PURPOSE AND SCOPE

This Specification describes the functional and performance requirements and the facilities to be provided for the numerical protection of busbars at 400 kV, 275 kV and 132 kV double busbar switching stations. It also defines the interfaces to the appropriate bay level specifications.

The requirements for two different types of numerical busbar protection are specified in this document, distributed numerical busbar protection and centralised numerical busbar protection. The requirements in this specification apply equally to both types of busbar protection unless this is stated in the relevant heading. Where requirements are different, dedicated sub-sections provide the required detail for each type of scheme. The selection of the type of numerical busbar protection applied at a substation shall be based on the capability of the scheme to comply with the functional requirements in Section 1, engineering assessment and cost comparison.