BHEL HARIDWAR BLOCK 4 Study on manufacturing process of 500MW turbo generator stator winding bar.

1. MANUFACTURING PROCESS OF 500 MW
TURBO GENERTOR STATOR WINDING
BAR
AT BHEL HARIDWAR
HARSHIT AGARWAL
08070105022

2. INTRODUCTION
In 1956 India took a major step towards the establishment of its
heavy 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.

3. 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 MANUFACTURING
BLOCK
BLOCK V: FEEDER BLOCK AND KNOWN AS FABRICATION
AND FORGE BLOCK
BLOCK VI: STAMPING AND DIES MANUFACTURING BLOCK
BLOCK VII: WOODWORKING BLOCK
BLOCK VIII: HEAT EXCHANGER BLOCK, IS DESIGNED TO
.
MANUFACTURE HEAT EXCHANGER UNIT FOR
STEAM TURBINES.

4. COIL & INSULATION MANUFACTURING
SHOP (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 different
machines

5. 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

6. Layout of CIM, Block-IV

7. Sections in Block IV
1) Assembly Section 2) Stator Bar Winding Section
It is equipped with small size It is equipped with
• Drilling machines •Conductor cutting, insulation and
• Welding sets transposition section.
• Hydraulic testing equipment •Stack consolidation section,
for manufacturing turbo- forming and lug brazing sections.
generator mechanical •Insulation taping sections with
assemblies. automatic taping facilities in air-
conditioned
3) Impregnation Section
It is equipped with
• Impregnation tank
• Ovens for impregnation of DC pole coils.

8. 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

9. Types of Generators
The generator may be classified based upon the cooling
system used in the generators such as: THRI, TARI, THDI,
THDD, THDF, THFF, and THW
Stands for
Stands for the Stands for the Stands for type
Stands for type cooling media
cooling media type of cooling of cooling for
of generator used for Stator
for Rotor for Rotor Stator
coil
• T- Turbo • H- Hydrogen • R- Radial • I- Indirect • W- Water
Generator gas • D- Direct • D- Direct
• H- Hydro • A- Air • F- Forced • F- Forced
Generator • I- Indirect

10. Why do we call it bar?
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 top
bar or upper bar.

11. No. of Bars in current products
Set Type Upper Upper Lower Lower Total No. of
Ordinary Terminal Ordinary Terminal Bars Bus
Bars
500MW 42 6 42 6 96 6
THDF
210MW 54 6 54 6 120 9
THW
250MW 48 12 48 12 120 9
THRI

12. 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 which
could be increased when kept at temperature of 50C.
 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.

13. INSULATION CLASSIFICATION:
• Upto 90 °C
Class
Y • Cotton, Silk, or Paper.
• Upto 105 °C
Class
A • Reinforced Class-Y materials with impregnated varnish.
• Upto 120 °C
Class
E • Cotton lamination & Paper lamination.
• Upto 130 °C
Class
B • Inorganic material is hardened with adhesives.
• Upto 150 °C
Class
F • Class-B materials that are upgraded with adhesives.
• Upto 180 °C
Class
H • Made of inorganic material glued with silicone resin.
• > 180 °C Upto 220 °C
Class
C
• Made of 100% inorganic material

14. Transposition
Transposition 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 staggered
manner 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.

15. Transposition is done in two ways:
Half Pitch Transposition: In this transposition, the first
conductor 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, the
first 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.
Need of transposition.
1. To reduce eddy current losses.
2. Equalize the voltage generator.
3. To minimize skin effect of ac current.

16. Testing
Tan δ 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 conducting
material 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 δ

17. H.V. Test:
•Each bar is tested momentary at high voltage increased gradually
to 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 the
generator. 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 processes
are repeated again

18. 500 MW Turbo generators at a glance
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

19. Salient technical data:
Rated output: 588 MVA , 500 MW
Terminal voltage: 21 KV
Rated stator current: 16 KA
Rated frequency: 50 Hz
Rated power factor: 0.85 Lag
Efficiency: 98.55%
Important dimensions & weights:
Heaviest lift of generator stator : 255 Tons
Rotor weight : 68 Tons
Overall 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

20. Picture Of Bars

21. THANK YOU