West Coast Main Line autotransformer electrification system - test site design and principles

Substantial reinforcement of the electrification distribution system is an inherent requirement of modern main-line railway upgrade projects. This is particularly true of lines which are intended to operate as future high-speed/dense service routes, such as the UK West Coast Main Line. The use of autotransformer feeding is the most efficient design for high-power distribution on heavily loaded lines, and provides a system with the capacity for future load growth at minimal cost. New high-speed double-track lines have widely adopted the 2 × 25 kV autotransformer distribution system as standard. However, application of the autotransformer system to a multi-track existing route such as the West Coast Main Line, together with implementation and conversion whilst maintaining a service, have been considered in the past to be impractical. This has severely limited the options for future electrification system development. This presentation describes the development of the first conversion of a 25 kV-electrified line to autotransformer feeding in the UK: namely the West Coast autotransformer system Test Site between Long Buckby Wharf and Blisworth in Northamptonshire. The development of this site has been based upon providing a design which can be applied to the route with minimal disruption to service, and also provide for future multi-track autotransformer feeding. The approach is based upon the use of enhanced modelling and simulation techniques. The presentation considers traction load analysis, signalling interference suppression, distribution system design, and protection and control systems. In particular the use of non-standard and novel system design is considered as a means of phasing the introduction of autotransformer feeding and conversion to a full route autotransformer system.