JP2011232288A - Partial discharge diagnostic method and partial discharge diagnostic device for gas insulated switchgear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a partial discharge diagnostic method and a partial discharge diagnostic device for a gas insulated switchgear which do not require a skill for diagnosing a partial discharge and which facilitates the construction of an algorithm for self-diagnosis.SOLUTION: A gas insulated switchgear accommodates a center conductor 3 in metal containers 1 and 2 filled with insulation gas. An electromagnetic wave signal of a partial discharge is measured by using a sensor 6, and a voltage applied to the center conductor 3 is measured through a voltage divider 9. Based on a φ-q-n distribution obtained from the partial discharge signals measured, a region, which is a bundle of the signals, is defined. Two parameters, a center of gravity and an occurrence frequency ratio, are then calculated from the region and an aggregation of the regions. A partial discharge diagnosis is performed using these parameters alone.

Description

  The present invention relates to a partial discharge diagnostic method and a partial discharge diagnostic device for a gas insulated switchgear.

  In the conventional partial discharge diagnosis method for electric power equipment, as in Patent Document 1, parameters such as discharge frequency n, discharge charge amount q, discharge generation phase φ are extracted from a partial discharge signal detected by means such as a sensor, The diagnosis of partial discharge is carried out according to the distribution of each parameter.

JP-A-6-34696

  The conventional method as described above needs to perform diagnosis by reading the correlation from a plurality of parameters such as φ-q distribution and φ-qn distribution. This is a method that is more efficient and simplified than diagnosing by observing the original discharge signal, but it is still difficult for non-experts and requires knowledge and experience.

  Further, in the conventional method as described above, when performing automatic diagnosis by an algorithm, there are a plurality of parameters, and thus there is a problem that the algorithm is complicated and difficult to construct.

  The present invention has been made in view of the above problems, and does not require skill in diagnosis of partial discharge, and it is easy to construct an algorithm for automatic diagnosis. An object is to provide a partial discharge diagnostic apparatus.

  In order to solve the above-described problems and achieve the object, a partial discharge diagnosis method for a gas-insulated switchgear according to the present invention includes a gas-insulated switchgear in which a central conductor is housed in a metal container filled with an insulating gas. A method for diagnosing partial discharge in which a step of detecting an electromagnetic wave radiated from a discharge source of partial discharge in the metal container by a sensor, and an applied voltage applied to the central conductor by an applied voltage signal acquisition unit Reducing the voltage to a predetermined voltage and acquiring it as an applied voltage signal, separating the noise from the electromagnetic wave signal output from the sensor by the partial discharge signal detection unit and detecting the partial discharge signal, and a discharge map generation unit With respect to all the partial discharge signals detected within a predetermined time, the partial discharge signal is compared with the position on the applied voltage phase-signal intensity plane based on the applied voltage signal. The step of creating a discharge map representing the applied potential phase-signal intensity-occurrence frequency distribution by counting the raw frequency, and the density calculation pattern of the discharge signal on the applied potential phase-signal intensity plane by the gravity center calculating unit. For the region that is the region represented, a step of calculating a dynamic center of gravity when the occurrence frequency is regarded as mass, and an occurrence frequency ratio calculation unit determines whether the center of gravity of each region is positive or negative of the applied voltage signal. Each region is divided into two types, a positive polarity discharge region and a negative polarity discharge region, depending on whether the positive frequency discharge region is included. The sum of the occurrence frequencies of the positive polarity added for the regions of the negative polarity and the sum of the occurrence frequencies included in the regions of the negative discharge are all the negative frequencies. A step of calculating an occurrence frequency ratio that is a ratio of the total occurrence frequency of negative polarity added for the region of the negative discharge, and a step of outputting the center of gravity and the occurrence frequency ratio as a diagnosis result by a partial discharge diagnosis unit; It is characterized by including.

  According to the present invention, the diagnosis of partial discharge can be performed based on the two parameters of the center of gravity and the occurrence frequency ratio, so that the diagnosis is simplified, no skill is required, and an algorithm for automatic diagnosis There is an effect that it is easy to construct.

FIG. 1 is a schematic diagram illustrating a configuration of a partial discharge diagnostic device for a gas-insulated switchgear according to a first embodiment. FIG. 2 is a functional block diagram for partial discharge diagnosis processing realized by a computer. FIG. 3 is a diagram for explaining a method of generating a discharge map. FIG. 4 is a diagram showing an example of a discharge map showing the region and the center of gravity. FIG. 5 is a diagram showing an example of the distribution of the center of gravity on the potential application phase when the discharge source or the discharge position changes. FIG. 6 is a diagram illustrating an example of discharge diagnosis performed using the center of gravity and the occurrence frequency. FIG. 7 is a diagram illustrating an example of the distribution of the occurrence frequency ratio when the discharge source or the discharge position is changed.

  Embodiments of a partial discharge diagnostic method and a partial discharge diagnostic device for a gas insulated switchgear according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a schematic diagram showing a configuration of a partial discharge diagnostic device of a gas insulated switchgear according to the present embodiment. In FIG. 1, as main components of the gas insulated switchgear, cylindrical metal containers 1, 2 that are filled with an insulating gas and connected to each other, and stored in these metal containers 1, 2 are charged. The center conductor 3 to be electrified, the metal containers 1 and 2 are partitioned into a plurality of gas spaces, the spacer 4 made of an insulator for supporting the center conductor 3, the power transmission / distribution circuit system (not shown), and the gas A bushing 5 for connecting an insulated switchgear is shown. Depending on the power transmission / distribution circuit system in which the gas insulated switchgear is incorporated, a cable head may be attached instead of the bushing 5.

  In FIG. 1, as main components of the partial discharge diagnostic apparatus, a sensor 6 for detecting an electromagnetic wave signal, a signal amplifier 7 connected to the sensor 6, and an A / D converter connected to the signal amplifier 7 are used. 8, a voltage divider 9 as an applied voltage signal acquisition unit that divides and outputs an applied voltage applied to the center conductor 3, an A / D converter 10 connected to the voltage divider 9, and A A computer 11 is shown as a data processing unit to which both outputs of the / D converters 8 and 10 are input.

  The sensor 6 is a partial discharge sensor for measuring electromagnetic waves radiated from a partial discharge discharge source. The discharge source is generated when there is an insulation defect inside the gas insulated switchgear. In FIG. 1, the sensor 6 is illustrated as a sensor that detects an electromagnetic wave leaking from the spacer 4 to the outside of the gas-insulated switchgear, but may be of a type installed inside the gas-insulated switchgear. .

  The signal amplifier 7 has a function of amplifying the electromagnetic wave signal detected by the sensor 6. The analog signal amplified by the signal amplifier 7 is converted into a digital signal by the A / D converter 8, and this digital signal is sent to the computer 11.

  On the other hand, the voltage divider 9 steps down the applied voltage applied to the central conductor 3 to a predetermined voltage and outputs this signal to the A / D converter 10. The A / D converter 10 converts the output signal of the voltage divider 9 from an analog signal to a digital signal, and outputs the divided applied voltage signal to the computer 11 as a digital signal. The computer 11 uses the electromagnetic wave signal input from the A / D converter 8 and the applied voltage signal input from the A / D converter 10 to perform real-time processing or storage in a storage device (not shown). The partial discharge is diagnosed by post-processing.

  Next, the operation of the present embodiment will be described. Since the operation until the signal is input from the A / D converters 8 and 10 to the computer 11 is as described above, signal processing by the computer 11 will be described below. FIG. 2 is a functional block diagram for partial discharge diagnosis processing realized by the computer 11. As shown in FIG. 2, the computer 11 as a signal processing unit includes functions of a partial discharge signal detection unit 12, a discharge map generation unit 13, a center of gravity calculation unit 14, an occurrence frequency ratio calculation unit 15, a partial discharge diagnosis unit 16, and the like. Is provided.

  The partial discharge diagnostic apparatus according to the present embodiment processes a discharge signal with a certain time Tf as a processing unit. Tf can be set to, for example, about 30 seconds to 10 minutes. If Tf is short, it is possible to cope with a phenomenon that changes quickly. Further, if Tf is long, stable diagnosis with little variation can be performed. The partial discharge signal detection unit 12 separates the electromagnetic wave signal input from the A / D converter 8 into noise and partial discharge signal, and extracts only the partial discharge signal as a processing target. There is no limitation on the separation method. For example, there is a method in which a certain signal intensity is used as a threshold, and a signal equal to or higher than the threshold is separated as a partial discharge signal.

  Next, based on the partial discharge signal output from the partial discharge signal detection unit 12 and the applied voltage signal output from the A / D converter 10, the discharge map generation unit 13 performs all the observations during Tf. For the partial discharge pulse, a discharge map is created by counting the occurrence frequency n (count number) of the partial discharge with respect to the position on the applied potential phase φ-discharge charge amount q plane. Note that the applied voltage phase φ is the phase of the applied voltage signal. Further, q may be a signal intensity proportional to the discharge charge amount.

  FIG. 3 is a diagram for explaining a method of generating a discharge map. As shown in FIG. 3, a mesh structure is constructed by dividing the φ axis and the q axis, for example, at regular intervals (the intervals are Δφ and Δq) on the potential applied phase φ-signal intensity q plane, for example. A small area that is each square of the mesh is called a slot. Each slot is characterized by a representative value of (φ, q) coordinates and Δφ, Δq. The discharge map generator 13 determines a corresponding slot from the discharge generation phase and the signal intensity for each partial discharge pulse, and counts the number of occurrences for each slot. Then, the construction of the discharge map is completed by finishing counting all the partial discharge pulses generated during Tf. In FIG. 3, for example, in the slot described as “18”, it means that the partial discharge corresponding to the condition of this slot has occurred 18 times. When the discharge map is displayed, it can be displayed by a two-dimensional color map in which n is converted to an appropriate color scale or a three-dimensional map. In this way, one discharge map is created for each Tf.

  In the discharge map created in this way, the partial discharge signals are observed as dense signals due to their phase synchronism. That is, there is a correlation between the type of discharge source and the discharge generation phase, and many partial discharge signals have a characteristic of appearing as a dense pattern on the discharge map.

  In the present embodiment, such a dense pattern of signals on the discharge map is defined as a region, and the centroid calculation unit 14 calculates the centroid for each region. Here, the center of gravity is a mechanical center of gravity when the occurrence frequency n is regarded as mass, and is calculated for each region. The center of gravity can be interpreted as a point where the information of the discharge signal is collected.

  The region extraction method does not matter. For example, the center of gravity calculation unit 14 may extract a connected region including slots whose n value is not 0 in the φ-q plane as a region, or simply divide into positive discharge and negative discharge. The φ-q plane may be divided into two regions (each region of 0 ≦ φ <π and π ≦ φ <2π) depending on whether the applied voltage is positive or negative. That is, positive discharge corresponds to 0 ≦ φ <π, and negative discharge corresponds to π ≦ φ <2π.

  The calculation of the center of gravity can be performed, for example, by regarding the slot having the occurrence frequency n in the region as the mass point of the mass n and obtaining the mechanical center of gravity. Alternatively, each discharge pulse may be regarded as a mass point of mass 1 in the region, and the mechanical center of gravity may be obtained. The center of gravity is one index indicating the place where discharge is most active in the discharge signal distribution of φ−q−n, and is a point representing the region.

  Next, the occurrence frequency ratio calculation unit 15 classifies each region into two types, that is, a positive discharge region and a negative discharge region, and the sum of occurrence frequencies n included in the positive discharge region is all positive. The sum Np of the occurrence frequency of the positive polarity added for the region is calculated, and the sum Nn of the occurrence frequency of the negative polarity obtained by adding the sum of the occurrence frequencies n included in the negative polarity discharge region for all the negative polarity regions is calculated. Further, the occurrence frequency ratio R = Np / Nn of both polarities is calculated. If the generation frequency ratio R is larger than 1, the occurrence frequency of the positive polarity discharge is higher, and if it is smaller than 1, the occurrence frequency of the negative polarity discharge is higher.

  The classification method of the positive discharge region and the negative discharge region is not limited. For example, in the φ-q plane, the region may be classified according to whether the area of the region is included in 0 ≦ φ <π or π ≦ φ <2π, or the center of gravity of the region is 0 ≦ φ <π and π ≦ You may classify | categorize according to whether it is contained in (phi) <2pi. Note that 0 ≦ φ <π corresponds to the positive of the applied voltage signal, and π ≦ φ <2π corresponds to the negative of the applied voltage signal.

  Subsequently, the partial discharge diagnosis unit 16 displays a discharge map in a format as shown in FIG. 4 by a display device (not shown). FIG. 4 is an example of a discharge map showing the region and the center of gravity. In FIG. 4, the horizontal axis is the applied voltage phase (φ), the vertical axis is the signal intensity (q), and the discharge frequency (n) is indicated by the difference in color gradation. At the same time, the position of the calculated center of gravity (G) in the discharge map is also displayed for each region. At this time, a numerical display of the discharge frequency ratio (R) is also performed separately from the display of the discharge map.

  The diagnostician may perform discharge diagnosis by comparing the displayed information with past test results, and by comparing with the threshold values obtained from past test results and experiences. it can. For example, when a discharge is generated in 4 × 2 patterns with the discharge source being a floating electrode or a needle electrode and the discharge source position being on the central conductor 3 or on the metal containers 1 and 2, When attention is paid, the distribution is as shown in FIG. As shown in FIG. 5, the center conductor / needle electrode discharge (represents the center conductor and needle electrode discharge; hereinafter the same), the metal container / needle electrode discharge, and the metal container / floating electrode discharge, There are portions where the distributions overlap each other, and it is difficult to uniquely identify each discharge. In FIG. 6, the pattern of the applied potential phase distribution at the center of gravity common to the center conductor / needle electrode discharge, the metal container / needle electrode discharge, and the metal container / floating electrode discharge is defined as pattern A. The pattern of the applied potential phase distribution at the center of gravity of the floating electrode discharge is distinguished as a pattern B.

  On the other hand, FIG. 7 is a diagram showing an example of the distribution of the occurrence frequency ratio R when the discharge source or the discharge position changes. As shown in FIG. 7, for the center conductor / floating electrode discharge and the metal container / floating electrode discharge, there are overlapping portions in the distribution of the occurrence frequency ratio R, but on the center conductor / needle electrode discharge and the metal container -Regarding the needle electrode discharge, the distribution of the occurrence frequency R is different from each other. That is, the occurrence frequency ratio R of the center conductor / needle electrode discharge is approximately 0, and the occurrence frequency ratio R of the needle electrode discharge / on the metal container is approximately 1. In FIG. 6, regarding the occurrence frequency ratio, the pattern of the occurrence frequency ratio on the center conductor / needle electrode discharge is pattern C, and the pattern of the occurrence frequency ratio on the metal container / needle electrode discharge is pattern D. The pattern of the occurrence frequency ratio of the electrode discharge and the discharge on the metal container / floating electrode is represented by pattern E. Thus, in addition to the center of gravity, by paying attention to the occurrence frequency ratio, it can be further classified into three patterns C, D, and E in addition to the patterns A and B. Thus, by using two indices, the center of gravity and the frequency ratio, as shown in FIG. 6, the center conductor / needle electrode discharge is a combination of patterns A and C, and the metal container / needle electrode discharge is pattern A. -The combination of D can be identified by the combination of patterns B and E on the central conductor and floating electrode discharge, and the combination of patterns A and E on the metal container and floating electrode discharge. The four patterns of the metal container / needle electrode discharge, the central conductor / floating electrode discharge, and the metal container / floating electrode discharge can be uniquely identified.

  In addition, the partial discharge diagnosis unit 16 can be given a function of automatically identifying the type of discharge source (for example, the type identified by the above four patterns). In this case, the partial discharge diagnosis unit 16 holds a discrimination rule or database that relates the type of discharge source, the center of gravity, and the occurrence frequency ratio, and compares the calculated center of gravity and occurrence frequency ratio with the discrimination rule or data on the database. As a result, the type of discharge source is specified, and the type of discharge source is output as a diagnosis result. The database may be created in advance based on actual measurement, simulation, or the like, or may be constructed by adding or learning data as appropriate.

  Conventionally, the discharge source has been identified based on the so-called Point on Wave concept by paying attention to the phase where discharge is active in the φ-n graph and the like. However, in this case, the information to be referred to is super multidimensional information of φ × n, so that it is difficult for non-experts to diagnose, and it is difficult to handle automatic diagnosis by a computer.

  On the other hand, in the present embodiment, from the characteristic that the discharge signal appears as a certain dense pattern on the discharge map due to phase synchronization, a cluster of closely distributed signals is defined as a region, and as a statistical feature for each region, The center of gravity as a two-dimensional parameter and the discharge frequency ratio as a one-dimensional parameter are calculated and diagnosed. Thus, diagnosis can be performed only by referring to the two low-dimensional parameters, and simplification of the discharge power source diagnosis can be realized.

  In addition, according to the present embodiment, when automatic diagnosis is performed by an algorithm, since the determination rules for two low-dimensional parameters, the center of gravity and the occurrence frequency ratio, are set, the algorithm can be easily constructed. This automatic diagnosis can be realized by the computer 11 whose operation is controlled by a program in which the procedure of the above-described diagnosis method is described. The computer 11 is usually provided with a control device such as a CPU, a storage device such as a ROM and a RAM, an external storage device such as an HDD, a display device such as a display device, and an input device such as a keyboard and a mouse. Can be used.

  As described above, the present invention is useful as a partial discharge diagnostic method and a partial discharge diagnostic device for a gas insulated switchgear.

1, 2 Metal container 3 Central conductor 4 Spacer 5 Bushing 6 Sensor 7 Signal amplifier 8, 10 A / D converter 9 Voltage divider
DESCRIPTION OF SYMBOLS 11 Computer 12 Partial discharge signal detection part 13 Discharge map production | generation part 14 Center of gravity calculation part 15 Occurrence frequency ratio calculation part 16 Partial discharge diagnosis part

Claims (12)

A partial discharge diagnosis method for a gas insulated switchgear in which a central conductor is housed in a metal container filled with an insulating gas,
Detecting electromagnetic waves radiated from a partial discharge discharge source in the metal container with a sensor;
A step of stepping down the applied voltage applied to the central conductor by the applied voltage signal acquisition unit to a predetermined voltage to obtain the applied voltage signal;
Separating the noise from the electromagnetic wave signal output from the sensor by the partial discharge signal detection unit and detecting the partial discharge signal;
With respect to all the partial discharge signals detected within a predetermined time by the discharge map generator, the frequency of occurrence of the partial discharge is determined with respect to the position on the applied potential phase-signal intensity plane based on the applied voltage signal. Creating a discharge map representing the applied voltage phase-signal intensity-occurrence frequency distribution by counting;
For a region that is a region representing a dense pattern of discharge signals on the applied potential phase-signal intensity plane by a centroid calculating unit, calculating a dynamic centroid when the occurrence frequency is regarded as mass;
The occurrence frequency ratio calculation unit divides each region into two types, a positive discharge region and a negative discharge region, depending on whether the center of gravity of each region corresponds to positive or negative of the applied voltage signal. The sum of the occurrence frequencies included in the positive discharge region is added to all the positive discharge regions, and the sum of the occurrence frequencies included in the negative discharge region. Calculating an occurrence frequency ratio that is a ratio to the sum of the occurrence frequencies of the negative polarity obtained by adding all of the negative discharge regions,
A step of outputting the center of gravity and the occurrence frequency ratio as a diagnosis result by a partial discharge diagnosis unit;
A partial discharge diagnostic method for a gas-insulated switchgear characterized by comprising:   After the center of gravity and the occurrence frequency ratio are calculated, the partial discharge diagnosis unit uses the determination rule or database that relates the type of discharge, the center of gravity and the occurrence frequency ratio, and the center of gravity and the occurrence frequency ratio. The partial discharge diagnosis method for a gas-insulated switchgear according to claim 1, characterized in that the type of discharge is specified by comparing the determination rule or the database with the discrimination rule and the database, and the identification result is output.   When the discharge map is created by the discharge map generation unit, the applied voltage phase-signal intensity plane is divided into a plurality of small regions, and the corresponding small regions are detected for each partial discharge signal detected. The partial discharge diagnosis method for a gas insulated switchgear according to claim 1 or 2, wherein the occurrence frequency is counted for each of the small regions. A partial discharge diagnosis method for a gas insulated switchgear in which a central conductor is housed in a metal container filled with an insulating gas,
Detecting electromagnetic waves radiated from a partial discharge discharge source in the metal container with a sensor;
A step of stepping down the applied voltage applied to the central conductor by the applied voltage signal acquisition unit to a predetermined voltage to obtain the applied voltage signal;
Detecting a partial discharge signal by separating noise from an electromagnetic wave signal output by the sensor by a partial discharge signal detection unit;
With respect to all the partial discharge signals detected within a predetermined time by the discharge map generator, the frequency of occurrence of the partial discharge is determined with respect to the position on the applied potential phase-signal intensity plane based on the applied voltage signal. Creating a discharge map representing the applied voltage phase-signal intensity-occurrence frequency distribution by counting;
For a region that is a region representing a dense pattern of discharge signals on the applied potential phase-signal intensity plane by a centroid calculating unit, calculating a dynamic centroid when the occurrence frequency is regarded as mass;
The generation frequency ratio calculation unit determines whether the area of each region on the applied potential phase-signal intensity plane is greater in the applied phase from 0 to π or π to 2π. Occurrence of positive polarity by dividing each region into two types of positive polarity discharge region and negative polarity discharge region, and adding the sum of the occurrence frequencies contained in the positive discharge region for all the positive discharge regions Calculating an occurrence frequency ratio that is a ratio of the sum of the frequencies and the sum of the occurrence frequencies of the negative polarity obtained by adding the sum of the occurrence frequencies included in the negative discharge region for all the negative discharge regions When,
A step of outputting the center of gravity and the occurrence frequency ratio as a diagnosis result by a partial discharge diagnosis unit;
A partial discharge diagnostic method for a gas-insulated switchgear characterized by comprising:   After the center of gravity and the occurrence frequency ratio are calculated, the partial discharge diagnosis unit uses the determination rule or database that relates the type of discharge, the center of gravity and the occurrence frequency ratio, and the center of gravity and the occurrence frequency ratio. 5. The partial discharge diagnosis method for a gas insulated switchgear according to claim 4, wherein the type of discharge is specified by comparing the determination rule or the database with the determination rule, and the identification result is output.   When the discharge map is created by the discharge map generation unit, the applied voltage phase-signal intensity plane is divided into a plurality of small regions, and the corresponding small regions are detected for each partial discharge signal detected. The partial discharge diagnosis method for a gas insulated switchgear according to claim 4 or 5, wherein the occurrence frequency is counted for each of the small regions. A partial discharge diagnostic device for a gas insulated switchgear in which a central conductor is housed in a metal container filled with an insulating gas,
A sensor capable of detecting an electromagnetic wave radiated from a partial discharge discharge source in the metal container;
An applied voltage signal acquisition unit that acquires an applied voltage applied to the central conductor by stepping down to a predetermined voltage;
A partial discharge signal detector for detecting a partial discharge signal from an electromagnetic wave signal output by the sensor;
For all the partial discharge signals detected within a certain period of time, partial discharge is performed with respect to the position on the applied voltage phase-signal intensity plane based on the applied voltage signal output from the applied voltage signal acquisition unit. A discharge map generation unit for generating a discharge map representing a potential applied phase-signal intensity-occurrence frequency distribution by counting the occurrence frequency;
For a region that is a region representing a dense pattern of discharge signals on the applied voltage phase-signal intensity plane, a centroid calculating unit that calculates a dynamic centroid when the occurrence frequency is regarded as mass;
Depending on whether the center of gravity of each region corresponds to positive or negative of the applied voltage signal, each region is divided into two types, a positive discharge region and a negative discharge region, and the positive discharge region The sum of the occurrence frequencies included in the positive discharge frequency region is added to all of the positive discharge regions, and the sum of the occurrence frequencies included in the negative discharge regions is added to all the negative discharges. An occurrence frequency ratio calculation unit that calculates an occurrence frequency ratio that is a ratio of the total occurrence frequency of negative polarity added for the regions of
A partial discharge diagnosis unit that outputs the center of gravity and the occurrence frequency ratio as a diagnosis result;
A partial discharge diagnostic device for a gas insulated switchgear characterized by comprising:   The partial discharge diagnosis unit has a discrimination rule or a database that associates the type of discharge with the centroid and the occurrence frequency ratio, and after calculating the centroid and the occurrence frequency ratio, the centroid and the occurrence frequency ratio The partial discharge diagnostic apparatus for a gas-insulated switchgear according to claim 7, wherein the type of discharge is specified by comparing the determination rule or a database and the identification result is output.   The discharge map generation unit divides the potential applied phase-signal intensity plane into a plurality of small areas, determines a small area to which a discharge phase and a signal intensity of the detected partial discharge signal belong, and 9. The partial discharge diagnostic apparatus for a gas insulated switchgear according to claim 7, wherein the occurrence frequency is counted for each region. A partial discharge diagnostic device for a gas insulated switchgear in which a central conductor is housed in a metal container filled with an insulating gas,
A sensor capable of detecting an electromagnetic wave radiated from a partial discharge discharge source in the metal container;
An applied voltage signal acquisition unit that acquires an applied voltage applied to the central conductor by stepping down to a predetermined voltage;
A partial discharge signal detector for detecting a partial discharge signal from an electromagnetic wave signal output by the sensor;
For all the partial discharge signals detected within a certain period of time, partial discharge is performed with respect to the position on the applied voltage phase-signal intensity plane based on the applied voltage signal output from the applied voltage signal acquisition unit. A discharge map generation unit for generating a discharge map representing a potential applied phase-signal intensity-occurrence frequency distribution by counting the occurrence frequency;
For a region that is a region representing a dense pattern of discharge signals on the applied voltage phase-signal intensity plane, a centroid calculating unit that calculates a dynamic centroid when the occurrence frequency is regarded as mass;
Depending on whether the area of each region on the applied phase-signal intensity plane is greater than the region where the applied phase is 0 to π or the region of π to 2π, each region is subjected to positive discharge. Dividing into two types of regions or regions of negative discharge, the sum of the occurrence frequencies included in the positive discharge region is added to all the positive discharge regions, and the negative occurrence frequency An occurrence frequency ratio calculation unit that calculates an occurrence frequency ratio that is a ratio of a sum of the occurrence frequencies included in the regions of the negative discharge and a sum of the occurrence frequencies of the negative polarity obtained by adding all the negative discharge regions;
A partial discharge diagnosis unit that outputs the center of gravity and the occurrence frequency ratio as a diagnosis result;
A partial discharge diagnostic device for a gas insulated switchgear characterized by comprising:   The partial discharge diagnosis unit has a discrimination rule or a database that associates the type of discharge with the centroid and the occurrence frequency ratio, and after calculating the centroid and the occurrence frequency ratio, the centroid and the occurrence frequency ratio The partial discharge diagnosis apparatus for a gas-insulated switchgear according to claim 10, wherein the type of discharge is specified by comparing the discrimination rule or a database and the identification result is output.   The discharge map generation unit divides the potential applied phase-signal intensity plane into a plurality of small areas, determines a small area to which a discharge phase and a signal intensity of the detected partial discharge signal belong, and The partial discharge diagnosis device for a gas insulated switchgear according to claim 10 or 11, wherein the occurrence frequency is counted for each region.

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