Partial discharge counter for electric power gis system diagnostic

A partial discharge counter device for diagnosing a GIS(Gas insulated Switchgear) is provided to detect the generation and size of GIS partial discharge in counting the number of GIS partial discharge times by using a reference level setting unit. In a partial discharge counter device for diagnosing a GIS, a partial discharge sensor(1) detects partial discharge of a UHF(Ultra High Frequency) when partial discharge is generated due to internal defects of the GIS. A surge input preventing circuit(20) protects the counter device by separating a surge signal from an output stage of the partial discharge sensor. A low frequency converter(21) filters a low frequency signal by filtering a high-frequency output signal of a UHF band detected by the partial discharge sensor, through a band pass filter(21-a) and holds a peak value of a peak holding circuit(21-c) by forming a low-frequency signal by detecting only a peak value of a peak detecting circuit(21-b). The low frequency converter resets the peak holding circuit by a peak reset circuit(21-d). An ADC(Analog-Digital Convert) circuit(22) converts a peak holding signal outputted from the low frequency converter into a digital signal. A synchronizer(27) synchronizes an output signal of the ADC circuit with the frequency of phase voltage(4) by converting the phase voltage into a square wave signal of TTL(Transistor-Transistor Logic) level and then outputs synchronized partial discharge data. A digital signal processing unit(23) reads the synchronized partial discharge data in a predetermined cycle and then applies reset pulse to the peak reset circuit. The digital signal processing unit compares the read synchronized partial discharge data with a set value and counts the number if the read synchronized partial discharge data is over the set value. A set displayer(24) sets the set value by a set button(5) and displays the set value to the user. Counters(28,29) display values counted by the digital signal processing unit.