VOCATIONAL TRAINING REPORT , 2011

PROJECT COMPLETED: MANUFACTURING PROCESS OF 500MW STATOR BAR.

BLOCK ASSIGNED: Block 4 (CIM)

PROJECT INCHARGE: Shree A.K. Dhimaan Dep. Manager, Block 4, BHEL Haridwar.

SUBMITTED BY: Eshan Shailendra Bsc(Engg.), 2nd year (Electrical),

Dayalbagh Educational Institute, Agra.

TRAINING DURATION: 27th May to 5th July (40 days).

ACKNOWLEDGEMENTS

I would sincerely like to express my gratitude for BHEL Haridwar, for providing me the opportunity of pursuing my vocational training in this renowned industry and endowing me with an unparallel experience and deep understanding of a wide array of processes and manufacturing methods taking place in different workshops of the industry.I would also take this opportunity to thank our training incharge, Mr. A.K. Dhimaan whose guidance and motivation went a long way in our understanding of different sections of the industry.Furthermore, I would thank my institute, DEI for giving me opportunity of visiting the industry and increasing my practical knowledgebase.Last, but not the least, I would also like to acknowledge the immense pleasure, brought about by my friends as they pursued their training along with me. We shared some unforgettable moments together. Thank you all.

Eshan Shailendra

CONTENTS

1. BHEL, Haridwar – a brief introduction. Manufactured products,

(a) For power generation sector,(b) For power distribution and transmission sectors,(c) For other industries.

Transportation,

International projects and export,

Research and development,

The Human Resource and Development Centre.

2. Block description of BHEL workshops: Block 1,2,3,4,5,6,7 and 8.

3. Sectional description of Block 4: Bay 1,2 and 3.

4. Manufacturing process of 500MW T.G. stator bar in detail: Conductor cutting, Transposition, Crossover insulation, Stack consolidation, Inter strand

short test, Forming, Brazing of coil lugs, Nitrogen leak test, Thermal shock, Helium

leakage test, Multi layered insulation, Impregnation, Baking, Finishing, Varnish coating, H.V. testing, Tanδ testing, Packaging and Dispatch.

5. Conclusion.

BHEL, Haridwar - An Introduction

BHEL is the largest engineering and manufacturing enterprise in India in the energy

related infrastructure sector today. BHEL was established more than 40 years ago when

its first plant was setup in Bhopal, ushering in the indigenous Heavy Electrical

Equipment Industry in India, a dream which has been more than realized. with a well

recognized track record of performance and worldwide recognition, it has been

earning profits continuously since 1971-72.

BHEL caters to core sectors of the Indian Economy viz., Power Generation's &

Transmission, Industry, Transportation, Telecommunication, Renewable

Energy, Defense, etc. The wide network of BHEL's 14 manufacturing division, four

power Sector regional centers, over 150 project sites, eight service centers and 18

regional offices, enables the Company to promptly serve its customers and provide

them with suitable products, systems and services - efficiently and at competitive

prices. BHEL has already attained ISO 9000 certification for quality management,

and ISO 14001 certification for environment management.

MANUFACTURED PRODUCTS

BHEL manufactures a wide array

POWER GENERATION

Power generation sector comprises thermal, gas, hydro

and nuclear power plant business as of 31.03.2001, BHEL supplied

sets account for nearly 64737 MW or 65% of the total installed

capacity of 99,146 MW in the country, as against nil till 1969-70.

BHEL has proven turnkey capabilities for executing

power projects from concept to commissioning; it possesses the

technology and capability to produce thermal sets with super

critical parameters up to 1000 MW unit rating and gas turbine

generator sets of up to 240 MW units rating. Co-generation

and

combined-cycle plants have been introduced to achieve higher

plant efficiencies. To make efficient use of the high-ash-content

coal available in India, BHEL supplies circulating fluidized bed

combustion boilers to both thermal and combined cycle power

plants.

The company manufactures 235 MW nuclear turbine generator sets

and has commenced production of 500 MW nuclear turbine

Generator sets.

Custom made hydro sets of Francis; Pelton and Kapian types for

different head discharge combination are also engineering and

manufactured by BHEL.

In all, orders for more than 700 utility sets of thermal, hydro, gas

and nuclear have been placed on the Company as on date. The

power plant equipment manufactured by BHEL is based on

contemporary technology comparable to the best in the world and

is also internationally competitive.

POWER TRANSMISSION & DISTRIBUTION (T & D)

BHEL offer wide ranging products and systems for T & D

applications. Products manufactured include power transformers,

instrument transformers, dry type transformers, series - and stunt

reactor, capacitor tanks, vacuum - and SF circuit breakers gas

insulated switch gears and insulators.

A strong engineering base enables the Company to undertake

turnkey delivery of electric substances up to 400 kV level series

compensation systems (for increasing power transfer capacity of

transmission lines and improving system stability and voltage

regulation), shunt compensation systems (for power factor and

voltage improvement) and HVDC systems (for economic transfer of

bulk power). BHEL has indigenously developed the state-of-the-

art controlled shunt reactor (for reactive power management on long

transmission lines). Presently a 400 kV Facts (Flexible AC

Transmission System) project under execution.

INDUSTRIES

BHEL is a major contributor of equipment and systems to

industries. Cement, sugar, fertilizer, refineries, petrochemicals,

paper, oil and gas, metallurgical and other process industries lines

and improving system stability and voltage regulation.

BHEL is a major contributor of equipment and systems to

industries, cement, sugar, fertilizer, refinances, petrochemicals,

paper, oil and gas, metallurgical and other process industries. The

range of system & equipment supplied includes: captive power

plants, co-generation plants DG power plants, industrial steam

turbines, industrial boilers and auxiliaries. Water heat recovery

boilers, gas turbines, heat exchangers and pressure vessels,

centrifugal compressors, electrical machines,pumps,valves,

seamless steel tubes, electrostatic precipitators, fabric filters,

reactors, fluidized bed combustion boilers, chemical recovery

boilers and process controls.

The Company is a major producer of large-size thruster devices. It

also supplies digital distributed control systems for process

industries, and control & instrumentation systems for power plant

and industrial applications. BHEL is the only company in India

with the capability to make simulators for power plants, defense

and other applications.

The Company has commenced manufacture of large desalination

plants to help augment the supply of drinking water to people.

Transportation BHEL is involved in the development design, engineering, marketing,

production, installation, maintenance and after-sales

service of Rolling Stock and traction propulsion systems. In the

area of rolling stock, BHEL manufactures electric locomotives up

to 5000 HP, diesel-electric locomotives from 350 HP to 3100 HP,

both for mainline and shunting duly applications. BHEL is also

producing rolling stock for special applications viz., overhead

equipment cars, Special well wagons, Rail-cum-road vehicle etc.,

Besides traction propulsion systems for in-house use, BHEL

manufactures traction propulsion systems for other rolling stock

producers of electric locomotives, diesel-electric locomotives,

electrical multiple units and metro cars. The electric and diesel

traction equipment on India Railways are largely powered by

electrical propulsion systems produced by BHEL. The company

also undertakes retooling and overhauling of rolling stock in the

area of urban transportation systems. BHEL is geared up to

turnkey execution of electric trolley bus systems, light rail systems

etc. BHEL is also diversifying in the area of port handing

equipment and pipelines transportation system.

International Operations

BHEL has, over the years, established its references in around 60

countries of the world, ranging for the United States in the West to

New Zealand in the Far East. These references encompass almost

the entire product range of BHEL, covering turnkey power projects

of thermal, hydro and gas-based types, substation projects,

rehabilitation projects, besides a wide variety of products, like

transformers, insulators, switchgears, heat exchangers, castings and

forgings, valves, well-head equipment, centrifugal compressors,

photo-voltaic equipment etc. Apart from over 1110MW of boiler

capacity contributed in Malaysia, and execution of four prestigious

power projects in Oman, Some of the other major successes

achieved by the Company have been in Australia, Saudi Arabia,

Libya, Greece, Cyprus, Malta, Egypt, Bangladesh, Azerbaijan, Sri

Lanka, Iraq etc.

The Company has been successful in meeting demanding

customer's requirements in terms of complexity of the works as

well as technological, quality and other requirements viz extended

warrantees, associated O&M, financing packages etc. BHEL has

proved its capability to undertake projects on fast-track basis.

Technology up gradation and Research & Development

To remain competitive and meet customers' expectations, BHEL

lays great emphasis on the continuous up gradation of products

and

related technologies, and development of new products. The

Company has upgraded its products to contemporary levels

through continuous in house efforts as well as through acquisition

of new technologies from leading engineering organizations of the

world.

The Corporate R&D Division at Hyderabad, spread over a 140

acre complex, leads BHEL's research efforts in a number of areas of

importance to BHEL's product range. Research and product

development centers at each of the manufacturing divisions play a

complementary role.

BHEL's Investment in R&D is amongst the largest in the corporate

sector in India. Products developed in-house during the last five

years contributed about 8.6% to the revenues in 2000-2001.

BHEL has introduced, in the recent past, several state-of-the-art

products developed in-house: low-NQx oil / gas burners,

Circulating fluidized bed combustion boilers, high-efficiency

Pelton hydro turbines, petroleum depot automation systems, 36 kV

gas-insulated sub-stations, etc. The Company has also transferred a

few technologies developed in-house to other Indian companies for

commercialization.

Some of the on-going development & demonstration projects

include: Smant wall blowing system for cleaning boiler soot

deposits, and micro-controller based governor for diesel-electric

locomotives.

Human Resource Development InstituteThe most prized asset of BHEL is its employees. The Human

Resource Development Institute and other HRD centers of the

Company help in not only keeping their skills updated and finely

honed but also in adding new skills, whenever required.

BHEL, as an integral part of business performance and in its

Endeavour of becoming a world-class organization and sharing the

growing global concern on issues related to Environment.

Occupational Health and Safety, is committed to protecting

Environment in and around its own establishment, and to providing

safe and healthy working environment to all its employees.

POWER TRANSMISSION & DISTRIBUTION

In the T&D sector, BHEL is both a leading equipment manufacturer

and a system-integrator.BHEL manufactured T&D products have a

proven track

record in India and abroad.

In the area of T&D systems, BHEL provides turnkey solutions to

utilities. Substations and shunt compensation installations set up by

BHEL are in operation all over the country. EHV level series

compensation schemes have been installed in KSEB, MSEB,

SMPSEB and POWERGRID networks. Complete HVDC systems

can be delivered by BHEL. The technology for state-of-the-art

Flexible AC Transmission Systems (FACTS) is being developed.

CHAPTER II

BLOCKS IN BHEL

Block-1 Hydro & turbo generators, AC/DC machines

Block-2 Fabrication (steam, hydro & gas turbine)

Block-3 Gas, hydro & steam turbine

Block-4 CIM and ACM

Block-5 Heat exchangers, forging & fabrication

Block-6 Electrical repair & maintenance of transformer

Block-7 wooden packing works

Block-8 Fabrication, seamless tuber and heat exchanges

CHAPTER III

BRIEF SUMMARY OF CIM SHOP (BLOCK-4)

BAY-I: - Bar winding shop: Manufacturing of stator winding bars

of generator.

BAY-II: - Manufacturing of motor stator coil: DC armature coil,

main pole coil, inter-pole coil, equalizer coil etc.Also

manufactured heavy duty generator stator bars with New CNC

M/c No, 3-464 i.e. Robol bar centre.

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 generator that may be turbo-generator or hydro-

generator.

Why do we call it bar: - It is quite difficult (rather impossible)

to manufacture, handle and wind the coil in 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

is Bottom part of coil called bottom or tower bar and other part of

coil is called top bar or upper bar.

HG Bars: - The manufacturing of bars of different capacity as

required by the customer depends upon the water head available

at site. The Hydro generator is air cooled generator of Comparison

to its tagger diameter. (Note: - The manufacturing of Hydro Gen

Stator Bars has been shifted from BHEL Hardwar to BHEL Bhopal

to since 2008.)

TURBO-GENERATORS: - The manufacturing of bars of

standard capacity such as: 100MW, 130MW, 150Mw,

210/235MW.The plant has capacity and technology to

manufacture 500MW, 600MW, 800MW and 1000MW genera

CHAPTER IV

MANUFACTURING PROCESS FLOW CHART OF 500 MW TG STATOR BAR

1. Conductor Draw from Store.

2. Conductor cutting and end cleaning.

3. Transposition of conductor.

4. Assembly of all conductors to be used in stator Bars.

5. Cross over insulation.

6. Consolidation if slot portion of Bar.

7. IS Test (i.e. inter strand test).

8. Forming or Bar (to shape overhang portion).

9. Pickling of bar ends (1)

10. Mounting of Contact sleeve & bottom part of water box.

11. Brazing of Contact sleeve & bottom part of water box.

12. Pickling of bar ends (2)

13. Mounting of water box leak test.

14. Repacking.

15. Water flow and N2 test.

16. Thermal Shock Application.

17. Helium Leak Test.

18. Reforming of Bar.(i.e. overhang portion).

19. Insulation of bar on CNC machine.

20. Impregnation a curing of bar insulation.

21. Surface finishing of stator bar.

22. OCP on stator Bar.

23. Preparation of bar for HV and Tanq Test.

24. If O.K. Dispatch to Bicck-1 for lying in the generator.

INSULATION CLASSIFICATION:-

Thermal classification of insulation depends upon the

temperature Withstand capability of the insulation.

Class – Y up to 90 C

Class – A up to 105 C

Class – E up to 120 C

Class – B up to 130 C

Class – F up to 150 C

Class – H up to 180 C

Class – C 180 C up to 220 C.

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.

T-> First alphabet signifies the type of generator i.e. turbo-

generator or Hydro-generator.

H/A-> Second alphabet stands for the coding media used for the

cooling of rotor i.e. hydrogen gas or air.

R/D/F/I-> Third alphabet signifies the type of cooling or rotor

E.g. Radial, indirect, forced, direct etc.

I/D/F-> Last alphabet stands for the type of cooling of stator

E.g. indirect cooling, direct cooling, forced cooling.

W-> Cooling media used for cooling of stator coil e.g. water.

Resin system:-

a) Rich Resin or Thermo reactive insulation system:

- In this type of insulation system the bond content in resin 36-

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

and working on temperature 20-25':C. Its life is one year when

kept at temperature 20 C which could be increased when kept at

temperature of 5 C.

b) 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 not required. The insulating material is

applied on job and then the same is impregnated (fully dipped) in

the resin.

CHAPTER V

MANUFACTURING PROCESS OF BARS:-

Some Points of Manufacturing Process are in brief as below:-

Conductor Cutting:-

This process is done by automatic CNC machine. In this process

the pre-insulated copper conductor is cut into number of required

length. Insulation is removed from both ends of the conductor

cut.

Lower Bar:-

Conductor size: - 8*4.6*1.5 mm (Hollow), 8*2.8 mm

(Solid)

L - 10200 mm: - C- 500 mm

Conductor No. In 1 bar: - Hollow – 20, Solid - 20

Upper Bar:-

U – 10050 mm: - c- 5 mm

Conductor size: - 8*4.6*1.5 mm (Hollow) 8*1.3 mm (Solid)

Conductor No. in 1 bar: - Hollow – 20, Solid – 40

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.

Crossover Insulation:-

The pre insulation of the copper conductor may get damaged due

to mechanical bending in die during transposition, hence the

insulating spacers are provided at the crossover portion of the

conductors. A filler material (insulating putty or molding is

provided along the height of the bar to maintain the rectangular

shape and to cover the difference of level of conductors.

To eliminate inter turn short at bends during edges wise bending

and leveling of bars in slots portion for proper stack pressing.

Stack Consolidation:-

The core part of the bar stack is pressed in press (closed box)

under pressure (varies from product to product) and temperature

of 160 C for a given period. The consolidated stack is withdrawn

from the press and the dimensions are checked.

Inter Strand Short Test:-

The consolidated bar stack is tested for the short between any

two conductors in the bar, if found then it has to be rectified. This

is done to ensure that no local current is flowing due to short

circuit between conductors. (300 A/C supply)

Forming:-

The straight bar stack is formed as per overhang profile (as per

design), the overhang portion is consolidated after forming.

Brazing of coil lugs:-

For water cooled generator bars, the electrical connection contact

and water box for inlet and outlet of water are brazed.

Nitrogen Leak Test:-

The bar is tested for water flow test, nitrogen leak test and

pressure test for given duration.

Thermal shock test:-

The cycles of hot (80C) and cold (30°C) water are flown through

the bar to ensure the thermal expansion and contraction of the

joints.

Helium leakage test:-

After thermal shock test bar is tested for any leakage with the

help of helium gas.

Insulation:-

The bar is insulated with the given number of layers to build the

wall thickness of insulation subjected to the generating voltage of

the machine.

Impregnation and baking:-

a) Thermo reactive system:-

In case of rich resin insulation the bar is pressed in closed box in

heated condition and baked under pressure and temperature as

per requirement for a given period.

b) Micalastic system:-

In case of poor resin system the insulated bars are heated under

vacuum and the impregnated (dipped) in heated resin so that all

the air gaps are filled, layer by layer, with resin. Then extra resin is

drained out and bars are heated and baked under pressed

condition in closed box fixture.

VPI Micalastic system:-The bars already lay in closed fixture and full fixture is

impregnated (dipped) in resin and then fixture with box is baked

under given temperature for given duration.

VIP Micalstic system:-

The individual (separate) bar is heated in vacuum and

impregnated in resin. Then bar is taken out and pressed in closed

box fixture and then baked at given temperature for given

duration.

Finishing:-

The baked and dimensionally correct bars are sanded-off to

smoothen the edges and the surface is calibrated, if required, for

the dimension.

Conducting varnish coating:-

i) OCP (Outer Corona Protection) coating:-

The black semi-conducting varnish coating is applied on the bar

surface on the core length.

ii) ECP (End Corona Protection) coating:-

The grey semi-conducting varnish is applied at the bend outside

core end of bars in gradient to prevent from discharge and

minimize the end corona.

Testing:-

a) Tan@ test:-

This test is carried out to ensure the healthiness of dielectric

(Insulation) i.e. dense or rare and measured the capacitance loss.

b) H.V. Test:-

Each bar is tested momentary at high voltage increased gradually

to three times higher than rated voltage.

Dispatched for Winding:-

The bars preserved with polythene sleeves to protect from dust,

dirt, oil, rain etc are send to Block-I (Electric Machines Production

Block – I, Turbo Generators and Hydro Generators) for winding.

CONCLUSION

Engineering students will have to serve in the public and private

sector industries, laboratories and workshops based training &

teaching in classroom has its own limitations. The lack of exposure

to real life, materials processes and functioning of industrial

organization is the measure hindrances in the student

employment.

In the open economy era of fast modernization and tough

competition, technical institutes should procedure pass outs as

near to job function as possible.

Practical training is one major step in this direction. This training

helped me in gaining in depth knowledge of the working of a

telephone exchange.

At last I would only say that this training was helpful for my future

prospects.