmediausedforStator

coil

W-Water


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It is quite difficult (rather impossible) to manufacture, handle

and wind in the stator slot of generator of higher generation

capacity because of its bigger size and heavy weight. That is

why we make coil in two parts. One part its bottom part of coil

called bottom or lower bar and other part of coil is called topbar or upper bar.

Why do we call it bar?


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Set Type Upper

Ordinary

Upper

Terminal

Lower

Ordinary

Lower

Terminal

Total

Bars

No. of

Bus

Bars

500MWTHDF

42 6 42 6 96 6

210MW

THW

54 6 54 6 120 9

250MW

THRI

48 12 48 12 120 9

No. of Bars in current products


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Poor Resin or Micalastic insulation system

In this type of insulation the bond content in the resin is 5

7%and insulating material is prepared with accelerator treatment.

The temperature control need is not required. The insulating

material is applied on job and then same is impregnated (fully

dipped) in the resin.

Resin System: Rich Resin or Thermo-reactive insulation system:

In this type of insulation system the bond content in resin is

35 37 %. The raw materials are ready to use and require

preservation and working on temperature 20 250C. Its shelf

life is one year when kept at a temperature of 200C whichcould be increased when kept at temperature of 50C.


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INSULATION CLASSIFICATION:Class

Y

Upto90C

Cotton,Silk,orPaper.

ClassA

Upto105C

ReinforcedClass-Ymaterialswithimpregnatedvarnish.

Class

E

Upto120C

Cottonlamination&Paperlamination.

ClassB

Upto130C

Inorganicmaterialishardenedwithadhesives.

Class

F

Upto150C

Class-Bmaterialsthatareupgradedwithadhesives.

ClassH

Upto180C

Madeofinorganicmaterialgluedwithsiliconeresin.

ClassC

>180CUpto220C

Madeof100%inorganicmaterial


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TranspositionTransposition means changing/shifting of position of each

conductor in active core (slot) part.

After cutting the required number of conductors

The conductors are arranged on the comb in staggeredmanner and then bends are given to the conductors with the

help of bending die at required distance.

Then the conductors are taken out from the comb and die and

placed with their ends in a line and transposition is carried out.This process is repeated for making another half of the bar

which would be mirror image of the first half.

The two halves of the bar are overlapped over each other and

a spacer is placed between the two halves.


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Need of transposition.1. To reduce eddy current losses.

2. Equalize the voltage generator.

3. To minimize skin effect of ac current.

Transposition is done in two ways:

Half Pitch Transposition: In this transposition, the firstconductor at one end of the bar becomes the last conductor at

the other end of the bar.

Full Pitch Transposition: In this method of transposition, thefirst conductor at one end of the bar becomes the last

conductor in the mid of the bar and then again becomes the

first conductor at the other end of the bar.


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TestingTan test:

This test is carried out to ensure the healthiness of dielectric(Insulation) i.e. dense or rare & measured the capacitance loss.

Bar will act as capacitor when it is laid in the stator of the

generator.

Schearing Bridge which works on the principle of wheat-stone

bridge is used to find the unknown capacitance of the bar.

For good efficiency, capacitance of the bar should be high but we

never approach pure capacitance.Bar is wrapped with aluminum to make the bar conductive

throughout the outer surface of the bar. The two conductingmaterial i.e. the aluminum sheet and the conductors of the bar act

as two plates of the capacitor and the insulation on the bar act as

dielectric medium for the capacitor thus the capacitance is found.

Of angle of deviation due to impurity in the insulation is obtained

from the formula: C4 * R4 * 10^-4 = tan


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H.V. Test:

Each bar is tested momentary at high voltage increased graduallyto three times higher than rated voltage.

This test is also known as insulation test because this test is

performed to check the insulation of the bar.

For 500 MW the working voltage of the bar is 64.5 KV & for 210

MW the working voltage of the bar is 63 KV.

In this test the bar which is already wrapped with aluminum is

used.

High voltage is applied to the bar using auto-transformer and it is

increased in steps according to the working voltage of thegenerator. If the insulation is weak the bar will puncture at the

place of weaker insulation.

If any of the bar fails this test i.e. bar is punctured at any point

then the bar is sent back for re-insulation and all the processesare repeated again


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2-Pole machine with the following features:

Direct cooling of stator winding with water.

Direct hydrogen cooling for rotor.

Micalastic insulation system.Spring mounted core housing for effective transmission of

vibrations.

Brushless Excitation system.

Vertical hydrogen coolers

500 MW Turbo generators at a glance


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Important dimensions & weights:

Heaviest lift of generator stator : 255 Tons

Rotor weight : 68 TonsOverall stator dimensions [L*B*H] : 8.83m*4.lm*4.02m

Rotor dimensions(Dia. and length) : 1.15m and 12.11m

Total weight of turbo generator : 428 Tons

Salient techn ical data:

Rated output: 588 MVA , 500 MWTerminal voltage: 21 KV

Rated stator current: 16 KA

Rated frequency: 50 Hz

Rated power factor: 0.85 LagEfficiency: 98.55%


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Picture Of Bars


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THANK YOU

Documents

600 mw stator bar training report