Partial discharge counter for diagnosis of gas insulated switchgear

1. A partial discharge counter device for diagnosis of a Gas Insulated Switchgear (GIS), the device measuring a number of times a partial discharge occurs in the GIS to perform diagnosis of insulation of the GIS, comprising:

a partial discharge detection sensor for detecting a partial discharge attributable to an abnormality inside the GIS when the partial discharge occurs;

a first surge inflow prevention circuit for separating a surge signal from an output terminal of the partial discharge detection sensor, thus protecting the counter device from the surge signal;

a channel 1 frequency conversion module for extracting a low-frequency component from a high-frequency output signal detected by the partial discharge detection sensor and forming a low-frequency signal;

a noise detection sensor for detecting noise when the noise occurs outside the GIS;

a second surge inflow prevention circuit for separating a surge signal from an output terminal of the noise detection sensor, thus protecting the counter device from the surge signal;

a channel 2 frequency conversion module for extracting a low-frequency component from a high-frequency output signal detected by the noise detection sensor and forming a low-frequency signal;

an Analog-Digital Counter (ADC) circuit for converting analog signals, output from the channel 1 frequency conversion module and the channel 2 frequency conversion module, into digital signals, and generating partial discharge data and noise data;

a synchronization device for dropping a phase voltage and converting the dropped phase voltage into a square wave signal, thus enabling the partial discharge data and the noise data, that is, output signals of the ADC circuit, to be output in synchronization with a frequency of the phase voltage;

a digital signal processing unit for comparing the synchronized partial discharge data and the noise data, determining whether a partial discharge has actually occurred, and counting a number of times the partial discharge occurs only when the partial discharges have actually occurred and exceed a set value; and

counting units for displaying a count value obtained by the digital signal processing unit so as to allow a user to view the count value.

2. The partial discharge counter device according to claim 1 , wherein each of the channel 1 frequency conversion module and the channel 2 frequency conversion module extracts a low-frequency component from a high-frequency output signal in an Ultra-High frequency (UHF)-band, detected from an input signal, using a band pass filter, detects only peak values and forms a low-frequency signal of several tens of kHz using a peak detection circuit, holds the peak values using a peak-hold circuit, and resets the peak-hold circuit through a peak reset circuit.

3. The partial discharge counter device according to claim 1 , wherein the digital signal processing unit is connected to a warning unit for generating a warning.

4. The partial discharge counter device according to claim 1 , wherein the digital signal processing unit is connected to a wired/wireless communication module for transmitting a count value to an external monitoring room via a wired or wireless connection.

5. The partial discharge counter device according to claim 1 , wherein the counters comprise a reset counting unit for counting a number of times a partial discharge occurs for a predetermined period.

6. The partial discharge counter device according to claim 5 , wherein the reset counting unit is configured such that the number of times the partial discharge occurs is initialized using a resetting button.

7. The partial discharge counter device according to claim 1 , wherein the set value is a set reference level required to determine whether to count partial discharge signals based on magnitude of the partial discharge signals.