JP2009210541A - Partial discharge detection method and partial discharge detector of epoxy-insulated electrical equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve the detection of an electrical tree produced by the partial discharge of an epoxy insulating part of epoxy-insulated electrical equipment at low cost, and to facilitate utilization of a steady measurement and monitoring system. <P>SOLUTION: An antenna 30, arranged near the epoxy-insulated electric equipment 20a housed in the metallic box body 11 of a cubicle 10, is connected to a sensor body 40 installed outside the box body 11 by a coaxial cable 50. The presence or absence of electrical tree generation, and the status of electrical tree development are detected by detecting electromagnetic waves radiated by the partial discharging of the epoxy insulating part 21 of the electrical equipment 20a with the antenna 30, and by verifying the magnitude of antenna received voltage, in specific frequency components of 150-400 MHz within the detected electromagnetic waves with the sensor body 40. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a partial discharge detection method and a detection apparatus for an epoxy insulation type electric device installed in a high voltage power distribution facility of a substation.

  A cubicle, which is a high-voltage power distribution facility installed in a substation or the like, has a metal box that houses various high-voltage electrical devices such as switches and disconnectors. The metal box is a grounded metal box, and the inside is partitioned into a plurality of device storage spaces by metal partition plates, and electrical devices are stored in each storage space and wired with conductors. Insulation of electrical equipment including a conductor is generally performed by gas insulation with SF6 gas or solid insulation with epoxy resin or the like.

  In high-voltage power distribution facilities such as cubicles, if there are abnormalities such as voids, foreign objects, and construction defects in the solid insulation of electrical equipment, the electric field concentrates on the abnormal parts of the insulation during high-voltage power distribution, causing partial discharge. In some cases, partial discharge progresses, causing dielectric breakdown in the insulating portion. For example, if there is a defective part such as a foreign substance or a void in an insulating part of solid insulation such as epoxy insulation, an electrical tree due to partial discharge is generated in the defective part, and the electrical tree may progress and lead to dielectric breakdown. Therefore, in a power distribution facility equipped with solid-insulated electrical equipment, it is being monitored whether or not partial discharge has occurred in the solid-insulated portion of the solid-insulated electrical equipment and the progress.

  In general, partial discharges that occur in the insulation of electrical equipment in high-voltage power distribution facilities greatly fluctuate, including whether they occur, due to voltage fluctuations associated with load fluctuations and overvoltages caused by lightning surges entering from the outside. . As a technique for detecting such a partial discharge, there is a technique for detecting a current, electromagnetic wave, sound wave (AE), light, and X-rays peculiar to the partial discharge generated when the partial discharge occurs. In the case of epoxy-insulated electrical equipment, the speed from the occurrence of an electrical tree due to an initial partial discharge to dielectric breakdown is much faster than that of oil insulation, so it is important to adopt a constant measurement and monitoring system to avoid dielectric breakdown It is said that. The following technologies (1), (2), and (3) have been put into practical use as partial discharge detection techniques for epoxy insulating portions for adopting this system.

  (1) A partial discharge signal detected through a coupling capacitor sensor or the like is measured using a partial discharge detector (see, for example, Patent Document 1).

  (2) A current change is measured by inserting a Rogowski coil sensor or the like into the ground wire of the electric device (see, for example, Patent Document 2).

(3) The sound wave from the part discharge generation | occurrence | production location of an electric equipment is detected (for example, refer patent document 3).
JP 2000-212229 A JP 11-326429 A JP 2007-292489 A

  The partial discharge detection devices of (1) and (2) above require expensive sensors to detect high-frequency components superimposed on the power supply line and the like, so that the entire device becomes expensive. Therefore, it is financially difficult to adopt this partial discharge detection device in a cubicle installed at a substation, a partial discharge constant measurement monitoring system for power distribution facilities such as factories and large buildings.

  Further, since the partial discharge detection device according to the above (3) that detects a sound wave (AE wave) at the time of occurrence of partial discharge does not have an effective means as a noise countermeasure for the AE signal, a signal other than the partial discharge signal can also be a partial discharge signal. Detect as. Therefore, the sonic partial discharge detection device is not accurate and reliable, and in particular, it should be applied to epoxy insulation partial discharge detection and the constant measurement monitoring from the generation of electrical trees due to partial discharge to the breakdown. The current situation is difficult.

  The present invention has been made in view of such circumstances, and the purpose of the present invention is to realize the partial discharge detection of the epoxy insulation part of the epoxy insulation type electric equipment at a low cost, and to put the practical measurement monitoring system into practical use. It is an object of the present invention to provide a partial discharge detection method and a detection device that facilitate the above.

  The method of the present invention that achieves the above object is a partial discharge detection method for detecting the occurrence of an electrical tree in an epoxy insulation part of an electrical device having an epoxy insulation part, wherein an electromagnetic wave generated due to the partial discharge of the epoxy insulation part is an antenna. And detecting whether or not an electric tree is generated based on the magnitude of the antenna reception voltage in a specific frequency component of 150 MHz to 400 MHz of the detected electromagnetic wave.

  Here, the epoxy-insulated electrical device that is a partial discharge detection target device is one or a plurality of types of electrical devices used in power receiving and distribution equipment such as a power plant or a substation cubicle. This electric device has an epoxy resin insulating portion partially or entirely. Electromagnetic waves generated by partial discharge at the epoxy insulation part of an epoxy insulation type electric device are detected by an antenna. The frequency component of the electromagnetic wave detected by the antenna is a low frequency component (approximately 100 MHz or less) due to creeping discharge or air discharge of the electrical equipment, and a high frequency component due to partial discharge of the epoxy insulating portion. This inventor investigated the frequency component of the electromagnetic wave by the partial discharge of an epoxy insulation part by various experiment. As a result, a characteristic partial rise in the antenna reception voltage and voltage fluctuations over time appear in the frequency component band of 150 MHz to 400 MHz of the electromagnetic waves detected by the antenna. Electric tree generation due to partial discharge occurs in this frequency band. Confirmed that it can be identified. Therefore, 150 MHz to 400 MHz of the electromagnetic waves detected by the antenna is defined as a specific frequency component, and the presence / absence of electric tree generation is detected by verifying the magnitude of the antenna reception voltage at the specific frequency component. It is practically desirable to verify the magnitude of the antenna reception voltage by comparing it with a preset threshold voltage for electric tree detection. Further, the frequency component of less than 150 MHz of the electromagnetic wave detected by the antenna is not used for verification of the presence / absence of electric tree generation, but can be used for detection of the presence / absence of initial discharge such as air discharge.

  The electromagnetic wave accompanying the generation of an electric tree due to partial discharge of the epoxy insulating part also has a frequency component exceeding 400 MHz. However, the higher the frequency, the lower the received voltage at the antenna, and the higher the frequency of the small antenna that can be installed in the cubicle. Since accurate detection becomes difficult, 400 MHz is appropriate for practical use as the upper limit of the specific frequency component. Further, according to an experiment, the electromagnetic wave intensity generated when an electrical tree is generated in the epoxy insulating part is particularly large in the frequency band of 150 MHz to 200 MHz. The presence or absence of the generation of the electrical tree depends on the antenna reception voltage at the frequency component of 150 MHz to 200 MHz of the electromagnetic wave. It is desirable to detect the size of. Furthermore, the threshold voltage for electric tree detection that compares the antenna reception voltage is the sensitivity determined by the quality and length of the antenna that directly detects electromagnetic waves generated by partial discharge, the distance between the epoxy insulation part and the antenna, the installation location of the antenna, etc. Therefore, it is desirable to determine by actual measurement.

  Further, in the present invention, the progress of the electric tree can be determined based on the number of occurrences of the electric tree detected based on the antenna reception voltage and the time transition of the magnitude of the antenna reception voltage for each frequency. .

  Here, the progress of the electric tree is a situation in which the generated electric tree is continuously or intermittently developed without disappearing. According to an experiment, when a high voltage is applied to a void or an abnormal part of a foreign substance in an epoxy insulating part to generate a partial discharge, the epoxy insulating gasifies and a whisker-like electric tree is generated. The initial electrical tree is very small and does not cause immediate dielectric breakdown, but it does not disappear but progresses continuously or intermittently, resulting in the distance from the ground electrode becoming gradually shorter. Thus, the electric field gradually increases and the possibility of causing dielectric breakdown increases. By detecting the progress of the electrical tree, breakdown can be avoided with certainty.

  The device of the present invention that achieves the above object is a partial discharge detection device that detects the occurrence and progress of an electrical tree in an epoxy insulation part of an electrical device having an epoxy insulation part, and is generated along with the partial discharge of the epoxy insulation part. The number of occurrences of electrical tree detection based on the magnitude of the antenna reception voltage at a specific frequency component of 150 MHz to 400 MHz of the electromagnetic wave detected by the antenna, and the antenna reception voltage for each occurrence And a sensor main body for determining and storing a time transition of the size.

  Further, the device of the present invention can have a structure in which the antenna is housed in a cubicle metal box, the sensor body is fixed to the box, and the antenna and the sensor body are cable-connected.

  A commercially available VHF antenna can be used as the antenna here. A cubicle is a power distribution facility such as a cubicle-type gas-insulated switchgear that is installed in a substation or the like, and houses one or a plurality of epoxy-insulated electric devices in a metal box that is a ground metal box. One or more antennas are installed using magnets or the like at fixed locations around the epoxy insulation part of the epoxy insulation type electrical equipment in the box. The sensor body connected to the antenna by the cable generates a detection circuit, a specific frequency setting circuit, an electromagnetic wave containing a specific frequency component of 150 MHz to 400 MHz among electromagnetic waves detected by the antenna by comparing the antenna reception voltage and the threshold voltage. Various electric circuits such as a counter and a memory circuit for counting the number of times and determining and storing the magnitude and time transition of the antenna reception voltage for each number of occurrences are incorporated in a common case. The sensor body case is directly attached to the outer wall of the cubicle box, and the antenna inside and outside the box is connected to the sensor body with a coaxial cable penetrating the outer wall. Such a partial discharge detection device comprising an antenna and a sensor body can be manufactured at low cost because it does not use expensive sensors, and can be easily attached to existing power distribution facilities such as cubicles.

  In the device of the present invention, the sensor main body detects the number of occurrences of the electrical tree detected based on the magnitude of the antenna reception voltage in the specific frequency component of 150 MHz to 400 MHz among the electromagnetic waves detected by the antenna, A structure in which the information recording medium for determining and storing the time transition of the magnitude of the antenna reception voltage is detachable can be provided.

  As the information recording medium here, a commercially available card type memory or disk type memory can be applied. Various information such as the number of occurrences of electrical trees, the time of occurrence, and time transitions are recorded on the information recording medium of the sensor body installed in the cubicle. Then, an administrator (such as a patrolman) of a power receiving / distributing facility such as a cubicle takes out an information recording medium from the sensor main body, reads the recorded information with a personal computer or the like, and performs trend management on the presence / absence and occurrence of an electrical tree. Such trend management can be performed at the site where the cubicle is located, and it is possible to cope with insulation breakdown avoidance in a short time.

  Further, in the device of the present invention, the sensor body can be shared by the plurality of cubicles by connecting the antennas in the boxes of the plurality of cubicles and the sensor body with an antenna switching device of a multistage switching system.

  Commercially available products such as a TV radio wave switch can be used as the antenna switch here. Since many cubicles are juxtaposed in a large-scale substation, for example, by connecting two adjacent cubicle antennas and one sensor body with a single-stage antenna switch, One sensor body can be shared in a cubicle. It is also possible to connect the antennas of three adjacent cubicles and one sensor body with a two-stage antenna switch. Thus, by sharing one sensor body for a plurality of cubicles, the cost of the partial discharge detection device can be reduced, and the partial discharge constant measurement monitoring system for large-scale power distribution facilities can be easily adopted. .

  According to the present invention, the detection and management of partial discharge of an epoxy-insulated electric device is performed at low cost by using an antenna that detects electromagnetic waves generated due to partial discharge and a sensor body that performs arithmetic processing on the reception voltage of the antenna. It is possible to achieve the excellent effect of facilitating the practical application of the partial discharge constant measurement and monitoring system for power distribution facilities such as cubicles.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  An example of a cubicle installed at a substation is shown in FIG. The cubicle 10 includes a metal box 11 which is a ground metal box. The box 11 is vertically long, and the inside thereof is partitioned into a plurality of electrical device storage chambers 13 by a metal partition plate 12. The storage room 13 is a bus bar room, a power receiving room, a control room, a power distribution room, or the like. Various electrical devices 20 such as a disconnector and a circuit breaker are provided in each of the plurality of storage chambers 13. A ventilation port 14 is formed in the upper part of the box 11, and the ventilation port 14 and each storage chamber 13 are communicated with each other by a partition plate such as punching metal so that each storage chamber is ventilated. For example, one of the electric devices 20 in FIG. 1 is an epoxy insulated electric device. The epoxy insulation part 21 of the epoxy insulation part type electric device 20a is a part in which a conductor is insulated and fixed with an epoxy resin.

  The partial discharge detection device of the present invention applied to the cubicle 10 of FIG. 1 includes one or a plurality of antennas 30 detachably attached to a fixed position inside the box 11 with a magnet or the like, and a magnet or the like on the outer wall of the box 11. One sensor body 40 is detachably attached. The antenna 30 and the sensor body 40 are connected by a coaxial cable 50. The antenna 30 is a VHF antenna and is installed at a fixed position near the epoxy insulating portion 21. The sensor body 40 is installed on the front side of the box 11. The mounting position of the antenna 30 and the sensor body 40 has an optimum position depending on the model of the cubicle 10, and is determined by several measurements.

  The antenna 30 detects an electromagnetic wave generated by partial discharge of the epoxy insulating part 21 in a wide frequency band of about 1000 MHz, for example. When it is difficult to detect such electromagnetic waves with a single antenna, a plurality of antennas 30 ′ are provided in the box 11 as indicated by a chain line in FIG. 1. The sensor body 40 detects and records the occurrence of an electrical tree in the epoxy insulating part 21 based on the magnitude of the antenna reception voltage in the specific frequency component of 150 MHz to 400 MHz among the electromagnetic waves detected by the antenna 30.

  The function and configuration example of the sensor body 40 will be described with reference to FIG. The sensor main body 40 shown in the flowchart of FIG. 2 includes a rectangular case 41. Various electromagnetic wave arithmetic processing circuit sections are accommodated in the case 41 in a compact manner. A detector 42 connected to the antenna 30 by cable detects an electromagnetic wave from the epoxy insulation type electric device 20a. The presence or absence of a specific frequency component of 150 MHz to 400 MHz in the detected electromagnetic wave is determined by the specific frequency component setting unit 43. If there is no specific frequency component of 150 MHz to 400 MHz, the timer unit 48 is activated, and the second time after a certain period of pause. Is detected. If there is a specific frequency component of 150 MHz to 400 MHz among the electromagnetic waves detected by the antenna 30, the magnitude of the antenna reception voltage of the specific frequency component of 150 MHz to 400 MHz is determined by the discharge level determination unit 44. The magnitude of the antenna reception voltage of a specific frequency component of 150 MHz to 400 MHz is compared with a preset threshold voltage E for detecting an electrical tree. The counter unit 45 counts the number of times that the antenna reception voltage level is equal to or higher than the threshold voltage E, and the counted number is recorded in the memory unit 46. The counted time is recorded based on the calendar unit 47. .

  An example of the operation of detecting the electrical tree and determining the progress status by the sensor body 40 will be described based on Experimental Example 1 shown in FIGS. 3 to 8 and experimental data shown in Example 2 of FIGS.

[Experiment 1]
3 to 8 are experimental data in which voids are experimentally formed in an epoxy insulating portion of 30 wt% glass and an electric tree is generated by partial discharge. FIG. 3C is a photograph in which a 0.6 mm void is formed up to the tip of the extracted electrode trace 2 by inserting an electrode needle into the epoxy insulating portion 1 of the sample. FIG. 3A is a voltage level graph showing the relationship between the antenna reception voltage after 0 minutes and the frequency of electromagnetic waves when a voltage of 16 kV is applied for partial discharge. It has become. FIG. 3B is a plot of voltage level peaks picked up in each frequency band. It can be seen from FIG. 3 that the antenna reception voltage increases further from 0 MHz to 100 MHz immediately after the start of partial discharge, and the voltage level is small and hardly fluctuates above 100 MHz. The voltage level of the antenna reception voltage of 0 MHz to 100 MHz here is due to the air discharge in the void, and is inappropriate for use in detecting the occurrence of an electrical tree.

  The experimental data in FIG. 4 is obtained 10 minutes after the occurrence of partial discharge. As shown in FIG. 4C, the electric tree 3 is generated in the epoxy insulating portion 22 with a size of 0.3 mm from the electrode trace 2. At this time, as shown in FIGS. 4A and 4B, it can be seen that the voltage level of the antenna reception voltage increases and fluctuates at a frequency component of 100 MHz to 200 MHz.

  The experimental data in FIG. 5 is obtained 20 minutes after the occurrence of the partial discharge. It can be seen from the experimental data of FIG. 5 that the electric tree 3 is progressing in a complicated manner. The experimental data in FIGS. 6 and 7 are those after 30 minutes and 40 minutes after the occurrence of the partial discharge. None of these experimental data is significantly different from the experimental data in FIG. 3 shows almost no progress.

  The experimental data shown in FIG. 8 is obtained 50 minutes after the occurrence of partial discharge. In this case, as shown in FIG. 8C, it can be seen that the electric tree 3 has progressed to 0.4 mm and is complicated. In addition, as shown in FIG. 8A, it can be seen that the antenna reception voltage rises greatly around 200 MHz and around 400 MHz. More specifically, as shown in FIG. 8B, it can be seen that the antenna reception voltage rises also in the vicinity of 600 MHz and 800 MHz.

  When the experimental data shown in FIGS. 3 to 8 are integrated, it can be seen that there is a high probability that the magnitude of the antenna reception voltage rises around 200 MHz due to the generation of an electrical tree due to the partial discharge of epoxy insulation. The state of occurrence of electrical trees based on such experimental data varies depending on the experimental conditions such as the epoxy insulator sample and the applied voltage, but the voltage level of the antenna reception voltage is intensively high when the frequency component is approximately 150 MHz to 400 MHz. Thus, by determining whether or not the voltage level exceeds the threshold voltage, it is possible to detect whether or not an electric tree is generated with high accuracy.

[Experimental example 2]
9 to 12 are experimental data in which voids are experimentally formed in a thermosetting epoxy insulating part made of 70 wt% silica and an electric tree is generated by partial discharge. A voltage level graph showing the relationship of the frequency of electromagnetic waves, (C) is a photograph. FIG. 9C is a photograph in which a 0.4 mm void is formed up to the tip of the extracted electrode trace by inserting an electrode needle into the epoxy insulating portion 1 of the sample. FIG. 9A is a voltage level graph after 0 minute when a voltage of 16 kV is applied in order to cause partial discharge, and several tens of times of measurement values are integrated and averaged. As in Experimental Example 1, immediately after the start of partial discharge from FIG. 9, the antenna reception voltage increases further from 0 MHz to 100 MHz, and when it exceeds 100 MHz, the voltage level is small and hardly fluctuates.

  The experimental data in FIG. 10 is obtained 30 minutes after the occurrence of partial discharge. As indicated by the circles in FIG. 10A, it can be seen that the voltage level of the antenna reception voltage partially increases near 200 MHz to 300 MHz, and an electrical tree is generated and progresses.

  The experimental data in FIG. 11 is obtained 40 minutes after the occurrence of partial discharge. As shown by a circle in FIG. 11A, it can be seen that the voltage level of the antenna reception voltage partially increases in the frequency band of 150 MHz to 400 MHz, and an electrical tree is generated and progresses. In this case, the electric tree is slightly extended from the void, and the intensity of the electromagnetic wave is considerably weak, so that it is difficult to visually recognize the photograph in FIG.

  The experimental data in FIG. 12 are those after 70 minutes from the occurrence of partial discharge. In this case, the progress of the electrical tree is stopped, and as shown by a circle in FIG. 12A, the antenna reception voltage hardly changes in the frequency band exceeding 200 MHz.

  Even when the experimental data of FIGS. 9 to 12 are integrated, it can be seen that there is a high probability that the magnitude of the antenna reception voltage rises around 200 MHz due to the generation of an electrical tree due to the partial discharge of epoxy insulation. Then, similarly to Experimental Example 1, the voltage level of the antenna reception voltage is intensively increased when the frequency component is approximately 150 MHz to 400 MHz, and it is determined whether or not this voltage level exceeds the threshold voltage. It can be seen that the presence or absence of occurrence can be detected with high accuracy.

  In the discharge level determination unit 44 of the sensor main body 40 of FIG. 2, whether an electric tree has occurred by determining whether or not the voltage level of the antenna reception voltage exceeds the threshold voltage E when the frequency component is 150 MHz to 400 MHz. Whether or not can be detected. This determination is performed every time a specific time has passed as in Experimental Example 1 in FIGS. 3 to 8 and Experimental Example 2 in FIGS. 9 to 12, and the number of times that the voltage level of the antenna reception voltage exceeds the threshold voltage E is determined. Counting, measuring and recording the time, and investigating this record can detect the progress of the electrical tree generated with high accuracy.

  The memory unit 46 of the sensor main body 40 in FIG. 2 applies an information recording medium that can be attached to and detached from the sensor main body 40 and other personal computers. Hereinafter, when the memory unit 46 is referred to as an information recording medium 46, the information recording medium 46 is set in the sensor body 40, and the sensor body 40 is attached to the cubicle 10 in FIG. Always measure and monitor.

  The equipment manager of the cubicle 10 takes out only the information recording medium 46 from the sensor body 40 periodically or arbitrarily. An information recording medium 46 indicated by a chain line in FIG. 2 is taken out from the sensor main body 40. By connecting the information recording medium 46 to the partial discharge management personal computer 60 and reading the recorded information, the presence or absence and progress of the electrical tree due to the partial discharge in the cubicle 10 can be detected with high accuracy.

  Next, the embodiment shown in FIG. 13 will be described. FIG. 13 shows an outline of a partial main hall detector applied to a plurality of cubicles 10 juxtaposed at a substation. The plurality of cubicles 10 is a total of 8 units of S box, A box, and M box, and 5 K boxes, each of which accommodates the antenna 30. Boxes 11 of eight cubicles 10 are juxtaposed in succession. The antenna connection cable 50 is led out from the front face of two adjacent boxes 11 and connected to one sensor body 40 via one antenna switch 70. The antenna switcher 70 is of a one-stage type, and alternately switches the connection between the antenna 30 and the sensor body 40 in the two adjacent boxes 11. By attaching one antenna switching unit 70 and one sensor body 40 to two of each of the eight cubicles 10, the antenna switching unit 70 and the sensor body 40 used for the eight cubicles 10 are 4 respectively. It becomes a stand. Commercially available small products can be applied to the four antenna switchers 70, and the installation space can be reduced by arranging these four antennas side by side. In addition, since the number of sensor bodies 40 used for the eight cubicles 10 is reduced to four, the adoption of a partial discharge constant measurement and monitoring system for a large-scale cubicle can be advantageous in terms of cost.

  It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

It is a side view of a cubicle showing an embodiment. It is a flowchart for demonstrating the function and structure of a sensor main body used for the cubicle of FIG. It is the (A) antenna reception voltage-frequency diagram at the time of partial discharge generation | occurrence | production 0 minutes which shows the example 1 of partial discharge generation | occurrence | production, (B) Antenna reception voltage-frequency diagram, (C) The photograph of the partial discharge generation | occurrence | production location. (A) Antenna reception voltage-frequency diagram, (B) Antenna reception voltage-frequency diagram, and (C) Partial discharge occurrence location 10 minutes after the occurrence of partial discharge in Experimental Example 1. (A) Antenna reception voltage-frequency diagram 20 minutes after partial discharge occurrence in Experimental Example 1, (B) Antenna reception voltage-frequency diagram, (C) A photograph of a partial discharge occurrence location. It is (A) antenna reception voltage-frequency diagram 30 minutes after partial discharge generation of Experimental Example 1, (B) antenna reception voltage-frequency diagram, and (C) a partial discharge occurrence photo. It is (A) antenna reception voltage-frequency diagram 40 minutes after partial discharge generation of Experimental Example 1, (B) antenna reception voltage-frequency diagram, and (C) a photograph of a partial discharge generation location. It is (A) antenna reception voltage-frequency diagram 50 minutes after partial discharge generation of Experimental Example 1, (B) antenna reception voltage-frequency diagram, and (C) a photograph of a partial discharge occurrence location. It is the (A) antenna receiving voltage-frequency diagram at the time of partial discharge generation | occurrence | production 0 minutes which show the example 2 of partial discharge generation, (C) The photograph of the partial discharge generation | occurrence | production location. It is (A) antenna reception voltage-frequency diagram 30 minutes after partial discharge generation of Experimental Example 2, and (C) a photograph of a partial discharge generation location. It is (A) antenna reception voltage-frequency diagram 40 minutes after partial discharge generation of Experimental Example 2, and (C) a photograph of a partial discharge generation location. It is (A) antenna reception voltage-frequency diagram 70 minutes after partial discharge generation of Experimental Example 2, and (C) a photograph of a partial discharge generation location. It is a conceptual top view of the cubicle which shows other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Cubicle 11 Metal box 12 Metal partition 13 Storage room 14 Ventilation opening 20a Epoxy insulation type electric equipment 21 Epoxy insulation part 30 Antenna 40 Sensor main body 41 Case 42 Detection part 43 Specific frequency component setting part 44 Discharge level judgment part 45 Counter unit 46 Memory unit 46 Information recording medium 47 Calendar unit 48 Timer unit 50 Coaxial cable 60 Partial discharge management personal computer 70 Antenna switch E Electric tree detection threshold voltage

Claims (7)

A partial discharge detection method for detecting the occurrence of an electrical tree in the epoxy insulation part of an electrical device having an epoxy insulation part,
An electromagnetic wave generated by partial discharge of the epoxy insulating part is detected by an antenna, and the presence or absence of occurrence of an electrical tree is detected based on the magnitude of the antenna reception voltage in a specific frequency component of 150 MHz to 400 MHz of the detected electromagnetic wave. A method for detecting partial discharge of an epoxy insulated electrical device.   2. The epoxy insulated electric device part according to claim 1, wherein the presence or absence of electric tree generation is detected by comparing the antenna reception voltage with an electric tree detection threshold voltage set corresponding to the antenna. 3. Discharge detection method.   The state of progress of the electric tree is determined based on the number of occurrences of the electric tree detected based on the antenna reception voltage and the time transition of the magnitude of the antenna reception voltage for each frequency. The partial discharge detection method of the epoxy insulation type electric equipment of 1 or 2. A partial discharge detection device for detecting the occurrence and progress of an electrical tree in the epoxy insulation part of an electrical device having an epoxy insulation part,
An antenna for detecting electromagnetic waves generated due to partial discharge of the epoxy insulating portion, and generation of an electrical tree detected based on the magnitude of the antenna reception voltage in a specific frequency component of 150 MHz to 400 MHz among the electromagnetic waves detected by the antenna. A partial discharge detection device for an epoxy-insulated electric device, comprising: a sensor body that determines and stores a time transition of the magnitude of the antenna reception voltage for each occurrence and the number of occurrences.   5. The epoxy insulation according to claim 4, wherein the electric device and the antenna are housed in a metal box of a cubicle, the sensor main body is installed in the box, and the antenna and the sensor main body are cable-connected. A partial discharge detector for electrical equipment.   The sensor body is configured to detect the number of occurrences of an electrical tree detected based on the magnitude of an antenna reception voltage in a specific frequency component of 150 MHz to 400 MHz among electromagnetic waves detected by the antenna, and the magnitude of the antenna reception voltage for each occurrence. 6. The partial discharge detection device for an epoxy insulation type electrical apparatus according to claim 4, further comprising an information recording medium for determining and storing the time transition and detachable.   The antenna in the box of the plurality of cubicles and the sensor body are connected by a multi-stage switching type antenna switch, and the sensor body is shared by the plurality of cubicles. Partial discharge detector for epoxy insulated electrical equipment.