The Moyle Interconnector is a 500megawatt HVDC link between Scotland and Northern Ireland, running between Auchencrosh in

Ayrshire Ayrshire ( gd, Siorrachd Inbhir Àir, ) is a historic county and registration county in south-west Scotland, located on the shores of the Firth of Clyde. Its principal towns include Ayr, Kilmarnock and Irvine and it borders the counties of Re ...

and Ballycronan More in County Antrim. It went into service in 2001 and is owned and operated by Mutual Energy.

Specifications

The HVDC Moyle Interconnector has a capacity of 500MW. It consists of two coaxial 250kV DC cables with integrated return conductors (IRC), each cable having a transmission capacity of 250MW. The IRCs have failed through the events below, and their function restored by laying separate return conductors. The converter stations are equipped with light-triggered thyristors. The converter station at Auchencrosh is connected via a single-circuit 275kV overhead three-phase AC line, which is installed on delta-type pylon, to Coylton substation, where the connection with the high voltage grid of Great Britain takes place. The connection to Northern Ireland is then made through dual long monopolar cables, of which are submarine cables. The Ballycronan More converter station is connected into the Northern Ireland grid through two 275kV circuits.

Operating history

In August 2011, the interconnector went out of service. Repairs were made and the cable became operational again with 450MW in February 2012. However, further faults meant that a major part of the interconnector had to be taken out of service until it could be augmented with the additional LV return cables, completed in 2016. This restored capacity to the full 500MW. This was carried out by Nexans (Norway) with the aid of Morrows (NI) and Romac Civil Engineering (NI). In February 2017, the cable suffered another fault, halving capacity to 250MW. However full capacity was restored in September 2017, following repairs by Nexans.

Mutual Energy

Mutual Energy is a mutual company which manages the Moyle Interconnector (and some high pressure gas transmission assets including the Scotland-Northern Ireland Pipeline) for the benefit of Northern Ireland's energy consumers.

Economic aspects

Intraday capacity trading is not available, but is being discussed. Since November 2017, exports to Scotland are limited to 80 MW due to National Grid UK transmission constraints. However, 2-day ahead projections of wind in Scotland are used to allow flows of up to 300MW. The 80MW constraint is expected to rise to 500 MW by 2022 Moyle also provides frequency support services to both

Eirgrid EirGrid plc is the state-owned electric power transmission operator in Ireland. It is a public limited company registered under the Companies Acts; its shares are held by the Minister for the Environment, Climate and Communications. It is one of ...

and the National Grid. These services provide for fast change of power flow in the event of a network disturbance on either the NI or Scotland transmission systems.

Sites

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External links

* * * * * * {{Energy in the United Kingdom, sources Electrical interconnectors to and from Great Britain Electrical interconnectors to and from the island of Ireland HVDC transmission lines Electric power infrastructure in Scotland Electric power infrastructure in Northern Ireland Scottish coast Buildings and structures in South Ayrshire Buildings and structures in County Antrim 2001 establishments in Northern Ireland 2001 establishments in Scotland