Download - 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