PARTIAL DISCHARGE MEASUREMENT SYSTEM AND PARTIAL DISCHARGE MEASUREMENT METHOD BY REPEATED IMPULSE VOLTAGE

摘要

An impulse voltage generator uses a predetermined rectangular waveform signal and a high voltage to generate an impulse voltage. The high voltage is obtained by boosting an instruction voltage of the rectangular waveform signal on a per-cycle basis. A partial discharge frequency calculation section receives detection signals based on partial discharges occurring in an object to be measured by the application of the impulse voltage and counts the detection signal on a per-cycle basis as a partial discharge frequency. An application voltage signal observation circuit observes an application voltage signal indicating the impulse voltage applied to the object to be measured. In a first cycle in which the partial discharge frequency reaches a specified frequency or more, a voltage value acquiring section sets, as a partial discharge starting voltage, the peak value of the voltage indicated by the application voltage signal output from the application voltage signal observation circuit.

主权项

1: A partial discharge measurement system based on repeated impulse voltage, the system comprising:
a DC power supply that outputs high voltage as a voltage obtained by multiplying an instruction voltage by a set factor; a signal generator that generates a pulse signal representing a predetermined pulse width and a predetermined pulse repetition frequency, and superimposes a period setting signal whose one period includes a pulse supply period and a pulse pause period following the pulse supply period and the pulse signal on each other to generate a rectangular waveform signal in which a predetermined number of the pulse signals are generated only in the pulse supply period; a semiconductor switch that charges a capacitive element with the high voltage from the DC power supply when a voltage value of the rectangular waveform signal is lower than a preset voltage threshold, while applies an impulse voltage having a peak value equal to a value of the high voltage from the capacitive element to an object to be measured when the voltage value of the rectangular waveform signal is equal to or higher than the voltage threshold; a signal instruction section that outputs, to the signal generator, a square wave instruction signal in which the predetermined pulse width, the predetermined pulse repetition frequency, and the predetermined number are set; a voltage instruction section that outputs, to the DC power supply, a voltage instruction signal in which an initial voltage is set as the instruction voltage in a first period of the rectangular waveform signal and sets in the voltage instruction signal, in second and subsequent periods, a voltage obtained by adding a predetermined increment voltage lower than the initial voltage to the instruction voltage in the immediately previous period as the instruction voltage; a detection signal observation circuit that observes a detection signal based on a partial discharge generated in the object to be measured to which the impulse voltages are applied; a partial discharge frequency calculation section that counts the number of inputs of the detection signal on a per period basis as a partial discharge frequency; an application voltage signal observation circuit that observes an application voltage signal representing the impulse voltage to be applied to the object to be measured; and a voltage value acquiring section that sets, in a period in which the partial discharge frequency first becomes equal to or more than a specified frequency, a peak value of a voltage represented by the application voltage signal from the application voltage observation circuit as a partial discharge starting voltage.