Protection and Specification of Clutches to be Used With Gas Turbine Generators

The use of self-actuating clutches in gas tubine driven electrical power generators is examined, in relation to operation of the clutch during fault conditions. Clutches are employed in the main shaft between the power turbine and the electrical generator, to enable the unit to operate as a synchronous compensator. Five particular fault conditions are identified which could cause overstressing of the clutch. Protection is not universally provided to protect the clutch under all five conditions, and methods of providing protection are suggested. Analysis of the fault conditions is developed to identify the differential acceleration requirement for the clutch. The analysis is extended to demonstrate the limited capability of a gas turbine generator, when operating as a synchronous compensator, to provide spinning reserve capacity for an electrical system.