Electrical Considerations for HVDC Transmission Lines
Joe Mooney, PE
y,
“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. As such, it does not p
p
p
,
include content that may be deemed or construed to be an
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copyright laws. Reproduction, distribution, display and use of the
educational activity without written permission of the presenter is
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prohibited.
© POWER E i
© POWER Engineers 2009
2009
Learning Objectives
Learning Objectives
At the end of this presentation you will be able to:
At the end of this presentation you will be able to:
•
•
•
•
•
•
•
•
Identify the electrical requirements for HVDC lines.
Id tif th
Identify the components used in AC to DC conversion.
t
d i AC t DC
i
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.
Understand the insulation requirements for an HVDC line.
HVDC
A Brief History
• First HVDC System Commissioned in 1954
First HVDC System Commissioned in 1954
– Gotland, Sweden
– ±100kV, 20MW, 60miles of submarine cable
±100kV 20MW 60miles of submarine cable
• First Installation in North America in 1969
– Vancouver Island, BC
– ±260kV, 312MW, 46miles of submarine cable
HVDC
A Brief History
f
• Last Mercury
Last Mercury‐Arc
Arc Valve Installation
Valve Installation
– Pacific DC Intertie ‐ 1970
– 1440MW, ±400kV
1440MW ±400kV
– Currently at 3100MW, ±500kV
Graphic Courtesy ABB
Photo Courtesy ABB
HVDC
A Brief History
f
• Longest Distance in Operation Longest Distance in Operation – 1062 miles
1062 miles
– Democratic Republic of Congo, Africa
– 1983, ±500kV, 560MW, overhead line
1983 ±500kV 560MW overhead line
• Highest Voltage in Operation ‐ ±600kV
Graphic Courtesy ABB
– Itaipu, Brazil
– 1987, two circuits@3150MW each, 490+ miles
Graphic Courtesy ABB
HVDC
A Brief History
f
• First Multi
First Multi‐Terminal
Terminal HVDC System
HVDC System
– Quebec‐New England
– 1992, ±450kV, 2000MW
1992 ±450kV 2000MW
• Longest Submarine Cable
– Norway to Netherlands
– 362 Miles
– 2008, ±450kV, 700MW
Graphic Courtesy ABB
HVDC A Snapshot of the Future
h
f h
• Highest Voltage ‐ ±800kV
– Two circuits in China
T
i i i Chi
– 5000MW, 890 miles (2010)
– 6400MW, 1295 miles (2011)
Graphic Courtesy ABB
Graphic Courtesy Siemens
• Longest Circuit – Over 1550 miles
– Rio Maderia in Brazil
– ±600kV, 3150MW
– Scheduled to be in operation in 2012
Graphic Courtesy ABB
When to Use HVDC
When to Use HVDC
•
•
•
•
•
Long Distance
Long Underground/Submarine Cables
Long Underground/Submarine Cables
Asynchronous Systems
Controlled Power Transfer
Reduce Right‐of‐Way
g
y
HVDC Projects Planned in China
j
Source: MarketAvenue
6000MW ‐ HVDC vs. AC
Right of Way Comparison
Right‐of‐Way Comparison
±500kV DC
500kV AC
±500kV vs. 500kV AC
±800kV vs. 800kV AC
Typical HVDC Converter Station
Typical HVDC Converter Station
Graphic Courtesy ABB
HVDC Technology
HVDC Technology
• HVDC Classic
HVDC Classic
– Line Current Commutated; Thyristors
– Large blocks of power; 1000
Large blocks of power; 1000’ss of MW
of MW
– High voltage applications; ±800kV
• HVDC Light/PLUS
HVDC Li ht/PLUS
– Voltage Source Commutated; IGBT
– Small blocks of power; 100’s of MW
– Lower voltages; ±200kV
HVDC Classic Design
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
HVDC Classic Valve Groups
HVDC Classic Valve Groups
Photos Courtesy Siemens
HVDC Classic Converter Transformer
HVDC Classic Converter Transformer
Photos Courtesy ABB
HVDC Classic AC Filters
HVDC Classic AC Filters
Photos Courtesy ABB
3000MW HVDC Classic Station
3000MW HVDC Classic Station
Photo Courtesy ABB
HVDC Light Design
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
HVDC Light Components
HVDC Light Components
Photos Courtesy ABB
HVDC Light Station
HVDC Light Station
Photos Courtesy ABB
HVDC Operation
HVDC Operation
• Monopole
– Single positive dc voltage (e.g., +500kV)
• One high voltage conductor
One high voltage conductor
– Neutral return
• Metallic return via low voltage conductor
Metallic return via low voltage conductor
• Earth return through ground electrode
– Limited Operation
ed Ope a o
• Fault or maintenance results in outage
AC Power Syystem
AC P
Power System
AC Power Systtem
Monopole HVDC
p
AC
C Power System
m
HVDC Operation
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 monopole configuration as needed
Operate in monopole configuration as needed
• Allows for maintenance or outage of one pole
p
p
p
• Up to half of rated power output
Bipole Operation
Earth Return
h
Earth Return
Ground Electrode
HVDC
Cable/OH Line
AC Powe
er System
AC Powe
er System
HVDC
C
Cable/OH Line
Bipole Operation
Metallic Return
ll
LVDC
Cable/OH Line
HVDC
Cable/OH Line
AC Powe
er System
AC Powerr System
HVDC
Cable/OH Line
Cost Comparison
HVDC vs. AC
• HVDC
HVDC has a higher installation cost due to the has a higher installation cost due to the
converter stations and filtering requirements.
• The cost of an HVDC line is less than the cost The cost of an HVDC line is less than the cost
of an AC line.
• Long AC lines are more expensive due to shunt L
AC li
i d
h
and series compensation requirements.
Cost vs. Distance for HVDC and AC
Cost vs. Distance for HVDC and AC
Electrical Considerations
Electrical Considerations
•
•
•
•
Insulation
Metallic or earth return (ground electrode)
Audible Noise
dibl
i
Magnetic and Electric Fields
Insulation Requirements
Insulation Requirements
• Air Clearance Requirements
Air Clearance Requirements
– Switching Performance
– Lightning
• Altitude
• Pollution/Contaminants
Air Clearance Requirements
Air Clearance Requirements
8
6
EHV AC
EHVAC Air Clearance Requirements
(meter)
– Switching – primary
– Lightning – secondary
2.6 p.u.
1.8 p.u.
4
2
HVDC
0
500
8
800
System
y
voltage
g ((kV))
1100
HVDC Air Clearance Requirements
(meter)
Air Clearance Requirements Air
Clearance Requirements
are Significantly Lower for HVDC
HVDC.
6
4
2
0
400
Graphic Courtesy ABB
– Switching Switching – secondary
– Lightning – primary 600
System voltage (±kV)
800
Effect of Altitude
Effect of Altitude
Relative increase in insulation requirements with altitude
EHV AC
1.30
– Ai
Air Clearance Cl
(switching)
– Insulation (pollution)
(p
)
Lightning
1.25
Switching
Pollution
1.20
1.15
HVDC
1.10
– Air Clearance (lightning)
– Insulation (creepage)
1 05
1.05
1.00
0.95
0.90
0
Graphic Courtesy ABB
500
1000
1500
Altitude (meter)
2000
Insulation Requirements for HVDC are More Sensitive to Altitude
Sensitive to Altitude
Earth Return
Earth Return
• Metallic Return
Metallic Return
– Same current rating as main conductor
– Insulated for voltage drop caused by current flow
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
IPP Southern Electrode
IPP HVDC
IPP HVDC
Ground G
d
Electrode Connection to Tower
Corona and Audible Noise
Corona and Audible Noise
• Weather
Weather has Smaller Effect on Corona Losses has Smaller Effect on Corona Losses
for HVDC Lines
• Requirement for Conductor Bundling is Requirement for Conductor Bundling is
Reduced for HVDC Lines to Meet Audible Noise Requirements
Noise Requirements
Corona and Audible Noise
Corona and Audible Noise
Typical corona losses (kW/km)
Frost
Rain
Fair
Corona Losses on HVDC are less
HVDC are less Sensitive to Weather Conditions
1000
EHVAC
100
HVDC
10
EHVAC, HVDC
1
0
Graphic Courtesy ABB
500
1000
Altitude (m)
1500
2000
UHVAC Conductor Bundles for 55dB Maximum
2000
6
6
9
5
6
8
4
5
8
1500
Altitude (meter) 1000
500
0
700
800
900
1000
1100
System voltage (kV)
Graphic Courtesy ABB
HVDC Conductor Bundles f
for 45dB Maximum
d
3
4
6
7
2
4
5
6
2
3
4
5
500
600
700
800
2000
Altitude (meter)
1500
1000
500
0
400
System voltage (±kV)
Graphic Courtesy ABB
Magnetic and Electric Fields
Magnetic and Electric Fields
• No
No Magnetic Induction from DC
Magnetic Induction from DC
• Current flow in Opposite Directions Cancel Magnetic Field Effect on HVDC
Magnetic Field Effect on HVDC
– Comparable to Earths Magnetic Field (50µT)
• Field Requirements for DC are less Stringent than AC
– Greater Public Acceptance…
Itaipu HVDC and EHV System
HVDC Line Cost about 70% of AC Line
ITAIPU
2 x 6300 MW
6300
3 x 765 kV AC, 2 intermediate S/S
6300 MW with SC
4500 MW without SC
3 i it
3 circuits
2 x ± 600 kV DC
6300 MW, 2 converters per pole
4700 MW with pole outage
4 l
4 poles
Photo Courtesy ABB
Itaipu 765kV Ac Lines
p
Line 1. 891 km 1982, 86, Line 2. 891 km 1989
Line 3. 915 km 1999, 00, 01
Photo Courtesy ABB
•
About 70% Guyed Vee
•
Average weight 8500 kg, guyed
Average weight 8500 kg, guyed
•
Self supporting, weight 14000 kg
•
15.80 m Phase spacing, guyed
•
14.30 m Phase spacing, self support
•
Conductor 4xBluejay 564 mm² ACSR
•
450 mm subconductor spacing
450 mm subconductor spacing
•
35 Insulators
•
95 m RoW one line
•
178 m RoW two lines
Itaipu ±600kV HVDC Lines
Itaipu ±600kV HVDC Lines
Bipole 1792 km 1984
Bipole 2820 km 1987
Photo Courtesy ABB
•
About 80% Guyed Mast
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
•
16.40 m pole spacing
•
72 m RoW per circuit
72 m RoW
per circuit
Thank you for your time.
QUESTIONS?
This concludes the educational content of this activity
This concludes the educational content of this activity.
Joe Mooney, P.E.
Sr Project Manager
Sr. Project Manager
www.powereng.com
March 2010