1.52k likes | 1.8k Vues
Impacts of HVDC Lines on the Economics of HVDC Projects Task Force JWG-B2/B4/C1.17 Brochure 388. Jose Antonio Jardini João Felix Nolasco John Francis Grahan Günter Bruske
E N D
Impacts of HVDC Lines on the Economics of HVDC Projects Task Force JWG-B2/B4/C1.17 Brochure 388 Jose Antonio Jardini João Felix Nolasco John Francis Grahan Günter Bruske jardini@pea.usp.br nolascojf@gmail.comjohn.graham@br.abb.combruske@siemens.com
Impacts of HVDC Lines on the Economics of HVDC Projects From José Antonio Jardini, João Felix Nolasco on behalf of CIGRE JWG-B2.17/B4/C1.17 João Francisco Nolasco, JWG Convenor (Brazil); José Antonio Jardini, TF Convenor (Brazil); John Francis Graham, Secretary (Brazil) Regular members: João F. Nolasco (Brazil); John F. Graham (Brazil); José A. Jardini (Brazil); Carlos A.O. Peixoto (Brazil); Carlos Gama (Brazil; Luis C. Bertola (Argentina); Mario Masuda (Brazil); Rogério P. Guimarães (Brazil); José I. Gomes (Brazil); P. Sarma Maruvada (Canada); Diarmid Loudon (Norway); Günter Bruske – (Germany); Hans-Peter Oswald (Germany); Alf Persson (Sweden); Walter Flassbeck (Germany) Corresponding members: Kees Koreman (Netherlands); Tim Wu (USA); Dzevad Muftig (South Africa); Bernard Dalle (France); Pat Naidoo (Zaire); José Henrique M. Fernandes (Brazil); Jutta Hanson (Germany); Riaz Amod Vajeth (Germany); Angus Ketley (Australia) Reviewers: Rob Stephen (South Africa); Elias Ghannoun (Canada); Samuel NguefeuGabriel Olguin (Chile) (France)
Content • Overview and Configurations Studied • Transmission Line Considerations • Converter Station Cost Equation • Electrodes, Electrode Lines and Metallic Return • System Economics • Conclusions • REFERENCES
Overview and Configurations Studied Configurations Table 3.1 Transmission line configuration capacities
System Configuration Figure 3.2.a Ground Return Figure 3.2.b Metallic Return
One per pole - 3,000 MW Two Series - 6,000 MW Two Parallel - 6,000 MW Figure 3.3 Basic converter station configurations
TOPICS • Overvoltages • Insulation Coordination • Corona Effects and Fields • Line cost • Line economics
Overvoltages Switching Surge Operating Voltage Lightning
Switching Surge Related to (L-C) oscillations • Energization • Reclosing • Fault Clearing • Load Rejection • Resonances • All above are important in the AC side of the stations (limitted by surge arrester) • DC side control ramp up and ramp down (no overvoltages) • Fault Application(the only one to be considered)
Fault at mid point of the line base case overvoltage profile
red middle, green end; of the sound pole (1,500 km line) Figure 4.2: Fault at mid point of the line, base case, overvoltage profile.
Table 4.2: Sensitivity of the results. Maximum overvoltage at mid point of one pole, fault at mid point of the other pole.
Insulation Coordination • Operating Voltage • Switching Surge • Lightning Surge • Insulator String • Clearances to (tower, Guy wires, Cross arm, ground, objects at ground)
Contamination Severity HVDC very light light moderate heavy leakage distance cm/kV 2 - 2.5 2.5 – 3.2 3.2 – 4 4 - 7 HVAC IEC71-1 light medium heavy very heavy cm/kV(ph-ph rms) 1.6 2.0 2.5 3.1
- Anti-fog insulator, pitch of 165mm and leakage distance 508mm; • hardware length: 0,25m. • ITAIPU 27 mm/kV OK
Operating Voltage Clearances Table 4.4: Clearances for operating voltages (m).
REGION I Line altitude: 300 to1000 m Average temperature: 16ºC Ratio of vertical/horizontal span : 0.7 wind return period: 50 years Alfa of Gumbel distribution (m/s)-1: 0.30 Beta of Gumbel distribution (m/s): 16.62 Distribution with 30 years of samples Note: mean wind intensity 10 min 18.39 m/s standard deviation of 3.68 m/s. wind intensity is 29.52 m/s for 50 year return period Terrain classification: B calculations based on CIGRE Brochure 48 REGION II ICE
Swing Angle to be used together with Operating Voltage Clearances 1MCM=0.5067 mm2
Insulation Coordination for Switching Surge V50= k 500 d 0,6 V50 is the insulation critical flashover (50% probability) in kV d is the gap distance in m k is the gap factor: K= 1,15 conductor-plane K= 1,30 conductor–structure under K= 1,35 conductor–structure (lateral or above) K= 1,4 conductor-guy wires K= 1,50 conductor–cross arms (with insulator string)
Risk of Failure P1 Withstand (1- P1) N gaps withstand (1- P1) n Risk n 1-(1- P1) n ~ n P1 P1=0,02 2% with 200 gaps P=4%
Table 4.7: Swing angle to be used together with Switching Surge Clearances according [8] CIGRE Brochure 48
w dmin 2R
Pole Spacing Determination • Pole Spacing Required for Operating Voltage • DPTO = (R + dmin + (L + R) sin) 2 + w • dmin : operating voltage clearance (m) • R: bundle’s radius (m) • L: insulators string length (m) • : swing angle (degree) • w: tower width (m)
I string governed by operating voltage (OV) plus conductor swing
Table 4.10 - Pole Spacing (m) for Operating Voltage I strings
Current capability • wind speed (lowest) 1 m/s • wind angle 45 degree • ambient temperature 35ºC • height above sea level 300 to 1000 m • solar emissivity of surface 0.5 • solar absorvity of surface 0.5 • global solar radiation 1000 W/m2 R I2 + Wrad = k Δθ + W dessip θcond = θambient + Δθ
EDS Every Day Stress condition . Traction 20% of the rupture load . Temperature 20 oC
Conductor (hp) and shield wire (hg) heights Conductor and shield wire height at tallest tower (2 shield wires - for one add 2.5 m to hg)
Shield Wire Position position of the shield wire => to provide effective shielding against direct strokes in the conductors. The better coupling => means as closed as possible of the conductor terrain “rolling” hp*= hp b*= (hg-hp) + (Sc-Sg)(2/3) hg*= hp* +b*
shield wire and conductor protection θ ground protection ground
Protection angle As the shield wires should be close to the conductors a protection angle of 10 degrees can be assumed when using 2 shield wires. If one shield wire is used than the protection is almost good for tower with V strings. If I string are used than one shield wire may be used in location with low lightning activity.
Right Of Way ( I strings) Operating Voltage plus conductor swing due to high wind. Verification of corona effects and fields
Corona Visual G < 0.95 G0