MANUFACTURING PROCESS OF TURBO GENERATORS
MANUFACTURING PROCESS OF TURBO GENERATORS A Mini Project Work Submitted in partial fulfilment of the Requirements for the award of degree of BACHELOR OF TECHNOLOGY In
ELECTRICAL ENGINEERING By
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
ACKNOWLEDGEMENT “An 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.
INDEX 1. 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 OVERVIEW The 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. BHEL’s 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, HARIDWAR Against 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.
HARIDWAR HEEP (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 Faraday’s 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.
*Faraday’s 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 dϕ/dt
2.3 SIZING OF GENERATOR MODULE: Basic equation for sizing of electrical machines P=K.As.Bδ.D2 L .ns It can also be written as D2L=P/ (K.As. Bδ .ns) Here P = MW output As = Electric Loading (Amp.cond/cm) Bδ = 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 STATOR STATOR
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 α Kh . βmax1.6
Eddy Current losses: Due to the e.m.f induced in the core eddy currents are produced and produce losses. Eddy current loss is given by
We α βmax2 . t2 For 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 thickness of varnish should be around 8-10 microns. Each lamination should be dried for around 90 sec at constant speed.
3.4 ASSEMBLY OF CORE: The stator laminations are assembled as separate cage without stator frame. The entire core length is made in the form of packets separate by radial ducts to provide ventilating passage for the cooling of core. The thickness of lamination is about 0.5mm and the thickness of lamination separating the packets is about 1mm. The segments are staggered from layer to layer so that a core of high mechanical strength and uniform permeability of magnetic flux is obtained.
Fig: assembly of core
To obtain the maximum compression and eliminate under setting during operation, the laminations are hydraulically compressed and heated during the stacking procedure when certain heights of stack is reached. The complete stack is kept under pressure and located in stator frame by means of clamping bolts and pressure plates.
Fig .Compression of Core
3.5 STATOR WINDING: The stator winding of Turbo Generator is three phase two layer lap winding with the pitch of winding so adjusted as to reduce the 5th and 7th harmonics. The number of slots for generation of three phase power must be a multiple of 3 or 6. Each stator slot accommodates two stator bars.
3.5.1 CONDUCTOR CONSTRUCTION: The bar consists of a large number of separately insulated strands which are transposed to reduce the skin effect losses. The strands of small rectangular cross-section are provided with braided glass insulation and arranged side by side over the slot width. The individual layers are insulated by vertical separator. In the straight slot portion the strands are transposed by 540o. The transposition provides for a mutual neutralization of the voltages induced in the individual strands due to the slot cross-field and end winding flux leakage and ensures that minimum circulation current exist. The current flowing through the conductor is thus uniformly distributed over the entire cross-section so that the current-dependent losses will be reduced
Fig. Transposition of bars
3.5.2 THDF BAR CONSTRUCTION: The bar consists of hollow and solid strands distributed over the entire bar crosssection so that good heat dissipation is ensured. At the bar ends, all the solid strands are jointly brazed into a connecting sleeve and the hollow strands into a water box from which the cooling water enters and exists via Teflon insulating hoses. The strands are transposed by 540o in the slot portion.
fig. Stator bar of THDF
3.5.3 INSULATION: Insulation is basically done to prevent any kind of short circuit between the bar and the stator core when the bar is assembled in the stator of the machine. The stator bars are insulated with Micalastic (trade name) insulation. Advantages of Micalastic insulation are as follows: Good conductor of heat Low inflamability High resistance to moisture and chemical action Retains properties even after years of operation
3.6 STATOR END COVER: The ends of the stator frame are closed by pressure containing end shields .The end covers are made up of non-magnetic material (Aluminium castings) to reduce stray load and eddy current losses. The end shields feature a high stiffness and accommodates generator bearings, hydrogen coolers etc. The end shields are horizontally split to allow for assembly. The end shield used at the turbine end and exciter end side is different in construction for 500MW. The end cover used in 250 MW is similar in construction.
EXCITER END SIDE (500MW)
TURBINE END SIDE (500MW)
3.7 BUSHINGS: The beginning and ends of the three phase windings are brought out from the stator frame through bushings, which provides for high voltage insulation. The bushings are bolted to the stator frame at the exciter end.
Fig. Bushings
3.8 GENERATOR TERMINAL BOX: The phase and neutral leads of the three phase stator windings are brought out of the generator through six bushings located in the generator terminal box at the exciter end of the generator.
Terminal box
Fig. Generator terminal box
Bushing
CHAPTER 4 ROTOR
4. ROTOR 1. Rotating part of turbo generator 2. A high strength alloy steel single forging prepared by vacuum cast steel. 3. Longitudinal slots for housing field winding 4. Damper winding is provided which safeguards the asymmetrical and asynchronous operative conditions. 5. Rotor of cylindrical type used in turbo generator. 6. Supported on two journal bearings. 7. Provision of axial fan for forced ventilation.
Fig. Rotor
Approximately 60% of the rotor circumference is provided with longitudinally slots which hold the field windings. The slot pitch is selected so that two solid poles are obtained with a displacement of 180 degrees.
Due to the non uniform slot distribution is on the circumference, different moments of inertia are obtained in the main axis of rotor. This in turn causes vibration. These vibrations are reduced by transverse slotting of the poles. The rotor winding is provided with a lateral gap pick up system of cooling in the slot portion, ensuring uniform temperature distribution of the winding.
4.1 MAIN PARTS OF ROTOR
Fig. Main parts of rotor
4.2 ROTOR WINDING: The rotor of turbo generator accommodates field winding. Turbo generator is a two pole machine rotating at a speed of 3000 R.P.M. There are 28 slots cut on two-third of the periphery which support field winding. The field winding consists of several series connected coils inserted into the longitudinal slots of rotor body. The coils are wound so that two poles are obtained. The conductors are made up of copper with a silver content of approximately of 0.1%. The solid conductors have a rectangular cross section and are provided with axial slots for radial discharge.
Fig. Rotor bar
The individual bars are bent to obtain half turns. After insertion into the rotor slots, these turns are brazed to obtain full turns. The series connected turns of one slot constitute one coil. The individual coils are connected in a way that north and south poles are obtained.
Fig.Rotor winding
4.3 INSULATION: The insulation between the individual turns is made of layer of glass fibre laminate. The coils are insulated from the rotor body with L-shaped strips of glass fibre laminate with nomex interlines. Insulation between overhang is done by blocks mad of HGL.
4.4 ROTOR SLOT WEDGES: The rotor of turbo generator is rotating at a very high speed therefore to protect the winding against the effects from centrifugal forces they are secured firmly by rotor slot wedges. The slots wedges are made of copper alloy. They are also use ad damper winding bars. The wedge and retaining ring act as damper winding in case of asymmetrical and asynchronous operation. The ring is coated with silver which acts as short circuit rings in damper windings.
Fig. Rotor slot wedge
4.5 ROTOR RETAINING RING: To protect end winding of rotor from flying out from the rotor due to centrifugal forces rotor retaining ring is used. Retaining rings are made from high tensile nonmagnetic alloy steel forgings in order to reduce stray losses. These act as short circuit rings to the induced current to the damper system. To ensure low contact resistance retaining rings are coated with nickel, aluminium, silver.
Fig. Retaining ring
4.6 FIELD CONNECTION: The field current is supplied to the rotor winding through radial terminal bolts and two semicircular conductors located in the hollow bores of the exciter and rotor shafts. The field connection provides electrical connection between the rotor winding and exciter.
4.6.1 TERMINAL LUG: The terminal lug is a copper conductor of rectangular cross section. One end of terminal lug is braced to the rotor winding while the other end is screwed to the radial bolt.
4.6.2 RADIAL BOLT: The field current leads located in the shaft bore is connected to the terminal lug at the end winding through a radial bolt.
4.6.3 FIELD CURRENT LEAD: The leads are run in the axial directions from the radial bolt to the end of rotor. They consist of two semicircular conductors insulated from each other by an intermediate plate and from the shaft by tube.
Fig. Field current lead
4.7 ROTOR FAN: The cooling air in generator is circulated by axial fans located on the rotor shaft. In 250 MW rotor two axial flow fans are located on both turbine as well as exciter end side whereas in 500 MW axial fans are located on turbine end side only.
Fig. Rotor fan
CHAPTER 5 EXCITATION SYSTEM
5. EXCITATION SYSTEM 5.1 Brushless Excitation: The main parts of brushless excitation system are as follows: 1. Pilot exciter 2. Main exciter 3. Rectifier wheel 4. Automatic voltage regulator The three phase pilot exciter has a revolving field with permanent magnet poles. The armature winding is housed on the stator. The three phase a.c. generated by the pilot exciter is rectified and controlled by automatic voltage regulator to provide variable D.C. for exciting the main exciter. The three phase main exciter has stationary field with revolving armature. Thus three phase a.c. power is produced in main exciter which is rectified by rotating rectifier bridge and is fed to the field winding of the rotor (turbo generator) through dc leads.
Permanent magnet generator
fan
main exciter
rectifier wheel
5.2 Pilot Exciter: Three phase pilot exciter is 16 pole revolving field units. The stator accommodates three phase armature winding and magnetic poles are placed on the rotor. Thus rotating flux is produced which cuts the stationary armature conductors and three phase a.c. is generated.
PMG ROTOR AND FAN
5.3 Main Exciter: The three phase main exciter is a 6 pole armature type unit. The stator frame accommodates the field winding. The field winding is placed on the magnetic poles. The armature consists of stacked lamination and the three phase winding is inserted into the slots of the laminated armature. Stator core Stator Frame
magnetic pole
Fig. main exciter
damper winding
5.4 Rectifier wheel: Components in the rectifier wheel are as follows: 1. Silicon diodes 2. Aluminium heat sink 3. Fuses 4. RC circuit
DC leads
heat sink
Diodes rectifier wheel
Fig. rectifier wheel
The main component in the rectifier wheel is silicon diodes which are arranged in rectifier wheel in three phase bridge circuit. The direct current from rectifier wheel is fed to DC leads and then to the field winding of the rotor.
5.5 Flowchart of Brushless Excitation:
Pilot exciter
Main Exciter
Permanent magnet field on rotor, Armature on stator
Armature on rotor, field winding on stator
Silicon Diode bridge on shaft
To alternator field Thyristor Controlled Bridge
Regulator
Output from alternator
5.6 Advantages of Brushless Excitation: Eliminates slip rings and brushes Eliminates all problems associated with transfer of current via sliding contacts Eliminates the hazard of changing brushes on load Brush losses are eliminated Minimum operating and maintenance cost High response excitation with fast acting AVR Rotor Earth Fault Measurement through provision of Instrument Slip Rings
CHAPTER 6 COOLING SYSTEM
6. COOLING SYSTEM Power output of electrical machine is given by P=K.As.Bδ.D2 L .ns It can also be written as D2L=P/ (K.As. Bδ .ns) Machine Size is a critical and important aspect of design of very Large Capacity Machines from handling, transportation point of view. From Output Equation, Machine Size is inversely proportional to ‘As’. Electrical loading ‘As’ is indicative of Winding Losses. Higher the losses are allowed, more Output Power can be obtained from the Machine. Winding temperature increases with increase in Losses. Size can only be limited with very high ‘As’. This can be achieved by efficient cooling system since higher value of ‘As’ means higher losses.
6.1 COOLING METHODS FOR TURBOGENERATOR: STATOR WINDING: Indirectly Air Cooled ROTOR WINDING: Directly Air Cooled STATOR WINDING: Indirectly Hydrogen Cooled ROTOR WINDING: Directly Hydrogen Cooled STATOR WINDING: Directly Water Cooled ROTOR WINDING: Directly Hydrogen Cooled
6.2 AIR COOLED TURBO GENERATOR: In Air Cooled Turbo generator stator winding is indirectly air cooled whereas the rotor winding and stator core is directly air cooled. This type of cooling is applicable for rating of 30 MW- 60 MW generators. In this type of turbo generator there are vertically side mounted cooler in a separate housing.
fig. Cooling of rotor and stator Hot air Cold air
6.3 HYDROGEN COOLING AND HYDROGEN COOLED T.G. (THRI): When the problem of increasing generator rating was talked in it became clear that the air cooled machine did not provide the necessary scope for progress. Not only in circulating the requisite of air through the machine but also because high fan power required to circulate. Evidently to push up generator ratings hydrogen is used as cooling medium.
Advantages of Hydrogen as Cooling Medium: a) Increased efficiency: The density of H2 is only 0.07 times the density of air and therefore the power required to circulate H2 is less than that required in air. b) Increase in rating: H2 has a heat transfer coefficient 1.5 times and its thermal conductivity is 7 times that of air. Consequently when H2 is used as a coolant, the heat is more rapidly taken up from the machine parts and dissipated. c) Elimination of fire hazard: The outbreak of fire inside the machine is impossible as H2 does not support combustion. d) Smaller size of coolers: The size of cooler required is smaller in size.
Cooler
Stator core
Stator
Rotor
fig. Cooling of rotor and stator
Bushings
6.4 HYDROGEN/WATER COOLED T.G. (THDF): In large rating machines, hydrogen cooling is not sufficient to remove the entire heat generated. For additional cooling, a Primary Water (PW) cooling system with demineralised water flowing through the hollow stator conductors is used. The rotor conductors are hydrogen cooled.
Cooler
water box
stator core
rotor
fig. Cooling of rotor and stator
CHAPTER 7 GENERATOR TECHNICAL DATA
7. GENERATOR TECHNICAL DATA
Chapter 8 TESTING OF TURBO GENERATOR
8. TESTING OF TURBO GENERATOR: To ensure that all functional requirements are fulfilled, and to estimate the performance of generator, the TURBO GENERATORS are required to undergo some tests. 8.1 SHORT CIRCUIT TEST: The machine is run at rated speed and drive motor input voltage and current are noted and excitation is gradually increased in steps, at 20, 40, 60, 80, 100% rated current of machine. The short circuit characteristics is plotted from short circuit results by selecting X-axis as field current and Y-axis as % rated current. From the Short Circuit test, we will get copper losses. 8.2 OPEN CIRCUIT TEST: The machine is run at rated speed and the motor input voltage and current are noted and excitation is gradually increased in steps, at 20, 40, 60, 80, 90, 95, 100, 105, 110 and 120 % of rated voltage of machine. The open circuit characteristics is plotted from open circuit results by selecting X-axis as field current and Y-axis as % rated voltage. From the open circuit test, we will get Iron Losses. 8.3 INTER STRAND TEST: This testing is basically done to check any short circuit between ant two consecutive conductors of a bar. For this test all the bare conductors at both the ends are separated from each other so that they do not short circuit. Then a live wire is connected to a conductor and received from it consecutive conductor to
light a lamp. Hence if the lamp lights up it shows short circuit between the two conductors due to improper insulation between them. It shows insulation failure between the conductors, these conductors are then replaced and bar is followed through all the previous processes. Similarly all the conductors are checked for any short circuit. 8.4 HIGH
VOLTAGE
TEST
ON
ROTOR
AND
STATOR
WINDING
(MACHINE AT REST): The High Voltage is applied to windings by increasing gradually to required value and maintained for one minute and reduced gradually to minimum. The transformer is switched off and winding is discharged to earth by shorting the terminal to earth using earthing rod connected to earthen wire. The test is conducted on all the phases and rotor winding separately. When High Voltage test is done on one phase winding, all other phase windings, rotor winding, instrumentation cables and stator body is earthed. This test is done to check the insulation of the winding and hence it is also known as insulation test. High Voltage test levels: Stator winding = (2 Ut +1) KV Rotor winding = (10 * Up) V Here, Ut = Rated voltage of the machine under test Up = Excitation voltage
8.5 HELIUM TEST: Helium test is done to check leakage within the bar and at the brazed portions. Any minute leakage which couldn’t be checked by water test can easily be observed by helium test because helium is one of the lightest gas. In helium test, whole of the bar is wrapped in the polythene excluding the end points. The helium gas at pressure of 11Kg/Cm2 is passed through the bar and a probe connected to the gauge is inserted inside the polythene at different places. The gauge will show deflection if there is any helium atom present. Gauge will show reading even if 1 helium atom in 100000 atoms is present.
CHAPTER 9 CONCLUSION
CONCLUSION The Vocational training at BHEL Haridwar helped us in improving our practical knowledge and awareness regarding Turbo Generator to a large extent. Here we came to know about the technology and material used in manufacturing of turbo generators. Besides this, we also visualized the parts involved or equipments used in the power generation. Here we learnt about how the electrical equipments are being manufactured and how they tackle the various problems under different circumstances. At least we could say that the training at BHEL Haridwar is great experience for us and it really helped us in making or developing our knowledge about turbo generator and other equipment used in power generation.
REFERENCES http://www.bhel.com/about_publication.php http://en.wikipedia.org/wiki/Turbo_generator http://en.wikipedia.org/wiki/Hydrogen-cooled_turbogenerator A text book of electrical machines by P.S.BIMBRA A text book of electrical technology by B.L.THERAJA BHEL Internal material
