Impact Loading of Isolated Generators

Voltage and frequency response of a generator are important considerations when a sudden load is applied or a large motor is started on an isolated system. The speed change of gas and steam turbine-driven generators are examined after the application of suddenly applied loads. Generator recovery voltage as a function of generator impedance, open-circuit time constant, and inertia are shown with different magnitudes of suddenly applied loads. The size of the generator may be determined by the starting kilovoltampere demand and minimum voltage allowed rather than by the total connected load.