high voltage engineering term project hazem hamam 962864
TRANSCRIPT
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.
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
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
TRF 1
TRF 2Converting
Valve
Converting Valve
Converting Valve
Converting Valve TRF 2
TRF 1
Diagram of the Line
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$