KR20090036933A - Partial discharge detector of gas insulated switchgear apparatus having ring shape patch and circle shape patch - Google Patents

Abstract

A partial discharge detector with of gas insulated switchgear apparatus is provided to supply wideband width by controlling a distance between a ring patch and a short pin. An antenna reception part(100) detects a partial discharge signal generated in a metal case. A slot is arranged to be symmetry at a circular patch, and ring patch including a plurality of short circuit pieces which are separated from the circular patch by a certain interval. The circular patch detects a high frequency signal, and the ring patch detects the low-frequency signal.

Description

PARTIAL DISCHARGE DETECTOR OF GAS INSULATED SWITCHGEAR APPARATUS HAVING RING SHAPE PATCH AND CIRCLE SHAPE PATCH}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a partial discharge detection device of a gas insulated switchgear. Particularly, a part of a gas insulated switchgear having a ring patch and a circular patch for effectively detecting a partial discharge signal in a wide band during operation of the gas insulated switchgear. It relates to a discharge detection device.

Power equipment used in substations, such as gas insulated switchgear, gas insulated busbar, and gas insulated transformer, is a gas insulated switchgear which is insulated and supported by a high voltage conductor in a sealed metal container filled with insulated gas. When present, the local electric field is locally increased, causing partial discharge.

If the partial discharge is left as it is, it may lead to insulation breakdown and lead to a major accident. Therefore, it is necessary to find a partial discharge occurring inside the metal container early and take countermeasures.

By detecting such partial discharge in the form of a signal, it is possible to predict insulation breakdown in advance, and it is important as a preventive maintenance method of a gas insulation switchgear.

However, the partial discharge in the insulating gas is a high voltage phenomenon in which a sudden pulse current is generated. The electromagnetic waves generated by the partial discharge radiate into the space at the moment, propagate in the metal container, and the electromagnetic wave is almost discharged from the closed metal container to the outside. It is not radiated.

From this, a partial discharge detection device of a gas insulated switchgear which detects a signal generated inside a metal container which is a sealed container with an external measuring device using an airtight terminal has been proposed.

For example, in patent application No. 1999-7010683 (name of the invention: partial discharge detection device of gas insulated device), electromagnetic waves resulting from partial discharge occurring at the time of internal abnormality of gas insulated device (ie gas insulated switchgear). Is detected by an external measuring device using a wideband, highly sensitive antenna.

As shown in Figs. 1 and 2, the partial discharge detection device of the conventional gas insulated switchgear has a very low partial discharge signal and is affected by external noise. Since the antenna receiver 11 supported by the antenna support 12 is not satisfactory, two semicircle plates are formed in the metal container 17 on a plane to detect electromagnetic waves of partial discharge with wideband and high sensitivity. .

In this case, since the area of the antenna receiver 11 is large, the capacitance C1 of the high voltage conductor 19 and the antenna receiver 11 and the capacitance C2 of the flange 20 and the antenna receiver 11 are reduced. Increasingly, high sensitivity potential measurement in a gas insulated switchgear is enabled.

In addition, since the dipole antenna having a high directivity is used in the antenna receiver 11, it is possible to detect in a wideband by one antenna which part of the partial discharge detection device installed in the gas insulation switchgear. Economical because there is no need to install multiple antennas.

The signal detected by the antenna receiver 11 is transmitted to the coaxial structure of the sealing terminal 13, the coaxial sealing terminal 14, and the coaxial cable 15, so that the high voltage conductor 19 is provided by the insulating support 18. ) Can be transmitted to the measuring device 16 without attenuating a signal of 100 MHz or more received by the partial discharge in the metal container 17 supported by, and can measure up to a high frequency band of several GHz.

In addition, since the antenna receiver 11 is grounded and used, the antenna itself can be used as the ground potential without using the float electrode, so that the occurrence of the disturbance can be reduced even when placed inside the gas insulated switchgear.

However, the technology applied to the detection device has the following problems.

In other words, the antenna receiver is composed of two metal conductors and has a characteristic of radiating to the side. When the antenna receiver of the dipole structure is placed in the handhole of the gas insulated switchgear, the internal width affects the performance. Will receive.

In addition, since the dipole antenna structure has a size determined according to the length of the wavelength and has a narrow bandwidth having a single resonance frequency, there is a limit to detecting a wide band partial discharge signal when detecting a partial discharge.

In addition, when the gas insulation switchgear includes a complicated section, there is a problem that it is difficult to detect the partial discharge signal.

Accordingly, an object of the present invention is to provide a partial discharge detection device for a gas insulated switchgear having a ring patch and a circular patch to detect a partial discharge signal in a wider signal bandwidth.

Another object of the present invention is to detect a partial discharge signal in a low frequency signal band, a high frequency signal band and an intermediate band thereof.

Another object of the present invention is to reduce the attenuation by multipath reflection so that the partial discharge signal can be detected even if the inside of the device under measurement is complicated.

According to a feature of the present invention for achieving the above object, an antenna receiver for detecting a partial discharge signal generated in a metal container is provided, the antenna receiver, a circular patch, the slot is formed symmetrically, the circular patch A ring patch is provided with a plurality of short circuit pins spaced apart at predetermined intervals, and two circular patches having different radii in a partial discharge generation frequency band are virtually overlapped to detect the high frequency signal and the ring patch. Detects the low frequency signal.

The slot of the circular patch is an L-slot, and the bandwidth is changed in the low frequency band according to the ratio of the horizontal arm and the vertical arm of the L-slot, and the spacing between the circular patch and the ring patch and the distance between the short pins. By changing, the bandwidth can be changed even in the high frequency band. At this time, the bandwidth is increased to have a wide frequency range in the operating frequency band.

Further, a signal is additionally detected when partial discharge occurs in an intermediate band of the high frequency band and the low frequency band by using the distance between the circular patch and the ring patch and the short circuit pin.

On the other hand, the circular patch and the ring patch is located on the same plane, the gap between the circular patch and the ring patch to serve as a slot of the circular patch to provide a circular polarization characteristics to enable multi-path reflection attenuated even if there is an obstacle Signal detection is effective because it is small.

According to this configuration, the partial discharge signal can be detected in a wide band, and the signal detection capability is improved.

According to the partial discharge detection device of the gas insulated switchgear having the ring patch and the circular patch of the present invention having such a configuration, the following effects can be expected.

First, the partial discharge signal may be additionally detected not only in the low frequency signal band and the high frequency signal band but also in the intermediate signal band.

That is, the three elements provided in the present invention, that is, 1) the ratio of the horizontal arm and the vertical arm of the L-slot formed in the circular patch, 2) the distance between the circular patch and the ring patch, and 3) the distance between the shorting pins are appropriate. In this case, it is possible to provide a wider frequency bandwidth, and thus to detect a partial discharge signal in a wide band.

In addition, since the antenna receiver of the present invention provides circular polarization characteristics, multipath reflection is possible, and thus, even if the internal structure of the gas insulated switchgear is complicated or obstructed, there is less attenuation, so that the partial discharge signal can be sufficiently detected. .

Hereinafter, a partial discharge detection device of a gas insulated switchgear having a ring patch and a circular patch according to the present invention will be described in detail with reference to a preferred embodiment shown in the accompanying drawings.

3 is a longitudinal sectional view showing a partial discharge detection device of a gas insulated switchgear with a structure of an antenna receiver as a preferred embodiment of the present invention. 4 is a graph illustrating the change of the low frequency signal according to the L-slot change of the circular patch of FIG. 3, and FIG. 5 is a two element variation of the circular patch, the ring patch spacing, and the shorting pin distance in FIG. 3. A graph illustrating the change in bandwidth is shown.

First, referring to FIG. 3, a hand hole is installed at one side of the body of the metal container of the gas insulated switchgear, and a flange 105 for sealing the hand hole is installed.

A signal line 101 and a shorting pin 102 having a predetermined height and diameter are provided at a predetermined portion of the flange 105, and are coupled to the signal line 101 and the shorting pin 102, and the monopole feeding antenna is a circular antenna receiver. 100 is provided. The structure of the antenna receiver 100 will be described later in detail.

When partial discharge occurs in the metal vessel 106, a current pulse containing a high frequency of several kHz (0.5 to 1.5 GHz) is generated, and electromagnetic waves generated therefrom propagate in the metal vessel 106. do. At this time, when the electromagnetic wave is received by the antenna receiver 100, the voltage is induced in the antenna receiver 100 and drawn out to the outside of the metal container 106 through the signal line 101, and the N-type connector 107 and the coaxial cable And to the measurement device 109 via 108.

That is, the partial discharge detection device of the gas insulated switchgear having a sensor according to an embodiment of the present invention includes an antenna receiver 100, a signal line 101, and a shorting pin 102 in the handhole. Will be installed in combination.

Next, the configuration of the antenna receiver 100 will be described.

First, in order to detect a partial discharge signal having a wider frequency band in the gas insulated switchgear, a low frequency signal (0.5 to 1 GHz, f _L ) and a high frequency signal (1 to It should be possible to detect a partial discharge signal in two signal bands of 1.5 kHz, f _H ).

Thus, the antenna receiver 100 according to the present invention is provided with two signal patches.

The signal patch is composed of a circular patch 103 at the center and a ring patch 104 spaced apart from each other around the circular patch 103 by a predetermined interval, and each patch 103 and 104 is arranged on the same plane. Located in In the circular patch 103, two L-slots 111 are formed to be symmetric with each other. 111a of the L-slot 111 is called a horizontal arm, and 111b is called a vertical arm. In addition, the ring patch 104 has a structure in which two shorting pins 102 are connected.

Due to this structure, the circular patch 103 detects a high frequency signal (1 to 1.5 GHz) in the 0.5 to 1.5 GHz band, which is a partial discharge generation frequency band, and the ring patch 104 is a low frequency signal (0.5 to 1 GHz). ) Will be detected.

That is, when the antenna receiver 100 is designed with the circular patch 103 and the ring patch 104 as shown in FIG. 3, a double resonance band is formed. In practice, the circular patch 103 and the ring patch 104 are physically spaced apart from each other, but due to the fringing effect in the circular patch 103, the ring patch (the edge of the circular patch 103) When coupled as an antenna, two circular patches of different radii can be virtually superimposed to detect two signals of low and high frequencies.

On the other hand, although the present invention has a double resonance band as described above, signal detection can be performed in a wider band when partial discharge occurs.

The following three factors apply to this.

One). The ratio of the horizontal arm and the vertical arm of the L-slot formed in the circular patch,

2). The gap between the round patch and the ring patch,

3). The distance between the shorting pins.

In this description, the L-slot 111 formed in the circular patch 103 and the basic characteristics provided by the shorting pin 102 of the ring patch 104 will be described first. By changing the bandwidth will be described that substantially the bandwidth of the double resonant band increases.

First, the L-slot 111 formed in the circular patch 103 serves to move the resonance frequency of the low frequency band among the bands formed by the coupling of the circular patch 103 and the ring patch 104. This will be described in detail with reference to FIG. 4 below.

In addition, the two shorting pins 102 of the ring patch 104 also serve to adjust the resonance frequency. The shorting pin 102 serves to widen the bandwidth along with the gap between the circular patch 103 and the ring patch 104. The shorting pin 102 is used in a planar inverted antenna (PIFA), which is typically used for a terminal antenna, and serves to determine a resonance frequency.

If the shorting pin 102 is composed of a conductor, the shorting pin can be assumed to be a short circuit of series inductance L and parallel capacitance C in a short transmission line having a length t. At this time, the series inductance (L) and the parallel capacitance (C) can be expressed as the following equation (1) and (2).

L = (tμ / π) cosh ^-1 (d / 2a) ----- Formula (1)

C = tπε / (cosh ^-1 (d / 2a)) ----- Equation (2)

Here, 'a' is the radius of the short pin, 'd' is the distance between the short pin.

The resonance frequency can be determined using the above equations (1) and (2). For example, when the diameter of the short pin 102 increases, the value of the inductance L increases and the resonance point moves to a high frequency region, while when the number of short pins 102 increases, the capacitance C increases. The resonance point moves to the low frequency region.

Next, the increase in bandwidth by the above three factors will be described in detail with reference to FIGS. 4 and 5.

4 is a graph illustrating a change in low frequency signal according to the L-slot change of the circular patch of FIG.

The L-slot 111 is composed of a horizontal arm 111a and a vertical arm 111b. The resonance point of the low frequency signal can be changed by changing the ratio of the horizontal arm 111a and the vertical arm 111b.

4, the length ratio of the vertical arm 111b to the horizontal arm 111a decreases as the length of the vertical arm 111b decreases in the X-axis of the graph, and the value for the length ratio decreases. The frequency shift is changing as time goes by.

The frequency shift causes little change in the high frequency f _H , while widening the bandwidth of the low frequency f _L. It can be seen from FIG. 4 that the bandwidth has increased by approximately 15%.

In other words, it has a wide bandwidth at low frequency according to the ratio of the horizontal arm 111a and the vertical arm 111b of the L-slot 111 formed in the circular patch 103 among the three elements.

Meanwhile, 2) above. 3) the spacing between the round patch and the ring patch; If the distance between the short pin is changed to have a wide bandwidth at high frequency, which will be described with reference to FIG. 5 is a graph showing that the bandwidth is changed by the change of the circular patch, the ring patch interval, and the shorting pin distance.

In order to explain the frequency change by the element change of 2) and 3), the 0.5-1.5 GHz band, which is the partial discharge generation frequency band, may be divided into three bands.

In FIG. 5, band 1 (f ₁ ) is a low frequency band of 0.5 to 0.8 Hz, band 2 (f ₂ ) is an intermediate band of 0.8 to 1.2 Hz, and band 3 (f ₃ ) is a high frequency band of 1.2 to 1.5 Hz. Indicates.

In this case, the low frequency band of band 1 (f ₁ ) decreases to narrow the bandwidth, and the middle band of band 2 (f ₂ ) and the high frequency band of band 3 (f ₃ ) increase to increase the bandwidth. It can be seen. In addition, it can be seen that a new intermediate band, which is band 2 (f ₂ ), is generated. And the overall bandwidth f _T is decreasing. That is, the bandwidth that changes according to the ratio of the horizontal arm 111a and the vertical arm 111b of the L-slot 111 is reduced in overall bandwidth f _T than that of having a limited change of a specific band.

However, since the intermediate band of band 2 (f ₂ ) and the high frequency band of band 3 (f ₃ ) have a wider band, a signal can be detected when partial discharge occurs in various bands.

In other words, due to the generation of the intermediate band, the partial discharge signal can be detected in a wider band range than the detection of the signals of the high frequency band and the low frequency band from the 0.5 to 1.5 GHz band that is the partial discharge generation frequency band.

On the other hand, the present invention, as described above, the structure of the antenna receiver 100 consisting of a circular patch 103 and a ring patch 104 provides a circular polarization characteristic. The circular polarization is arranged by placing the circular patch 103 and the ring patch 104 on the same plane and the spacing between the circular patch 103 and the ring patch 104 to serve as a slot of the circular patch 103 appear.

Here, the circular polarization is performed while drawing a circular spring-shaped trajectory, so that multi-path refection is possible, so that the circular polarization is applied when designing a repeater antenna or a satellite antenna of a city with many obstacles.

That is, since the circular polarization having the above advantages is provided to the antenna receiver 100, the present invention allows the partial discharge signal to be detected by using the circular polarization characteristic. In general, when the gas insulation switchgear has a complicated structure, it is difficult to detect a partial discharge signal with a conventional detection sensor. However, when the antenna receiver 100 having the circular polarization function is applied to the gas insulated switchgear, the partial discharge signal is detected due to the circular polarization even if the gas insulated switchgear is complicated.

Although described with reference to the illustrated embodiment of the present invention as described above, this is merely exemplary, those skilled in the art to which the present invention pertains various modifications without departing from the spirit and scope of the present invention. It will be apparent that other embodiments may be modified and equivalent. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

1 is a longitudinal sectional view showing a partial discharge detection device of a conventional gas insulated switchgear.

FIG. 2 is a longitudinal sectional view showing an example where the partial discharge detection device of FIG. 1 is applied to the potential measurement of gas insulation. FIG.

Figure 3 is a longitudinal sectional view showing a partial discharge detection device of the gas insulated switchgear with the structure of the antenna receiver as a preferred embodiment of the present invention.

4 is a graph illustrating a change in low frequency signal according to the L-slot change of the circular patch of FIG.

FIG. 5 is a graph illustrating a change in bandwidth through two factors, a circular patch, a ring patch spacing, and a shorting pin distance.

* Description of the symbols for the main parts of the drawings *

100: antenna receiver 101: signal line

102: short circuit pin 103: round patch

104: ring patch 111: L-slot

111a: horizontal arm 111b: vertical arm

Claims (6)

An antenna receiver for detecting a partial discharge signal generated in the metal container is installed, The antenna receiver, A circular patch in which the slots are formed symmetrically, It is composed of a ring patch spaced apart a predetermined interval around the circular patch having a plurality of short circuit pins, In the frequency band of the partial discharge, two circular patches having different radii are virtually superimposed so that the circular patch detects a high frequency signal and the ring patch detects a low frequency signal. Partial discharge detection device of switchgear. The method of claim 1, The slot of the round patch is an L-slot, Partial discharge detection device of the gas insulated switchgear equipped with a ring patch and a circular patch characterized in that the bandwidth is changed in the low frequency band according to the ratio of the horizontal arm and the vertical arm of the L-slot. The method of claim 1, The spacing between the round patch and the ring patch, and Partial discharge detection device of the gas insulated switchgear provided with a ring patch and a circular patch characterized in that the bandwidth is changed in the high frequency band by changing the distance between the short-circuit pins. The method of claim 3, Gas insulation provided with a ring patch and a circular patch further detects a signal even in the middle band of the high frequency band and the low frequency band when partial discharge occurs by using the distance between the circular patch and the ring patch and the short circuit pin. Partial discharge detection device of switchgear. The method according to claim 2 or 3, And the bandwidth is increased so as to have a wide frequency range in the operating frequency band. The method of claim 1, The circular patch and the ring patch are located on the same plane, Partial discharge detection device of a gas insulated switchgear having a ring patch and a circular patch, characterized in that the circular patch and the ring patch between each other to serve as a slot of the circular patch to provide a circular polarization characteristics.

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