JPH1152003A - Partial discharge diagnostic device for gas insulated electrical equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a partial discharge diagnostic apparatus for efficiently and surely distinguishing between a partial discharge generated inside a gas-insulated electric device and an external noise entering from the outside. SOLUTION: A sensor 1e having directivity is installed in a grounding tank 10 of a bushing 11, and this sensor 1e is provided.
The observation device 2e, the discrimination device 7e, and the command device 9 are connected to e. On the gas-insulated electric device main body 32 side, sensors 1a to 1d are installed on each of the spacers 21a to 21d provided on the connection mother pipe 34, and the observation devices 2a to 2d and the discriminating devices 7a to 7d are provided for these sensors 1a to 1d. Connect. When noise is detected by the sensor 1e and the discrimination device 7e determines that the noise is external noise, a command signal is output from the command device 9 to the observation devices 2a to 2d, during which the operation of the observation devices 2a to 2d is performed. Stops.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-insulated electric device in which a current-carrying conductor is housed in a grounding tank filled with an insulating gas, and more particularly to observing high-frequency electromagnetic waves generated when an abnormality occurs in insulation. The present invention relates to a partial discharge diagnosis device for diagnosing abnormalities by using the method.

[0002]

2. Description of the Related Art Conventionally, various partial discharge diagnosis methods for detecting a partial discharge generated inside a gas-insulated electric device have been developed. As one of such partial discharge diagnosis methods, there is known a method in which an electrode is grounded in a grounded tank and this is used as a sensor to measure high-frequency electromagnetic waves due to partial discharge.

FIG. 4 is a configuration diagram showing an example of a gas insulated electric device to which such a partial discharge diagnosis method is applied. As shown in this figure, a gas insulated electrical apparatus 100, SF ₆
A grounding tank 24 filled with an insulating gas such as a gas, an insulating spacer 21 for mechanically connecting and electrically insulating adjacent grounding tanks 24, and the insulating spacer 2
1 has a high voltage conductor 23 insulated and supported in a ground tank 24. In such a gas-insulated electric device 100, the shield electrode 22 is provided inside the insulating spacer 21 near the ground tank 24.
2 is connected to an external observation device 2 via a signal drop line 8.

In this case, the observation device 2 has a filter 5 for extracting a signal of a specific frequency, and an amplifier 6 for amplifying the signal extracted by the filter 5. A discriminating device 7 is connected to the observation device 2. Discriminator 7
Detects partial discharge by, for example, determining whether an output signal from the observation device 2 has exceeded a certain value.

[0005] The conventional partial discharge diagnostic apparatus thus configured operates as described below. That is, when a partial discharge pulse (corona pulse) is generated in the grounding tank 24, a signal including a high-frequency component caused by the discharge is generated.
The signal is input to the observation device 2 via the signal drop line 8.

Then, in the observation device 2, after a signal of a specific frequency corresponding to a partial discharge pulse is extracted by the filter 5 from the signal containing the above high frequency components, the signal is amplified by the amplifier 6, and It is output to the discriminating device 7. In the determination device 7, a noise determination level is set in advance, and it is determined whether the input signal exceeds the noise determination level. As a result, it is detected that partial discharge has occurred inside the gas insulated electric device 100. You.

In the gas-insulated electric device 100 described above, the shield electrode 22 provided on the insulating spacer 21 for insulatingly supporting the high-voltage conductor 23 is used as the sensor 1 to observe the high frequency generated by the partial discharge. I have.

However, in such a method, the observed high frequency is due to a partial discharge which is a precursor of an insulation abnormality generated inside the gas insulated electric device, or due to external noise entering from a transmission line or the like. It was an issue to distinguish between them. Methods for distinguishing these have been studied in the past, and for example, the following methods have been proposed. One is the noise that intrudes from the transmission line,
Since this is a stationary air wave such as a broadcast wave and an electromagnetic wave due to corona discharge, this method monitors in a frequency band in which the wave does not exist (hereinafter referred to as a frequency window). Another method is to monitor at a considerably high frequency, utilizing the fact that corona discharge in the air has only a low frequency component compared to partial discharge in gas. is there.

[0009]

However, such a conventional method has the following problems. In other words, the former method cannot always completely eliminate noise, and is insufficient in reliability as a partial discharge diagnostic device for a device that requires considerably high reliability. Furthermore, the above-mentioned frequency windows are different depending on conditions such as an installation place and a season, and it is necessary to strictly investigate what frequency should be selected before installing the partial discharge diagnostic device. .

In the latter method, higher reliability can be obtained than in the former method. However, there is a problem that the reliability is not sufficient, and the diagnosis apparatus is expensive because a high frequency is used. there were. Also, at high frequencies, special phenomena such as the skin effect appear remarkably and the attenuation is severe,
The range that can be monitored by one sensor is narrow. Therefore, in order to perform observation in a wide range, it is necessary to install a large number of sensors, and there has been a problem that the cost is increased.

The present invention has been proposed to solve the above-mentioned problems of the prior art, and its object is to provide a partial discharge, which is a precursor to an insulation abnormality occurring inside a gas-insulated electric device, and a transmission line. Highly reliable by efficiently and reliably distinguishing external noise that enters from
An object of the present invention is to provide a low-cost partial discharge diagnostic device.

[0012]

In order to achieve the above object, a partial discharge diagnosis apparatus for a gas insulated electric device according to the present invention has a bushing for drawing in an air transmission line and an insulating gas. Partial discharge diagnosis of a gas-insulated electrical device for detecting a partial discharge occurring inside a gas-insulated electrical device in which a high-voltage conductor is housed in an enclosed grounded metal container while supporting a high-voltage conductor insulated. The device is characterized by comprising a sensor having directivity and detecting a high-frequency signal in the gas-insulated electric device.

According to the first aspect of the present invention having the above configuration, the following operation and effect can be obtained. For example, a sensor is provided near the entrance of external noise that enters from the outside, and the direction of the directivity of the sensor is either a direction from the outside toward the inside of the gas insulated electric device or a direction from the inside of the gas insulated electric device to the outside. Or one of them. That is,
When the directivity is adjusted in a direction from the outside to the inside of the gas-insulated electric device, the sensor detects a high-frequency signal due to external noise. On the other hand, when the directivity is adjusted in the direction toward the outside, the sensor detects a high-frequency signal due to a partial discharge generated inside the gas-insulated electric device. As described above, by appropriately setting the installation direction of the sensor, the direction in which the high-frequency signal is generated can be detected. For example, in the above example, an abnormality due to external noise and an abnormality due to partial discharge inside the gas insulated electric device can be detected separately.

According to a second aspect of the present invention, there is provided a partial discharge diagnosis apparatus for a gas-insulated electric device according to the first aspect, wherein the two sensors having the same structure are arranged adjacent to each other. The direction of the directivity is set to be shifted by 180 degrees, and a comparator for comparing high-frequency signals detected by the sensors, and a high-frequency signal in the gas-insulated electric device based on a comparison result by the comparator. And a judging means for judging from which direction the signal is generated.

According to the second aspect of the present invention having the above configuration, the following operation and effect can be obtained. For example, a sensor is provided in the vicinity of an entrance where external noise enters from the outside, and the directionality of each sensor is set such that one is directed from the outside to the inside of the gas-insulated electric device, and the other is set from the inside of the gas-insulated electric device. Set the direction to the outside. Then, the comparator compares the high-frequency signal from any of the sensors, and as a result, the determination unit determines whether the high-frequency signal in the gas-insulated electric device is due to external noise or due to internal partial discharge. Is determined. That is, since the propagation direction of the observed high frequency can be predicted, if this propagation direction is different from the known noise propagation direction, it can be determined that there is an abnormality inside the gas-insulated electric device. Also, by comparing the outputs of the two sensors relatively, it is possible to make an appropriate determination even when the absolute value of the high-frequency signal itself changes significantly.

According to a third aspect of the present invention, there is provided a partial discharge diagnosis apparatus for a gas-insulated electric device according to the first or second aspect, wherein the sensor is configured to observe a high-frequency surface current flowing through a metal surface. It is characterized by consisting of.

According to the third aspect of the present invention having such a configuration, a high-frequency surface current detector is employed as a sensor having directivity. Therefore, high-frequency signals can be effectively detected.

According to a fourth aspect of the present invention, there is provided a partial discharge diagnosis apparatus for a gas insulated electric device according to any one of the first to third aspects.
In the invention described in the paragraph, the sensor is provided near the bushing.

According to the fourth aspect of the present invention having such a configuration, external noise invading from the air transmission line and partial discharge generated inside the gas insulated electric device can be efficiently and accurately reduced. Can be distinguished.

According to a fifth aspect of the present invention, there is provided a partial discharge diagnostic apparatus for a gas insulated electric device, comprising a bushing for drawing an air transmission line, and insulatingly supporting a high-voltage conductor in a grounded metal container filled with an insulating gas. A high-frequency signal generated in the grounded metal container is detected by a partial discharge diagnostic device for a gas-insulated electric device for detecting a partial discharge generated inside the gas-insulated electric device housed in a state where the gas-insulated electric device is housed. A first sensor, a first determining means for determining whether or not a partial discharge has occurred in the grounded metal container based on a high-frequency signal detected by the first sensor; A second sensor for detecting a high-frequency signal due to external noise entering the device; and a second sensor for detecting the external noise based on the high-frequency signal detected by the second sensor. A second determining means for determining the presence / absence of the noise, and when the second determining means determines that the external noise has entered, the first determining means stops the determination for a certain period of time. Command means for giving a command to cause the command to be performed.

According to the fifth aspect of the present invention having the above configuration, the following operation and effect can be obtained. That is, the first sensor detects a high-frequency signal due to partial discharge generated in the gas-insulated electric device, and the second sensor detects a high-frequency signal due to external noise. Then, the high frequency signal of the external noise is detected by the second sensor,
When it is determined by the determination means that there is intrusion of external noise, control is performed so that the determination by the first determination means is stopped for a certain period. Therefore, when intrusion of external noise is detected, only external noise can be removed. That is, a high-frequency signal due to external noise and a high-frequency signal due to partial discharge generated in the gas-insulated electric device are
Efficient and reliable distinction can be eliminated.

According to a sixth aspect of the present invention, there is provided a partial discharge diagnosis apparatus for a gas-insulated electric device according to the fifth aspect, wherein the second sensor is a sensor having directivity.

According to the sixth aspect of the invention having such a configuration, since the second sensor is a sensor having directivity, only the high frequency signal due to external noise is detected, and the portion inside the gas-insulated electric device is detected. The configuration can be such that a high-frequency signal due to discharge is not detected.

According to a seventh aspect of the present invention, there is provided a partial discharge diagnostic apparatus for a gas insulated electric device according to the sixth aspect, further comprising a comparator to which a high frequency signal detected by the second sensor is inputted. The second sensor includes two sensors having the same structure arranged adjacent to each other. The direction of the directivity of one sensor is set to the traveling direction of external noise that enters from the outside, and the direction of the directivity of the other sensor is set. The direction of the gender is set to be shifted by 180 degrees from the direction of the directivity of the one sensor, the comparator compares high-frequency signals detected by the sensors, and the second determination unit When the high-frequency signal detected by the one sensor is larger than the high-frequency signal detected by the other sensor based on the comparison result by the comparator,
It is characterized in that it is determined that the high-frequency signal in the gas insulated electric device has been generated by external noise invading from the outside.

According to the seventh aspect of the present invention having the above configuration, the following operation and effect can be obtained. In other words, the comparator compares which of the second sensors the high-frequency signal is large, and as a result, the high-frequency signal from the sensor whose directivity is set in the direction of the external noise is large. In this case, the setting determining means determines that the high-frequency signal in the gas-insulated electric device is due to external noise. That is, by relatively comparing the outputs of the two sensors, it is possible to make an appropriate determination even when the absolute value of the high-frequency signal itself changes significantly.

According to an eighth aspect of the present invention, in the partial discharge diagnostic device for a gas insulated electric device according to the sixth or seventh aspect, the sensor is a high-frequency surface current detector for observing a high-frequency surface current flowing through a metal surface. It is characterized by consisting of.

According to the eighth aspect of the present invention, a high-frequency surface current detector is employed as a sensor having directivity. Therefore, high-frequency signals can be effectively detected.

According to a ninth aspect of the present invention, there is provided a partial discharge diagnostic device for a gas insulated electric device according to any one of the fifth to eighth aspects.
In the invention described in the item (2), the second sensor is provided near the bushing, and is configured to detect the external noise signal entering from the air transmission line.

According to the ninth aspect of the present invention having such a configuration, external noise invading from the air transmission line and partial discharge generated inside the gas insulated electric device can be efficiently and accurately reduced. Can be distinguished.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific embodiment of a partial discharge diagnosis apparatus for a gas-insulated electric device according to the present invention will be described below with reference to the drawings. Note that the same members as those in the above-described related art are denoted by the same reference numerals, and description thereof will be omitted.

[1. First Embodiment] Claims 1, 4,
One embodiment corresponding to the inventions described in 5, 6, and 9 will be described below as a first embodiment with reference to FIG.

[1-1. Configuration] FIG. 1 shows a gas-insulated electric device 100 using a partial discharge diagnostic device according to the present embodiment.
FIG. 3 is a diagram showing the configuration of FIG. In FIG. 1, reference numeral 11 denotes a bushing to which an aerial power transmission line 12 is connected.
0. 30 is a bushing 11
Bushing part 31 made of a material and the like and gas-insulated electric device main body 3
2 is a connection bus connecting the first and second buses.

Further, in the gas-insulated electric device main body 32, reference numeral 33 denotes a circuit breaker, and upper and lower terminals 33a and 33b are provided above and below. In the upper terminal 33a,
The connection bus 3 via the connection bus 34 and the disconnector 35
0 is connected. A main bus 37 is connected to the lower terminal 33b via a connection bus 36.

In the bushing section 31 of the gas-insulated electric device 100, a directional sensor 1e is installed inside the installation tank 10 below the bushing 11. The sensor 1e is provided so as to detect only external noise such as an air corona entering from the air transmission line 12. Specifically, the sensor 1e is installed in such a manner that its directivity is matched to the direction in which only the high-frequency electromagnetic field traveling from the air transmission line 12 through the bushing 11 to the grounding tank 10 is detected.

The sensor 1e includes an observation device 2e,
It is connected to the discriminating device 7e and the command device 9. The observation device 2e, the discrimination device 7e, and the command device 9 operate according to a signal from the sensor 1e. The observation device 2e and the discrimination device 7e have the same configuration as the conventional observation device 2 and discrimination device 7 shown in FIG. That is, the observation device 2e extracts a signal of a specific frequency from the detection signal from the sensor 1e, amplifies and shapes the signal, and outputs the signal. The discriminating device 7 outputs a discriminating signal to the command device 9 only when the input signal from the observation device 2 exceeds a certain noise determination level.

Further, when the discriminating signal is input from the discriminating device 7, the commanding device 9 outputs the command signal for a certain period of time thereafter. This time interval is set longer than the time during which external noise that has entered through the bushing 11 reaches the entire gas-insulated electric device main body 32.

In the gas-insulated electric device main body 32, the insulating spacers 21a to 21d provided on the connection bus 34 are provided.
Are provided with sensors 1a to 1d, respectively. These sensors 1a to 1d measure high-frequency electromagnetic fields at different places. In this figure,
Although the sensors 1a to 1d are installed on the insulating spacers 21a to 21d, only the insulating spacers 21a to 21d are shown here, so that they correspond to this. It is assumed that all sensors are installed. In addition, the sensors 1a to 1a
1d is configured by, for example, a shield electrode or the like, similarly to the conventional sensor shown in FIG. Each of the sensors 1a to 1d includes an observation device 2a to 2d and a discrimination device 7a.
To 7d.

The observation devices 2a to 2d are connected to a command device 9, and are controlled so as to stop operation while the command signal is being output from the command device 9. . That is, while the command signal is being output from the command device 9, the control is performed such that the signals sent from the observation devices 2a to 2d to the discriminating devices 7a to 7d become zero.

[1-2. Operation] The operation of the present embodiment having the above configuration is as follows. That is,
When the sensor 1e attached to the inside of the grounding tank 10 detects noise, this detection signal is output to the observation device 2e, and after amplification and waveform shaping in the observation device 2e,
It is output to the determination device 7e. Then, the determination device 7e determines whether or not the input signal exceeds a certain noise determination level. As a result, if the input signal does not exceed the noise determination level, it is determined that no external noise has entered the gas-insulated electric device. At this time, no signal is output from the determination device 7e to the command device 9.

Accordingly, since the observation devices 2a to 2d are all operating, when noise is detected by the sensors 1a to 1d, the detection signals are amplified and shaped in the observation devices 2a to 2d, respectively. Then, each of the discriminating devices 7a to 7
At d, the output signals from the observation devices 2a to 2d are determined, and the presence or absence of partial discharge inside the gas-insulated electric device main body 32 is determined. In this manner, when a partial discharge occurs near any of the sensors 1a to 1d, it is detected.

On the other hand, when the discrimination device 7e determines that the input signal exceeds the noise determination level, it is determined that external noise has entered the gas-insulated electric device 100, and the discrimination device 7e issues a command to the command device 9. Is output. Thereby, the observation device 2 is transmitted from the command device 9 to the observation device 2.
command signals are output to the observation devices 2a to 2d.
The operation of 2e stops. That is, during this time, the sensor 1
Even if noise is detected by a to 1d, the observation device 1a
2d are not operating, so that the discrimination devices 7a to 7d do not discriminate noise. Therefore, when the intrusion of the external noise into the gas insulated electric device 100 is detected, the partial discharge in the gas insulated electric device main body 32 is not observed for a certain period of time.

[1-3. Effects] According to the above-described embodiment, the following effects can be obtained. That is, when the intrusion of the external noise is detected, the observation of the partial discharge inside the gas insulated electric device 100 is automatically stopped, so that the external noise and the partial discharge inside the gas insulated electric device 100 are separated. Can be distinguished exactly. Therefore, external noise can be effectively removed. Also, since the sensor 1e has directivity, even noise generated inside the gas-insulated electric device 100 is not removed.

As described above, there are two types of external noise that enter from the aerial transmission line 12, a stationary one such as a broadcast wave, and a pulse-like random one generated by corona discharge in the aerial transmission line 12. are categorized. Since the frequency of stationary noise such as broadcast waves has a fixed frequency, it is sufficient to remove only that frequency, and it is possible to easily remove it by other means. Removal was difficult because it was not possible. In the present embodiment, such random noise can also be effectively removed.

In the present embodiment, the directivity of the sensor 1e is set in the direction from the air transmission line 12 to the gas-insulated electric device main body 32. By setting the direction toward the middle transmission line 12, only the partial discharge signal generated inside the gas-insulated electric device 100 can be detected.

Further, for example, the command signal of the command device 9 is
It is also possible to stop the function of the gas-insulated electric device when external noise enters by inputting to a control device (not shown) of the gas-insulated electric device 100.

[2. Second Embodiment] Claims 2, 3,
One embodiment corresponding to the inventions described in 4, 7, 8, and 9 will be described below as a second embodiment with reference to FIG.

[2-1. Configuration] FIG. 2 shows a gas-insulated electric device 100 using the partial discharge diagnostic device according to the present embodiment.
FIG. 2 is a view showing the configuration of the grounding tank 1 of the bushing 11.
1 illustrates a cross-sectional view near 0 and a partial configuration of a partial discharge diagnostic device. It is to be noted that a portion (not shown) has a configuration similar to that of the above-described first embodiment.

In this embodiment, a high-frequency surface current detector (hereinafter, referred to as a sensor) is provided inside the grounding tank 10 as a sensor.
1f and 1g are provided. These detectors 1f and 1g are described in the paper "High-frequency surface current detector" (Nagasawa et al., IEICE Transactions, Vol. J66-B, N.
o. 3, 1983-3). That is, the detectors 1f, 1g
Are configured to vectorly detect a high-frequency surface current flowing on the surface of the ground tank, which is a metal surface.

Here, the directions of the detectors 1f and 1g, ie, the directivities are opposite to each other. That is, the directivity of the detector 1f is set in the traveling direction of the external noise entering from the air transmission line, and the directivity of the detector 1g is set in the direction opposite to the traveling direction of the external noise. ing. Since the detectors 1e and 1f have the same structure and are installed adjacent to each other, it is considered that measurement conditions such as measurement sensitivity and frequency are completely the same.

The detection signal of the detector 1f is transmitted to the observation device 2
f, and the detection signal of the detector 1g is input to the observation device 2g, and is amplified and waveform-shaped, respectively.

Further, in both the observation devices 2f and 2g, the comparator 8
It is connected to the. The comparator 8 compares the magnitude of the output of the observation device 2f with the magnitude of the output of the observation device 2g. When the comparator 8 determines that the output of the detector 1f is larger than the output of the detector 1g, the comparator 8 outputs a comparison signal to the determination device 7. The determination device 7 determines that external noise has entered only when the comparison signal from the comparator 8 is input. The discrimination signal of the discrimination device 7 is input to a command device (not shown), as in the first embodiment.

[2-2. Operation] The operation of the present embodiment having the above configuration is as follows. That is,
The noises detected by the detectors 1f and 1g are amplified and waveform-shaped by the observation devices 2f and 2g, respectively, and then output to the comparator 8. Then, the comparator 8 compares the magnitudes of the signals, and outputs a comparison signal when the output from the observation device 2f is large. When this comparison signal is output, the determination device 7 determines that external noise has entered. As a result, a discrimination signal is output from the discriminating device 7 to a command device (not shown), and a command signal is output to an observation device (not shown) on the gas-insulated electric device main body side, as in the first embodiment.

[2-3. Effects] According to the above-described embodiment, the following effects can be obtained. That is, 2
Since the outputs of the two detectors are relatively compared, even when the absolute value of the signal itself is largely changed, the intrusion of external noise can be accurately determined. Further, since the two detectors have the same structure, accurate determination can be made even when their directivities are incomplete. Furthermore, since the command device outputs the command signal, it is not necessary to set an absolute specified value (noise determination level) in advance, and the determination is performed by the relative comparison of the detection signals. It becomes possible.

[3. Other Embodiments] The present invention
The present invention is not limited to the above embodiments, and various other embodiments can be implemented. For example, a sensor having directivity may be installed on the gas-insulated electric device main body side instead of the bushing portion. That is, since the external noise from the air transmission line is the largest and is most difficult to remove, the sensor is installed in the bushing in each of the above embodiments, but since there are other noise entry points,
The sensor may be installed at such a location. Examples of such a portion include, for example, the inside of a ground tank at a connection portion with a power cable and a connection portion with a transformer.

FIG. 3 shows a sensor 1 having directivity at a connection portion with a power cable in a gas-insulated electric device main body 32.
e is installed. Here, 13 is a cable head part, and 14 is an insulation division part. In such a configuration, other parts (not shown) have the same configuration as those of the above-described embodiments.

[0056]

As described above, according to the present invention, the partial discharge which is a precursor of the insulation abnormality occurring inside the gas insulated electric device and the external noise which intrudes from the power transmission line and the like can be efficiently and efficiently. , Can be reliably distinguished. Thereby,
A highly reliable and low-cost partial discharge diagnostic device can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a partial discharge diagnosis device for a gas-insulated electric device according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a part of a partial discharge diagnosis device for a gas-insulated electric device according to a second embodiment of the present invention.

FIG. 3 is a schematic configuration diagram showing a part of a partial discharge diagnostic device of a gas insulated electric device according to another embodiment of the present invention.

FIG. 4 is a schematic structural view showing an example of a conventional partial discharge diagnosis device for a gas-insulated electric device.

[Explanation of symbols]

 1a, 1b, 1c, 1d, 1e: Sensors 1f, 1g: High-frequency surface current detectors 2a, 2b, 2c, 2d, 2e, 2f, 2g: Observation device 5: Filter 6: Amplifiers 7a, 7b, 7c, 7d, 7 discriminating device 8 comparator 9 commanding device 10 ground tank 11 bushing 12 aerial transmission line 13 cable head 14 insulating section 21 a, 21 b, 21 c, 21 d insulating spacer 22 shield electrode 23 … High voltage conductor

Claims (9)

[Claims] 1. A gas-insulated electric device having a bushing for drawing an air transmission line and housing a high-voltage conductor in an insulated and supported state in a grounded metal container filled with an insulating gas. A partial discharge diagnostic device for a gas-insulated electric device for detecting a partial discharge generated inside, comprising: a gas having directivity and a sensor for detecting a high-frequency signal in the gas-insulated electric device. Partial discharge diagnostic device for insulated electrical equipment. 2. A high-frequency signal detected by each of the sensors, wherein two sensors having the same structure are arranged adjacent to each other, and the directionality of each sensor is set to be shifted by 180 degrees. And a judging means for judging in which direction the high-frequency signal in the gas-insulated electric device is generated based on the result of the comparison by the comparator. 2. A partial discharge diagnostic device for a gas-insulated electric device according to claim 1. 3. The apparatus according to claim 1, wherein said sensor comprises a high-frequency surface current detector for observing a high-frequency surface current flowing through a metal surface. 4. The sensor according to claim 1, wherein the sensor is provided near the bushing.
A partial discharge diagnostic device for a gas-insulated electrical device according to claim 1. 5. A gas insulated electric device having a bushing for drawing an air transmission line and housing a high-voltage conductor in an insulated and supported state in a grounded metal container filled with an insulating gas. In a partial discharge diagnostic device for a gas-insulated electric device for detecting a partial discharge generated inside, a first sensor that detects a high-frequency signal generated in the grounded metal container, and is detected by the first sensor First determining means for determining whether or not a partial discharge has occurred in the grounded metal container based on a high-frequency signal; and second detecting means for detecting a high-frequency signal due to external noise entering the gas-insulated electric device from outside. A sensor; a second determination unit that determines whether or not the external noise has entered based on a high-frequency signal detected by the second sensor; Commanding means for giving a command to the first determining means to stop the determination for a predetermined period when it is determined that the external noise has entered. Partial discharge diagnostic device for electrical devices. 6. The apparatus according to claim 5, wherein the second sensor is a sensor having directivity. 7. A comparator to which a high-frequency signal detected by the second sensor is input, wherein the second sensor includes two sensors having the same structure arranged adjacent to each other. The direction of the directivity of the sensor is set to the traveling direction of external noise that enters from the outside, and the direction of the directivity of the other sensor is set to be shifted by 180 degrees from the direction of the directivity of the one sensor, The comparator compares a high-frequency signal detected by each of the sensors, and the second determination unit converts a high-frequency signal detected by the one sensor into the other sensor based on a comparison result by the comparator. And determining that the high-frequency signal in the gas-insulated electric device is generated by external noise intruding from the outside when the high-frequency signal is larger than the high-frequency signal detected by the device. Item 7. A partial discharge diagnostic device for a gas-insulated electric device according to Item 6. 8. The partial discharge diagnostic device for a gas insulated electric device according to claim 6, wherein said sensor comprises a high-frequency surface current detector for observing a high-frequency surface current flowing through a metal surface. 9. The air conditioner according to claim 5, wherein the second sensor is installed near the bushing and configured to detect the external noise signal entering from the air transmission line. A partial discharge diagnostic device for a gas-insulated electrical device according to any one of the preceding claims.