PURPOSE

The purpose of this procedure, is to provide a model process for the checks and tests to be performed on a circuit breaker fail scheme which is being extended (as a result of adding a new Feeder Bay), at an existing double busbar substation with a common relay room. The procedure is also applicable where an existing circuit breaker fail scheme is being replaced. The tests are to be performed both before and after connection to the existing D.C. bus wiring associated with the back-tripping scheme. These checks and tests are required to ensure that:

• Appropriate checks and tests have been performed on the new circuit breaker fail scheme - to ensure that it has been correctly installed and is fully functional.

• The system provided is compatible with the existing system already installed.