PARTIAL DISCHARGE COUNTER FOR DIAGNOSIS OF GAS INSULATED SWITCHGEAR

• US 20100324746A1
• Filed: 08/28/2009
• Published: 12/23/2010
• Est. Priority Date: 06/19/2009
• Status: Active Grant

• Current Assignee: Hanbit EDS Co., Ltd.
• Original Assignee: Hanbit EDS Co., Ltd.
• Inventors: JEONG, Jae Kee
• Granted Patent: US 8,010,239 B2
• Time in Patent Office: Days
• US Class Current: 700/292
• CPC Class Codes: G01R 31/1254 of gas-insulated power appliances or vacuum gaps testing switches G01R31/327; detecting electrical or mechanical defects in encased switchgear H02B13/065
• CPC Class Codes: H02H 1/0015 Using arc detectors
• CPC Class Codes: H02H 1/04 Arrangements for preventing response to transient abnormal conditions, e.g. to lightning or to short duration over voltage or oscillations; Damping the influence of dc component by short circuits in ac networks

Abstract

The present invention relates generally to a partial discharge counter for the diagnosis of a GIS. The partial discharge counter includes a partial discharge detection sensor for detecting a partial discharge. A first surge inflow prevention circuit separates a surge signal from an output terminal of the partial discharge detection sensor. A channel 1 frequency conversion module forms a low-frequency signal. A noise detection sensor detects noise. A second surge inflow prevention circuit separates a surge signal from an output terminal of the noise detection sensor. A channel 2 frequency conversion module forms a low-frequency signal. An ADC circuit generates partial discharge data and noise data. A synchronization device enables the partial discharge data and the noise data to be output in synchronization with frequency of the phase voltage. A digital signal processing unit counts a number of times the partial discharge occurs. Counting units display a count value.

Claims

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.