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 ACSR ,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= Ohms.

12. Design of 500kv, 2GW AC TL Inductive reactance=272.033.
Capacitive reactance =
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= MW.
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 , 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 , 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 ,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 , 54, 7
2 bundles
CCC=950A/bund
V=380kV
S=600MVA
I=912A
PF=0.9 leading
Y winding
3p ACSR ,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 ,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 ,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 , 54, 7
3 bundles per pole
CCC per pole = 950A
Total I per pole = 2750A
R = ohms
Span = 200 m
DC Filters
DC Filters
V = kV DC
P = MW
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 =21.9m.

32. Design of 400kV, 2GW DC TL Diagram of the Line 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. Economic Comparison Table of Equipment: 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
50,000$
DC Conductors
4/m
160$

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.