JP3861736B2 - Partial discharge diagnostic equipment for gas insulation equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a partial discharge diagnostic apparatus for gas insulation equipment that monitors and diagnoses partial discharge generated in gas insulation equipment constituting a substation facility.
[0002]
[Prior art]
In recent years, substation facilities are installed in remote areas, and unmanned facilities are increasing.
Gas insulation equipment at the center of substation facilities may cause partial discharges due to foreign matters or scratches, leading to serious accidents, so it is required to be monitored at maintenance monitoring centers such as power control stations, sales offices, and manufacturers. Is done.
[0003]
For example, a technique for detecting partial discharge of a gas insulating device (hereinafter sometimes referred to as GIS) is, for example, the publication “Electrical Collaborative Research” Vol. 46, No. 4 (Electric Collaborative Research Group), 1990, 147- As described in Chapter 6 “Application of sensor technology in substation department” on page 167, there are an external radiated electromagnetic field sensor system, a ground line current sensor system, an electrostatic partial pressure sensor system, and the like.
[0004]
The external radiated electromagnetic field sensor method detects a partial discharge generated inside the GIS by a loop antenna provided outside the tank, and the detection level is about 1500 pC (picocoulomb). pC is a charge amount. The ground line current sensor system detects a partial discharge generated inside by detecting a pulse current flowing in the tank ground line, and has a detection level of about 100 pC.
[0005]
The electrostatic partial pressure sensor method detects an electromagnetic wave accompanying a partial discharge pulse by an intermediate electrode (antenna) provided in a GIS tank, and has a detection level of about 100 pC. It has been reported that the electrostatic partial pressure sensor system can detect several pC by removing noise by frequency analysis. In recent years, the electrostatic partial pressure sensor system is more sensitive than other systems. Many are used.
[0006]
By the way, the frequency component of the corona in the air is generally 500 MHz or less. However, since the partial discharge generated inside the GIS becomes a steep pulse, it propagates in the pipeline as an electromagnetic wave having a high frequency component of 500 MHz or more. To do. The usefulness of the method of monitoring the frequency component of the sensor signal by utilizing the frequency characteristics of the partial discharge has been reported and applied to a partial discharge diagnostic apparatus.
[0007]
For example, in Japanese Patent Laid-Open No. 10-170596, a voltage phase pattern at a frequency with a high intensity of a signal detected using a spectrum analyzer and a voltage phase pattern for each defect type registered in advance are recognized by neuro processing, A method for diagnosing the type and degree of abnormality and the degree of deterioration of equipment is disclosed.
[0008]
[Problems to be solved by the invention]
However, since wireless devices such as mobile phones also use a specific frequency of 500 MHz or more, detection of these radio frequency signals during insulation diagnosis is extremely frequent, causing erroneous diagnosis. In order to prevent misdiagnosis, a method of removing a specific frequency band that causes noise in an arithmetic device that performs signal processing or a method of cutting a specific frequency band by using a filter circuit in hardware is applied.
[0009]
However, such a method has a problem that the detection accuracy is lowered because the partial discharge signal is also excluded at the same time in the specific frequency band. In particular, the use frequency band is widened due to a significant increase in wireless devices such as mobile phones, and the frequency band that must be excluded is increasing, so that partial discharge cannot be detected with high accuracy.
[0010]
An object of the present invention is to provide a partial discharge diagnostic device for a gas-insulated device that can accurately detect a partial discharge without excluding a partial discharge frequency signal in a use frequency band of a wireless device.
[0011]
[Means for Solving the Problems]
The feature of the present invention is that it is determined whether the frequency of the discharge frequency signal detected by the partial discharge sensor for detecting the partial discharge of the gas-insulated equipment is within the radio frequency band assigned to the radio equipment. The discharge frequency signal pattern and the radio frequency signal pattern in the frequency band are compared and collated, and a discharge frequency signal that does not match the radio frequency signal pattern outside the radio frequency band is input and collated with the partial discharge pattern to determine the discharge factor. It is in that.
[0012]
According to the present invention, partial discharge can be detected with high accuracy because the partial discharge frequency signal in the entire frequency band where partial discharge occurs is detected without excluding the partial discharge frequency signal in the use frequency band of the wireless device.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
First, before describing the embodiment of the present invention, partial discharge generated in GIS will be described.
[0014]
A gas-insulated device such as a gas-insulated switchgear or a gas circuit breaker generates a partial discharge when foreign matter is mixed during manufacturing or a defect in the insulator exists. If these are left unattended, they will be stressed by lightning surges and switching surges, causing ground faults and short circuit accidents. The partial discharge mainly propagates in the pipeline as an electromagnetic wave having a frequency component in the UHF band of 500 to 2000 MHz. The partial discharge has a unique voltage phase pattern (frequency signal pattern) depending on the type of defect, and the type of defect can be determined by recognizing this frequency signal pattern.
[0015]
FIG. 1 shows an embodiment of the present invention.
In FIG. 1, a partial discharge sensor 2 for detecting partial discharge is attached to a gas insulating device 1 of a target substation facility. The sensor 2 can be of a built-in electrode (antenna) type embedded in the gas insulating device 1 or a spacer antenna type of spacer unit surface installation type.
[0016]
The discharge frequency signal detected by the partial discharge sensor 2 is input to the partial discharge diagnostic device 3 . The discharge frequency signal input to the partial discharge diagnostic device 3 is amplified by the signal detection unit 4 and a frequency component is extracted. Further, the detected discharge frequency signal is processed into voltage phase information based on one cycle of the commercial power supply frequency. The signal detection unit 4 gives a discharge frequency signal (voltage phase information) to the frequency determination unit 5.
[0017]
The radio frequency band table 10 stores radio frequency bands assigned to radio devices such as mobile phones. The frequency determination unit 15 determines whether the frequency of the discharge frequency signal is within the radio frequency band stored in the radio frequency band table 10.
[0018]
Frequency determining unit 5 provides a discharge frequency signal discharge frequency signal is determined to be within a radio frequency band to the signal width check unit 6, also provide a discharge frequency signals outside the radio frequency band to the discharge factor determination unit 9. The signal width confirmation unit 6 is given the signal width of one packet of the radio frequency signal (radio signal) as a set width, and compares it with the signal width of the discharge frequency signal.
[0019]
The signal width confirmation unit 6 gives the discharge frequency signal to the signal phase matching unit 7 when the signal width of the discharge frequency signal is substantially the same as the set width, and discharges when the signal width of the discharge frequency signal is larger or smaller than the set width. A frequency signal is given to the discharge factor determination unit 9.
[0020]
The signal phase matching unit 7 shifts the discharge frequency signal so that the discharge frequency signal pattern can be easily compared with the radio signal pattern (radio frequency signal pattern) stored in the radio signal pattern table 11. In the shift process, a process of moving the phase pattern of the discharge frequency signal to the phase origin (0 °) of the radio frequency signal pattern is executed.
[0021]
The signal pattern recognition unit 8 collates the shift-processed discharge frequency signal waveform with the shift-processed radio signal pattern registered in advance in the radio signal pattern table 11. If the patterns of both signals match, the signal pattern recognition unit 8 determines that the signal is a wireless communication signal from a mobile phone or the like and excludes it.
[0022]
The discharge factor determination unit 9 receives the discharge frequency signal determined by the frequency determination unit 5, the signal width confirmation unit 6 and the signal pattern recognition unit 8, performs pattern recognition processing, and collates with the partial discharge pattern of the partial discharge pattern table 12. To determine various factors of partial discharge.
[0023]
FIG. 2 shows an example of the signal pattern. FIG. 2 is a graph in which the horizontal axis is divided into 48 phase angles (0 to 360 °) of one cycle of the commercial power supply voltage applied to the gas insulating apparatus 1, and the vertical axis represents the maximum signal intensity for each phase. is there. The maximum signal intensity in one cycle is represented by a normalized graph.
[0024]
Examples of partial discharge pulse patterns in the publication "Technical Report of the Institute of Electrical Engineers of Japan", No. 502, page 73, Table 4.5, show that there is a difference in the pattern and rise timing in one cycle depending on the size of foreign matter, the degree of adhesion, and the applied voltage. Is shown in
[0025]
The phase of one cycle of partial discharge is often characteristic depending on the defect type, and the defect type can be determined by the phase pattern. From this, it is possible to derive the defect type by registering the phase pattern for each defect type and comparing it with the phase data of the detection signal.
[0026]
An example of a partial discharge phase pattern is shown in FIGS. For example, in the case of the spacer crack in FIG. 2A, the pattern is equal to the positive and negative with respect to the voltage phase. Further, in the case of the high-voltage conductor protrusion of FIG. 2B or the tank bottom surface foreign substance of FIG. 2C, the pattern has a large width centering on the positive and negative peaks.
[0027]
FIG. 2D is an example of a mobile phone, but it has a single rectangular wave shape, a waveform that rises at a random timing phase angle between 0 ° and 360 °, and the appearance location is not constant. It becomes difficult. However, the width of the rectangular wave has a characteristic that does not always change.
[0028]
In the present invention, signal discrimination for a known radio frequency signal such as a cellular phone is performed by the following processing.
[0029]
The signal detection unit 4 amplifies the discharge frequency signal detected by the partial discharge sensor 2 and extracts a frequency component. The signal detector 4 processes the discharge frequency signal as voltage phase information for one cycle with the commercial power supply voltage as a reference. In this embodiment, the phase information is processed into 48-divided data for each voltage phase of 7.5 °. In the present embodiment, all voltage phases are represented by a pattern obtained by dividing the voltage phase by 48 for every 7.5 °, but the present invention is not limited to this.
[0030]
The frequency determination unit 5 performs a discharge frequency signal determination process. The frequency determination unit 5 performs processing for determining whether the signal is a radio frequency signal of a mobile phone or the like or a frequency signal of a partial discharge that is actually generated.
[0031]
For example, in the case of a mobile phone in Japan, 800 MHz or 1500 MHz is allocated as an occupied frequency band. In the case of 800 MHz, the correct operating frequency band is 810 MHz to 958 MHz and 1500 MHz, and 1429 MHz to 1501 MHz is defined and assigned by the Radio Law.
[0032]
The frequency determination unit 5 compares the frequency of the detected discharge frequency signal with the set radio frequency band preset in the radio frequency band table 10. When the frequency of the discharge frequency signal is within the set radio frequency band, it may be a radio frequency signal of a mobile phone or the like, and the discharge frequency signal is also included.
[0033]
FIG. 3 shows a conceptual diagram. Radio frequency bands 31a and 31b are frequency bands used in mobile phones. The detection signal 32 is a discharge detection signal, but the detection signal 33 is either a radio frequency signal or a discharge frequency signal of a mobile phone. The radio frequency band table 10 is a table of the frequency bands 31a and 31b.
[0034]
An example of a table configuration of the radio frequency band table 10 is shown in FIG. The start point of the frequency to be set is set to F1n, and the end point of the frequency is set to F2n. As shown in the figure, F11 (810 MHz) and F12 (958 MHz) are arranged in the first row. Similarly, when setting the frequency bands of a plurality of mobile phones and radio signals, the frequency bands of a plurality of places n are set as shown in the figure. The number of the symbol n is from the low frequency side in the order of 1, 2,.
[0035]
Frequency determining unit 5 provides a discharge frequency signal discharge frequency signal is determined to be within a radio frequency band to the signal width check unit 6, also provide a discharge frequency signals outside the radio frequency band to the discharge factor determination unit 9. The signal width confirmation unit 6 is given the signal width of one packet of the radio frequency signal (radio signal) as a set width, and compares it with the signal width of the discharge frequency signal.
[0036]
The signal width confirmation unit 6 gives the discharge frequency signal to the signal phase matching unit 7 when the signal width of the discharge frequency signal is substantially the same as the set width, and discharges when the signal width of the discharge frequency signal is larger or smaller than the set width. A frequency signal is given to the discharge factor determination unit 9.
[0037]
Since the voltage phase width of the signal of the mobile phone is always constant as described above, the signal width confirmation unit 6 compares the sum of 48 phase widths (signal widths) with the discharge frequency signal as a set width. If the discharge frequency signal matches the set width, there is a possibility of a radio frequency signal, but if it is larger or smaller than the set width, it is determined as a discharge frequency signal.
[0038]
As shown in FIG. 2, the radio frequency signal of the mobile phone does not change the signal width but appears in different phase angles. The signal phase matching unit 7 moves (shifts) the phase to 0 ° which is the phase origin in order to facilitate the discrimination of the radio frequency signal.
[0039]
The signal phase matching unit 7 shifts the discharge frequency signal so that the discharge frequency signal pattern can be easily compared with the radio signal pattern (radio frequency signal pattern) stored in the radio signal pattern table 11.
[0040]
An example of the flow of the shift process executed by the signal phase matching unit 7 is shown in FIG.
In process 51, whether the rising edge is one phase as shown in FIG. 6A (1 packet in the radio signal, hereinafter referred to as 1 packet), or a phase pattern of 3 packets or more as shown in FIG. 6B. Determine. If it is 1 packet or 3 packets or more, the process proceeds to processing 54, and the packet is shifted to '0 °' which is the phase origin as shown by the broken line in FIGS. 6 (a) and 6 (b).
[0041]
If it is determined in process 51 that the number of packets is not 1 packet or 3 packets or more, in process 52, when the start point of the first packet is other than “0 °” as shown in FIG. As shown by the broken line in c), the shift is made to “0 °”. In the process 53, if the end point of the second packet is “360 °” as shown in FIG. 6D, the start point of the second packet is shifted to “0 °” from the beginning. This is because in the case of FIG. 6D, it can be considered as one continuous pattern.
[0042]
The signal pattern recognition unit 8 collates the shifted discharge frequency signal waveform with the radio signal pattern subjected to shift processing registered in advance in the radio signal pattern table 11 and executes pattern recognition processing. If the patterns of both signals match, the signal pattern recognition unit 8 determines that the signal is a wireless communication signal from a mobile phone or the like and excludes it.
[0043]
FIG. 7 shows an example configuration of the wireless signal pattern table 11. Registered in this table 11 is radio signal pattern data obtained by performing shift processing with actually measured mobile phone and radio device signal data and a phase pattern in consideration of attenuation, that is, matching the phase origin. In FIG. 7, phase patterns of signals of two types of cellular phones with different patterns are registered.
[0044]
If the discharge frequency signal pattern matches the radio signal pattern, the signal pattern recognition unit 8 can determine that the radio frequency signal is a radio device. By performing collation processing using the shifted signal pattern as described above, it is possible to perform collation processing by grasping fine features such as phase width and signal strength.
[0045]
The discharge factor determination unit 9 receives the discharge frequency signal determined by the frequency determination unit 5, the signal width confirmation unit 6 and the signal pattern recognition unit 8, performs pattern recognition processing, and collates with the partial discharge pattern of the partial discharge pattern table 12. To determine various factors of partial discharge.
[0046]
FIG. 8 shows an example configuration of the partial discharge pattern table 12. Similar to the radio signal pattern shown in FIG. 7, the partial discharge phase pattern actually measured is registered in the table 12 as teacher data for each defect type. FIG. 8 shows an example in which a partial discharge pattern of spacer cracks is registered first and a partial discharge pattern of foreign matters on the tank bottom is registered second.
[0047]
The discharge factor determination unit 9 can derive the defect type when the discharge frequency signal matches the partial discharge pattern registered in the table 12.
[0048]
There are various processing methods for comparing patterns. In the present invention, a neuro technology is applied. The neural network technique is for realizing processing close to human judgment by a computer, and is applied to pattern recognition such as character recognition. The advantage of neuro is that it can handle ambiguous diagnoses and make judgments closer to humans if it is limited to pattern recognition. In the field of pattern recognition, it is applied to various technologies.
[0049]
In this way, the partial discharge of the gas insulated device is detected, but it is detected by the partial discharge frequency signal in the entire frequency band where the partial discharge occurs without excluding the partial discharge frequency signal in the frequency band used by the wireless device. Therefore, the partial discharge can be detected with high accuracy.
[0050]
Further, in the above-described embodiment, the discharge frequency signal and the radio frequency signal are distinguished by the signal width (phase width), so that the signal pattern verification can be simplified. In addition, since the table for registering phase patterns such as partial discharge and mobile phone has a simple configuration and the memory capacity of the table body is small, it can be mounted on a general-purpose computing device.
[0051]
【The invention's effect】
In the present invention, the partial discharge can be detected with high accuracy because the partial discharge frequency signal in the entire frequency band where the partial discharge occurs is detected without excluding the partial discharge frequency signal in the use frequency band of the wireless device.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an embodiment of the present invention.
FIG. 2 is a pattern characteristic diagram for explaining the present invention.
FIG. 3 is a signal intensity-frequency characteristic diagram for explaining the present invention.
FIG. 4 is an example configuration diagram of a radio frequency band table for explaining the present invention.
FIG. 5 is a flowchart of shift processing of the present invention.
FIG. 6 is an explanatory diagram of shift processing according to the present invention.
FIG. 7 is an example configuration diagram of a radio signal pattern table for explaining the present invention.
FIG. 8 is an exemplary configuration diagram of a partial discharge pattern table for explaining the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Insulation apparatus (GIS), 2 ... Partial discharge detection sensor, 3 ... Partial discharge diagnostic apparatus, 4 ... Signal detection part, 5 ... Frequency determination part, 6 ... Signal width confirmation part, 7 ... Signal phase adjustment part, 8 ... Signal pattern recognition unit, 9 ... partial discharge determination unit, 10 ... radio frequency band table, 11 ... radio signal pattern table, 12 ... partial discharge pattern table.

Claims (1)

A partial discharge sensor for detecting a discharge frequency signal due to partial discharge of the gas insulation device, and the partial discharge sensor based on one cycle (0 ° to 360 °) of a commercial power supply voltage applied to the gas insulation device. A signal detection means for extracting a frequency component of the discharge frequency signal; and a discharge frequency signal when the frequency of the discharge frequency signal detected by the partial discharge sensor is outside a radio frequency band assigned to a mobile phone ; Compared with a set width corresponding to the signal width of one packet of the radio frequency signal in the mobile phone when the discharge frequency signal is in a radio frequency band and whether the discharge frequency signal is within the radio frequency band, a signal width checking means for discharging frequency signals and determines to output when a small radio frequency signal patterns of the phase 0 ° of the commercial power supply voltage as a phase origin Storage means for storing the emissions, and the signal phase matching means for moving the start point phase to the phase 0 ° of the commercial power source voltage when the end point phase of the radio frequency signal of the phase 360 ° of the commercial power source voltage, The radio frequency signal phase-matched by the signal phase matching means is compared with the radio frequency signal pattern, and if not matched, a signal pattern recognition means for determining and outputting a discharge frequency signal , the frequency judgment means, and a signal width A partial discharge of a gas-insulated device, comprising: a discharge factor determination unit that inputs the discharge frequency signal determined by the confirmation unit and the signal pattern recognition unit, and compares the partial discharge pattern to determine a discharge factor Diagnostic device.

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