When generators are operated in parallel condition,it necessary to be arrange for both real power ( kW ) and reactive load ( kVar ) sharing in proportion to their standard rating.Real load output from generator determined by torque applied to the shaft and this can only be controlled by controlling the prime mover driving the generator.

Reactive load is a function of generator excitation.Under parallel operation,adjustment to field excitation does not affect to output voltage.In general,an under-excited machine will generate at a more lagging power factor current.

The three phase sensing regulator operates in similar manner except that the voltage across the reactor carrying a current proportion to one phase current is added to the voltage of that phase. read more