High Voltage Engineering Term Project Hazem Hamam 962864

High Voltage Engineering

Term ProjectHazem Hamam962864

Design of HVAC & HVDC Transmission Lines

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.

Power Transmission

Importance of power transmission. Means to transmit and sell power.

Distant energy sources. Trading energy. Generation away from cities.

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.

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.


Entering current.Appropriate conductor’s CCC.Transformer (TRF) rating.Conductors between TRF and TL.Bundling.


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


TRF protection. Over-load margin. CT ratio. Mismatch. Percentage operation line. Pickup value.

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.


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.


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.


Pr=565.5MW.Efficiency=93.8%.Voltage Regulation=54.7%. (Very High)TSSSL=908.662MW.PLL=618.16MW.


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.


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.


Sag = 7m.Tension = 31222.4 lb.Lower circuit of tower’s height =20m.Upper circuit of tower’s height =32m.

AC Line Diagrams

TRF 1

TRF 2

TRF 4

TRF 3

TRF 5

TRF 6

TRF 8

TRF 7

AC Tower Dimensions

25 – 30 m

20m

12m

32m

5.678m

12m

DC Transmission Design

Converting Station is expensive.Converting TRF.Converting Valve. (quad valves).AC & DC filtering.DC Transmission Line. Pole ConfigurationSmaller, Cheaper DC Towers.Line Commutation.


6-pulse configurations.

Converting TRF +

DC-

Thyristor Module


12-Pulse Configuration

DC Side

AC Side

Mid-point DC bus arrestor

Thyristor Quad-valve

Thyristor Module

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.

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.


Bus-Bar at: 380kV1200MVA2 conductors entering1 conductor leaving.

3p ACSR 874500, 54, 72 bundlesCCC=950A/bundV=380kVS=600MVAI=912APF=0.9 leading

After 20m of ACSR 874500, 54, 7cond.:Drops negligible

Converter TRF:V=380kV/400kVS=1200MVA3p 3 windings

3p ACSR 874500,54,7 2 bundlesCCC=950A/bundV=380kVS=1200MVAI=1824A

After 40m of ACSR 874500,54,7:Drops and losses negligible

Delta winding

Y winding

AC Filters TRF

protection

TRF protection

TRF protection


400kV DC Side

400kV AC Side

Delta Side:V=400kVS=600MVAI=866AConductors are ACSR 795000,26,7 CCC=900Length 20 m drops & losses negligible

Y Side:V=400kVS=600MVAI=866AConductors are ACSR 795000,26,7 CCC=900Length 20 m drops & losses negligible

866A

Mid-point DC bus arrestor

+DC-

3000A


From the DC side of the converting Valve

DC Filters

Transmission LineACSR 874500, 54, 73 bundles per poleCCC per pole = 950ATotal I per pole = 2750AR = 17.18 ohmsSpan = 200 m

To the DC side of the converting ValveDC Filters

V = 400kV DCP = 1100MWI = 2750

V = 352.75kV DCP = 970.08MWI = 2750


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.


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.


Vr = 352.75kV.Pr= 970.8MW.Voltage Regulation = 13%.Voltage Drop = 11%.Efficiency = 88%.


Lower design than AC is for less voltage.500kV DC performance is: 8.2% Voltage Regulation. 7.5% Voltage Drop. 93% efficiency.


Span = 200 MSag = 8.94mTension = 31433.82Pole’s Height 13 + 8.9 =21.9m.


TRF 1

TRF 2Converting

Valve

Converting Valve

Converting Valve

Converting Valve TRF 2

TRF 1

Diagram of the Line


15-20m

12m

22m

DC Tower Dimensions

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$.

Economic Comparison

Table of Equipment:Equipment Number Per Unit PriceTRF 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$

AC & DC Costs

1. 98,644,000 $ for AC TL.2. 91,040,000 $ for DC TL.

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.

Documents

High Voltage Engineering Term Project Hazem Hamam 962864