METHOD OF PROTECTING SYNCHRONOUS GENERATORS FROM GROUND FAULT AT ONE POINT OF EXCITATION CIRCUIT

摘要

FIELD: electricity.;SUBSTANCE: method of protecting synchronous generators from ground (case) fault at one point of the excitation circuit is impacting the source overlay of low frequency AC voltage via a passive frequency filter to isolate the excitation circuit relative to the case, measuring complexes and the first output voltage of that source, converting the measured complexes of the first voltage and current circuit insulation resistance measurement of excitation and comparing the obtained measurement resistance parameters of operation of the measuring bodies. With the aim of improving the accuracy of protection, impedance of a passive crossover at the frequency of the source overlay is pre-determined, current flowing through it is recorded, the second voltage complex is determined as the voltage drop across this filter, the third voltage complex is determined as the difference between the systems of the first and the second voltages, the fourth voltage complex is measured between the contacts of the relay and the grounding brushes to the generator shaft, the fifth voltage complex is determined as a sum of complexes of the third and the fourth voltages, and the insulation resistance is measured in the fifth voltage and current complexes.;EFFECT: increasing the accuracy of measuring the insulation resistance without complicating the design of the protection device.;1 dwg