Application of a New Distance Protection Scheme to a Single-Pole Autotransformver Electrification System on the UK West Coast Main Line Railway

This paper describes the protection scheme implemented on an autotransformer electrification system on the West Coast main line of network rail in the UK. The design is significantly different from autotransformer systems used in continental Europe and the channel tunnel rail link because it uses greater selectivity isolating the faulted line while leaving remaining lines energised. This is important on a heavily used route such as the West Coast main line railway to reduce the impact of power loss. The autotransformer system was first installed on a 40 km section on the West Coast route on a dual double-track section. The protection philosophy proved successful in demonstrating that a discriminating scheme can be achieved. The paper explains the settings methodology for the new system, details of load and fault measurement analysis during operation and discusses the additional issues encountered following commissioning of the first conversion section.