scope:

PURPOSE AND SCOPE

This document is the highest level specification in a three tier structure. Each successive level provides greater detail in a specific discipline and, collectively, these documents define National Grid's technical requirements for plant, equipment and apparatus for use on its electricity transmission system. These documents translate the actual operating characteristics of the National Grid electricity transmission system (National Grid System) into standardised values that assure safe & reliable operation. As far as possible, ratings and requirements are selected from values given in appropriate international standards. Deviations from these standards relate to particular requirements of National Grid network configurations or operational & safety procedures.

Greater detail regarding the actual operating characteristics of the National Grid System are detailed in CI 01 "Technical and Operational Characteristics of the National Grid Transmission System". Suppliers of plant, equipment and apparatus for use on the National Grid System should be familiar with CI 01.

The requirements of this document apply to all plant, equipment and apparatus which is part of the National Grid System. Requirements contained herein may be modified on a more specific basis by lower level specification however, unless such modifications are explicitly detailed, the requirements of this document apply.

Ratings are specified explicitly for plant with nominal voltages of 66kV and above and 13kV transformer tertiary connections. Rating for other nominal voltages are specified in TS 2.29.

Derogation from the requirements of the TS suite will normally be permitted only where it can be demonstrated that the proposed derogation is not detrimental to the safety, reliability and availability of the National Grid System.