dokumen.tips_manufacturing-of-turbo-generators-in-bhel-ppt (1).pptx

manufacturing of turbogenerators

1. STUDY PROJECT ON MANUFACTURE OF TURBO GENERATORS 1

2. INTRODUCTION WORKING PRINCIPLE OF GENERATOR 2

3. Components of Turbo Generators 3

4. STATOR 4

5. STATOR FRAME welding steel single piece construction in order to support the laminated core and windings 5

6. STATOR CORE 6

7. OPERATIONS IN MANUFACTURING OF LAMINATIONS A .The cold rolled non grained oriented (CRNGO) steel sheets in the required shapes according to the size of the laminations are cut by the feeding the sheet into shearing press . B .Compounding operation or blanking &notching operation. C. Deburring operation D. Varnishing E. The prepared laminations are subjected to following tests: i) Xylol test-to measure the chemical resistance ii) Mandrel test-when wound around mandrel there should not be any cracks iii) Hardness test-minimum 7h pencil hardness iv) Ir value test-for 20 layers of laminations insulation resistance should not be less than 1 mega ohm 7

8. PURPOSE OF STATOR CORE To support stator windings To carry the electromagnetic flux generated by rotor winding. Hence selection of material for building up of core plays a vital role. The losses in the core are of two types: Hysteresis losses Wh a b max 1.6ft Eddy current losses We a b max 2 f 2 t 2 In order to reduce the hysteresis loss silicon alloyed steel, which has the low hysteresis constant is used for the manufacture of the core. the composition of silicon steel is Steel-95.8% Silicon-4.0% Impurities-0.2% 8

9. STATOR COILS 1. Set the straightening and cutting machine using guide pilot 2. Cut the conductor strips as per requirement 3. Set the press for “Roebel transposition” 4. Assemble strips with respect to template and transpose 5.Assembling both halves of the coil sides to form i)One roeble half bar ii)Inserting insulation in straight part 9

10. 6.Baking process 7. remove insulation at the ends of the strips and testing for the inter strips and inter halves shorts 8. Set the universal former as per standards and bending the stator coils in roebel shape 9.Tapping process 10

11. STATOR END COVERS Phase connections Resistance Temperature detectors 11

12. STATOR WINDINGS Two types of coils Diamond pulled multiturn coil (full coiled) Roebel bar (half coil) Winding Stator 12

13. Connecting Rings Stator Terminals Insulated Copper Bars are placed in the slots to form 3Ø winding HGL End Winding Support Clamping Plates & Rings STATOR WITH ALL STATOR WINDINGS INTERCONNECTIONS 13

14. ROTOR 14

15. ROTOR SHAFT SINGLE PIECE SOLID ROTOR BODY MILLING THE FIELD WINDINGS INTO THE ROTOR BODY MACHINED ROTOR Rotor Slots 15

16. CONSTRUCTION Several series connected coils inserted into the longitudinal slots of rotor body. CONDUCTOR MATERIAL INSULATION 16

17. ROTOR SLOT WEDGES Slot wedges are made of copper alloy featuring high strength +good electric conductivity Protect the windings against the centrifugal forces . Windings are secured in the slots with wedges 17

18. END WINDING BRACES ROTOR RETAINING RINGS ROTOR FANS 18

19. BEARINGS High mechanical stability and reduced vibration in operation To prevent damage to the journals due to the shaft currents, bearings and oil piping on either side of the non-drive end bearings are insulated from the foundation frame. For facilitating and monitoring the healthiness of bearing insulation, split insulation is provided 19

20. COOLING SYSTEM There are various methods of cooling. They are i ) Air cooling –60 MW ii) Hydrogen cooling – 100 MW iii) Water cooling – 500 MW iv)Hydrogen and water cooling – 100 MW DISADVANTAGES OF HYDROGEN OVER AIR COOLING: a) Hydrogen is explosive when it combines with oxygen. b) Greater precautions are to be taken to avoid leakage of Hydrogen. c) Cost of cooling system is high compared to air cooling system 20

21. AIR COOLING Flow path 1: is directed into the rotor end winding space and cools the rotor winding, part of the cooling air flows past the individual coils for cooling the rotor end winding and then leaves the end winding space via bores in the rotor teeth at the end of the rotor body. Flow path 2 :is directed over the stator end winding to the cold air ducts and into the cold air compartments in the stator frame space between the generator housing and the rotor core. Flow path 3: is directed into the air gap via the rotor retaining ring. core. 21

22. EXCITORS Exciter is brushless and takes the form of the stationary field generators Rotor of Brushless Exciter Rotating Diodes & Fuses Permanent Magnets E/f Monitoring Slip Rings Armature Diode Wheel 22

23. EXCITATION SYSTEM COMPRISES OF ROTOR ROTOR WINDINGS RECTIFIER VARISTORS MAIN EXCITORS ROTATING RECTIFIER WHEEL 23

24. CONCLUSION AND FUTURE SCOPE 24

25. THANK YOU 25

26. 26