HVDC Moyle

Aerial photograph of area where Moyle Ballycronan More HVDC converter station is. It is situated left-up the power station
Country	United Kingdom (Scotland & N. Ireland)
From	Auchencrosh, South Ayrshire
To	Ballycronan More, County Antrim
Owner	Mutual Energy
Commissioned	2001
Type	submarine cable
Type of current	HVDC
Total length	63.5 km (39.5 mi)
Power rating	500 MW (Currently restricted to 250 MW)
DC Voltage	250 kV
No. of poles	2

The HVDC Moyle Interconnector is the 500 MW HVDC link between Auchencrosh, South Ayrshire in Scotland and Ballycronan More, County Antrim in Northern Ireland, which went into service in 2001. It is owned and operated by 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.

Work was completed in 2016 to replace the subsea sections of the LV return conductors with two new return cables. This was carried out by Nexans (Norway) with the aid of Morrows (N.I) and Romac Civil Engineering (N.I).

The HVDC Moyle Interconnector has a capacity of 500 MW. It consists of two monopolar 250 kV DC cables with a transmission capacity of 250 MW each. The converter stations are equipped with light triggered thyristors.

The converter station at Auchencrosh is connected via a 64 kilometres (40 mi) single-circuit 275 kV 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 63.5-kilometre (39.5 mi) long monopolar cables, of which 55 kilometres (34 mi) are submarine cables. The Ballycronan More convertor station is connected into the Northern Ireland grid through two 275kV circuits.

As of October 2011^[update], the interconnector was out of service, repair efforts were being made, and the cable became operational again with 450 MW 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 return cables, completed in 2016. This restored capacity to the full 500MW.

In February 2017 the cable suffered another fault, halving capacity to 250 MW.