Electrical Considerations for HVDC Transmission Lines. Joe Mooney, PE

Transcription

1 Electrical Considerations for HVDC Transmission Lines Joe Mooney, PE

2 POWER Engineers has met the standards and requirements of the Registered Continuing Education Program. Credit earned on completion of this program will be reported to RCEPP. A certificate of completion will be issued to each participant. p As such, it does not include content that may be deemed or construed to be an approval or endorsement by NCEES or RCEPP.

3 Copyright Materials This educational activity is protected by U.S. and International copyright laws. Reproduction, distribution, display and use of the educational activity without written permission of the presenter is prohibited. POWER Engineers 2009

4 Learning Objectives At the end of this presentation you will be able to: Identify the electrical requirements for HVDC lines. Identify the components used in AC to DC conversion. Understand the history of HVDC conversion and transmission Understand the operation of HVDC conversion technology. Understand the requirements of an HVDC convertor station. Understand the differences between classic HVDC and new HVDC technology. Understand the fundamental requirements of HVDC transmission line design. Understand the insulation requirements for an HVDC line.

5 HVDC A Brief History First HVDC System Commissioned in 1954 Gotland, Sweden ±100kV, 20MW, 60miles of submarine cable First Installation in North America in 1969 Vancouver Island, BC ±260kV, 312MW, 46miles of submarine cable

6 HVDC A Brief History Last Mercury Arc Valve Installation Pacific DC Intertie MW, ±400kV Currently at 3100MW, ±500kV Graphic Courtesy ABB Photo Courtesy ABB

7 HVDC A Brief History Longest Distance in Operation 1062 miles Democratic Republic of Congo, Africa 1983, ±500kV, 560MW, overhead line Highest Voltage in Operation ±600kV Itaipu, Brazil 1987, two circuits@3150mw each, 490+ miles Graphic Courtesy ABB Graphic Courtesy ABB

8 HVDC A Brief History First Multi Terminal HVDC System Quebec New England 1992, ±450kV, 2000MW Longest Submarine Cable Norway to Netherlands 362 Miles 2008, ±450kV, 700MW Graphic Courtesy ABB

9 HVDC A Snapshot of the Future Highest Voltage ±800kV Two circuits i in China 5000MW, 890 miles (2010) Graphic Courtesy ABB 6400MW, 1295 miles (2011) Longest Circuit Over 1550 miles Rio Maderia in Brazil ±600kV, 3150MW Scheduled to be in operation in 2012 Graphic Courtesy Siemens Graphic Courtesy ABB

10 When to Use HVDC Long Distance Long Underground/Submarine Cables Asynchronous Systems Controlled Power Transfer Reduce Right of Way

11 HVDC Projects Planned in China Source: MarketAvenue

12 6000MW HVDC vs. AC Right of Way Comparison ±500kV DC 500kV AC ±500kV vs. 500kV AC ±800kV vs. 800kV AC

13 Typical HVDC Converter Station Graphic Courtesy ABB

14 HVDC Technology HVDC Classic Line Current Commutated; Thyristors Large blocks of power; 1000 s of MW High voltage applications; ±800kV HVDC Light/PLUS Voltage Source Commutated; IGBT Small blocks of power; 100 s of MW Lower voltages; ±200kV

15 HVDC Classic Design Twelve Pulse Converter Requires Specially Designed Transformers Power System Must Supply Reactive Power Thyristors are Switched on and turned off by reverse voltage Harmonic Filters are required

16 HVDC Classic Valve Groups Photos Courtesy Siemens

17 HVDC Classic Converter Transformer Photos Courtesy ABB

18 Photos Courtesy ABB HVDC Classic AC Filters

19 3000MW HVDC Classic Station Photo Courtesy ABB

20 HVDC Light Design Insulated Gate Bipolar Transistors Off the shelf transformer Switched on and off Pulse Width Modulation Power factor can be controlled Simple high pass filter for high order harmonics Graphic Courtesy ABB

21 HVDC Light Components Photos Courtesy ABB

22 Photos Courtesy ABB HVDC Light Station

23 HVDC Operation Monopole Single positive dc voltage (e.g., +500kV) One high voltage conductor Neutral return Metallicreturn via lowvoltage conductor Earth return through ground electrode Limited Operation Fault or maintenance results in outage

24 AC Power System AC Power System Monopole HVDC AC Power Syst tem AC Power System

25 HVDC Operation Bipole Positive and negative voltage (e.g., ±500kV) Two high voltage conductors Neutral return Metallic return via low voltage conductor Earth return through ground electrode Best Operational Flexibility Operate in monopoleconfiguration asneeded Allows for maintenance or outage of one pole Up to half of rated power output

26 Bipole Operation Earth Return HVDC Cable/OH Line AC Powe er System Earth Return Ground Electrode AC Powe er System HVDC Cable/OH Line

27 Bipole Operation Metallic Return HVDC Cable/OH Line AC Power System LVDC Cable/OH Line AC Powe er System HVDC Cable/OH Line

28 Cost Comparison HVDC vs. AC HVDC has a higher installation cost due to the converter stations and filtering requirements. The cost of an HVDC line is less than the cost of an AC line. Long AC lines are more expensive due to shunt and series compensation requirements.

29 Cost vs. Distance for HVDC and AC

30 Electrical Considerations Insulation Metallic or earth return (ground electrode) Audible Noise Magnetic and Electric Fields

31 Insulation Requirements Air Clearance Requirements Switching Performance Lightning Altitude Pollution/Contaminants

32 Air Clearance Requirements EHVAC Air Clearance Requirements (meter) 2.6 p.u. 1.8 p.u. EHV AC Switching primary Lightning secondary HVDC Switching secondary System voltage (kv) HVDC Air Clearance Requirements (meter) System voltage (±kv) 800 Graphic Courtesy ABB Lightning primary Air Clearance Requirements are Significantly Lower for HVDC.

33 Effect of Altitude Relative increase in insulation requirements with altitude Lightning Switching Pollution Graphic Courtesy ABB Altitude (meter) EHV AC Air Clearance (switching) Insulation (pollution) HVDC Air Clearance (lightning) Insulation (creepage) Insulation Requirements for HVDC are More Sensitive to Altitude

34 Earth Return Metallic Return Same current rating as main conductor Insulated for voltage drop caused by current flow Earth Return Expansive ground electrode Requires significant study Gravity survey, hydrological survey, electrical resistivity survey, geological modeling

35 IPP Southern Electrode

36 IPP HVDC Ground Electrode Connection to Tower

37 Corona and Audible Noise Weather has Smaller Effect on Corona Losses for HVDC Lines Requirement for Conductor Bundling is Reduced for HVDC Lines to Meet Audible Noise Requirements

38 Corona and Audible Noise Typical corona losses (kw/km) Frost Rain Fair EHVAC HVDC Corona Losses on HVDC are less Sensitive to Weather Conditions 1 Graphic Courtesy ABB EHVAC, HVDC Altitude (m)

39 UHVAC Conductor Bundles for 55dB Maximum Altitude (meter) System voltage (kv) Graphic Courtesy ABB

40 HVDC Conductor Bundles for 45dB Maximum Altitude (meter) System voltage (±kv) Graphic Courtesy ABB

41 Magnetic and Electric Fields No Magnetic Induction from DC Current flow in Opposite Directions Cancel Magnetic Field Effect on HVDC Comparable to Earths Magnetic Field (50µT) Field Requirements for DC are less Stringent than AC Greater Public Acceptance

42 Itaipu HVDC and EHV System HVDC Line Cost about 70% of AC Line ITAIPU 2 x 6300 MW 3 x 765 kv AC, 2 intermediate S/S 6300 MW with SC 4500 MW without SC 3 i it 2 x ± 600 kv DC 6300 MW, 2 converters per pole 4700 MW with pole outage 4 l 3 circuits 4 poles Photo Courtesy ABB

43 Itaipu 765kV Ac Lines Line km 1982, 86, Line km 1989 Line km 1999, 00, 01 About 70% Guyed Vee Average weight 8500 kg, guyed Self supporting, weight kg m Phase spacing, guyed m Phase spacing, self support Conductor 4xBluejay 564 mm² ACSR 450 mm subconductor spacing 35 Insulators 95 m RoW one line Photo Courtesy ABB 178 m RoW two lines

44 Itaipu ±600kV HVDC Lines Bipole 1792 km 1984 Bipole 2820 km 1987 About 80% Guyed Mast Average weight 5000 kg, guyed Self supporting, weight 9000 kg Conductor 4xBittern 644 mm² 45/7ACSR 450 mm subconductor spacing 32 Insulators 510 mm creep, 27 mm/kv m pole spacing 72 m RoW per circuit Photo Courtesy ABB

45 Thank you for your time. QUESTIONS? This concludes the educational content of this activity. Joe Mooney, P.E. Sr. Project Manager March 2010