scope:

PURPOSE AND SCOPE

The health of the National Grid Electricity Transmission System is critically dependent upon correct relay settings. It is therefore essential that this process is adhered to both rigorously and diligently.

The purpose of this procedure is to define the management process for the preparation, application, verification, dissemination, recording and auditing of protection and control relay settings. This procedure defines both the Client side (i.e. National Grid Electricity Transmission) tasks, responsibilities and levels of surveillance, and the Contractor side tasks and responsibilities.

The procedure applies to all protection and control relays owned by National Grid Electricity Transmission (NGET), or for which NGET has entered into an arrangement to carry out and hold the settings. The procedure is formatted on the basis that relay settings calculations will be carried out by UKBP/TP141 authorised Contractor engineers either as part of a capital scheme, or as part of ongoing support through a Post Delivery Support Agreement (PDSA) or Secondary System Support Contract (SSSC).

The scope of this procedure covers all protection and control equipment which require a setting, including associated equipment such as current transformers and facility selection functions. It covers the settings process associated with

• the capital programme

• maintenance & operations

• following equipment failure

• third party interfaces as required by the Grid Code

• setting changes requested by the Transmission Network Control Centre (TNCC).