ABB has delivered the East West Interconnector to EirGrid, the Irish transmission system operator. The 500-megawatt (MW) HVDC (High Voltage Direct Current) Light transmission connection is the highest capacity link of its kind, based on voltage source converter (VSC) technology, to go into commercial operation.
The interconnector establishes an important link between the Irish and UKgrids, enabling cross-border power flows and enhancing grid reliability and security of electricity supplies. The new link also facilitates power trading between the two countries and connects Ireland to the European grid. As Ireland expands its wind power capacity, it can export surplus electricity to the UK, and can import power when required.
A 262 km (163 mi) cable system connects Woodland in County Meath, Ireland and Deeside in north Wales. The cables are equipped with extruded polymeric insulation that provides strength and flexibility to endure the severe conditions of the Irish Sea. HVDC Light’s “black start” capability can help restore power quickly in the event of an outage, without the aid of external energy sources.
ABB pioneered HVDC technology nearly 60 years ago and has been awarded around 90 HVDC projects representing a total installed capacity of more than 95,000 megawatts (MW), accounting for about half the global installed base.
The classical HVDC technique was first introduced in Sweden (Gotland link) in 1954 by ASEA (a founding company of ABB). Typically, a classical HVDC transmission has a power of more than 100 Megawatt (MW) and many are in the 1,000 - 3,000 MW range. There are classical HVDC transmissions that use overhead lines and that use undersea (and underground) cables (or combinations of cables and lines).
HVDC Light is a fundamentally new power transmission technology developed by ABB in the 1990s. HVDC Light uses underground or submarine cables. The technology extends the economical power range of HVDC transmission down to just a few tens of Megawatts (MW). In the upper range, the technology can reach 1,200 MW and ±320 kV.
One of the characteristics of HVDC Light is its superior ability to stabilize the AC voltage at the terminals, according to ABB. This is particularly important for wind parks, where the variation in wind speed can cause severe voltage fluctuations.
It is increasingly being deployed across a range of applications including integration of renewable energies from land-based and offshore wind farms; mainland power supply to islands and offshore oil and gas platforms; city center in-feeds where space is a major constraint; and interconnections, often across the seas. ABB leads the way in this space, and has delivered 13 of the 14 commissioned HVDC links based on VSC technology.