NR NR/SP/ELP/21075 ISSUE 2 PDF

This specification applies to all new d.c. immune isolating transformers installed at the interfaces between the two electrification systems.

Purpose

This specification states the requirements for the design, manufacture and testing of outdoor, d.c. immune, 25 kV, single phase, isolating transformers for use at interfaces between a.c. and d.c. electrified lines. The transformers provide electrical isolation between the two systems thereby preventing d.c. traction current entering the a.c. system.

The document is to be read in conjunction with the relevant procurement specification.