HVDC
High Voltage Direct Current
Transmission
Adam Holbrook, Kyle Holcomb, Bo Liu, Phillip Pardue,
Mitchell Smith, Nina Wong
1 November 2013
Outline
• Background


History
Basic Theory
• Modern HVDC
• Impact of HVDC


Advantages
Disadvantages
• R&D Challenges
• Demonstrated Technologies
• Related Published Research
1-2
The War of Currents




Thomas Edison
pioneered DC
distribution while
Tesla and
Westinghouse
adopted AC
Voltage conversion was not efficiently possible with the
DC grid. Voltage drop, then, wreaked havoc as loads
varied and at the ends of lines.
DC distribution was manageable in urban locations but
impossible in rural areas due to low customer density.
The majority of loads ran at ~100 volts. Larger loads,
though required separate circuits be ran at very high costs.
Innovations in DC Technology


Mercury-Arc Tubes and Vacuum Diodes allowed for
the rectification of AC to DC
Thyristors and IGBTs allow conversion both to and
from DC
Heated
Cathode
Rectifier, c.
1930
Mercury-Arc
Rectifier,
c.1970
Thyristor
Rectifier,
2009
DC Transmission Theory


DC generation is not practical on a large scale
due to the need for large permanent magnets or
brushes. DC, then, is only viable as a
transmission method between AC grids
HVDC lines typically run in the hundreds of kV,
generally around 500 kV.
Why use DC for Transmission Anyway?



DC is more efficient than AC for
transmission. It does not exhibit losses
due to skin effect thus conductors can be
sized smaller.
DC can serve as a link between nonsyncronized AC grids.
Line losses are largely eliminatedcapacitive, inductive, radiation.
Outline
• Background


History
Basic Theory
• Modern HVDC
• Impact of HVDC


Advantages
Disadvantages
• R&D Challenges
• Demonstrated Technologies
• Related Published Research
1-8
Modern HVDC
• Several different designs which share
several qualities.
• Innovative field watched closely by the
Power Community
1-9
Thyristor Valve Advances
• Thyristor valves have made significant
advances in the past ten years
• Development of light triggered thyristors
• Control unit advancement
• Has helped keep electrically triggered
thyristors as the popular choice
Thyristor Valves from Manitoba Hydro
IGBT Valves


Insulated gate bipolar transistor valves
allow the current in the lines to be
extinguished completely and quickly
This property allows for much more
versatility than standard HVDC lines can
provide
Active DC Filters


Digitally controlled amplifiers actively
cancel interfering currents on lines
Compared to the use of shunt filter
branches, this is cheaper and easier to
maintain and operate
Optical Direct Current Transducers
• Use high precision shunt at high potential
to send signals over glass optical fibers
• Allows for much smaller components than
the porcelain counterparts
• Cheap and effective method for lowering
flashover probability.
Outline
• Background


History
Basic Theory
• Modern HVDC
• Impact of HVDC


Advantages
Disadvantages
• R&D Challenges
• Demonstrated Technologies
• Related Published Research
1-15
Advantages
• Most benefits stem from inherently
fewer components:



DC eliminates need for three-phase
system
No “skin effect”
Easier repairs in event of outage
Advantages, continued
Lower losses / higher transmission
efficiency
 Good long-distance underground
and underwater transmission
 Eliminates need for substations near
far-reaching delivery point

Disadvantages
• Higher cost over short distances

Efficient DC-AC converting stations
• Harmonics


System oscillation when integrated with
AC networks
Overvoltages
• More complicated switching
infrastructure

Heat dissipation of breaker
Outline
• Background


History
Basic Theory
• Modern HVDC
• Impact of HVDC


Advantages
Disadvantages
• R&D Challenges
• Demonstrated Technologies
• Related Published Research
1-19
Challenges
•
•
•
•
•
Conversion
Switching
Control
Availability
Maintenance
Research
• HVDC Offshore and Onshore Energy




Great for long distance energy transmisson.
Wind Power
Solar Power
Hydro Power
• Multi Terminal HVDC (MTDC)



Will be the most commonly used in the Future.
Popular for offshore energy networking.
Underwater cables or overhead powerline.
Research
• Multi Terminal HVDC (MTDC)



Series, Parallel, Hybrids
Parallel systems are becoming the easiest to
control because of Voltage Source
Convertors.
Area to Area Transmisson
Research
•
•
•
•
HVDC Breakers
Power Flow Control
Automatic Network Restoration
HVDC Converter for the exchange of
renewable energies.
Development
• SIEMENS






2015 Offshore HVDC Plus link HelWin2,
Germany
2014 Offshore HVDC Plus link SylWin1, Germany
2014 INELFE, France-Spain
2013 Offshore HVDC Plus link HelWin1,
Germany
2013 Offshore HVDC Plus link BorWin2,
Germany
2010 Trans Bay Cable Project, USA
Development
• ABB





2016 Celio Upgrade, Pacific Intertie, USA
2015 LitPol Link, Lithuania-Poland
2015 Troll A 3&4 offshore, Norway
2015 DolWin2, Germany
2015 NordBalt, Lithuania – Sweden
Outline
• Background


History
Basic Theory
• Modern HVDC
• Impact of HVDC


Advantages
Disadvantages
• R&D Challenges
• Demonstrated Technologies
• Related Published Research
1-26
Demonstrations
• First demonstrations in 1882 with single
DC machines. Since been dismantled
• 1964 saw the first plants to be upgraded
rather than shut down.

Demonstrations centered around Europe
• Early 2000s, China, Japan, and India take
over with demonstrations and installed
stations
1-27
Applications
• Mainly for country-country interconnects
• Submarine transmission lines
• European HVDC
www.wikipediaorg



Existing
Under Construction
Considered Projects
1-28
The Neptune Project
• Regional Transmission System (RTS)



65 mile, undersea and underground cable
500 kV DC cable
660 MW capability (600,000 homes)
 20% of Long Island’s electrical needs
• Construction began June 2005, completed
June 2007

Ahead of schedule and on budget
• Thyristor based system
1-29
The Neptune Project cont.
www.neptunerts.com
1-30
The Neptune Project Details
• No overhead lines

60 miles under water, 15 miles under ground
• Three cable bundle



Main 5” 500 kV cable
Medium voltage “return” cable
Fiber-optic cable for system control
www.neptunerts.com
1-31
The Neptune Project Details cont.
One of two identical converter
stations with filter banks located
outside of the facility.
One in Sayreville, NJ and the
other on Duffy Ave in NY
Thyristor valves for power
conversion supplied by Siemens.
www.neptunerts.com
1-32
NorNed
• Submarine HVDC cable from Feda,
Norway to Eemshaven, Netherlands


Longest submarine cable in the world, 360 mi
Bipolar HVDC link
 ±450 kV with 700 MW capacity
 300 kV AC on Feda end, 400 kV AC at Eemshaven

Passes under the North sea
• Construction began 2006


Commissioned in 2008
Over budget (€550m budget, €600m actual)
1-33
NorNed cont.
• Unique construction


One 12-pulse converter on either end
Symmetric Monopole configuration
 Earthed via high impedance, no earth current
www.abb.com
1-34
NorNed Installation
http://www.energibransjen.no
1-35
Outline
• Background


History
Basic Theory
• Modern HVDC
• Impact of HVDC


Advantages
Disadvantages
• R&D Challenges
• Demonstrated Technologies
• Related Published Research
1-36
from HVDC to MTDC
Drive: Interconnection of offshore generation resources (wave and wind)
Increase Reliability
Increase transmission capacity
Cost-effective
1-37
Challenges of MTDC
1. DC fault current breaking and blocking
ABB hybrid DC breaker, 2012:
1-38
Challenges of MTDC
2. DC power flow control: in case of overload (VSC and DC line)
V1 − V2 − VX
I=
R3
1-39
Thank you!
Questions? Comments?
1-40
References






http://en.wikipedia.org/wiki/HVDC
http://en.wikipedia.org/wiki/War_of_Currents
http://phanichakravarthi.blogspot.com/2011/12/war
-of-currents.html
http://large.stanford.edu/courses/2010/ph240/ham
erly1/images/f3big.gif
http://upload.wikimedia.org/wikipedia/commons/a/
a7/12_pulse_bridge_with_mercury_arc_valves.pn
g
http://www.siemens.com/press/pool/de/pressebild
er/2009/power_transmission/072dpi/soept200911
01-01_072dpi.jpg
Sources
• https://en.wikipedia.org/wiki/Highvoltage_direct_current
• https://en.wikipedia.org/wiki/Skin_effect
• http://ieeexplore.ieee.org/stamp/stamp.jsp?tp
=&arnumber=5650015
• http://www.gao.gov/assets/100/95343.html
References
• http://www.abb.us/industries/ap/db0003db
004333/2eaf1b10de87a2bec12574ea0051
27de.aspx.
• www.ieeexplore.ieee.org
• http://www.energy.siemens.com/us/en/pow
er-transmission/hvdc/hvdcplus/references.htm
Reference
[1]: “HVDC Grid Feasibility Study”, Cigre B4 533, 2013
[2]: ABB, “Proactive Hybrid HVDC Breakers-A key innovation for reliable HVDC grids ”,
2011
[3]: ABB, “The high voltage DC breaker, The power grid revolution ”, 2012
[4]: “Power Flow Analysis in Multi-Terminal HVDC Grid”, 2011
[5]: “Multi-Terminal HVDC Grid with Power Flow Controllability”, Cigre B4-301, 2012
1-44