A transmission constraint arises where the system is unable to transmit the power supplied to the location of demand due to congestion at one or more parts of the transmission network. In the event that the system is unable to flow electricity in the way required, National Grid will take actions in the market to increase and decrease the amount of electricity at different locations on the network.
The exact way in which a constraint is managed depends on a number of factors including the nature of the flows on the transmission system, the duration of the requirement, the local level of generation output, and the local level of system demand. Therefore the technical requirements will be specific to the location of the constraint and defined in the Commercial Services Agreement.
For more detailed information on Transmission Constraint Agreement principles please view the information in our Balancing Services Contracts Information Pack.
Constraint Management Service
National Grid is currently developing a new balancing service to help manage transmission constraints. An overview of the service was presented at the Interim Operational Forum on 12th December 2007.
The following document contains draft 2 of the service terms, presented as a clause and schedule for insertion into a Commercial Services Agreement. The terms have been updated to reflect ongoing service developments and comments received since draft 1.
A 'Question and Answer' document has been produced to accompany draft 2 of the service terms.
Please contact your Account Manager or Ian Pashley of our Contracts & Settlements team (+44 (0)1926 653446, ian.pashley@uk.ngrid.com) at your earliest convenience to discuss the potential to provide this service and to provide comments and feedback on Draft 2 of the service terms.