HVDCHigh 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

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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

Increasing Current

and voltage capacity

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 non-syncronized AC grids.

Line losses are largely eliminated- capacitive, inductive, radiation.

Outline

• Background History Basic Theory

• Modern HVDC• Impact of HVDC

Advantages Disadvantages

• R&D Challenges• Demonstrated Technologies• Related Published Research

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Modern HVDC

• Several different designs which share several qualities.

• Innovative field watched closely by the Power Community

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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

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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

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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

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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

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Applications

• Mainly for country-country interconnects• Submarine transmission lines• European HVDC

Existing Under Construction Considered Projects

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www.wikipediaorg

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

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The Neptune Project cont.

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www.neptunerts.com

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

1-31www.neptunerts.com

The Neptune Project Details cont.

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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

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)

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NorNed cont.

• Unique construction One 12-pulse converter on either end Symmetric Monopole configuration

Earthed via high impedance, no earth current

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www.abb.com

NorNed Installation

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http://www.energibransjen.no

Outline

• Background History Basic Theory

• Modern HVDC• Impact of HVDC

Advantages Disadvantages

• R&D Challenges• Demonstrated Technologies• Related Published Research

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from HVDC to MTDC

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Increase transmission capacity

Increase Reliability

Cost-effective

Drive: Interconnection of offshore generation resources (wave and wind)

Challenges of MTDC

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1. DC fault current breaking and blocking

ABB hybrid DC breaker, 2012:

Challenges of MTDC

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2. DC power flow control: in case of overload (VSC and DC line)

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3

XV V VI

R

Thank you!

Questions? Comments?

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References

http://en.wikipedia.org/wiki/HVDC http://en.wikipedia.org/wiki/War_of_Curre

nts http://phanichakravarthi.blogspot.com/201

1/12/war-of-currents.html http://large.stanford.edu/courses/2010/ph

240/hamerly1/images/f3big.gif http://upload.wikimedia.org/wikipedia/com

mons/a/a7/12_pulse_bridge_with_mercury_arc_valves.png

http://www.siemens.com/press/pool/de/pressebilder/2009/power_transmission/072dpi/soept20091101-01_072dpi.jpg

Sources

• https://en.wikipedia.org/wiki/High-voltage_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/db0003db004333/2eaf1b10de87a2bec12574ea005127de.aspx.

• www.ieeexplore.ieee.org• http://

www.energy.siemens.com/us/en/power-transmission/hvdc/hvdc-plus/references.htm

Reference

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[1]: “HVDC Grid Feasibility Study”, Cigre B4 533, 2013

[4]: “Power Flow Analysis in Multi-Terminal HVDC Grid”, 2011

[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

[5]: “Multi-Terminal HVDC Grid with Power Flow Controllability”, Cigre B4-301, 2012