ABB technology to address overhead wire voltage drops

ABB has secured a major project with High Speed 1 — the organisation that owns the assets of the Channel Tunnel Rail Link and develops and maintains the infrastructure — to design, manufacture and install the capacitive compensators to prevent voltage drops along the 25kV supply serving the 68-mile (109km) High Speed 1 route from St Pancras International to the Channel Tunnel at Dover.

High Speed 1 is used by Eurostar trains operating the international high-speed routes between London, Paris and Brussels, as well as high-speed domestic trains that provide a commuter service between London and Kent. The railway lines are electrified on the 2 x 25kV principle using autotransformers.

Although High Speed 1’s nominal line voltage is 25kV, there are some areas of the line where it can drop as low as 17.5kV due to the design of the power-hungry isolation transformers (used to isolate between High Speed 1’s AC traction power supply and the adjacent Network Rail DC traction power supply), which are located in the existing substations along the line.