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High Voltage Engineering

High Voltage Engineering

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High Voltage Engineering

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  1. High Voltage Engineering Term Project Hazem Hamam 962864

  2. Design of HVAC & HVDC Transmission Lines

  3. Outline • Design of AC TL. • Design of DC TL. • Design of a 500kV, 2GW AC TL. • Design of a 400kV, 2GW DC TL. • Economic Comparison. • Conclusion.

  4. Power Transmission • Importance of power transmission. • Means to transmit and sell power. • Distant energy sources. • Trading energy. • Generation away from cities.

  5. AC Transmission • Dominated transmission for a long time. • Needs synchronization. • Simple & cheap terminals. • Expensive towers. • Works well for short distances. • Use of models to represent lines.

  6. AC Transmission Design • PLL at 5% VD, 30-45o AD. • Double or single circuit lines. • Margin to minimize over-loading. • Number of lines=total P/PLL.

  7. AC Transmission Design • Entering current. • Appropriate conductor’s CCC. • Transformer (TRF) rating. • Conductors between TRF and TL. • Bundling.

  8. AC Transmission Design • Insulation design criteria. • Withstand of standard unit = 15kv. • Adjacent centers at 0.146m. • Minimum clearance. • Sag and tension. • Tower dimensions.

  9. AC Transmission Design • TRF protection. • Over-load margin. • CT ratio. • Mismatch. • Percentage operation line. • Pickup value.

  10. Design of 500kv, 2GW AC TL • PLL = 700MW. • Needs 3 lines, margin 2 lines double circuit. • P/Circuit = 600MW, (670MVA) • I=3376.7A at 380kV. • 4 incoming ACSR1033500,54,7 CCC=1060A.

  11. Design of 500kv, 2GW AC TL • Each conductor to TRF 380/500kV 700MVA. • TRF Secondary 500kV, 780A. • From TRF Secondary 2 ACSR795,26,7 per bundle CCC=900A to first Tower. • Line Length = 700kM. • Ra=28.175 Ohms.

  12. Design of 500kv, 2GW AC TL • Inductive reactance=272.033. • Capacitive reactance = 0.0029068. • SIL= 815.1MW. • Is=773.65A. • Ps=603MW. • Vr=512.47kV, V-angle=-0.05o. • Ir=660.7A.

  13. Design of 500kv, 2GW AC TL • Pr=565.5MW. • Efficiency=93.8%. • Voltage Regulation=54.7%. (Very High) • TSSSL=908.662MW. • PLL=618.16MW.

  14. Design of 500kv, 2GW AC TL • A withstand voltage of 30kV. • Switching Surge Criteria. • 1 MV Insulation. • 34 Units. • Two Strings for more mechanical Strength. • Min clearance from ground is 12m.

  15. Design of 500kv, 2GW AC TL • Phase-phase min clearance is 12m. • Surge Arrestors at beginning, 1/3, 2/3 and end of line. • SBD, more wind in the center. • TRF relays slope= 20% pickup 68.6A on 380kV side, 52.8 on 500kV side.

  16. Design of 500kv, 2GW AC TL • Sag = 7m. • Tension = 31222.4 lb. • Lower circuit of tower’s height =20m. • Upper circuit of tower’s height =32m.

  17. AC Line Diagrams TRF 1 TRF 5 TRF 2 TRF 6 TRF 3 TRF 7 TRF 4 TRF 8

  18. AC Tower Dimensions 12m 12m 32m 5.678m 20m 25 – 30 m

  19. DC Transmission Design • Converting Station is expensive. • Converting TRF. • Converting Valve. (quad valves). • AC & DC filtering. • DC Transmission Line. • Pole Configuration • Smaller, Cheaper DC Towers. • Line Commutation.

  20. DC Transmission Design • 6-pulse configurations. Converting TRF + DC - Thyristor Module

  21. DC Transmission Design • 12-Pulse Configuration Thyristor Module Mid-point DC bus arrestor AC Side DC Side Thyristor Quad-valve

  22. Design of 400kv, 2GW DC TL • 400kV DC and 500kV AC. • Converting Valves 400kV. • 4kV thyristors, (100 LTT/valve) • Entering AC is 3380A at 380kV, in 4 ACSR 874500, 54, 7 of CCC 950A. • Every 2 conductors terminate in a HV Bus-Bar at 380kV and 1200MVA.

  23. Design of 400kV, 2GW DC TL • From BB to Conv.TRF ACSR 874500, 54,7 CCC=950 in 2 conductors/bundle to the TRF. I = 1800A. • The Conv.TRF is a 3-windings 380kV/400kV 1200MVA.

  24. Design of 400kV, 2GW DC TL After 20m of ACSR 874500, 54, 7cond.: Drops negligible After 40m of ACSR 874500,54,7: Drops and losses negligible Delta winding Bus-Bar at: 380kV 1200MVA 2 conductors entering 1 conductor leaving. TRF protection AC Filters Converter TRF: V=380kV/400kV S=1200MVA 3p 3 windings TRF protection TRF protection 3p ACSR 874500, 54, 7 2 bundles CCC=950A/bund V=380kV S=600MVA I=912A PF=0.9 leading Y winding 3p ACSR 874500,54,7 2 bundles CCC=950A/bund V=380kV S=1200MVA I=1824A

  25. Design of 400kV, 2GW DC TL Delta Side: V=400kV S=600MVA I=866A Conductors are ACSR 795000,26,7 CCC=900 Length 20 m drops & losses negligible 3000A 866A Mid-point DC bus arrestor + DC - 400kV AC Side Y Side: V=400kV S=600MVA I=866A Conductors are ACSR 795000,26,7 CCC=900 Length 20 m drops & losses negligible 400kV DC Side

  26. Design of 400kV, 2GW DC TL From the DC side of the converting Valve To the DC side of the converting Valve Transmission Line ACSR 874500, 54, 7 3 bundles per pole CCC per pole = 950A Total I per pole = 2750A R = 17.18 ohms Span = 200 m DC Filters DC Filters V = 352.75kV DC P = 970.08MW I = 2750 V = 400kV DC P = 1100MW I = 2750

  27. Design of 400kV, 2GW DC TL • Insulation for 800kV. • Number insulator units = 800kV / 30kV = 26.67=27 units/ string. • 12m clearance from phase-phase and phase to neutral. • Surge arrestors at withstand of 1MV. • SA at beginning, 1/3,2/3,end of line.

  28. Design of 400kV, 2GW DC TL • TRF protection assumes 30% overload. • CT 2400:5 and 1200:5. • Slope is 20%. • 25% pickup means: • 380kV pickup = 115.2A. • 400kV pickup = 56.4A.

  29. Design of 400kV, 2GW DC TL • Vr = 352.75kV. • Pr= 970.8MW. • Voltage Regulation = 13%. • Voltage Drop = 11%. • Efficiency = 88%.

  30. Design of 400kV, 2GW DC TL • Lower design than AC is for less voltage. • 500kV DC performance is: • 8.2% Voltage Regulation. • 7.5% Voltage Drop. • 93% efficiency.

  31. Design of 400kV, 2GW DC TL • Span = 200 M • Sag = 8.94m • Tension = 31433.82 • Pole’s Height 13 + 8.9 =21.9m.

  32. Design of 400kV, 2GW DC TL Converting Valve Converting Valve TRF 1 TRF 1 Converting Valve Converting Valve TRF 2 TRF 2 Diagram of the Line

  33. Design of 400kV, 2GW DC TL 12m 22m 15-20m DC Tower Dimensions

  34. Economic Comparison • Break-Even Distance. • AC Cost Estimation Legend: • TRF >500MVA, 1MVA=150$. • AC Towers 200m span = 80,000$. • 1m of conductor for AC = 80$. • DC Cost Estimation Legend: • 1 Station = 10,000,000$. • DC Towers 200m span = 45,000$. • 1m of conductor for AC = 160$.

  35. Equipment Number Per Unit Price TRF 380/500kV 700MVA 8 105,000$ AC Tower 200m span 3,500 80,000$ AC Conductors 12/m 80$ Converter Station 2 10,000,000$ DC Tower 200m Span 3,500 50,000$ DC Conductors 4/m 160$ Economic Comparison • Table of Equipment:

  36. AC & DC Costs • 98,644,000 $ for AC TL. • 91,040,000 $ for DC TL.

  37. Conclusion • AC TL higher Tower and conductor costs and lower terminal costs. • DC TL lower Tower and conductor costs and higher terminal costs. • Economics determines the design to be used. • Line length determines which one is more economic.