Static exciter system for large turbo-generators

In the summer of 1986, a problem was found which affected a number of similar AC exciters on 300 MW generators in use in SSEB power stations. There was a need to find some way of releasing a first set of exciters for modification which could then be used to start a rolling programme of modifications, while minimising any loss of availability of generation. Unit 4 at Cockenzie power station was chosen as the first to be modified. This is a coal fired 300 MW unit. The author discusses the replacement of rotating exciter system by a static excitation system which gives enhanced performance and lower losses than the original system