JP4969319B2 - Method and apparatus for partial discharge diagnosis of gas insulated switchgear - Google Patents

Description

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

  A gas-insulated switchgear encloses an insulating gas in a space between a metal container, which is an outer conductor at a ground potential, and a high-voltage conductor, which is a central conductor disposed therein. When the gas insulation performance deteriorates, a partial discharge, which is a local breakdown, may occur. The cause of partial discharge varies depending on the components of the gas-insulated switchgear (insulators, high-voltage conductors, mixed foreign matter, etc.), but this partial discharge can eventually lead to a serious situation where the entire path is destroyed. It has sex.

  In other words, the partial discharge diagnosis reliably detects the partial discharge before the destruction of the entire path, determines whether or not the partial discharge has a high risk of causing the destruction of the entire path, and The purpose is to prevent it.

  However, in the installation environment of the gas-insulated switchgear, unnecessary signals such as electromagnetic waves and broadcast radio waves caused by discharge generated in overhead power transmission lines connected through bushings etc. come out as external noise. It is necessary to be able to distinguish whether the detected electromagnetic wave signal is an electromagnetic wave signal due to partial discharge generated inside the gas insulated switchgear or an electromagnetic wave signal due to external noise. And in the case of partial discharge generated inside the gas insulated switchgear, in order to make it possible to prepare replacement parts, whether the discharge source is on the metal container side, the high voltage conductor side, It is necessary to be able to determine the type such as the side.

  Therefore, for example, in Patent Document 1, gas insulation is obtained by correlating the generation time interval of the detected partial discharge signal with the phase of the power system voltage applied when the partial discharge signal is detected. A diagnostic method has been proposed in which a partial discharge generated in a switchgear and a discharge source are determined.

JP 2005-156442 A

  However, in the above conventional technique, it is necessary to acquire an accurate phase of the system voltage waveform applied to the gas-insulated switchgear, and thus there are the following problems.

  That is, the exact phase of the system voltage waveform can be obtained from the output of the instrument transformer connected to the gas insulated switchgear. However, in many cases, the output of the instrument transformer is already used for applications other than partial discharge diagnosis, so it is difficult to add a partial discharge diagnosis application from the viewpoint of reliability of power system operation. is there.

  On the other hand, even if it is possible to use the output of the instrument transformer for the purpose of partial discharge diagnosis, the gas insulated switchgear in which partial discharge is generated has various discharge sources. There will be many parts and non-charged parts. In order to diagnose the discharge source in such a situation, it is necessary to take in the outputs of a large number of instrument transformers, so that the configuration of the diagnostic apparatus becomes complicated and the wiring scale increases.

  The present invention has been made in view of the above, and provides gas insulation that enables partial discharge determination and discharge source type determination without using phase information of a system voltage waveform applied to a gas-insulated switchgear. It is an object of the present invention to obtain a partial discharge diagnosis method and apparatus for a switchgear.

In order to achieve the above-mentioned object, a partial discharge diagnosis method for a gas insulated switchgear according to the present invention is a discharge sensor arranged to detect a partial discharge signal which is an electromagnetic wave signal due to partial discharge generated in a gas insulated switchgear. among the detected electromagnetic wave signal at, it detects an electromagnetic wave signal exceeding the threshold value as the partial discharge signals, each partial discharge signal detection period of the system voltage which periodic is applied to the gas insulated switchgear and A first step of recording in association with the phase of an equal predetermined periodic signal, and the quantity of each partial discharge signal over a plurality of periods of the periodic signal recorded in the first step, for each period in the plurality of periods wherein a second step of integrating the time, etc. divided corresponding time segments each Niso respectively, the time division number is the maximum of the second accumulation portion discharge signal at step plurality Plotted for each period to create the time series change pattern of the partial discharge signal, and a third step of determining the type of the discharge source of the generated partial discharge in the gas insulated switchgear by series change pattern when the created , Including.

  According to the present invention, the frequency and period of the system voltage applied to the gas-insulated switchgear for the partial discharge signal exceeding the threshold provided for detecting the partial discharge generated in the gas-insulated switchgear are the same. Corresponding to the number of each partial discharge signal collected over a plurality of periods collected over a plurality of periods of a periodic signal whose phases do not necessarily match and the number of each partial discharge signal over the collected periods divided into equal parts in time A time series change pattern of partial discharge signals in a time section where the number of accumulated partial discharge signals is the maximum is generated. When the time-series change pattern created in this way is due to partial discharge, it has a characteristic part unique to the discharge source, and therefore the type of discharge source can be determined. When the created time-series change pattern does not have a characteristic part unique to the discharge source, it can be determined that it is not due to partial discharge.

  In this way, partial discharge diagnosis and discharge power source type determination can be made without using phase information of the system voltage waveform applied to the gas-insulated switchgear, so that the partial discharge diagnostic device has a simple configuration. There is an effect that can be.

  Exemplary embodiments of a partial discharge diagnosis method and apparatus for a gas insulated switchgear according to the present invention will be described below in detail with reference to the drawings.

Embodiment 1 FIG.
1 is a block diagram showing a configuration of a partial discharge diagnostic apparatus for a gas insulated switchgear according to Embodiment 1 of the present invention.

  In FIG. 1, the gas-insulated switchgear 1 houses electrical devices such as switching parts, instrument transformers, and current transformers in metal containers 11 and 12 as external conductors at a ground potential. In FIG. 1, the high voltage conductor 13 which is a center conductor arrange | positioned in the metal containers 11 and 12 among the electric equipment is shown. Insulating gas is sealed in the space between the metal containers 11 and 12 and the high voltage conductor 13. Since the high voltage conductor 13 is supported by an insulating spacer 14 interposed between the metal containers 11 and 12, the gas space in the metal containers 11 and 12 is separated from the gas space on the metal container 11 side by the insulating spacer 14. It is partitioned into a gas space on the container 12 side. A bushing 15 for connecting the gas insulated switchgear 1 to an overhead transmission line (not shown) is provided on the outer wall on the metal container 12 side. The bushing 15 may be replaced with a cable bed depending on the power system in which the gas insulated switchgear 1 is incorporated.

  Such a partial discharge diagnostic device 2a for diagnosing partial discharge in the gas insulated switchgear 1 includes a discharge sensor 21, an amplification unit 22, a detection unit 23, a count processing unit 24, a determination unit 25, a period, And a signal generator 26a. Here, when showing the correspondence with the claims, the discharge sensor 21 corresponds to the discharge sensor of the same name. The detector 23 corresponds to a partial discharge signal detector. The count processing unit 24 corresponds to a partial discharge signal integrating unit. The determination unit 25 corresponds to a partial discharge determination unit.

  The discharge sensor 21 is an antenna arranged for the purpose of capturing an electromagnetic wave signal (that is, a partial discharge signal) radiated from a partial discharge discharge source generated when an insulation defect exists in the gas insulated switchgear 1. However, an electromagnetic wave signal coming from the outside of the gas insulated switchgear 1 is also captured.

  In FIG. 1, the discharge sensor 21 detects the electromagnetic wave signal (partial discharge signal) due to partial discharge leaking to the outside of the gas insulated switchgear 1 through the insulating spacer 14, so that the gas insulated switchgear 1 of the insulating spacer 14 is detected. Although the case where it arrange | positions in the outer vicinity is shown, the system which embeds the metal ring which surrounds the high voltage conductor 13 in the inside of the insulating spacer 14 may be used.

  The amplifying unit 22 amplifies the electromagnetic wave signal (including the partial discharge signal and the electromagnetic wave signal coming from outside the gas-insulated switchgear 1) detected by the discharge sensor 21 and gives the amplified signal to the detecting unit 23.

  The detection unit 23 sets a threshold value for discriminating between the partial discharge signal and the electromagnetic wave signal coming from the outside of the gas-insulated switchgear 1, and compares the magnitude relationship between the threshold value and the electromagnetic wave signal amplified by the amplification unit 22. When the electromagnetic wave signal amplified by the amplification unit 22 exceeds the threshold value, it is detected as an “event signal”, and the detected event signal is incorporated in synchronization with the phase of the periodic signal from the periodic signal generation unit 26a. Record one by one in the storage unit (see FIG. 2).

  The count processing unit 24 uses the periodic phase attached to the event signal recorded by the detection unit 23 over a plurality of cycles of the periodic signal from the periodic signal generating unit 26a, and the periodic signal from the periodic signal generating unit 26a. 1 is arranged for each time segment divided into equal time, and the cumulative count is performed, and the cumulative count result is recorded in a built-in storage unit (see FIG. 3). The count processing unit 24 repeats the above-described integration process while resetting the counter every plural cycles of the periodic signal from the periodic signal generating unit 26a.

The determination unit 25 counts in the time segment indicating the maximum count result from the integration count results in the one cycle that the count processing unit 24 has integrated for each one time segment performed for a certain plurality of cycles. extracting, to the expansion process to the series change pattern when equally dividing partition the system integrated voltage cycle into a plurality, carried out by changing a plurality of cycles of count processing unit 24 is the integrated target one after the other (Fig. 4).

  Partial discharge includes discharge due to protrusions present on the high-voltage conductor 13, discharge due to protrusions present on the inner wall surfaces of the metal containers 11 and 12, discharge due to metal foreign objects present on the insulating spacer 14, and insulating spacer 14 Various discharge sources such as discharge due to cracks and voids (voids) present in the metal, discharge due to the floating electrode on the high voltage conductor 13 side, discharge due to the floating electrode on the metal container 11 and 12 side, discharge due to metal foreign matter existing in the gas space, etc. Caused by. The time-series change pattern of the event signal in each segment obtained by dividing the system voltage cycle into a plurality of equal divisions as described above is inherent to such various discharge sources when it is due to partial discharge. It has the characteristic part.

  Therefore, the determination unit 25 includes a discharge source determination table 25a indicating a correspondence relationship between the time series change pattern of the event signal and the discharge source, and the event is divided into a plurality of equally divided system voltage periods as described above. When the time-series change pattern of the signal is created, the type of the discharged power is determined with reference to the discharged power determination table 25a, and when there is no corresponding pattern in the discharged power determination table 25a, the type of the discharged power cannot be determined. The event signal detected by 23 is determined to be an electromagnetic wave signal (that is, external noise) that has arrived from outside the gas-insulated switchgear 1. The determination result is recorded as necessary.

  The periodic signal generator 26a generates a periodic signal that has the same period as the frequency (50 Hz or 60z) of the high-voltage system voltage applied to the gas-insulated switchgear 1, but does not necessarily match the phase.

Incidentally, low AC power obtained in an electric station, such as power plants and substations for gas insulated switchgear 1 is installed, position phase of the high pressure of the system voltage to be applied to the gas insulated switchgear 1 is not necessarily coincide, Since the periods coincide with each other, in the first embodiment, the periodic signal generator 26a is configured to generate a periodic signal using a low-voltage AC power source obtained at an electric station where the gas insulated switchgear 1 is installed. Yes.

  Next, a diagnostic operation of the partial discharge diagnostic device 2a will be described with reference to FIGS. 2 is a diagram for explaining the operation of the detector 23 shown in FIG. FIG. 3 is a diagram for explaining the operation of the count processing unit 24 shown in FIG. FIG. 4 is a diagram for explaining the operation of the determination unit 25 shown in FIG. 1 and the contents of a discharge / discharge determination table provided in the determination unit 25.

  2A shows a relationship between an electromagnetic wave signal including a partial discharge signal input to the detector 23 (hereinafter simply referred to as “partial discharge signal”) and a threshold value. (B) shows the relationship between the event signal to detect and a periodic signal. Reference numeral 30 denotes a waveform of a periodic signal generated by the periodic signal generator 26 a in synchronization with the frequency of the system voltage applied to the gas insulated switchgear 1.

  As shown in FIG. 2A, when a partial discharge occurs inside the gas-insulated switchgear 1, partial discharge signals 31 a and 31 b are input to the detection unit 23 from the amplification unit 22 at an arbitrary phase of the periodic signal 30. To do. The partial discharge signals 31a and 31b have a pulse-like waveform, and the amplitude value thereof is different for each occurrence of discharge. To show this, the amplitude value of the partial discharge signal 31a is expressed as VPDn, and the amplitude value of the partial discharge signal 31b is expressed as VPDn + 1.

  In the detector 23, a threshold value Vth is set for such partial discharge signals 31a and 31b. The detector 23 compares the partial discharge signals 31a and 31b with the threshold value Vth and detects a partial discharge signal exceeding the threshold value Vth as an “event signal”. In the example shown in FIG. 2A, since the partial discharge signals 31a and 31b both exceed the threshold value Vth, as shown in FIG. 2B, the partial discharge signal 31a is detected as the event signal 32a, and the partial discharge signal 31b is detected as an event signal 32b, and is recorded in the storage unit in association with the phase of the periodic signal 30 at the time of detection.

Next, as shown in FIG. 3, the count processing unit 24 manages the 1 / N phase division section 33, which is a time section obtained by equally dividing one period of the periodic signal 30, in synchronization with the phase of the periodic signal 30. The event signal 32 detected by the detector 23 is extracted in synchronization with the phase of the periodic signal 30 and integrated in the corresponding time segments in the first to n-th periods of the periodic signal 30. by executing each time segment in one cycle of the periodic signal 30, determined Mel histograms in time division the N. Counting processing unit 24 repeats that recorded in the storage unit thus calculates the n cycles, while resetting the counter every n cycles.

In the example shown in FIG. 3, as the eight histogram of time segments in which the phase of one period of the periodic signal 30 is divided 8, etc., the second time Classification 3 4a, 3 th time Classification 3 4b , 5 th time Classification 3 4c, 6 th time Classification 3 4d and 7 th time Classification 3 4e is shown.

  Next, the determination unit 25 prepares a time-series change pattern creation region as shown in FIG. 4 in the built-in storage unit. In FIG. 4, the system voltage cycle (that is, one cycle of the periodic signal generated by the periodic signal generator 26a) is shown in the horizontal direction, and the elapsed time per unit time is shown from the bottom to the top in the vertical direction. Yes. The system voltage cycle in the horizontal direction is divided into 32, for example.

Determination unit 25 extracts between division when the maximum and ing from one n cycles Starring San'yui results taken out from the storage unit of the count processing section 24, between Classification when extracted, is shown in FIG. 4 in the transverse direction 32 equal division is one section was the time series change pattern creation area, you plotted as indicated by the black marks in accordance with the elapsed time. In the example shown in FIG. 3, because 3 4a is a maximum, the second time interval is extracted, time series change pattern is created.

Determining unit 25, creating a pattern of one row transversely to the split 32 and the like of the time series change pattern creation area shown in FIG. 4, the following n cycles Starring San'yui from the storage unit of the counting processing unit 24 fruit was removed, extracted between division when the maximum and ing at the bottom, to create a pattern of above Symbol as well as one line. In this way, it repeated to create a pattern of one row. Then, when the ends to create a time series change pattern at the series change pattern producing area, to reset the time-series change pattern creation area is repeated to create as well from the first segment.

In Figure 4, Te all wedges odor divided 32 like in the lateral direction of the time series change pattern creation area, sections there is shown to Pas coater emissions at reference numeral 35 is different by discharge source, characterizes the discharge source Is.

That is, in a discharge source determination table 25 a determination unit 25 is provided, correspondence between the discharge source and the time series change pattern is shown.

  The determination unit 25 can determine the discharged power with reference to the discharged power determination table 25a. And even if the electromagnetic wave signal exceeding the partial discharge discrimination threshold prepared in the detection unit 23 jumps in from the outside, it can be surely excluded by the determination unit 25, so that the partial discharge discrimination accuracy can be increased. In FIG. 4, the system voltage cycle is divided into 32 equal parts, but a sufficient determination pattern can be obtained if the system voltage period is divided into 32 equal parts.

  As described above, according to the first embodiment, it is possible to perform partial discharge determination and discharge source type determination without using phase information of the system voltage waveform applied to the gas-insulated switchgear. There is no need to obtain the correct phase information by incorporating the output of the transformer into the partial discharge diagnosis processing system, and the partial discharge diagnostic device can be configured in a simple form.

Embodiment 2. FIG.
FIG. 5 is a block diagram showing a configuration of a partial discharge diagnostic device for a gas insulated switchgear according to Embodiment 2 of the present invention. In FIG. 5, the same reference numerals are given to components that are the same as or equivalent to the components shown in FIG. 1 (Embodiment 1). Here, the description will be focused on the portion related to the second embodiment.

  As shown in FIG. 5, the partial discharge diagnosis device 2b according to the second embodiment is different from the partial discharge diagnosis device 2a shown in FIG. 1 (first embodiment) in that it generates a periodic signal instead of the periodic signal generation unit 26a. A portion 26b is provided.

  The periodic signal generator 26b is configured to self-generate a 50 Hz or 60 Hz periodic signal using a battery as an operating power source. In other words, the periodic signal generator 26a in the partial discharge diagnostic device 2a shown in FIG. 1 (Embodiment 1) needs to secure a low-voltage AC power source at the electric station where the gas-insulated switchgear 1 is installed. However, this is not necessary in the periodic signal generator 26b in the partial discharge diagnostic device 2b shown in FIG. 5 (Embodiment 2).

  Therefore, according to the second embodiment, a portable partial discharge diagnostic apparatus that can be operated by a battery is obtained.

  As described above, the partial discharge diagnostic device for a gas-insulated switchgear according to the present invention is useful for simplifying the configuration of the partial discharge diagnostic device, and is particularly suitable for being portable.

It is a block diagram which shows the structure of the partial discharge diagnostic apparatus of the gas insulated switchgear by Embodiment 1 of this invention. It is a figure explaining operation | movement of the detection part shown in FIG. It is a figure explaining operation | movement of the count process part shown in FIG. It is a figure explaining operation | movement of the determination part shown in FIG. 1, and the content of the discharge / power determination table with which a determination part is provided. It is a block diagram which shows the structure of the partial discharge diagnostic apparatus of the gas insulated switchgear by Embodiment 2 of this invention.

Explanation of symbols

1 Gas insulated switchgear 2a, 2b Partial discharge diagnostic device 11, 12 Metal container (outer conductor)
13 High voltage conductor (center conductor)
DESCRIPTION OF SYMBOLS 14 Insulating spacer 15 Bushing 21 Discharge sensor 22 Amplification part 23 Detection part 24 Count processing part 25 Judgment part 25a Discharge power source determination table 26a, 26b Periodic signal generation part

Claims (8)

Among the electromagnetic wave signals detected by the discharge sensor arranged to detect the partial discharge signal which is an electromagnetic wave signal due to the partial discharge generated in the gas insulated switchgear, an electromagnetic wave signal exceeding a threshold is detected as the partial discharge signal, each partial discharge signal detection, a first step of periodic records in association with the phase of the cycle equal to a predetermined periodic signal of the system voltage to be applied to the gas insulated switchgear,
A second step of integrating the quantity of each partial discharge signal over a plurality of periods of the periodic signal recorded in the first step for each corresponding time section obtained by dividing each period in the plurality of periods by time, etc. When,
A time series change pattern of the partial discharge signal is created by plotting the time segment in which the number of the partial discharge signals integrated in the second step is maximum for each of the plurality of periods , and the created time series change pattern A third step of determining the type of discharge source of the partial discharge generated in the gas insulated switchgear by
A partial discharge diagnosis method for a gas-insulated switchgear comprising:   In the third step, the discharge power source determination table in which the correspondence relationship between the time series change pattern of the partial discharge signal and the discharge source is registered is searched by the created time series change pattern to determine the type of discharge source and registered. 2. The partial discharge diagnosis method for a gas insulated switchgear according to claim 1, wherein if it is not, it is determined that the created time-series change pattern is not due to partial discharge. The periodic signal, the gas insulated switchgear according to claim 1, characterized in that the period obtained by the substation where the gas insulated switchgear is installed is acquired periodically equal low AC power or al of the system voltage Partial discharge diagnosis method for apparatus.   The partial discharge diagnosis method for a gas-insulated switchgear according to claim 1, wherein the periodic signal is obtained from a device that generates a periodic signal indicating a system frequency of an electric power system using a battery as an operating power source. A discharge sensor disposed inside or outside the gas-insulated switchgear in order to detect a partial discharge signal that is an electromagnetic wave signal due to a partial discharge generated in the gas-insulated switchgear;
A periodic signal generator periodic generates a periodic equal predetermined periodic signal of the system voltage to be applied to the gas insulated switchgear,
Among the detected electromagnetic signals in the previous SL-discharge sensor detects the electromagnetic signal exceeding the threshold value as the partial discharge signal, partial discharge signals detected recording each partial discharge signal detection in association with the phase of the periodic signal And
A partial discharge signal that integrates the quantity of each partial discharge signal over a plurality of periods of the periodic signal recorded by the partial discharge signal detection unit for each corresponding time section obtained by dividing each period in the plurality of periods by time. An accumulator;
A time series change pattern of the partial discharge signal is created by plotting the time segment in which the quantity of the partial discharge signal accumulated by the partial discharge signal integration unit is maximum for each of the plurality of periods , and the created time series change A partial discharge determination unit that determines a type of discharge source of partial discharge generated in the gas-insulated switchgear according to a pattern;
A partial discharge diagnostic device for a gas insulated switchgear characterized by comprising:   The partial discharge determination unit includes a discharge power source determination table in which a correspondence relationship between a time series change pattern of a partial discharge signal and a discharge source is registered, and the discharge source determination table is searched by the created time series change pattern and released. 6. The partial discharge diagnostic device for a gas insulated switchgear according to claim 5, wherein the type of power source is determined, and if the registered time series change pattern is not registered, it is determined that the created time series change pattern is not due to partial discharge. .   6. The gas insulated switchgear according to claim 5, wherein the periodic signal generator generates the periodic signal using a low-voltage AC power source obtained at an electric station where the gas insulated switchgear is installed. Partial discharge diagnostic device.   6. The partial discharge diagnosis apparatus for a gas-insulated switchgear according to claim 5, wherein the periodic signal signal generator generates the periodic signal indicating a system frequency of an electric power system using a battery as an operation power source.

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