ACKNOWLEDGEMENT

“Training is the act of increasing the knowledge and skill of an employee for doing a particular job.”

This project report has been made as a part of the industrial training underwent at the B.H.E.L Haridwar plant, Uttarakhand.

I would like to extend sincere thanks to Mr.A.K.Dhiman, deputy manager for his prodigious guidance throughout my training and I would specially like to thank Mr.Vinod Bharadwaj and Mrs.M.Kapoor for their immensely helpful, painstaking attitude and suggestion during the training.

Efforts have been made to make the report as succinct as possible. Quantitative data has been presented through tables, charts and suitable illustrations.

The project would not have been possible without the help and cooperation of the aforementioned officials. Last but not the least; I would like to thank all the staff members of B.H.E.L. Block-4, Ranipur, Haridwar.

SUMIT MAURYA

B.Tech. 3rd year

Electrical and Electronics Engineering

JSSATEN

TABLE OF CONTENTS

CHAPTER 1- INTRODUCTION ON B.H.E.L.

CHAPTER 2- BLOCK 4 CIM SHOP

CHAPTER 3-MANUFACTURING PROCESS OF 500MW TG STATOR BARS

CONCLUSION

CHAPTER 1

INTRODUCTION ON BHEL

Bharat Heavy Electricals Limited (BHEL) is an Indian integrated power plant equipment manufacturer and operates as engineering and manufacturing company based in New Delhi, India. Established in 1964, BHEL ushered in the indigenous Heavy Electrical Equipment industry in India. The company has been earning profits continuously since 1971-72 and paying dividends since 1976-78.

It is engaged in the design, engineering, manufacture, construction, testing, commissioning and servicing of a wide range of products and services for the core sectors of the economy, viz. Power, Transmission, Industry, Transportation, Renewable Energy, Oil & Gas and Defence. It has 15 manufacturing divisions, two repair units, four regional offices, eight service centres, eight overseas offices and 15 regional centres and currently operates at more than 150 project sites across India and abroad. Most of its manufacturing units and other entities have been accredited to Quality Management Systems (ISO 9001:2008), Environmental Management Systems (ISO 14001:2004) and Occupational Health & Safety Management Systems (OHSAS 18001:2007).

It is the 7th largest power equipment manufacturer in the world. In the year 2011, it was ranked ninth most innovative company in the world by US business magazine Forbes. BHEL is the only Indian Engineering company on the list, which contains online retail firm Amazon at the second position with Apple and Google at fifth and seventh positions, respectively. It is also placed at 4th place in Forbes Asia's Fabulous 50 List of 2010. BHEL was established more than 50 years ago, ushering in the indigenous Heavy Electrical Equipment industry in India. The company has been earning profits continuously since 1971-72 and paying since 1976-77. 74% of the total power generated in India is produced by equipment manufactured by BHEL.

It is one of India's nine largest Public Sector Undertakings or PSUs, known as the Navratnas or 'the nine jewels'.In June 2012, BHEL commissioned 250 MW power generating unit at Harduaganj in Uttar Pradesh. This would add six million units of electricity on a daily basis.

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BHEL HARIDWAR

At the foothills of the majestic Himalayas, on the bank of the Holy Ganges in Ranipur, Uttarakhand is located Heavy electrical equipment plant (HEEP) of B.H.E.L.

BHEL, completely owned by the Government of India is an integrated engineering complex consisting of several plants of India, where about 70,000 workers are employed in the design and manufacturing of heavy electrical equipment.

At present, 70 % of country’s electrical equipment is generated at BHEL Haridwar.

PRODUCTS OF BHEL HARIDWAR AND THEIR CAPACITY RATINGS

1.

Thermal/nuclear set 210MW-1000MW

2.

Hydro set 115MW

3.

Generator according to requirement

4.

gas turbine 60MW-200MW

5.

heat exchangers, condensers Upto 800MW

6.

AC/DC electrical machine 5kW-2000kW(a)AC (250 kW-1600kW )(b)DC (7kW-1000kW)

BHEL has turnkey capabalities for executing power projectors from concept to commissioning. it possesses the technology and capability to produce thermal power plant equipment upto 1000MW rating and gas turbine generator

sets upto a unit rating of 240MW.Cogeration and combine cycle plants have been introduced to achieve higher plant efficiencies. To make efficient use of the higher ash content crash coil manufacturers 235MW nuclear turbine generator sets and has commenced the generation of 500 MW nuclear turbine generator head discharge combinations are also engineered and manufactured is equally competitive.

TRANSMISSION-

BHEL also supplies a wide range of transmission products and systems upto 400kV class. These include high voltage power, distribution transformers, instrument transformers, dry type transformer,SF6 switch gear, capacitor and insulator,etc.Series and shunt compensation systems have been also developed and introduced to minimize transmission losses.

TRANSPORTATION-

A high percentage of trains operated by the Indian Railways are equipped with BHEL’s traction and control equipment including the metro at Calcutta and Delhi.the company supplies broad gauge.

Electrical locomotive to Indian Railway and diesel shunting locomotives to various industries 5000/6000 hp AC/DC locomotive developed and manufactured by B.H.E.L. have been leased to Indian Railway, battery powered road.

INTERNATIONAL OPERATIONS-

B.H.E.L.’s product series and projects have been exported to countries ranging from United states in the west and New Zealand in the east and for India over 3000MW.a few notable ones are a 15o MW gas turbine to Germany ,utility boiler and open cycle gas turbine plant to Malaysia, Tripoli west, power station in Libya and Turkey .in Cyprus, hydro generator to New Zealand and hydro power plant to Thailand, Oman, Greece and Egypt.

CHAPTER 2

CIM SHOP (BLOCK – IV)

BAY-1: Bar winding shop: Manufacturing of stator winding bars of generator, Micalastic Tank & Oven

BAY-2: Heavy duty generator stator bars with New CNC M/c No, 3-464 i.e. Roebel bar centre, TIG Welding

BAY-3: Insulation detail shop: Manufacturing of hard insulation & machining of hares insulation part (Glass textolite) such as packing, washer, insulation box, wedges etc. & CNC Taping Machine

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.

TURBO-GENERATORS: The manufacturing of bars of standard capacity such as: 100MW, 130MW, 150Mw, 210/235MW, 500MW, 600MW.

The plant has capacity and technology to manufacture 660MW, 800MW and 1000MW generators.

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, 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.

TYPES OF INSULATION

Thermal classification depends upon the temperature withstand capability of the insulation.

class Y-upto 90 degree celsius

class A-upto 105 degree celsius

class E-upto 120 degree celsius

class B-upto 130 degree celsius

class F-upto 155 degree celsius

class H-upto 180 degree celsius

class C- > 180 degree celsius

ISSUE OF CONDUCTOR

CUTTING AND END CLEANING

TRANSPOSITION

ASSEMBLY OF CONDUCTORS

CROSS OVER INSULATION

I.S. TEST

FORMING

PICKLING

MOUNTING

BRAZING

REPICKLING

WATER FLOW AND NITROGEN TEST

THERMAL SHOCK TEST

HELIUM LEAK TEST

REFORMING OF OVERHANG PORTION

INSULATION ON CNC MACHINE

IMPREGNATION

SURFACE FINISHING

OUTER CORONA PROTECTION (OCP)

H.V. AND TAN ∆ TEST

CHAPTER 3

MANUFACTURING PROCESS OF BARS

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

1.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 Length Number of conductors

8*4.6*1.5mm(Hollow) 8*2.8 mm (Solid)

10200 mm Hollow- 20 Solid - 20

Upper Bar

Conductor size Length Number of conductors

8*4.6*1.5mm(Hollow) 8*1.3 mm (Solid)

10050 mm Hollow- 20 Solid - 40

2. 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.

1. To reduce eddy current losses. 2. 2.Equalize the voltage generator3. To minimize skin effect of ac current, small cross section of conductor is used and

also hollow conductors are used to effect cooling by D.M. water.

3. 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 micanite) 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.

4. 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 1600 C for a given period. The consolidated stack is withdrawn from the press and the dimensions are checked.

5. Inter Strand Short Test

The consolidated oar 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. (300V A/C supply)

6. Forming

The straight bar stack is formed as per overhang profile (as per design), the overhang portion is consolidated after forming.

7. Brazing of coil lugs

For water cooled generator bars, the electrical connection contact and water box for inlet and outlet of water are brazed.

8. Thermal shock test

26 cycles of hot (800C) and cold (30°C) water are flown through the bar to ensure the thermal expansion and contraction of the joints.

9. Helium leakage test

After thermal shock test bar is tested for any leakage with the help of helium gas.

10. 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.

11. Impregnation and baking

a) Thermoreactive 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 laid 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 Micalastic 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.

12. Finishing

The baked and dimensionally correct bars are sanded-off to smooth the edges and the surface is calibrated, if required, for the dimension.

13. 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.

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 shelf 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.

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. The capacitance of the bar is found and the angle of deviation due to the impurity in the insulation is obtained from the formula

C4*R4*10-4 =tan∆

b) H.V. Test:

(High Voltage 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

This training has proved to be quite faithful. This gave me, a chance to have an encounter with such heavy machines like turbo generator (TG) 500MW.The architecture of B.H.E.L. ,the way the various units are linked and the way the working of the whole plant is controlled, makes the student realize that engineering is not just the structural description but more of planning and management. It has provided an opportunity to learn that optimization of technology used at proper place and time can save a lot of labour.

The training has proved to be immensely helpful as it has helped me to have an exposure of the practical implementation of the theoretical knowledge that I have gained till date.