PARTIAL DISCHARGE DETECTION DEVICE AND PARTIAL DISCHARGE DETECTION METHOD

A partial discharge detection apparatus includes a low-speed AD converter, a high-speed AD converter, and a partial-discharge-detection digital signal processing unit. The low-speed AD converter converts an analog signal of an AC waveform flowing through a power cable into a digital signal. The high-speed AD converter converts an analog signal of a partial discharge current into a digital signal. The analog signal is in a plurality of Nyquist frequency domains defined for each of two different types of sampling frequencies. The partial-discharge-detection digital signal processing unit detects partial discharge based on the maximum value or the sum of a current value obtained from the digital signal of the partial discharge current, which is obtained by the conversion of the high-speed AD converter, for each phase of the AC waveform, which is obtained from the digital signal of the AC waveform flowing in the power cable. The digital signal is obtained by the conversion of the low-speed AD converter.