This Specification describes the functional and performance requirements for the protection of 400 kV and 275 kV oil-immersed quadrature boosters constructed in accordance with IEC 76 or equivalent.

The detailed requirements for back-up protection for quadrature boosters are specified in NGTS 3.6.7 Back-up Protection.

The requirements for devices for mechanical protection including gas and oil actuated relays, winding temperature instruments and oil flow fail detection devices, are specified in NGTS 2.3 Transformers and Reactors.

The requirements for the trip relay resetting scheme are specified in NGTS 3.6.15 Trip Relays and Trip Relay Resetting.