scope:

This Standard shall apply to London Underground's 22kV, 11kV, 600V and 400V AC distribution systems and any assets that form part of the Power PFI Contractors Operation and Maintenance responsibilities. The standard also lays down specific protection requirements associated with the Bulk Supply Points (BSP) and LU's Emergency Generation Facility.

This Standard includes the requirements for:

a) protection systems;

b) protection relays;

c) direct acting protective devices;

d) electronic protection within circuit breakers; including Moulded Case Circuit Breaker (MCCB).

e) fuses;

f) protection current and voltage transformers;

g) protection communications and intertripping;

This Standard specifically excludes any requirements for protective equipment onboard rolling stock.

Purpose

This Standard:

a) describes the minimum performance levels required of electrical protection on London Underground's (LU's) Alternating Current (AC) power distribution systems;

b) gives details of protection systems in terms of design principles and methods;

c) defines the requirements for all electrical protection equipment for power system circuits operating normally at or above 400V AC between conductors; and

d) provides the underlying principles applicable to protection systems in achieving minimum levels of safety, supply continuity and stability for AC power systems on the London Underground Power Distribution Network.