NG DH 04 PDF

PURPOSE AND SCOPE

The purpose of this handbook is to provide guidance on the feeder backup protection settings calculation for use on the National Grid 400kV and 275kV transmission system. The application and protection setting policy for the most commonly occurring electricity transmission primary arrangements within National Grid is laid down in PS (T) 010 – Issue 2.

This design handbook will ensure a consistent approach for the backup protection setting calculations. Guidance on backup protection settings for two-ended, three-ended, ‘teed’ transformers, transformer feeders and feeders directly connected to the LV side of an SGT is provided in this document.