Transmission constraint management

Constraint management is required where the electricity transmission system is unable to transmit power to the location of demand, due to congestion at one or more parts of the transmission network. Here you can find out how to provide this service.

For Information: Vector Shift - Loss of Mains Protection change

FAO: Distributed Generators: Loss of Mains Protection change, away from Vector Shift (VS)

In order to preserve the stability of the electricity system, loss of mains (LoM) protection settings on a limited volume of existing generators fitted with Vector Shift (“VS”) type protection must be changed immediately in targeted locations across the south of England.

In order to encourage your support, the TSO and DNOs have agreed to a compensation proposal outlined in the open letters on this page, subject to generating units meeting the relevant criteria.

  • Is your site located in the SSE, UKPN or WPD DNO areas?
  • Is your distributed generation scheme sized at >1MW?
  • Is your protection afforded by a discrete G59 relay which utilises Vector Shift as its loss of mains protection?

Please read the relevant proposal and respond as soon as possible, as you may be eligible for the compensation offered under the proposal; for which you will be required to transition from VS to High Setting RoCoF before 1 June 2018.

Context and additional information is outlined in the open letters below: