scope:

This standard applies to LU and London LU suppliers and to new 22/11kV Power Transformers and associated equipment to be installed on the LU power system.

Purpose

The purpose of this standard is to apply technical requirements for the design, manufacture and testing of 22/11 kV, 50 Hz, three phase power transformers, and associated equipment and documentation for use on London Underground (LU) power network to provide power for electric traction and other purposes, within an operational environment as described in S1916 'Physical and Electrical Environment of the System'.

Associated with each power transformer is an earthing reactor or resistor, which provides an earthed system star point through its winding(s) and is connected on the secondary side of the power transformer.

Note: Earthing reactors are specified in LU standard S1944 '22kV and 11kV Three Phase Earthing Reactors and Earthing Auxiliary Transformers for Use on The System'.