Impact of steam turbine valve closure on a synchronous machine and its reverse power protection

A waste recycling and generation plant experienced significant power and frequency fluctuations following a steam valve closure on the generators prime mover. The reverse power protection did not remove the electrical machine from the network as quickly as expected, and concerns were raised regarding the resulting damage potential. This paper presents the modelling of the system and the improved reverse power protection function developed and tested using the model, to trip the machine within an acceptable period of time following such an event.