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MANUFACTURING PROCESS OF TURBO GENERATORS

MANUFACTURING PROCESS OF TURBO GENERATORSA Mini Project Work Submitted in partial fulfilment of the Requirements for the award of degree of BACHELOR OF TECHNOLOGYIn

ELECTRICAL ENGINEERINGBy

NITIN GUPTA (2008UEE129) Under the guidance of

Mr.C.M.ARORA & Mr. V.K.JAIN

Dept. of Electrical Engineering MALAVIYA NATIONAL INSTITUTE OF TECHNOLOGY 2011-2012

ACKNOWLEDGEMENTAn engineer with only theoretical knowledge is not a complete engineer. Practical knowledge is very important to develop and apply engineering skills. It gives me a great pleasure to have an opportunity to acknowledge and to express gratitude to those who were associated with me during my training at BHEL. Special thanks to Mr.P.S.Jangpangi for providing me with an opportunity to undergo training under his able guidance. I am very great full to our training and placement officer Mr. ROHIT GOYAL for his support. I express my sincere thanks and gratitude to BHEL authorities for allowing me to undergo the training in this prestigious organization. I will always remain indebted to them for their constant interest and excellent guidance in my training work, moreover for providing me with an opportunity to work and gain experience.

INDEX1. BHEL-An Overview 2. Introduction 3. Stator 4. Rotor 5. Excitation System 6. Cooling system 7. Generator Technical Data 8. Testing Of Turbo Generator 9. Conclusion 10. References

CHAPTER 1 BHEL-AN OVERVIEW

BHEL-AN OVERVIEWThe first plant of what is today known as BHEL was established nearly 40 years ago at Bhopal & was the genesis of the Heavy Equipment industry in India. BHEL is today the largest Engineering Enterprise of its kind in India with excellent track record of performance, making profits continuously since 1971-1972 BHEL business operations cater to core sectors of the Indian Economy like Power Industry Transportation Transmission etc.

BHEL has 14 units spread all over India manufacturing boilers, turbines, generators, transformers, motors etc. Besides 14 manufacturing divisions the company has 4 power sector regional centres, 8 service centres and 18 regional offices and a large number of project sites thus enable the Company to promptly serve its customers and provide them with suitable products, systems and services efficiently and at competitive prices. The high level of quality & reliability of its products is due to the emphasis on design, engineering and manufacturing to international standards by acquiring and adapting some of the best technologies from leading companies in the world, together with technologies developed in its own R&D centres. BHELs vision is to become world-class engineering enterprise, committed to enhancing stakeholder value. The company is striving to give shape to its aspirations and fulfil the expectations of the country to become a global player.

BHEL, HARIDWARAgainst the picturesque Shivalik foot hill of the Himalayas and on the banks of the holy Ganga in Ranipur near Hardwar are located the two manufacturing plants of BHEL: Heavy Electrical Equipment Plant (HEEP) and Central Foundry Forge Plant (CFFP) employing about 10000 people. Heavy Electrical Equipment Plant is equipped to produce Steam and Hydro Turbines with matching Generators, Industrial Manufacturing Thermal sets up to 1000 MW capacity. Located immediately south of HEEP is the Central Foundry Forge Plant setup. The Heavy Electrical Equipment Plant was set up in technical collaboration with M/s Prommash-export of USSR. The construction of the plant commenced in 1962 and the production of equipment was initiated in early 1967. In 1976, BHEL entered into a collaboration agreement with M/s Kraftwerk Union A.G. of West Germany for design, manufacture, erection and commissioning of large size steam turbines and turbo generators of unit rating up to 1000MW. The BHEL plants in Haridwar have earned the ISO-9001 AND 9002 certificates for its high quality and maintenance. These two units have also earned the ISO-14001 certificates.

CHART SHOWING DIFFERENT BLOCKS OF BHEL, HARIDWAR

BHARAT HEAVY ELECTRICALS LTD.

HARIDWARHEEP (HEAVYEL ECTRICAL EQUIPMENT PLANT)HARDWAR

CFFP (CENTRAL FOUNDARY FORGED PLANT)

BLOCK-1: ELECTRICAL MACHINE SHOP

BLOCK-2: HEAVY FABRICATION SHOP

BLOCK-3: TURBINE MANUFACTURING BLOCK

BLOCK-4: CIM (COILS & INSULATION MANUFACTURING) BLOCK FACTURING) BLOCK BLOCK-5: CONDENCER FABRICATION & FORGR BLOCK

BLOCK-6: FABRICATION SHOP, DIE SHOP STAMPING SHOP) BLOCK-7: CARPANTARY SHOP

BLOCK-8: HEAT EXCHANGER SHOP

CHAPTER 2 INTRODUCTION

2. INTRODUCTION 2.1 TURBOGENERATOR:A turbo generator is a turbine directly connected to electric generator for the generation of electricity. They are mostly used as large capacity generator driven by steam/gas turbine.

2.2 PRINCIPLE OF OPERATION: In case of turbo generator, Rotor winding is supplied with DC current (through slip rings or brushless exciter) which produces constant magnetic field. 3 phase stator winding is laid in stator core. When generator rotor is rotated (by a turbine) magnetic flux produced by rotor winding also rotates. Voltage is induced in stator winding according to Faradays law*. 3 phase stator winding also produces magnetic flux revolving at synchronous speed (=120*f/2p). Rotor also rotates at synchronous speed. Both the magnetic fields are locked and rotate together.

*Faradays Law:E.M.F. (Voltage) is induced in a closed path due to change of flux linkages and is proportional to rate of change of flux linkages. The change in flux linkages can be caused by change in flux in a stationary coil or by motion of coil with constant flux or both. E = N d/dt

2.3 SIZING OF GENERATOR MODULE:Basic equation for sizing of electrical machines P=K.As.B.D2 L .ns It can also be written as D2L=P/ (K.As. B .ns) Here P = MW output As = Electric Loading (Amp.cond/cm) B = Magnetic Loading (gauss) D = Stator bore diameter (cm) L = Stator core length (cm) ns = Rated speed D2L = Volume of Rotor or Size of the Machine

MW Rating:Size of machine (D2L) is directly proportional to its output (MW)

Speed:Size of machine (D2L) is inversely proportional to its speed Synchronous Speed = 120*F/ P

2.4 SYNCHRONOUS GENERATOR CLASSIFICATION BASED ON THE MEDIUM USED FOR GENERATION: Turbo generators in Thermal, nuclear, Gas station High speed 3000 rpm No. of poles 2 poles Horizontal construction Cylindrical rotor Hydro generators in hydel plants Low speed 500 to 1000 rpm No. of poles 6 or more Vertical construction

Salient type of rotor 2.5 GENERATOR MODULE NOMENCLATURE:

2.6 GENERATOR MODULES: TARI: Air Cooled Turbo generator Stator Winding: Indirectly Air Cooled Rotor Winding/ Stator Core: Directly Air Cooled THRI: Hydrogen Cooled Turbo generator Stator Winding: Indirectly Hydrogen Cooled Rotor Winding/ Stator Core: Directly Hydrogen Cooled THDF: Hydrogen/Water Cooled Turbo generator Stator Winding: Directly Water Cooled Rotor Winding/ Stator Core: Directly Hydrogen Cooled 2.7 COMPONENTS USED IN TURBO GENERATOR: 2.7.1 STATOR Stator frame Stator core Stator winding End cover Bushings Generator terminal box

2.7.2 ROTOR Rotor shaft Rotor winding Rotor retaining ring Field connection

2.7.3 EXCITATION SYSTEM: Pilot exciter Main exciter

Diode wheel The following auxiliaries are required for operation: Bearings Cooling system Oil Supply System

CHAPTER 3 STATORSTATOR

3. STATOR The stator consists of following parts: 1. Stator frame 2. Stator core 3. Stator winding 4. Stator end cover 5. Bushings 6. Generator terminal box 3.1 Stator frame: Rigid fabricated cylindrical frame and is the heaviest section in the generator Withstands weight of core & winding, forces & torques during operation Provisions for H2/CO2 filling Provision for temperature measurements Foot plates for supporting on foundation Provision for H2 coolers

3.2 Stator core:The stator core is made from the insulated electrical sheet lamination to minimize eddy current losses. Each lamination layer is made of individual sections. The main features of core are: 1. To carry electric & magnetic flux efficiently. 2. To provide mechanical support.

3. To ensure perfect link between the core and rotor.

Fig: stator core

3.2.1 THE PURPOSE OF STATOR CORE: Support the stator winding To carry the magnetic flux generated by rotor winding. Therefore the selection of material for building up of core is very important. In selection of material the losses in the core are considered. There are basically two types of losses.

Hysteresis losses: Due to the residual magnetic flux in the core material.Hysteresis loss is given by

Wh Kh . max1.6

Eddy Current losses: Due to the e.m.f induced in the core eddy currents areproduced and produce losses. Eddy current loss is given by

We max2 . t2For the reduction of hysteresis loss, silicon alloyed steel is used since it has low value of hysteresis coefficient (Kh) for the manufacture of core. The composition of silicon steel is Steel-95.8% Silicon-4.0% Impurities-0.2% Since the eddy current loss depends on the square of thickness of the lamination. Hence to reduce eddy current loss core is made up from thin laminations which are insulated from each other. The thickness of lamination is about 0.5mm.

3.3 LAMINATION PREPARATION:The core is built up of 6 sectors, each of 600. The insulation used between the lamination is ALKYD PHENOLIC VARNISH dried at suitable temperature. The laminations are passes through a conveyor, which has an arrangement to sprinkle the varnish. The sheets are dried at a temperature around 300o-400oC. Two coatings of varnish are done. The thick