Dependence of the reactivity compensation degree of a synchronous compensator on its parameters.

The problems of asynchronous self-excitation of a synchronous machine with two windings on the rotor and a series capacitance in the circuit have been considered. A formula for calculating free oscillations has been given. It has been shown that, for a system consisting of a symmetric synchronous machine and a series capacitance, there are two natural frequencies, each corresponding to a certain zone of self-excitation. The equation of the curve that describes the region of self-excitation has been obtained. The effects of different parameters of machine on the lower part of the self-excitation zone have been investigated. It has been shown that this part of the zone is determined by the ratio between the active resistances of the machine circuits, but not their absolute values. A method to determine parameters providing the required compensation of the machine reactance has been given. [ABSTRACT FROM AUTHOR]