EE504.2.ppt
- 1. EE-504.2 1 DEPARTMENT OF TECHNICAL EDUCATION ANDHRA PRADESH Name : G.Venkateswara Rao Designation : Lecturer Branch : Electrical & Electronic Engg. Institute :G.P.T,Hyderabad Year/semester :v Semester Subject :Power systems-II ( Transmission & Distribution) Subject code :EE-504 Topic :Transmission lines Sub topic :Conductor material required for supply systems in head lines & under ground tables Duration :50 min Teaching Aids :ppt, diagrams.
- 2. EE-504.2 2 RECAP • The need of Transmission lines • Choice of supply systems • relative advantages of D.C and A.C systems. In the previous class, we have discussed about
- 3. EE-504.2 3 OBJECTIVES On completion of this period, you would be able to know • The Conductor material required by the supply systems for Over head lines and Under ground cables.
- 4. EE-504.2 4 The following assumptions are made for calculating conducting material • Equal amounts of power transmitted. • Equal lengths of line • Equal line loss. • The max. voltage between two conductors is same (Vm).
- 5. EE-504.2 5 CONDUCTOR MATERIAL REQUIRED FOR OVER HEAD LINE FOR VARIOUS SYSTEMS D.C system: 1.D.C two wire system with one conductor earthed Fig.1
- 6. EE-504.2 6 Vm is the max.potential difference between conductor and earth in volts. I is current in amperes, R is the resistance of the conductor in ohms. Line voltage = Vm Power transmitted = P = Vm I watts. Line loss or power loss = 2 I2 R watts.
- 7. EE-504.2 7 2. D.C Two wire system with mid point earthed: Fig.2
- 8. EE-504.2 8 Vm is the max.potential difference between conductor and earth in volts. I1 is current in amperes, R1 is the resistance of the conductor in ohms. Line voltage = 2 Vm Power transmitted = P = 2 Vm I1 watts. Line loss or power loss = 2 I1 2 R1 watts.
- 9. EE-504.2 9 Equating for equal power 2 Vm I1= Vm I I1 = I/2 Equating for equal power loss 2 I1 2 R1 = 2 I2 R R / R1 = I1 2 / I2 = (I / 2)2 / I2 = 1/4 = a1 / a
- 10. EE-504.2 10 Amt. of cond. Mat. Req. for D.C 2wire sys. with mid point earthed Amt. of cond. Mat. Req. for D.C 2wire sys. with one end earthed =1/4
- 11. EE-504.2 11 A.C SYSTEM 1.Single phase two wire system with one conductor earthed: Fig.3
- 12. EE-504.2 12 Vm is the max.potential difference between conductor and earth in volts. I2 is current in amperes, R2 is the resistance of the conductor in ohms and power factor = Rms voltage = Power transmitted = P = I2 watts. Line loss or power loss = 2 I2 2 R2 watts.
- 13. EE-504.2 13 Equating for equal power, I2 = Vm I I2 = I / Equating for equal power loss, 2 I2 2 R2 = 2 I2 R 2 ( I / )2 R2 = 2 I2 R R / R2 = 2 / = a2 / a
- 14. EE-504.2 14 Amt. of cond. Mat.Req.for A.C 2wire sys.with one cond.earthed Amt. of cond. Mat.Req. for D.C 2wire sys. with one end earthed
- 15. EE-504.2 15 Fig.4 2. Single phase two wire system with mid point earthed:
- 16. EE-504.2 16 Vm is the max.potential difference between conductor and earth in volts. I3 is current in amperes, R3 is the resistance of the conductor in ohms and power factor = Rms voltage = 2 = Power transmitted = P = I3 watts Line loss or power loss = 2 I3 2 R3 watts.
- 17. EE-504.2 17 Equating for equal power, I3 = Vm I I3 = I / Equating for equal power loss, 2 I3 2 R3 = 2 I2 R R / R3 = I3 2 / I2 = 1 / 2 = a3 / a
- 18. EE-504.2 18 Amt.of cond. Mat. Req.for A.C 2wire sys.with mid point earthed Amt.of cond. Mat. Req. for D.C 2wire sys. with one end earthed
- 19. EE-504.2 19 3. Three phase three wire system: Fig.6
- 20. EE-504.2 20 Vm is the max.potential difference between conductor and earth in volts. I5 is current in amperes, R5 is the resistance of the conductor in ohms and power factor = Rms voltage = Power transmitted = P = 3 I5 watts. Line loss or power loss = 3 I5 2 R5 watts.
- 21. EE-504.2 21 Equating for equal power, 3 I5 = Vm I I5 = (I / 3) Equating for equal power loss, 3 I5 2 R5 = 2 I2 R R / R5 = 3 I5 2 / 2 I2 = 1 / 3 = a5 / a
- 22. EE-504.2 22 Amt.of cond. Mat.Req.for A.C 3- 3wire system Amt.of cond Mat. Req.for D.C 2wire sys.with one end earthed
- 23. EE-504.2 23 CONDUCTOR MATERIAL REQUIRED FOR UNDERGROUND CABLES FOR VARIOUS SYSTEMS Fig.7 D.C system: 1.D.C two wire system
- 24. EE-504.2 24 Vm is the max.potential difference between conductor and earth in volts. I is current in amperes, R is the resistance of the conductor in ohms. Line voltage = Vm Power transmitted = P = Vm I watts. Line loss or power loss = 2 I2 R watts.
- 25. EE-504.2 25 2.D.C Two wire system with mid point earthed: Fig.8
- 26. EE-504.2 26 Vm is the max.potential difference between conductors. I1 is current in amperes, R1 is the resistance of the conductor in ohms. Line voltage = Vm Power transmitted = P = Vm I1 watts. Line loss or power loss = 2 I1 2 R1 watts.
- 27. EE-504.2 27 Equating for equal power Vm I1= Vm I I1 = I Equating for equal power loss 2 I1 2 R1 = 2 I2 R R / R1 = I1 2 / I2 = (I )2 / I2 = 1 = a1 / a
- 28. EE-504.2 28 Amt.of cond.Mat.Req.for D.C 2wire sys. with mid point earthed Amt.of cond.Mat. Req. for D.C 2wire system.
- 29. EE-504.2 29 A.C SYSTEM 1. Single phase two wire system: Fig.9
- 30. EE-504.2 30 Vm is the max.potential difference between conductors. I2 is current in amperes, R2 is the resistance of the conductor in ohms and power factor = Rms voltage = Power transmitted = P = I2 watts. Line loss or power loss = 2 I2 2 R2 watts.
- 31. EE-504.2 31 Equating for equal power, I2 = Vm I I2 = I / Equating for equal power loss, 2 I2 2 R2 = 2 I2 R 2 ( I / )2 R2 = 2 I2 R R / R2 = 2 / = a2 / a
- 32. EE-504.2 32 Amt.of cond.Mat.Req.for A.C 2wire system. Amt.of cond.Mat. Req. for D.C 2wire system.
- 33. EE-504.2 33 Fig.10 2. Single phase two wire system with mid point earthed:
- 34. EE-504.2 34 Vm is the max.potential difference between conductors. I3 is current in amperes, R3 is the resistance of the conductor in ohms and power factor = Rms voltage = Power transmitted = P = I3 watts. Line loss or power loss = 2 I3 2 R3 watts.
- 35. EE-504.2 35 Equating for equal power, I3 = Vm I I3 = I / Equating for equal power loss, 2 I3 2 R3 = 2 I2 R 2 ( I / )2 R3 = 2 I2 R R / R3 = 2 / = a3 / a
- 36. EE-504.2 36 Amt.of cond.Mat.Req.for 1 phase A.C 2wire system. Amt.of cond.Mat. Req. for D.C 2wire system.
- 37. EE-504.2 37 Fig.11 3. Three phase three wire system:
- 38. EE-504.2 38 Vm is the max. potential difference between conductors. I4 is current in amperes, R4 is the resistance of the conductor in ohms and power factor = Max voltage between conductor to neutral =
- 39. EE-504.2 39 Rms voltage = = Power transmitted = P = 3 I4 watts. Line loss or power loss = 3 I4 2 R4 watts.
- 40. EE-504.2 40 Equating for equal power, 3 I4 = Vm I I4 = I / 3 Equating for equal power loss, 3 I4 2 R4 = 2 I2 R 3 ( I / 3 )2 R4 = 2 I2 R R / R4 = 1 / = a4 / a
- 41. EE-504.2 41 Amt.of cond.Mat.Req.for A.C 3 phase 3 wire system. Amt.of cond. Mat. Req. for D.C 2wire system.
- 42. EE-504.2 42 COMPARISON OF VARIOUS SYSTEMS OF TRANSMISSION (The ratio of conductor material required in any system compared with that in the corresponding 2 wire D.C system) S.no System max.voltage to earth max.voltage bet.cond. D.C 1. Two wire 1 1 2. Two wire mid point earthed 0.25 1 A.C 1. Single phase two wire 2. Single phase two wire mid point earthed 3. Three phase three wire
- 43. EE-504.2 43 SUMMARY • Conductor material required for over head lines for different systems. • Conductor material required for under ground cables for different systems. We have discussed about
- 44. EE-504.2 44 a) Conductors b) Conductor and earth c) Tower to earth d) Tower to conductor QUIZ 1. In the over system the comparison of various system is made on the basis of max. voltage between.
- 45. EE-504.2 45 2. Transmission of electrical power is normally done by a) Two wire D.C b) Three wire D.C c) Three phase three wire A.C d) Single phase A.C QUIZ
- 46. EE-504.2 46 a) Unity b) 1.25 units c) 2/ d) 1.5/ QUIZ 3. On the basis of max. P.D between any conductor and earth, the conductor material required for single phase A.C two wire system over D.C two wire system is
- 47. EE-504.2 47 FREQUENTLY ASKED QUESTIONS 1. Compare the volume of the conductor material required in D.C two and A.C single phase two wire system? 2. Compare the volume of the conductor material required in D.C two and A.C three phase three wire system? 3. Compare the various systems of transmission on the basis of max.voltage between conductors for over head lines?
- 48. EE-504.2 48