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GRAHAK SANTUSTHA- HUM SANTUSTHA

Vocational Training Report ’11 (17 June2011 to 16 July 2011)

Submitted To –

Sh.A.K. Dhimaan Dep. Manager, Block 4, BHEL Haridwar

Submitted BY – Gambheer Singh Electrical Engineering (VII semester Final Year)

Govt. Engineering College, Ajmer (Raj.).

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: Gambheer Singh Electrical Engineering (VII semester Final Year ) Govt. Engineering College, Ajmer (Raj.).

TRAINING DURATION: 17th Jun to 16th July

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 unparalleled 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 in charge,

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.

Gambheer Singh

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

3. Sectional description of Block 4 (Bay –I, II, III)

4. Manufacturing process of 500MW T.G. stator bar in detail

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 Institute The 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 center.

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.