KR20010084956A - Apparatus for detecting a portion of discharge in a power machinery and tools - Google Patents

Abstract

PURPOSE: An apparatus for detecting a partial discharge of a power equipment is provided to easily maintain and repair the power equipment by searching a location of a partial discharging generator. CONSTITUTION: A partial discharge detecting apparatus(100) comprises a sensor(110) in order to detect an electromagnetic wave radiated by a partial discharge in a power equipment. The sensor(110) is composed of a type of a helical antenna. An electromagnetic wave detecting unit(120) is composed of an R/F(radio frequency) amplifying unit(122), IF(intermediate frequency) processing nit(124), and a noise eliminating filter(126). The electromagnetic wave detecting unit(120) amplifies the output signal of the sensor and modulates only an electromagnetic wave signal eliminated noise to an intermediate frequency and outputs it. A pulse creating unit(130) integrates the electromagnetic wave outputted from the electromagnetic wave detecting unit(120) by performing the intermediating, compares it with a former value, and outputs it to the pulse by partial discharge. An electromagnetic wave level processing unit(140) compares the electromagnetic wave performed intermediating to a plurality of reference voltage and outputs the electromagnetic wave pulses which are plural levels. A wave setting unit(150) performs the wave setting on the electromagnetic wave pulses and the pulse by partial discharge. A control unit(160) counts the pulse by partial discharge, calculates an average pulse number per one cycle, inputs the electromagnetic wave pulses, calculates an amount of partial discharge of predetermined unit, and transmits it with the average pulse number through a communication unit to outer monitoring system.

Description

Partial discharge detection device of power equipment {APPARATUS FOR DETECTING A PORTION OF DISCHARGE IN A POWER MACHINERY AND TOOLS}

The present invention relates to an insulation degradation monitoring system of a power device, and more particularly, to an apparatus for detecting a partial discharge of a power device by sensing electromagnetic waves caused by a partial discharge.

In order to check and diagnose the power equipment accidents, it is common to use a contact monitoring system and portable inspection equipment.

Conventional always-on monitoring device is attached to a sensor to measure the degree of degradation by attaching a sensor, there is a problem that can not be applied to the equipment already installed. In addition, there is a risk that an accident may always occur in these devices because the sensor may be damaged or the device may be damaged by a large current when a ground fault or surge is introduced.

On the other hand, portable inspection equipment can be divided into non-contact type and contact type, but it has a disadvantage that it is impossible to establish a regular monitoring system because it ends with a one-time inspection. In addition, when checking the power equipment using a portable device in the live state, there is always a risk of safety accidents such as electric shock accidents.

Therefore, in the field still uses the five senses of the human body, in this case there is a problem that can be obtained incorrect measurement results because it depends on the subjectivity of the measurer. In addition, in case of using simple measuring equipment such as infrared thermometer, corona detector, etc., it is impossible to check and measure the concealed part, so it is difficult to prevent accidents early. It has the disadvantage of investing a lot of expertise and time in measuring instrument degradation.

Accordingly, an object of the present invention is to provide a partial discharge detection apparatus using electromagnetic waves to support the monitoring of the degree of degradation of a power device at a remote location at all times.

It is still another object of the present invention to provide a partial discharge detection apparatus using electromagnetic waves, which can significantly reduce investment time and skilled workers for measuring degradation of power equipment.

Still another object of the present invention is to provide an apparatus for detecting a partial discharge of a power device using electromagnetic waves capable of searching for a position of the partial discharge generator.

Still another object of the present invention is to provide a partial discharge detection device for a power device using electromagnetic waves, which can reduce the probability of a safety accident and check the degree of degradation of the power device in checking the deterioration of the power device.

1 is a state diagram of a partial discharge detection device and a monitoring system connected to a remote location of a power device according to an embodiment of the present invention.

2 is a block diagram of a partial discharge detection device of a power device according to a first embodiment of the present invention.

3 is a circuit diagram of an analog circuit of the partial discharge detection device shown in FIG. 2;

4 is a circuit diagram of a digital circuit of the partial discharge detection device shown in FIG. 2;

5 is a flowchart illustrating an operation of the controller 160 of FIG. 2.

6 is an exemplary diagram of a partial discharge amount display waveform processed by the controller 160 in FIG. 2.

7 is a block diagram of a partial discharge detection device of a power device according to a second embodiment of the present invention.

Apparatus for detecting a partial discharge of a power device according to an aspect of the present invention for achieving the above object;

A sensor for detecting an electromagnetic signal emitted by the partial discharge in the power device;

An electromagnetic wave detection unit for amplifying the output signal of the sensor and modulating and outputting only the noise-removed electromagnetic wave signal at an intermediate frequency;

A pulse generator for integrating the intermediate frequency-treated electromagnetic wave and outputting a pulse by partial discharge by comparing with a value before integration;

An electromagnetic wave level processing unit for outputting electromagnetic pulses representing a plurality of levels by comparing the intermediate frequency processed electromagnetic wave with a plurality of reference voltages, respectively;

A waveform shaping unit configured to waveform-shape and output the electromagnetic pulses representing the plurality of levels and pulses caused by partial discharge;

Counting the pulses by the partial discharge waveform-shaped for a predetermined time to calculate the average number of pulses per cycle, input the electromagnetic pulses representing the plurality of levels of the waveform shaping to calculate the partial discharge amount of a predetermined unit the average pulse And a control unit for transmitting to the external monitoring system through the communication unit with the number.

According to an additional feature of the invention, the electromagnetic wave detecting unit at least;

An RF amplifying unit for amplifying and outputting only 30 MHz of electromagnetic waves due to a partial discharge emitted in a wide band by using a resonance circuit;

An IF processor for modulating and outputting the RF amplified electromagnetic wave signal at an intermediate frequency of 500 KHz through a plurality of intermediate frequency processing transformer circuits;

And a noise removing filter for full-wave rectifying the IF signal processed at the intermediate frequency and outputting only the electromagnetic signal from which the noise is removed.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

First, FIG. 1 is a diagram illustrating a connection state of a partial discharge detection device 100 and a monitoring system 200 located at a remote location of a power device according to an embodiment of the present invention.

The partial discharge detection apparatus 100 shown in FIG. 1 is installed in a place where a power device is located, for example, in a closed switchboard, and the partial discharge generated when the power device reaches its end of life or progresses in aging due to poor installation or material failure. After detecting the electromagnetic wave by using the analysis and transmitting the average number of pulses of the electromagnetic wave due to the partial discharge and the amount of partial discharge in the coulomb unit through the display unit and the RS-485 cable to the remote monitoring system 200.

On the other hand, the monitoring system 200 displays the partial discharge amount and the average pulse number of the coulomb unit input through the RS-485 cable so that the administrator can check the state of the power equipment located in the remote location on the monitor. As a result, the administrator can always check the power devices located in remote locations.

Hereinafter, the configuration and operation of the partial discharge detection apparatus 100 described above with reference to FIG. 2 will be described in detail.

2 is a block diagram of a partial discharge detection device of a power device according to a first embodiment of the present invention, Figure 3 is a circuit diagram constituting an analog circuit in the partial discharge detection device shown in FIG. 4 is a circuit diagram of a digital circuit in the partial discharge detection device shown in FIG. 2. 5 is a flowchart illustrating an operation of the controller 160 of FIG. 2.

2, first, the partial discharge detection apparatus 100 according to the embodiment of the present invention is provided with a sensor 110 for detecting the electromagnetic wave signal emitted by the partial discharge in the power device, such a sensor is a helical antenna It is composed of types. That is, the helical type antenna 110, which is a partial discharge detection sensor, detects only a 30 MHz band signal among electromagnetic wave signals emitted by the partial discharge in the power device and transmits the signal to the RF amplifier 122 of the rear stage. In general, electromagnetic waves emitted during partial discharge in power equipment have a certain frequency distribution band. A method for finding a frequency distribution band as a narrow band can be found by using an AR modeling method. The frequency distribution band found by this method is 30MHz.

On the other hand, the electromagnetic wave detection unit 120 is provided in the present invention to distinguish between the ambient noise (ground wave broadcast signal, etc.) and the electromagnetic wave signal in the closed switchboard. The electromagnetic wave detector 120 includes an R / F amplifier 122, an IF processor 124, and a noise removing filter 126 to amplify an output signal of the sensor and to modulate only the noise-removed electromagnetic wave signal to an intermediate frequency. To print. That is, the R / F amplifier 122, which is a component of the electromagnetic wave detector 120, amplifies and outputs only 30 MHz of electromagnetic waves emitted in a wide band using a resonance circuit as shown in FIG. The electromagnetic signal is then modulated to an intermediate frequency of 500 KHz through the modulation circuit and three intermediate frequency processing transformers (IFTs) as shown in FIG. 3 by the IF processor 124 and input to the noise removing filter 126.

As shown in FIG. 3, the IF signal input to the noise removing filter 126 passes through a buffer, an amplifying circuit, and a full-wave rectifying circuit, so that only the electromagnetic signal from which ambient noise is removed by full-wave rectification is generated by the pulse generator 130. And the electromagnetic wave level processing unit 140.

On the other hand, the pulse generator 130 integrates the electromagnetic wave processed by the intermediate frequency output from the electromagnetic wave detector 120 and compares it with the value before integration to output the pulse by the partial discharge. These partial discharge pulses are input to the control unit 160 through the waveform shaping unit 150 and used to calculate the average number of pulses per cycle.

The electromagnetic wave level processor 140 also compares the electromagnetic wave processed by the intermediate frequency detector 120 with the plurality of reference voltages as shown in FIG. Output as a signal. Electromagnetic signals representing the large, medium, and small levels are also input to the controller 160 through the waveform shaping unit 150.

As illustrated in FIG. 4, the waveform shaping unit 150 includes a Schmitt circuit and a time delay flip-flop for shaping a signal output from the pulse generator 130 and the electromagnetic wave level processing unit 140. The waveform shaping unit 150 performs waveform shaping so that the control unit 160 can process electromagnetic wave signals indicating large, medium, and small levels and pulse signals caused by partial discharge.

Meanwhile, the control unit 160 calculates an average number of pulses per cycle by counting the pulses caused by the partial discharge for a predetermined time (sampling time) according to the operation flow shown in FIG. 5, and outputs them from the electromagnetic wave level processing unit 140. The electromagnetic wave signal is calculated as a partial discharge amount in units of 1 degree, and transmitted along with the average number of pulses to the monitoring system 200 located at a remote location, and displayed on the display unit 180 provided in the partial discharge detection apparatus 100. Play the role of giving. In addition, although not shown, the controller 160 may store partial discharge amount data calculated in real time by having a memory therein.

The ID input unit 170 is an 8-pin dip switch and is used for ID input so that the partial detection apparatus 100 can be identified by the monitoring system 200 located at a remote location.

The communication unit converts the partial discharge amount and the average pulse number data by the electromagnetic wave under the control of the controller 160 and transmits the data to the monitoring system 200 located at a remote location through the RS-485 cable.

The display unit 180 displays various display data by the controller 160. The display unit 180 includes an LED and an LCD.

Hereinafter, the calculation and display of the partial discharge amount and the average pulse number by the electromagnetic wave will be described with reference to FIG. 5.

Referring to FIG. 5, first, the controller 160 counts the number of pulses input from the pulse generator 130 during a sampling time in step 200. In order to count the number of pulses, in the present invention, one cycle of the electromagnetic signal is first divided into 360 degrees, and if there is an electromagnetic wave within 1 degree (46 micro sec), the pulse number is counted for 2.5 seconds. Therefore, when the number of input pulses for the sampling time of 2.5 seconds is completed, the total number of pulses counted for 2.5 seconds can be converted to the average number of pulses per cycle. Therefore, the controller 160 determines the average number of pulses per cycle (0) in step 210. Has a maximum value of 360).

Thereafter, the controller 160 proceeds to step 220 and calculates the cumulative amount of discharges in units of 1 degree using large, medium and small levels (sizes) of the electromagnetic wave signals output from the electromagnetic wave level processing unit 140. In the calculation method, a variable is multiplied by each of the pulses within one degree having different levels to calculate them. For example, if the magnitude of the electromagnetic wave input from the electromagnetic wave size processing unit 140 is classified into three levels, the cumulative discharge amount within one degree is calculated by a formula of size 1 × α + size 2 × β + size 3 × γ. do. When the cumulative discharge amount within 1 degree is calculated as described above, the controller 160 proceeds to step 230 and calculates the partial discharge amount. The partial discharge amount can be obtained by dividing the cumulative discharge amount (size 1 × α + size 2 × β + size 3 × γ) by the number of pulses (size 1 + size 2 + size 3).

When the average number of pulses and the partial discharge amount per cycle are calculated in steps 210 and 230 as described above, the control unit 160 proceeds to step 240 and displays the number of pulses and the partial discharge amount per cycle on the display unit 180 and 250. In the step, the number of pulses and the partial discharge amount per cycle are transmitted to the monitoring system 200 located at a remote location through the communication unit.

Referring to the display form of the number of pulses per cycle and the partial discharge amount displayed on the monitoring system 200 and the display unit 180, first, the number of pulses and the partial discharge amount per cycle can be displayed as shown in Table 1 below. .

Metric Criteria normal Watch out More than Time difference 8250 or more 90-8250 Within 90 Electromagnetic Wave Count P / C (pps) Less than 180 180 to 240 More than 240 Electromagnetic Discharge Amount PD (pC) 50 or less 50-70 70 or more

The maximum number of pulses per cycle can be up to 360. If the number of electromagnetic waves representing the number of pulses per cycle is greater than 240, as shown in Table 1 above, an error has occurred in the power equipment. If the value is 180 to 240, a check is required. do. In addition, when the electromagnetic discharge amount, which is the partial discharge amount, is also 70 or more, an abnormality has occurred in the power device, and when the value is 50 to 70, a check is required.

Meanwhile, the partial discharge amount due to electromagnetic waves may be represented by the waveform of FIG. 6. FIG. 6 illustrates an example of the partial discharge amount display waveform processed by the controller 160 in FIG. 2. Referring to FIG. 6, it can be seen that the phases of the electromagnetic waves due to the partial discharge are distributed with three magnitudes around 90 degrees and 270 degrees. The longer the detection time, the longer the electromagnetic waves will be distributed around 90 degrees and 270 degrees.

Therefore, the administrator can always check the position and state of the power device in which the partial discharge occurs by looking at the waveform shown in FIG. 6.

7 is a block diagram of a partial discharge detection device of a power device according to a second embodiment of the present invention, the helical type antenna for detecting a noise signal in the partial discharge detection device shown in FIG. The configuration is the same as that of FIG. 2 except that 112, the RF amplifier 127, and the differential circuit 129 are added.

Referring to FIG. 7, the partial discharge detection apparatus 100 according to the second embodiment of the present invention includes sensors for detecting an electromagnetic wave signal and an ambient noise signal radiated by a partial discharge in a power device. Each consists of a helical antenna type. That is, the helical type antenna 110, which is a partial discharge detection sensor, detects only a 30 MHz band signal among electromagnetic wave signals emitted by the partial discharge from a power device and transmits the signal to the RF amplifier 122 of the rear stage, and a helical type that is a noise detection sensor. The antenna 112 detects a noise signal distributed over a wide band (10 to 100 MHz) and transmits it to the R / F amplifying unit 127 at a later stage. Therefore, two R / F amplifiers 122 and 127, which are one component of the electromagnetic wave detector 120, amplify and output the input electromagnetic wave signal and the noise signal, respectively, and the differential circuit 129 at the next stage has the same frequency band (30 MHz). ), Only the electromagnetic signal from the partial discharge is outputted by differentially outputting the electromagnetic waves from the partial discharge and the ambient noise pulse using the integrating circuit. The electromagnetic signal is then modulated to an intermediate frequency of 500 KHz by the IF processor 124 and input to the noise canceling filter 126, so that only the noise-removed electromagnetic signal is detected so that the pulse generator 130 and the electromagnetic wave level described with reference to FIG. After input to the processor 140, the control unit 160 counts the pulses caused by the partial discharge during the sampling time to calculate the average number of pulses per cycle, the magnitude of the electromagnetic wave input from the electromagnetic wave level processor 140 is 1 degree It is calculated as the partial discharge amount of the unit and transmitted to the monitoring system 200 located at a remote location together with the average number of pulses.

Therefore, the administrator can always check the position and state of the power device in which the partial discharge occurs by looking at the waveform shown in FIG. 6.

As described above, the present invention has the advantage of always being able to monitor the degree of deterioration of the power device from a remote location, and has the advantage of significantly reducing the time required for investment and the experts for measuring the deterioration of the power device. In addition, the present invention has the advantage that it is easy to maintain, since the location of the partial discharge generator can be reduced, and to reduce the probability of a safety accident in checking the deterioration of the power device.

On the other hand, the present invention has been described with reference to the embodiments shown in the drawings, which are merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention should be defined only by the appended claims.

Claims (8)

In the partial discharge detection device of the power equipment, A sensor for detecting an electromagnetic signal emitted by the partial discharge in the power device; An electromagnetic wave detection unit for amplifying the output signal of the sensor and modulating and outputting only the noise-removed electromagnetic wave signal at an intermediate frequency; A pulse generator for integrating the intermediate frequency-treated electromagnetic wave and outputting a pulse by partial discharge by comparing with a value before integration; An electromagnetic wave level processing unit for outputting electromagnetic pulses representing a plurality of levels by comparing the intermediate frequency processed electromagnetic wave with a plurality of reference voltages, respectively; A waveform shaping unit configured to waveform-shape and output the electromagnetic pulses representing the plurality of levels and pulses caused by partial discharge; Counting the pulses by the partial discharge waveform-shaped for a predetermined time to calculate the average number of pulses per cycle, input the electromagnetic pulses representing the plurality of levels of the waveform shaping to calculate the partial discharge amount of a predetermined unit the average pulse And a control unit which transmits the number to the external monitoring system through the communication unit. The apparatus of claim 1, further comprising an ID input unit for inputting ID information for remotely identifying the partial discharge detection device. The apparatus of claim 1 or 2, further comprising a display unit for displaying the average number of pulses and the partial discharge amount. The method according to claim 1 or 2, wherein the electromagnetic wave detection unit at least; An RF amplifying unit for amplifying and outputting only 30 MHz of electromagnetic waves due to a partial discharge emitted in a wide band by using a resonance circuit; An IF processor for modulating and outputting the RF amplified electromagnetic wave signal at an intermediate frequency of 500 KHz through a plurality of intermediate frequency processing transformer circuits; And a noise canceling filter for full-wave rectifying the IF signal processed at an intermediate frequency and outputting only the electromagnetic signal from which the noise has been removed. In the partial discharge detection device of the power equipment, Sensors for detecting an electromagnetic wave signal and an ambient noise signal emitted by the partial discharge in the power device, respectively; An electromagnetic wave detection unit for amplifying an output signal of the sensors and detecting only an electromagnetic signal from which noise is removed and modulating the intermediate signal at an intermediate frequency; A pulse generator for integrating the intermediate frequency-treated electromagnetic wave and outputting a pulse by partial discharge by comparing with a value before integration; An electromagnetic wave level processing unit for outputting electromagnetic pulses representing a plurality of levels by comparing the intermediate frequency processed electromagnetic wave with a plurality of reference voltages; A waveform shaping unit configured to waveform-shape and output the electromagnetic pulses representing the plurality of levels and pulses caused by partial discharge; Counting the pulses by the partial discharge for a predetermined time to calculate the average number of pulses per cycle, input the electromagnetic pulse indicating the plurality of levels to calculate the partial discharge amount of a predetermined unit and the communication unit with the average number of pulses And a control unit for transmitting to an external monitoring system through the apparatus. 6. The partial discharge detection apparatus of claim 5, further comprising a display unit for displaying the average number of pulses and the partial discharge amount. The apparatus of claim 5, wherein each of the sensor units has a helical antenna type. The method according to claim 5, wherein the electromagnetic wave detection unit; RF amplifiers for amplifying the electromagnetic signal and the noise signal output from each of the sensors; A differential circuit for inputting the output signals of the RF amplifiers to differentially output electromagnetic waves and ambient noise pulses by partial discharge in the same frequency band using an integrating circuit; An IF processor for modulating and outputting an electromagnetic signal by partial discharge, which is an output of the differential circuit, to an intermediate frequency of 500 KHz through a plurality of intermediate frequency processing transformer circuits; And a noise canceling filter for full-wave rectifying the IF signal processed at an intermediate frequency and outputting only the electromagnetic signal from which the noise has been removed.