JPH0945537A - Monitoring device for insulating state of high-voltage apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a monitoring device which is applied to a high-voltage apparatus and to various degradation patterns and by which an insulating state can be monitored and judged accurately. SOLUTION: A CTL (a low-frequency current transformer) 4 and a CTH (a high-frequency current transformer) 5 are installed at a first-kind grounding line 3 at a high- voltage apparatus 2. An insulating-state monitoring device 1, to which the detection current of the CTL 4 is input, detects data on the current value in one cycle of a high-voltage-apparatus application voltage of a leakage current by a leakage-current detection means 20, it stores the data into a memory L 10, it detects data on the peak value and on the generation timing of every peak of a pulse current due to a partial discharge by using a partial-discharge detection means 21, and it stores the data into a memory H 16. Then, a control means by a microcomputer 11 computes a leakage current value on the basis of data on the leakage current, it computes a maximum, discharge amount, a total-discharge electric charge amount, the number of discharge pulses and a discharge phase due to the partial discharge on the basis of data on the partial discharge, and it judges an insulation abnormality when a prescribed value for judgment is exceeded in them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulation state monitoring device for grasping the insulation state of high voltage equipment.

[0002]

2. Description of the Related Art In recent years, high voltage equipment such as load switches, transformers, high voltage capacitors, instrument transformers, and instrument current transformers have been used in cubicle and other power receiving and transforming equipment, causing equipment failure. In the event of a sudden power failure, various problems will occur, economic loss will be great, and a secondary disaster such as a fire will occur. Conventionally, measures such as installing a ground fault relay have been adopted to prevent secondary disasters, and the insulation state of high-voltage equipment is frequently inspected. Recently, in order to prevent a sudden power failure, load insulation and equipment temperature management as well as equipment insulation monitoring have become important.

A conventional insulation state monitoring device for high voltage equipment will be described below with reference to the drawings. FIG. 9 is a block diagram showing the configuration of an example of a conventional insulation state monitoring device for high-voltage equipment. As shown in FIG. 9, one line of the low voltage side of the transformer 95 is grounded to the second type, and a low frequency CT is connected to the ground line 96.
(Hereinafter referred to as CTL) 97 is provided, and the leakage current detector 98 detects the leakage current from the output signal thereof to monitor the insulation state on the low voltage side. Also, 10HZ for the second type ground wire
A means for measuring the leakage current of the resistance component on the low voltage side is also adopted by using another power supply of a certain frequency.

On the other hand, the detection of partial discharge by the antenna method has been considered for the continuous measurement of the insulation abnormality of the high voltage part during the live line.
Also, a means for detecting partial discharge by providing a CT on the first-type ground line has been attempted.

[0005]

[Problems to be Solved by the Invention] Such a conventional CT
The insulation state monitoring device for detecting the leakage current by providing L to the second type ground wire on the low voltage side of the transformer is a simple and inexpensive means, but is a means limited to the detection of the insulation state on the low voltage side. At the same time, if there is a load including an inverter circuit such as a robot or a circuit that releases current to the ground line, or if there is a load with a large capacitance between the ground, the leakage current becomes particularly large, and that value alone may cause insulation failure. Accurate judgment is difficult. In this case, it is necessary to increase the abnormality determination value of the leakage current, and it is difficult to take a countermeasure against the failure because the time from the detection of the large leakage current to the failure stop of the device is short. Further, the means for providing a separate power source for the second type grounding wire is complicated and expensive, and is a means for detecting only the insulation abnormality on the low voltage side of the transformer as in the above-mentioned means, and the insulation abnormality on the high voltage side. Not applicable to detection and other high voltage equipment.

On the other hand, on the high voltage side, the means for detecting partial discharge by the antenna method is difficult to detect due to the influence of electromagnetic wave noise, and requires an expensive and complicated device. Further, a means for detecting partial discharge by providing a CT on the first-class grounding line is a low frequency narrow band (several 100 KHZ) as a noise countermeasure.
) Was taken out in an analog manner, and the maximum value of the pulse signal was compared with the calibration pulse to determine the maximum charge amount of partial discharge. This method cannot detect partial discharge pulses containing high-frequency components of 1 MHz or higher, and ignores discharge pulses with a small number but a large number, and simply ends up with the presence / absence determination of whether or not a partial discharge has occurred, and thus an insulation abnormality is detected. The degree was not accurately determined. Further, since the frequency characteristics of CT and the signal processing circuit do not consider signal processing of megahertz or higher, it is greatly affected by noise, and a signal having a large signal-to-noise ratio, that is, SN, cannot be obtained. was difficult. In addition, since the partial discharge signal is often detected in the early stage of the failure, it may not fail for more than 5 years after the partial discharge signal is detected. When the decrease in the resistance value occurs entirely, the leakage current may detect the insulation abnormality more accurately than the partial discharge, and it may be difficult to make an accurate determination with only one means.

The present invention is to solve the above problems, and not only a transformer, but also a load switch, a transformer, a high voltage capacitor, an instrument transformer, and an instrument current transformer in a power receiving and transforming device such as a cubicle. It can be applied to various high-voltage equipment to accurately detect insulation abnormalities, and it can also be used as a signal quantity for partial discharge, such as maximum discharge charge quantity, total discharge charge quantity, discharge pulse number, and discharge phase range for equipment applied voltage. It can also support partial discharge deterioration patterns, can monitor the insulation of many devices with one processing device, can be retrofitted to existing equipment in a live state, and display the detection results and communicate to other devices such as the central control board. It is an object of the present invention to provide an insulation condition monitoring device for a high voltage device which is easy to use and convenient, and which uses general electric components and is inexpensive and has a simple structure.

[0008]

According to a first aspect of the present invention, a low-frequency current transformer and a high-frequency current transformer are provided by being inserted in a first-type grounding wire of a high-voltage equipment, and the low-frequency current transformer is provided. Leakage current detection means for extracting data relating to the current value of the leakage current consisting of low frequency components from the output of the transformer for one cycle of the applied voltage of the high voltage device, and high frequency components from the output of the high frequency current transformer Partial discharge detection means for extracting data relating to the peak value and generation timing of the pulse current for the one period, a leakage current value is calculated from the leakage current data, and a signal amount of the partial discharge is calculated from the pulsed current data. , The maximum discharge charge amount and the total discharge charge amount from the charge amount corresponding to the peak value, the number of discharge pulses from the number of pulses, the discharge phase range in which partial discharge occurs from the range of the relative phase The insulation state is determined by the leakage current value and the partial discharge signal amount, each of which is calculated and determines an insulation abnormality when there is a leakage current value or a partial discharge signal amount exceeding a corresponding predetermined value. The present invention according to claim 2 is a wideband current transformer for detecting from a low frequency to a high frequency in a first-class ground wire of a high-voltage device. And a leakage current detecting means for extracting data relating to the leakage current value of the leakage current including the high frequency component from the output of the current transformer, for one cycle of the applied voltage of the high-voltage equipment, and the leakage current from the leakage current data. The insulation state is monitored by a leakage current value calculated from a waveform including a high-frequency component, which is provided with a determination means for calculating a value and determining an insulation abnormality when the value exceeds a predetermined value. According to another aspect of the present invention, there is provided an insulation condition monitoring device for a high-voltage device, wherein the first-class grounding wire of the high-voltage device is provided with a wide-band current transformer for detecting from a low frequency to a high frequency. Demultiplexing means for demultiplexing the output of the current transformer and data relating to the current value of the leakage current consisting of low frequency components from the demultiplexed first wave are extracted for one cycle of the applied voltage of the high voltage device. Leakage current extraction means, partial discharge detection means for extracting pulse current data consisting of high frequency components from the demultiplexed second wave during the one cycle, and a leakage current value is calculated from the leakage current data. As the signal amount of partial discharge from the pulse current data, the maximum discharge charge amount and the total discharge charge amount from the charge amount corresponding to the peak value, the number of discharge pulses from the pulse number, the discharge phase range from the range of the relative phase The insulation state is determined based on the leakage current value and the partial discharge signal amount by calculating each and determining if there is an insulation abnormality when there is a leakage current value or a partial discharge amount that exceeds a corresponding predetermined value. The present invention according to claim 4 is an insulation state monitoring device for high-voltage equipment, wherein the first-type ground wire of each of the plurality of high-voltage equipment has a low-frequency transformer and a high-frequency transformer. A leakage current detecting means for selecting the output of the low-frequency current transformer and the output of the high-frequency current transformer, which are provided as a monitoring target of the high-voltage equipment, by a user setting. 2. An insulation condition monitoring device for high voltage equipment according to claim 1, further comprising input selection means for outputting to the partial discharge detection means, and monitoring the insulation status of the high voltage equipment selected by the input means. And, the invention is related to claim 5,
A wide band current transformer that detects from low frequency to high frequency is provided on each type 1 grounding wire of a plurality of high-voltage devices,
The high-voltage equipment selected by the input means includes an input selection means for selecting an output of a current transformer provided as a monitoring target of the high-voltage equipment according to a user setting and outputting the output to a leakage current detection means. The insulation state monitoring device for high voltage equipment according to claim 2 adapted to monitor the insulation state of the high voltage equipment, and the present invention according to claim 6 provides the first type ground wire for each of the plurality of high voltage equipment. A wide band current transformer that detects from low frequency to high frequency is provided, and an input selection unit that selects the output of the current transformer to be monitored among the high voltage devices according to the setting of the user and outputs it to the demultiplexing unit. An insulation state monitoring device for high voltage equipment according to claim 3, wherein the insulation state of the high voltage equipment selected by the input means is monitored, and the invention according to claim 7 is a high voltage equipment. Leakage detected from the device One or more of the current value, the maximum discharge charge amount of the partial discharge signal amount, the total discharge charge amount, the number of discharge pulses, and the discharge phase range with respect to the high voltage applied to the device, the insulation state determined from them, and the high-voltage device. An insulation condition monitoring device for high-voltage equipment according to any one of claims 1, 3, 4, and 6, further comprising a display for displaying a sensor number indicating a provided current transformer. The present invention according to claim 8 provides a display for displaying a leakage current value detected from a high-voltage device, an insulation state determined from the leakage current value, and a sensor number indicating a current transformer provided in the high-voltage device. And a leakage current value detected from the high-voltage device. The insulation-state monitoring device for a high-voltage device according to claim 2 or 5, further comprising: Maximum discharge charge of discharge signal amount , Discharge pulse number,
8. The insulation of the high-voltage equipment according to claim 7, further comprising communication means for communicating the total amount of discharged electric charges and one or more of the discharge phase ranges for the applied high voltage, the insulation state determined from them, and the sensor number to the outside. 9. A condition monitoring device, and the present invention according to claim 10 further comprises a communication means for communicating a leakage current value detected from a high voltage device, an insulation state determined from the leakage current value, and a sensor number. Is an insulation condition monitoring device for high voltage equipment.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the insulation state monitoring apparatus for high voltage equipment according to the first aspect of the present invention, low frequency means an audible frequency range and high frequency means a higher range. When detecting leakage current and partial discharge current for high voltage frequency, low frequency is less than 1KHz and high frequency is 100KH.
It is sufficient for frequencies above z to reach frequencies of 100 MHz or higher. The high-frequency current transformer uses a magnetic core such as permalloy, and the winding has a winding structure with a small distributed capacitance.

The leak current detecting means is necessary for obtaining the current value of the leak current consisting of the low frequency component from the output of the low frequency current transformer inserted in the type 1 grounding wire of the high voltage equipment for one cycle of the applied high voltage. Means a means for extracting various data. The leakage current composed of this low frequency component is extracted from the low frequency current transformer by a low pass filter. This waveform contains irregular fluctuations, and its effective value changes rather than being constant during the one period. Therefore, the data required to obtain the current value is obtained by converting the current waveform into a waveform having an effective value through an effective value detection circuit and extracting the digital data of the waveform at a predetermined time interval for one cycle. Also, instead of handling the current itself, the current-voltage conversion circuit converts the current into a voltage and handles it. Therefore, the leakage current detection means of the embodiment converts the output of the low frequency current transformer into a voltage by the IV conversion circuit, forms the voltage waveform of the low frequency component through the low pass filter, and then passes the effective value detection circuit, Leakage current data is extracted by converting a sampling value of the output at a predetermined time interval within the one cycle into digital data by an A / D converter and storing the digital data in a memory.

The time control for collecting the data for one period is performed by converting the applied high voltage into a low voltage by a voltage divider and detecting a zero cross point of the applied voltage by a zero cross detection circuit to determine a time reference point. The timing circuit controls a clock of a microcomputer (hereinafter, referred to as a microcomputer) according to the reference to control an A / D converter and a memory. Therefore, the voltage dividing circuit, the zero-cross detecting circuit, the timing circuit, and the microcomputer operation described above are also included in the leak current detecting means.

Further, the partial discharge detecting means extracts the pulse current generated by the partial discharge from the output of the high frequency current transformer inserted in the first type ground wire, and detects the pulse current in one cycle of the applied voltage. It means a means for detecting the peak value data and the data of the generation timing thereof. This pulse current consists of high frequency components and is extracted by a high pass or band pass filter. Also in this means, the current is converted into a voltage and handled. Therefore, in the following embodiments, the partial discharge detection means converts the current output of the high frequency current transformer into a voltage by the IV conversion circuit, extracts the pulse through the band pass filter or the high pass filter, and outputs each peak by the peak hold circuit. The voltage is held, the voltage is converted into digital data by the A / D converter and stored in the memory. Further, the data collection for one period and the measurement of the pulse generation timing are executed on the basis of the zero cross point of the applied voltage of the high-voltage equipment as described above. Therefore, the voltage divider, the zero-cross detection circuit, the timing circuit, and the microcomputer operation are also included in the partial discharge detection means. In this case, the sampling period is set short corresponding to the pulse waveform, and the pulse generation timing is measured by the relative phase angle with respect to the applied voltage waveform.

The determination means calculates the leakage current value based on the effective value waveform data in the leakage current data, and also multiplies the peak value of each pulse from the pulse current data by a conversion coefficient to obtain a discharge charge amount, The maximum discharge charge amount with respect to the peak value, the total discharge charge amount by the sum of the discharge charge amount of each pulse, the discharge pulse number by the pulse number, the discharge phase range is calculated from the relative phase range of each pulse, and the leakage current value and If there is a partial discharge signal amount that exceeds a predetermined value for determination, it is determined that the insulation is abnormal. The predetermined value is preset with a value peculiar to the high-voltage equipment to be monitored. In addition, it is estimated whether the high-voltage device is discharged or another high-voltage device is discharged depending on whether the pulse generation phase range matches the discharge pattern of the target high-voltage device. This judging means is realized by a microcomputer operation, and therefore the microcomputer is also a judging means.

In the present invention according to claim 2, the leakage current detecting means obtains the current value of the current including the high frequency component for one cycle of the applied voltage from the output of the current transformer which detects the low frequency component to the high frequency component. This means means for extracting necessary data, and is different from the leakage current detecting means in claim 1 in that all the currents including the high frequency components output from the current transformer are treated as leakage currents. The following embodiments are basically the same as the configuration in which the low-pass filter of the leakage current detecting means in claim 1 is replaced with a high-pass filter or a pan-pass filter. However, since pulse generation phase information is unnecessary, zero-cross detection or the like is not necessary for time control of one cycle of the applied voltage, and it is possible to simply perform time measurement by a microcomputer.

In the present invention according to claim 3, the demultiplexing means means for dividing the output of the current transformer into two, and in the following embodiment, instead of dividing the current output of the current transformer into two, I- The V conversion circuit converts the current into a voltage and then divides it into two. Therefore, in this case, the IV conversion circuit in the leak current detecting means and the partial discharge detecting means can be omitted.

The input selection means according to claim 4 is means for switching the output of the current transformer and inputting it to the leakage current detection means and the partial discharge detection means, and is an analog circuit constituted by a mechanical switch or an integrated circuit. It can be configured with a switch.

An embodiment of the insulation state monitoring apparatus for high voltage equipment according to the present invention will be described below.

[0018]

【Example】

(Embodiment 1) An embodiment of the insulation monitoring apparatus for high-voltage equipment according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of this embodiment. In the figure, 1 is an insulation state monitoring device of the present embodiment,
2 is a high-voltage device to be monitored, 3 is a type 1 grounding wire of the high-voltage device 2, 4 is a CTL (low-frequency current transformer), 5 is a CTH (high-frequency current transformer), and is a high-voltage device such as permalloy. It uses a magnetic permeability core, adopts a winding method that is non-inductive and has a small stray capacitance, and realizes it by electromagnetically shielding the whole. 6 is CTL
IV converter L for converting the output current signal of No. 4 into a voltage signal
(Current-voltage converter), 7 is an LPF (low-pass filter) that passes signals of 500 Hz or less, 8 is an effective value detection circuit, 9 is an A / D converter (A / D converter L), and 10 is a memory (memory). L) and 11 are microcomputers.

Further, 12 is an IV converter H (current-voltage converter) for converting the output current signal of the CTH 5 into a voltage signal,
Reference numeral 13 is a high-pass filter that passes a signal of 100 KHZ or more or a band-pass filter that passes a signal in the range of 100 KHZ to 100 MHZ (filter H), and 14 is a P / H circuit that holds the peak value at the output of the filter H. (Peak hold circuit), 15 is A
/ D converter (A / D converter H), 16 is a memory (memory H), 17 is a voltage divider that divides a high voltage applied to the high voltage device 2 into a predetermined low voltage, and 18 is a voltage divider 17. Voltage zero-cross detection circuit that detects the zero-cross point at the output,
Reference numeral 19 controls the clock of the microcomputer 11 based on the zero-cross point to control the P / H circuit 14, A / D converters 9 and 1
5, a timing circuit for supplying the memories 10 and 16.

The insulation state monitoring apparatus of this embodiment monitors the insulation abnormality of the high-voltage equipment 2 by means of the CTL4 and CTH5 provided on the first-type ground line 3. In leak current detection,
The output of the CTL4 is converted into a voltage by the IV converter L6, and passed through the LPF7 which passes a signal of 500 Hz or less,
The rms value detection circuit 8 converts the rms value waveform, and the microcomputer 11
The leak current data is sampled 18 to 60 times during one cycle of the commercial frequency applied to the high-voltage equipment 2 with the signal of No. 1, converted into digital data by the A / D converter L9, and stored in the memory L10. To extract. A / D
Before the input to the converter L9, the signal level is adjusted by the LPF 7 and the effective value detection circuit 8.

The microcomputer 11 determines whether or not the leakage current value is abnormal by calculating the leakage current value using the leakage current data stored in the memory L10 and comparing it with a predetermined set constant. If it is larger than the above constant, it is determined to be abnormal. At this time, it is also easy to set a plurality of the above-mentioned setting constants, for example, to set three, and to judge in three stages of caution, abnormality, and danger in ascending order.

The same applies to partial discharge detection. The output of CTH5 is converted into a voltage by the IV converter H12, and 100 KH
HPF or 100KHZ to pass signals above Z
A pulse waveform is extracted through a filter H13 composed of a BPF that passes a signal in the range of 00 MHZ, the P / H circuit 14 holds the peak of the pulse, and the A / D converter H15
The partial discharge data is extracted by converting the data into digital data and storing it in the memory H16. In addition,
Before inputting to the A / D converter H15, the signal level is adjusted by the filter H13 or the like. In addition, the P / H circuit 1 is used so that the pulse data is taken in by measuring the signal of the microcomputer 11 every 5 to 200 μS for one cycle of the commercial power supply.
4, controlling the A / D converter H15 and the memory H16.

The discharge timing with respect to the high voltage applied to the high voltage device 2 is detected by connecting the high voltage of the reference phase from the high voltage device 2 to the voltage divider 17 to make it a predetermined low voltage and a voltage zero cross detection circuit. The timing circuit 1 detects the zero crossing point when the voltage changes from negative to positive by 18
9 and adjusts the timing with the clock signal of the microcomputer 11 so that the zero-cross point becomes the origin of the phase, and the measurement for one cycle of the commercial power supply is performed. In this embodiment, it is easy to control the timing circuit 19 to adjust the timing of the A / D converter L9, the memory L10, the P / H circuit 14, the A / D converter H15, and the memory H16. When the high-voltage equipment 2 is a transformer, the voltage divider 17 can be made unnecessary by using the voltage on the low voltage side of the transformer as the equipment-applied high-voltage signal and correcting the phase difference from the high voltage.

In FIG. 1, 20 is a leakage current detecting means, 21 is a partial discharge detecting means, and 22 is a judging means.

FIG. 2 is a pattern diagram showing an example of observation of pulse current by partial discharge by oscilloscope. In the figure,
When p is the oscilloscope level and k is the conversion constant, the amount of discharged electric charge: qi = k · pi Maximum amount of discharged electric charge: qmax = k · pmax Total amount of discharged electric charge: Q = k (p1 + p2 + ·· + pn) Discharge pulse Number: n = n1 + n2 Discharge phase range for high voltage applied to device: φ Partial discharge as shown in the figure has a unique pattern depending on the type of high-voltage equipment and the location of insulation deterioration.

Whether or not the insulation is abnormal due to partial discharge is set in the microcomputer 11 by setting a reference constant for each of the above values, as in the case of the leakage current, and whether or not it is larger than the set constant. Determine with. At this time, a plurality of setting constants can be set to judge the insulation state in a plurality of steps, as in the case of the leakage current. Further, whether or not the deterioration due to the partial discharge is in progress can be determined by tracking the changes in the plurality of signals, and it can be determined whether or not it is noise.

When the insulation state is determined by the leakage current value alone or the partial discharge signal alone, a detection error may occur. However, if the signals of the two are changed, etc., the stoppage of the equipment is very close. There are many errors and the number of detection errors is reduced.

It is needless to say that the setting constants for the above signals can be set to different values corresponding to them, considering that the partial discharge patterns differ depending on the type of high-voltage equipment and the location of deterioration.

(Embodiment 2) An embodiment of an insulation state monitoring apparatus for high voltage equipment according to the present invention will be described below. FIG. 3 is a block diagram showing the configuration of the present embodiment. A CTHL (broadband current transformer) 31 for detecting from low frequency to high frequency is provided on the first type grounding wire 3 of the high voltage device 2,
A filter H3 composed of a bandpass filter that converts the output of CTHL31 into a voltage waveform by the IV conversion circuit 32 and passes a signal in the range of 100 KHZ to 100 MHZ.
3, an effective value detection circuit 34 forms an effective value waveform, and an output at a predetermined time interval is converted into digital data by the A / D converter 35 and stored in the memory 37 under the control of the microcomputer 36. In this embodiment,
It is not necessary to detect the timing of pulse current generation by the relative phase with respect to the applied voltage of the high-voltage equipment. Therefore, the voltage divider for generating the phase reference, the voltage zero cross detector, the timing circuit, etc. are not provided, and the applied voltage is rotated once The period control is performed by the count operation of the microcomputer 36. 39
Is a leakage current detecting means, and 40 is a judging means.

In the above structure, the detection of the waveform composed of the high frequency component as the leakage current means that the partial discharge signal which has advanced to some extent is captured, and the leakage current value and the partial discharge signal amount are detected respectively. In comparison, the results show that there are few mistakes in the abnormality determination and there is little variation in the period from the detection of the abnormality to the stop of the device. Further, the insulation state monitoring device 38 of the present embodiment has a simpler configuration than the insulation state monitoring device 1 of the first embodiment because it does not include a circuit for detecting partial discharge.

Either the filter H33 is a BPF or the HPF is
Whether to use a (high-pass filter) or not depends on how to collect the leakage current. For example, it is possible to measure up to 30 MHZ provided on the ground wire 42 of the mold transformer 41 whose creeping surface is forcibly deteriorated by carbon-containing abrasive water as shown in FIG.
The result of observing the signals of the TH (high frequency CT) 43 and the LR sensor 44 and the high voltage applied to the mold transformer 41 with the oscilloscope 46 via the voltage divider 45 is shown in FIG. According to this, the signal difference between the signal 52 of the LR sensor 44 and the signal 53 of the CTH 43 is seen near 270 degrees of the applied high voltage, and the width of the signal is smaller in the LR sensor which seems to have better frequency characteristics. . It is estimated that this is because there are many low frequency components, and in this case, the filter H33 is set to have a higher HPF than the BPF.
As described above, the abnormality detection is surely performed by measuring the leakage current including a large amount of high frequency components.

In the present embodiment, the waveform of only the high frequency component is treated as the leakage current, but the low frequency component to the high frequency component may be treated as the leakage current.

(Embodiment 3) An embodiment of an insulation state monitoring apparatus for high voltage equipment according to the present invention will be described below. FIG. 6 is a block diagram showing the configuration of the present embodiment. In the figure, a wide band current transformer CTHL61 for detecting from low frequency to high frequency in the first type grounding wire 3 of the high voltage device 2
And the output signal of the CTHL 61 is converted into an IV conversion circuit 62.
Is converted into a voltage signal by the demultiplexer 63 and demultiplexed into two waves by the demultiplexer 63, the first wave is passed through the LPF 7, and the second wave is filtered by the filter H.
After that, the insulation state monitoring device 64, which executes the same processing as that of the first embodiment, requires only one current transformer, can be constructed at low cost, and the wiring can be easily routed.

In FIG. 6, 65 is a demultiplexing means and 66.
Is a leakage current detection means, 67 is a partial discharge detection means, and 68 is a determination means.

(Embodiment 4) An embodiment of an insulation state monitoring apparatus for high voltage equipment according to the present invention will be described below. FIG. 7 is a block diagram showing the configuration of this embodiment. In the figure, a plurality of high voltage devices 71 and high voltage devices 7
2, CTAL (low-frequency current transformer) 75 and CTAH (high-frequency current transformer) 77 and CTBL (low-frequency current transformer) 76 are connected to the first-type ground line 73 and the first-type ground line 74, respectively. And CTBH (high-frequency current transformer) 78, and the high-voltage equipment 71 is provided with a CTALL (low-frequency current transformer) 80 as a transformer on the second-type ground wire 79 on the low-voltage side thereof. CTAL75, CTBL76, and CT
The output signals of ALL80 are input to the input switching circuit L81, the output signals of CTAH77 and CTBH78 are input to the input switching circuit H82, and the input signals are sequentially switched under the control of the microcomputer 11, respectively. A plurality of low-frequency current transformers and high-frequency current transformers can be processed by one insulation state monitoring device 83 to monitor the insulation state of the equipment. The low-frequency CT provided on the second-type ground line may be processed in the same manner as other low-frequency current transformers. Note that the setting constants for abnormality determination need to be adjusted according to the monitoring target.

By the same switching, a wide band current transformer for detecting a low frequency to a high frequency is provided for each high voltage device for monitoring a plurality of high voltage devices, and these are sequentially switched to include a high frequency. It is also possible to detect leakage current, and a current transformer that detects from low frequency to high frequency is provided for each high-voltage device, and they are sequentially switched to divide into two, and leakage current and high-frequency signal amount are detected. It is also possible to detect In FIG. 7, reference numeral 84 indicates an input selecting means.

(Embodiment 5) An embodiment of the insulation state monitoring apparatus for high voltage equipment according to the present invention will be described below. FIG. 8 is a pattern diagram showing the configuration of the display device in this embodiment. In the figure, display units 85 and 86 such as 7-segment LEDs for displaying the respective sensor numbers used for the leakage current and the partial discharge signal amount, and lamps 88 and 89 showing the respective judgment results are provided. A display unit such as a 7-segment LED is used for the signal amount, and a 4-digit display unit 91 is used for the maximum discharge charge amount.
The discharge pulse number is provided with a 3-digit display portion 92, the total discharge charge amount is provided with a 4-digit display portion 93, and the discharge phase range is provided with a display portion 94 for alternately displaying positive and negative electrodes in six digits. Further, the microcomputer 11 makes a comprehensive judgment according to a predetermined standard in accordance with each of the above judgments and the signal amount, and displays the result on the lamp 90. Needless to say, the display related to partial discharge can be omitted when only the leakage current is detected. Further, these display contents are provided with communication means for communicating with the central control panel or personal computer via a cable such as RS232C or RS485 or wirelessly, and the same content as shown in FIG. 8 is remotely displayed on the central control panel or personal computer. It can also be stored remotely.

[0038]

As is apparent from the above description, 1. The insulation state monitoring device for high-voltage equipment according to the present invention comprises a low-frequency current transformer and a high-frequency current transformer provided in the first-type grounding wire of the high-voltage equipment, or a wide-band current transformer that covers low to high frequencies. The leak current and partial discharge are detected by the above, and the insulation state is judged by comparing those values with the reference value corresponding to the high voltage equipment.For partial discharge, the maximum discharge charge amount and the total discharge charge are calculated as the signal amount. By detecting the amount, the number of discharge pulses, and the discharge phase range with respect to the device applied voltage, it is not limited to the high voltage side or the low voltage side. Therefore, not only the transformer but also the substation equipment such as cubicle. Can be applied to various high-voltage devices such as load switches, transformers, high-voltage capacitors, instrument transformers, instrument current transformers, and various partial discharge deterioration patterns.

Further, by detecting the leakage current up to the high frequency component, it is possible to make a determination only by detecting the leakage current when the deterioration is progressing.

2. INDUSTRIAL APPLICABILITY The insulation state monitoring device for high-voltage equipment according to the present invention is configured so that a signal is input from a current transformer provided for each high-voltage equipment. Can be monitored. Moreover, by switching and inputting the output of each current transformer of a plurality of high-voltage devices, a large number of high-voltage devices can be simultaneously monitored.

3. Since the insulation state monitoring apparatus for high-voltage equipment of the present invention inputs a signal from the current transformer provided in the first-type grounding wire of the high-voltage equipment, the current transformer may be retrofitted to the existing equipment in a live line state. Applicable.

4. The insulation state monitoring device for high-voltage equipment of the present invention can easily know the detection result by displaying the detection item, the sensor number used, the determination result, and the like on the display, and is also provided with the communication means. As a result, they can be remotely displayed on other devices such as the central control panel and can be stored remotely, which is convenient.

5. Since the insulation state monitoring device for high-voltage equipment of the present invention comprises a current transformer, a current-voltage conversion circuit, a filter, a P / H circuit, an A / D converter, a memory, a microcomputer, etc., a general commercial electric component is used. It can be realized at low cost.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of an insulation state monitoring apparatus for high-voltage equipment according to the present invention according to claim 1;

FIG. 2 is a pattern diagram showing an example of a high voltage waveform and a partial discharge waveform observed and measured by an oscilloscope in the same example.

FIG. 3 is a block diagram showing the configuration of an embodiment of an insulation state monitoring apparatus for high-voltage equipment according to the present invention according to claim 2;

FIG. 4 is a block diagram showing an example of a partial discharge measurement circuit.

FIG. 5 is a pattern diagram showing an example of an observed and measured waveform of a partial discharge by an oscilloscope.

FIG. 6 is a block diagram showing the configuration of an embodiment of an insulation state monitoring device for high-voltage equipment according to the present invention according to claim 3;

FIG. 7 is a block diagram showing the configuration of an embodiment of an insulation state monitoring device for high-voltage equipment according to the present invention according to claim 4;

FIG. 8 is a block diagram showing the configuration of an embodiment of an insulation state monitoring apparatus for high-voltage equipment according to the present invention according to claim 7;

FIG. 9 is a block diagram showing a configuration of a conventional insulation state monitoring device.

[Explanation of symbols]

 1,38,83 Insulation state monitoring device 2,71,72 High voltage equipment 3 First-class ground wire 4 CTL (low frequency current transformer) 5 CTH (high frequency current transformer) 6 I-V converter L (current voltage) Converter) 7 LPF 8 effective value detection circuit 9 A / D converter L 10 memory L 11,36 microcomputer 12 IV converter H 13,33 filter H 14 P / H circuit 15 A / D converter H 16 memory H 17 voltage divider 18 voltage zero cross detection circuit 19 timing circuit 20, 39, 66 leakage current detection means 21, 67 partial discharge detection means 22, 40, 68 determination means 31, 61 CTHL (broadband current transformer) 32, 62 I -V conversion circuit 34 effective value detection circuit 35 A / D converter 37 memory 63 demultiplexer 65 demultiplexing means 73, 74 first type ground line 75 CTAL (low frequency current transformer) 76 CTB (Low-frequency current transformer) 77 CTAH (high-frequency current transformer) 78 CTBH (high-frequency current transformer) 79 Second type ground wire 80 CTALL (low-frequency current transformer) 81 Input switching circuit L 82 Input switching circuit H 84 input Means of selection

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[Procedure amendment]

[Submission date] April 10, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction contents]

On the other hand, on the high voltage side, the means for detecting partial discharge by the antenna method is difficult to detect due to the influence of electromagnetic wave noise, and requires an expensive and complicated device. Further, a means for detecting partial discharge by providing a CT on the first-class grounding line is a low frequency narrow band (several 100 KHZ) as a noise countermeasure.
) Was taken out in an analog manner, and the maximum value of the pulse signal was compared with the calibration pulse to determine the maximum charge amount of partial discharge. And inability to detect the partial discharge pulses including the above high-frequency components 1MHZ This means, the level is small is ignored discharge pulse number is large, simply end the partial discharge occurred there was whether existence determination about insulation abnormalities The degree of was not determined accurately. Also, CT
Since the frequency characteristics of the signal processing circuit do not consider signal processing of megahertz or higher, it is greatly affected by noise, and a signal having a large signal-to-noise ratio, that is, SN, cannot be obtained, which makes practical application difficult. Moreover, since the partial discharge signal is often detected in the early stage of the failure, there are cases where the partial discharge signal does not fail for five years or more after the detection.
In addition, if a decrease in the resistance value on the surface of the entire surface occurs, such as in a device that has been exposed to water, the leakage current may detect the insulation abnormality more accurately than the partial discharge. In that case, it may be difficult to make an accurate judgment.

Claims (10)

[Claims] 1. A low-frequency current transformer and a high-frequency current transformer are provided by being inserted in a first-type grounding wire of a high-voltage equipment, and a current of a leakage current consisting of a low-frequency component from the output of the low-frequency current transformer. Leakage current detection means for extracting data related to the value for one cycle of the applied voltage of the high-voltage equipment, and data related to the peak value and generation timing of the pulse current composed of high-frequency components from the output of the high-frequency current transformer. The partial discharge detection means for extracting for one cycle and the leakage current value are calculated from the leakage current data, and the partial discharge signal amount is calculated from the pulse current data, and the maximum discharge charge is calculated from the charge amount corresponding to the peak value. Amount and total discharge charge amount, the number of discharge pulses from the number of the pulses, the discharge phase range in which partial discharge has occurred from the range of the relative phase, respectively, the leakage current value and the A high-voltage device equipped with a determination means for determining an insulation abnormality when there is a partial discharge signal amount exceeding a corresponding predetermined value, and monitoring the insulation state by the leakage current value and the partial discharge signal amount. Insulation condition monitoring device. 2. A data relating to a leakage current value of a leakage current including a high frequency component from the output of the current transformer, wherein a wide band current transformer for detecting from low frequency to high frequency is provided on the first type grounding wire of high voltage equipment. A leakage current detecting means for extracting for each cycle of the voltage applied to the high-voltage equipment, and a determining means for calculating a leakage current value from the leakage current data and determining an insulation abnormality when the value exceeds a predetermined value. An insulation condition monitoring device for a high-voltage device, comprising: a leakage current value obtained from a waveform including a high-frequency component. 3. A first-class grounding wire of a high-voltage device is provided with a wide-band current transformer for detecting from low frequency to high frequency, and a demultiplexing means for demultiplexing the output of the current transformer into two is provided. Leakage current extracting means for extracting data relating to the current value of the leakage current consisting of the low frequency component from the first wave for one cycle of the applied voltage of the high voltage device, and the high frequency component from the branched second wave. Partial discharge detection means for extracting pulse current data for the one period, a leakage current value is calculated from the leakage current data, and a charge corresponding to the peak value is calculated as a partial discharge signal amount from the pulse current data. Amount to the maximum discharge charge amount and the total discharge charge amount, the pulse number to the discharge pulse number, the relative phase range to the discharge phase range are calculated respectively, and the leak current value and the partial discharge amount are calculated respectively. An insulation condition monitoring device for high-voltage equipment, comprising: a judgment means for judging an insulation abnormality when there is a value exceeding a predetermined value corresponding thereto, and monitoring the insulation condition by a leakage current value and a partial discharge signal amount. 4. A low-frequency current transformer and a high-frequency current transformer are provided on each of the first-class ground wires of a plurality of high-voltage devices,
The output of the low-frequency current transformer and the output of the high-frequency current transformer, which are provided as a monitoring target of the high-voltage equipment, are selected by the user's settings to be the leakage current detection means and the partial discharge detection means, respectively. 2. An insulation state monitoring device for high voltage equipment according to claim 1, further comprising input selecting means for outputting, wherein the insulation state of the high voltage equipment selected by said input means is monitored. 5. A current transformer of a wide band for detecting from a low frequency to a high frequency is provided on each of the first type ground wires of a plurality of high-voltage devices, and a current transformer provided as a monitoring target of the high-voltage devices. 3. The high-level equipment according to claim 2, further comprising input selection means for selecting the output of the power supply device according to a user's setting and outputting it to the leakage current detection means, and monitoring the insulation state of the high-voltage equipment selected by said input means. Insulation monitoring device for voltage equipment. 6. An output of a current transformer to be monitored in the high voltage equipment, wherein a wide band current transformer for detecting from low frequency to high frequency is provided on each of the first type grounding wires of the plurality of high voltage equipment. 4. An input selection means for selecting the output signal according to the user's setting and outputting it to the demultiplexing means is provided, and the insulation state of the high-voltage equipment selected by the input means is monitored.
Insulation state monitoring device for high voltage equipment as described. 7. A leakage current value detected from a high voltage device,
One or more of the maximum discharge charge amount of the partial discharge signal amount, the total discharge charge amount, the number of discharge pulses, and the discharge phase range for the high voltage applied to the device, the insulation state determined from them, and the variation provided in the high-voltage device. The insulation state monitoring device for high-voltage equipment according to any one of claims 1, 3, 4, and 6, further comprising a display for displaying a sensor number indicating a sink. 8. A leakage current value detected from a high voltage device,
The insulation state of the high-voltage equipment according to claim 2 or 5, further comprising an indicator for displaying an insulation state determined from that and a sensor number indicating a current transformer provided in the high-voltage equipment. Monitoring equipment. 9. A leakage current value detected from a high voltage device,
Communication for communicating externally one or more of the maximum discharge charge amount of the minute discharge signal amount, the number of discharge pulses, the total discharge charge amount, and the discharge phase range for the applied high voltage, the insulation state determined from them, and the sensor number. An insulation condition monitoring device for high-voltage equipment according to claim 7, further comprising means. 10. The insulation state monitoring device for high voltage equipment according to claim 8, further comprising communication means for communicating the leakage current value detected from the high voltage equipment, the insulation state determined from the leakage current value, and the sensor number.