ABB has been awarded a contract worth just over £2m to refurbish and upgrade a 275kV National Grid substation on the Thames Estuary. The project includes the supply and installation of five new ABB 400kV HPL SF6 insulated puffer circuit breakers to replace the now time-expired air-blast circuit breakers installed in the 1960s, as well as associated civil and connection works and interfacing with the substation control and protection systems.
The new ABB HPL circuit breakers, capable of switching short-circuit currents up to 63kA, will be installed on five circuits – three outgoing and two from the substation transformers. National Grid has specified them at 400kV to provide the
