METHOD OF AUTOMATED MONITORING STATE OF CAPACITOR-TYPE PAPER-OIL INSULATION FOR GROUP OF THREE-PHASE ELECTRICAL DEVICES AT OPERATING VOLTAGE UNDER OPERATION CONDITIONS Russian patent published in 2009 - IPC G01R31/02 

FIELD: electricity.

SUBSTANCE: invention relates to electrical engineering and electrical power engineering and is meant for in-service inspection of the state of insulation of high-voltage equipment, for example, transformers, shunt reactors at operating voltage through measurement of partial discharge characteristics in the insulation. Average current of partial discharge pulses is measured and compared with a given value. Frequency of partial discharge pulses exceeding a certain value is also measured. Measurement is done in a given time interval, which is chosen for each phase in an angle interval from 7π/6 to 3π/2 of the voltage period of the corresponding phase. Further, there is successive comparison of the average current of partial discharge pulses in corresponding phases for all electrical devices between themselves and frequency of the said pulses with given values and between themselves. The faulty phase of an electrical device is selectively detected from average current and frequency of the said pulses in it exceeding given values and corresponding values in that phase for the rest of the electrical devices.

EFFECT: possibility of preventing failure of electrical equipment with severe consequences.

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