This Specification describes the functional and performance requirements for the protection of 13 kV delta tertiary winding connections and 132 kV LV connections to static compensation equipment associated with 400 kV and 275 kV transformer.

The protection of static compensation equipment that may be connected to a transformer tertiary winding or its LV connections shall meet the functional and performance requirements specified in NGTS 2.18 for >Relocatable= Static VAR Compensators (RSVCs) for Connection to Transformer Tertiary Windings, NGTS 3.6.18 for Shunt Reactors and NGTS 3.6.21 for 132 kV Mechanically Switched Capacitors (MSCs) as appropriate.

The requirements for devices for mechanical protection, including gas and oil actuated relays, and winding temperature instruments are specified in NGTS 2.3 Transformers and Reactors. This Specification only specifies their function within the electrical protection system.

The requirements for the protection of transformer LV Connections are specified in NGTS 3.6.14 Copperwork Protection.