High Voltage Engineering Term Project Hazem Hamam 962864
Jul 15, 2015
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.
AC Transmission Design
Entering current.Appropriate conductor’s CCC.Transformer (TRF) rating.Conductors between TRF and TL.Bundling.
AC Transmission Design
Insulation design criteria.Withstand of standard unit = 15kv.Adjacent centers at 0.146m.Minimum clearance.Sag and tension.Tower dimensions.
AC Transmission Design
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.
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.
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.
Design of 500kv, 2GW AC TL
Pr=565.5MW.Efficiency=93.8%.Voltage Regulation=54.7%. (Very High)TSSSL=908.662MW.PLL=618.16MW.
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.
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.
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.
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.
DC Transmission Design
6-pulse configurations.
Converting TRF +
DC-
Thyristor Module
DC Transmission Design
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.
Design of 400kV, 2GW DC TL
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
Design of 400kV, 2GW DC TL
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
Design of 400kV, 2GW DC TL
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
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.
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.
Design of 400kV, 2GW DC TL
Vr = 352.75kV.Pr= 970.8MW.Voltage Regulation = 13%.Voltage Drop = 11%.Efficiency = 88%.
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.
Design of 400kV, 2GW DC TL
Span = 200 MSag = 8.94mTension = 31433.82Pole’s Height 13 + 8.9 =21.9m.
Design of 400kV, 2GW DC TL
TRF 1
TRF 2Converting
Valve
Converting Valve
Converting Valve
Converting Valve TRF 2
TRF 1
Diagram of the Line
Design of 400kV, 2GW DC TL
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.