JPH04364483A - Detecting method of faulty or stained insulator - Google Patents

Abstract

PURPOSE:To discriminate a faulty or stained insulator by making evaluation by using a value which is obtained by dividing a difference between the maximum and the average value of measured values in a specific frequency band of a radio wave radiated from aerial transmission equipment, by a fundamental wave height at the time of occurrence of an extraordinary wave. CONSTITUTION:Measured radio wave data subjected to distance correction by a distance correction circuit 30 are supplied to a fast Fourier transform circuit 34 and a sudden wave detecting circuit 36 through a buffer memory 32. The circuit 34 divides the measured wave data into frequency channels CH1 to 22 and outputs them, while the circuit 36 outputs signals showing the position of occurrence, the crest value, the continuation width and the number of occurrences in a processing section of a sudden wave detected, respectively. These measured data are recorded, together with other necessary data, in a bulk data recording device 49. Measured values are subjected to an arithmetic processing by an evaluation value calculating circuit 102 and a value obtained by dividing a difference between the maximum value and the average value of the measured values by a fundbmental wave height at the time of occurrence of the sudden wave, that is, an evaluation value, is outputted. When the evaluation value exceeds a prescribed value, it is determined that a faulty or stained insulator is present.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting defective and soiled insulators, and more specifically to a method for detecting defective and/or soiled insulators installed on overhead power transmission lines and the like.

0002

[Prior Art] Overhead power transmission lines (including sleeves, spacers, and dampers) and their equipment (steel towers,
A method and device for detecting abnormalities in insulators, etc. are disclosed in Patent Application Publication No. 503324 (PCT/CH8
6/00066). The method disclosed in this publication involves flying a helicopter along an aerial overhead wire, receiving radio waves in the band of 20MHz to 200MHz using an antenna for detecting corona discharge mounted on the helicopter, and recording the waveforms on an oscilloscope (the same publication). Figures 5 to 9
(Fig.) to determine and detect the location of the problem.

0003

However, in the conventional example described above, the measurement frequency band is very high, mainly from 20 MHz to 200 MHz, and therefore high-speed and expensive circuit elements must be used in each part.

[0004] In addition, in the conventional example described above, the presence or absence and content of an abnormality are determined from the disturbance of the waveform of the oscilloscope, but since corona signals are generated at a speed of several tens of microseconds, such a determination method cannot quantitatively determine the content of the abnormality. Moreover, it is difficult to judge objectively. Since the judgment is made by human eyes, there are individual differences, day-to-day, and time-of-day differences, making it inaccurate. It is also difficult to locate the anomaly.

[0005] For example, in ultra-high voltage power transmission line equipment, 15 or more insulators are used, and even if there is a failure in one of the insulators located in the middle, it is not possible to identify and detect the failure. Furthermore, if some of the wires of an overhead power transmission line are broken near the insulator part of a transmission line tower, it is difficult to determine and identify whether the abnormality is the insulator or the overhead power transmission line.

[0006] The applicant proposed a method for solving these problems in the patent application No. 33544 published on February 14, 1990 (1990 Patent Application No. 33544).
A patent application was filed for the patent.

[0007] With the method and apparatus related to the patent application, it is difficult to objectively understand abnormalities. In particular, with regard to defective and soiled insulators for power transmission line towers, there is a problem in that it is difficult to distinguish between healthy insulators and defective/contaminated insulators from measured values unless one is very skilled.

An object of the present invention is to provide a method for detecting defective and contaminated insulators that solves the above-mentioned problems.

[0009]

[Means for Solving the Problems] According to the present invention, defective or contaminated insulators are determined based on the measured value of the approximately 1 KHz band of radio waves emitted from overhead power transmission equipment. A defective insulator is determined based on the value obtained by dividing the difference between the maximum value and the average value of the measured values in a band of approximately 1 KHz by the fundamental wave height at the time of occurrence of the abnormal wave. Further, a soiled insulator is determined based on a measured value of about 200 Hz or a ratio of this measured value to a measured value of about 1 KHz.

0010

[Operation] The value obtained by the above calculation shows a significantly different value for a defective or soiled insulator than for a sound insulator. Therefore, defective and soiled insulators can be objectively determined almost 100% without causing individual differences.

[0011]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In this example, corona discharge is measured using an apparatus basically similar to the apparatus described in the above-mentioned Patent Application No. 33544 of 1990. In this embodiment, this measured value is analyzed using a unique method to calculate an evaluation value that can clearly distinguish between defective/contaminated insulators and sound insulators.

[0013] Although a certain amount of corona discharge normally occurs in overhead power transmission lines and their equipment, corrosion and dirt on the wires,
Localized abnormal corona discharge occurs due to defects or abnormalities such as broken wires, defective insulators (cracks, moisture absorption, etc.), or contamination (dirt, rain leaks, etc.). Radio waves caused by this abnormal corona discharge and radio waves caused by the propagating electric power are radiated to the surroundings. As described in Patent Application No. 33544 of 1990, relatively low frequencies (
It has been found that the above defects or abnormalities can be detected using radio waves of up to about 10 KHz.

[0014] Furthermore, the frequency of radio waves caused by electric power propagating through overhead power transmission lines is the frequency of the electric power (50Hz or 60Hz).
z, hereinafter referred to as the fundamental wave), and its amplitude is generally proportional to the propagating power. As a result of observation, it was found that the amplitude of radiated radio waves due to propagating power is affected by grounding failure of the steel tower. That is, it is possible to determine whether there is a problem with the tower and its degree from the amplitude of the fundamental wave component of the radio waves from the overhead power transmission line and its equipment.

FIGS. 1 and 2 show schematic block diagrams of an embodiment of the present invention. FIG. 1 shows equipment mounted on a helicopter. In FIG. 1, 10 is a measurement antenna that receives the radio waves radiated from overhead power transmission lines and their equipment. In this embodiment, the measurement antenna 10 is 50 to 60H.
Any antenna can be used as long as it can receive radio waves from the fundamental wave of Z to about 10 KHz at most.

Reference numeral 12 denotes a radio distance meter that measures the distance to the object to be measured (overhead power transmission line and its equipment) using a radio wave method. In this embodiment, a rangefinder JRA-100 manufactured by Japan Aviation Electronics Industry, Ltd. was used as the radio rangefinder 12. This rangefinder JRA-100 has a transmission frequency of 4.3GHz.
The distance to the object is measured by emitting pulsed radio waves to the object and measuring the time it takes to receive the reflected radio waves from the object. This distance meter JRA-100 can measure distance with an accuracy of ±2 feet within the distance range targeted by this embodiment.

14 is a position and ground speed meter for measuring the position and ground speed of the helicopter; for example, the well-known GPS
(Global Positioning System). Reference numeral 16 denotes a position fixed marker that generates a fixed mark signal of a fixed point whose ground position is known (for example, a steel tower supporting an overhead power transmission line, a sleeve, a spacer, a damper, etc.). The position fixation marker 16 is equipped with a plurality of switches that individually generate different voltages so that the plurality of fixation points can be later distinguished. The fixed position marker 16 facilitates confirmation of the ground position when analyzing measurement data. The flight position, ie, the measurement position, can be accurately determined by the outputs of the ground speed meter 14 and the fixed position marker 16.

Reference numeral 18 indicates a measurement antenna 10 and a radio distance meter 1.
2. An interface circuit that converts signals from the ground speed meter 14 and fixed position marker 16 in order to record them on the data recorder 20. In the interface circuit 18, 92 is an amplifier that amplifies the weak radio waves received by the measurement antenna 10 to the input voltage range of the data recorder 20, 94 is an amplifier that amplifies the output voltage of the radio distance meter 12, and 96 is the ground speed meter 14. 98 is a low-pass filter (LPF) that extracts the low frequency component of the output of the amplifier 92; 100 is a pulse generation circuit that generates a pulse signal of a voltage corresponding to the button number of the position fixed marker 16; be.

The data recorder 20 is, for example, a digital audio tape recorder that has a plurality of recording channels and digitally records the measurement signals and output data of each of the above-mentioned elements on a magnetic tape 22.

A helicopter equipped with the equipment shown in FIG. 1 is hovered at a certain distance from the insulator of the steel tower where the abnormality is to be detected, and the distance between the helicopter and the overhead power transmission line is measured using the radio distance meter 12. Measurement antenna 1
0 to measure the radio waves from the tower for an appropriate period of time. The data recorder 20 is powered on in advance and placed in a recording pause state. During the measurement period, the recording pause of the data recorder 20 is canceled and the received radio wave data is transferred to the data recorder 20.
digitally recorded on the magnetic tape 22. at the same time,
Distance data to the measurement point output from the radio distance meter 12, output from the ground speed meter 14, and position information from the fixed position marker 16 are also digitally recorded on individual data channels of the magnetic tape 22 of the data recorder 20.

[0021]Although it is desirable that the distance between the helicopter and the insulator (or steel tower) to be measured be constant,
As will be described later, in this embodiment, radio wave attenuation due to distance is corrected, so even if the distance between the helicopter and the insulator varies, a defective or soiled insulator can be appropriately detected.

The magnetic tape 22 on which the measured data has been recorded is played back on the ground, and the measured radio wave data is analyzed by a computer and graphed. In addition, an evaluation value for determining defective/contaminated insulators is calculated through statistical processing.

FIG. 2 shows a block diagram of the structure of the analysis plotting device installed on the ground. In FIG. 2, 24 is a reproducing device that reproduces recorded data on the magnetic tape 22, and 90 is a computer that is in charge of analysis processing. The reproducing device 24 outputs the measured radio wave data by the measuring antenna 10 to the output signal line 24a, the power transmission line distance data by the distance measuring device 12 to the output signal 24b, and the position mark data by the position fixed marker 16 to the output signal line 24c. Ground speed data from the ground speed meter 14 is output to the output signal line 24d.

The distance data on the signal line 24b is input to the statistical processing circuit 26, where it is statistically processed. in particular,
Eliminate extreme values in distance data and smooth out its fluctuations. The voltage conversion circuit 28 converts the distance data output from the statistical processing circuit 26 into a voltage signal having a voltage value corresponding to the distance value.

The distance correction circuit 30 uses the output of the voltage conversion circuit 28, that is, the antenna 10, and the observation target (insulator or steel tower).
The measured radio wave data on the signal line 24a is corrected to the intensity at a predetermined constant distance according to the distance value between the signal line 24a and the signal line 24a. Even if a helicopter is to hover near a steel tower, it is practically impossible to maintain a constant distance to the tower. Theoretically, the radio waves emitted from the tower and its vicinity are inversely proportional to the square of the distance. Therefore, the measured radio wave data is corrected to a value at a certain distance using distance data measured at the same time. In addition, instead of performing correction using such a theoretical formula, the attenuation characteristics due to distance are actually measured, and the measured radio wave data is applied to the attenuation characteristic function obtained through measurement to correct the value at a certain distance. Good too. Regardless of the correction method, the distance correction circuit 30 is actually constituted by a digital arithmetic circuit, so it is easy to implement.

The measured radio wave data whose distance has been corrected by the distance correction circuit 30 is passed through a buffer memory 32 to a fast Fourier transform circuit (FFT) 34 and a sudden wave detection circuit 36.
supplied to In this embodiment, due to processing capacity, the buffer memory 32 applies 4,096 pieces of measured radio wave data to the sudden wave detection circuit 36, and receives 2,048 pieces of data from the beginning of the 4,096 pieces of data. The signal is supplied to the fast Fourier transform circuit 34. The fast Fourier transform circuit 34 divides the measured radio wave data into 22 frequency channels and outputs the divided frequency channels.

The frequency band of the output channel of the fast Fourier transform circuit 34 is shown in FIG. However, it should be understood that this is only an example, and the invention is not limited to such frequency divisions. Note that for detecting defective or contaminated insulators, it is sufficient to check the frequency band up to CH8 at most.

Since the output of the distance correction circuit 30 is distance corrected, as long as the grounding resistance of the tower of the overhead power transmission line is appropriate, the fast Fourier transform circuit 34 and the sudden wave detection circuit 36
The input signal consists of a fundamental wave of approximately constant amplitude of 50Hz or 60Hz, a noise component, and a sudden component due to corona discharge that occurs partially due to broken wires, defective or dirty insulators, etc. The signal waveform is as follows. The sudden wave detection circuit 36 is a circuit that detects such sudden waves superimposed on the fundamental wave. The internal configuration of the sudden wave detection circuit 36 is as follows:
This will be explained in detail later. The sudden wave detection circuit 36 outputs signals indicating the timing (ie, generation position), peak value, duration, and number of occurrences within the processing section (4,096 data) of the detected sudden wave.

Signal line 24c output from the reproducing device 24
The above position mark data is applied to mark extraction circuit 38. The mark extraction circuit 38 receives input position marks and
Among the data, position mark data of objects whose ground positions are known, such as steel towers, is extracted, and a corresponding pulse signal is generated.

The speed data on the signal line 24d output from the reproducing device 24 is input to the statistical processing circuit 42, where it is statistically processed. The output of the statistical processing circuit 42 is converted into a voltage signal by a voltage conversion circuit 44.

[0031] Overhead power transmission lines and their equipment have defects that exist over a certain distance due to corrosion and aging of the overhead power transmission lines, as well as problems such as poor grounding resistance of steel towers, broken wires, and poor insulation of insulators. There is a failure or abnormality that occurs in a specific part. The former appears as a low-frequency noise component superimposed on the 50 or 60 Hz fundamental wave over a certain length along the overhead power transmission line in the measured radio wave data (for example, the output of the distance correction circuit 30); appears as a sudden wave superimposed at a position corresponding to a fault or abnormality, or as a fluctuation component over a short period.

[0032] As a result of observation, such a noise component suggests that the overhead power transmission line is aging or that it is time to replace it.
It was found that it has a frequency band around Hz and 5 to 6 KHz. Therefore, the abnormality degree determination circuit 46 is a circuit that indicates, as an index, the abnormality detection time, replacement time, etc. of the overhead power transmission line and its equipment. The internal configuration of the abnormality degree determination circuit 46 is illustrated in FIG.

In FIG. 3, a division circuit 52 divides the wave height of the sudden wave by the amplitude of the fundamental wave, and an indexing circuit 54 divides the output value of the division circuit 52 into four levels, for example, 1, 2, 3, and 4. Applies to the classification and outputs an index value indicating the applicable classification. Based on this index value, it is possible to objectively judge whether an emergency field investigation is required, whether continuous monitoring is required, or whether monitoring is unnecessary for the time being.

Each frequency component of the measured radio wave data (output of the fast Fourier transform circuit 34), the height and width of the sudden wave, the number of sudden waves per unit processing section, the peak value of the fundamental wave at the sudden wave generation position, etc. (output of sudden wave detection circuit 36),
The output of the abnormality degree determination circuit 46, the distance value to the power transmission line (output of the voltage conversion circuit 28), and the fixed position mark are input to a drawing device 48 such as a plotter or printer, and along power lines),
Each measurement and analysis data value is printed and graphed on paper. In addition to the above data, flight speed data (output of the voltage conversion circuit 44) is also added to the data recording device 49 for large-capacity purposes such as detection of defective or contaminated insulators, and for subsequent re-analysis or more detailed analysis. It is recorded on a recording medium, such as a magneto-optical disk.

FIG. 4 shows an example of the output of the drawing device 48. However, the output of the sudden wave detection circuit 36 (number of sudden waves, width, height, and cut level for sudden wave detection), the distance to the power transmission line, and CH1~ of the fast Fourier transform circuit 34
Only 15 outputs are shown. The fixed line is a position reference line based on a fixed position mark signal output from the mark extraction circuit 38.

FIG. 5 shows a block diagram of the circuit configuration of the sudden wave detection circuit 36, and FIG. 6 is a waveform diagram in the process of separating the sudden waves and calculating the generation position of the sudden waves. For ease of understanding, FIG. 6 is illustrated in the form of an analog signal. As explained earlier, the sudden wave detection circuit 36 includes:
Data is supplied from the buffer memory 32 in units of 4,096 pieces. The input signal waveform of the sudden wave detection circuit 36 is shown in FIG.
As illustrated in (a), the waveform has a fundamental wave of 50 or 60 Hz superimposed with noise and a sudden wave due to corona discharge caused by defective/contaminated insulators, broken wires, etc.

The data from the buffer memory 32 is divided into a fundamental wave component and frequency components higher than the fundamental wave but not including the fundamental wave by a digital low-pass filter (LPF) 60 and a digital high-pass filter (HPF) 62. separated into That is, LPF60 is 50 to 60Hz
HPF62 is a digital filter for extracting fundamental wave components, and HPF62 extracts components other than the fundamental wave, specifically 80
This is a digital filter that extracts components above Hz.

The output of the HPF 62 has a waveform consisting of noise and sudden waves, as shown in FIG. 6(b), for example. Figure 6
(c) is an enlarged view of FIG. 6(b). Peak detection circuit 6
4 detects positive and negative peak values from the output of the HPF 62, and an absolute value circuit 66 converts the peak value detected by the peak detection circuit 64 into a positive value. The peak detection may be performed after first converting the output of the HPF 62 into an absolute value. Peak detection circuit 6
The peak detected at No. 4 includes both a sudden wave and noise. The statistical processing circuit 68 performs statistical calculations on the positive peak values output from the absolute value circuit 66 to reduce data variations and, if necessary, removes high frequency components above a predetermined value, and calculates the noise level. Calculate. The calculated noise level is sent to the noise cut circuit 7.
Applied to 0.

The output of the HPF 62 is also sent to the absolute value circuit 72.
The negative value is converted into a positive value by the noise cut circuit 70.
is applied to Noise cut circuit 70 subtracts the noise level from statistical processing circuit 68 from the output data of absolute value circuit 72. By this subtraction process, the output of the noise cut circuit 70 includes only the sudden wave. FIG. 6(d) shows the output signal waveform of the noise cut circuit 70. The output of the noise cut circuit 70 is applied to a sudden wave calculation circuit 76. The sudden wave calculation circuit 76 calculates noise and
From the output of the cut circuit 70, the sudden wave generation position, height,
The number of sudden waves per processing interval (4,096 pieces of data) and the period of occurrence (ie, width) of closely spaced sudden waves are calculated.

The fundamental wave height calculation circuit 78 is a circuit that calculates the peak value of the fundamental wave at the sudden wave generation position. Specifically, for example, the sudden wave generation timing signal from the sudden wave calculation circuit 76 is used as a sampling clock. As, LPF
60 outputs are sampled. The fundamental wave height value calculated by the fundamental wave height calculation circuit 78 is applied to the output circuit 80. The output circuit 80 is also applied with data regarding the sudden wave calculated by the sudden wave calculating circuit 76, and the output circuit 80 sends these data to the drawing device via individual signal lines or bus-type signal lines. 48 and data recording device 49
Output to. The output circuit 80 functions as an output buffer and as a circuit that adjusts the output timing of each data to be output.

As described in Patent Application No. 33544 of 1990, each frequency component of the measured radio wave basically shows the following changes in response to a malfunction in the overhead power transmission line and its equipment. In other words, if the wires of overhead power lines are corroded or dirty,
The noise level increases depending on the degree. When a wire breaks, a sharp sudden wave is generated depending on the degree of breakage, and the width of the sudden wave changes depending on the size of the break. Furthermore, if the ground resistance of the steel tower is poor, the level of the fundamental wave changes, and level changes also occur in other frequency bands. For example, in Fig. 4, A and B (both CH1) indicate poor grounding resistance of the steel tower, C (CH4) and D (CH12) indicate corrosion or staining of the wire, and the sudden wave in the sudden wave detection result. indicates that there is a sleeve or spacer at that position, or that there is a broken wire.

Defect factors in insulators include internal factors such as cracks and moisture absorption, and external factors such as dirt and rain leakage. In this specification, insulators with the former defect are referred to as defective insulators. Insulators with the latter defect are called stained insulators.

The tendency of the measured values (distance correction values) of each channel for these defective/contaminated insulators was examined. FIG. 8 shows the results of measurements of defective insulators, contaminated insulators, and sound insulators in the factory and comparison results. The horizontal axis is the frequency (
channel), and the vertical axis is the difference between the maximum value of the measured value of the defective/contaminated insulator (that is, the output of the FFT 34) and the maximum value of the measured value of the sound insulator. A solid line indicates a defective insulator, and a broken line indicates a contaminated insulator.

As can be seen from FIG. 8, regarding the defective insulator, CH4 shows a remarkable difference compared to the sound insulator. Therefore,
After considering this to make it clearer and to be able to use it for objective judgment, we found that a defective insulator can be objectively determined by dividing the difference between the maximum value and the average value by its abnormal wave height (fundamental wave height at the time of sudden wave occurrence). It was found that it was possible to distinguish The formula for calculating the evaluation value is as follows. That is, S1={(Amax-Aav)/Ah}/{(
Bmax-Bav/Bh)} However, Amax: Maximum value of defective/contaminated insulators Aav): Average value of defective/contaminated insulators Ah: Abnormal peak value of defective/contaminated insulators Bmax: Maximum value of sound insulators Bav: Maximum value of sound insulators Average value Bh: Abnormal wave height value of a sound insulator. FIG. 9 shows the above S1 obtained by an in-factory test. In FIG. 9, the horizontal axis is the frequency (channel), and the vertical axis is the evaluation value S1. Solid lines indicate defective insulators. S1 of CH4 greatly exceeds 1, and a defective insulator can be easily identified.

In actual use, it is difficult to obtain measurement values for only sound insulators, but generally only a small portion of the large number of insulators within the measurement range are defective or soiled. Therefore, during the field investigation, the overall average of the measured values was regarded as the value of a sound insulator, and the evaluation value S1 was calculated using the above evaluation formula. An example of the measurement results is shown in FIG. In Figure 10, the horizontal axis is the frequency (channel), the vertical axis is the frequency (channel), and the vertical axis is the (maximum value - average value)/abnormal wave height value of each tower normalized by the overall average value. . The solid line is a steel tower with a defective insulator, and the broken line is a steel tower with a sound insulator. In addition, we climbed each steel tower from the ground and measured the shared voltage of each insulator during high-voltage power transmission to confirm whether it was a defective insulator or a sound insulator. After surveying more than 200 steel towers,
It was possible to detect 100% of defective insulators.

In FIG. 9, the evaluation value S1 of the soiled insulator is shown by a broken line for reference. As can be seen from FIG. 9, the above S1
Therefore, soiled insulators cannot be clearly identified. Looking at Figure 8, CH2 becomes significantly larger for a contaminated insulator;
2, it is possible to identify a soiled insulator. In the ground experiment, CH2
The measured value (average value) showed a positive correlation with the degree of staining. Since a contaminated insulator is also generally considered to be only a part of the many insulators installed, by normalizing it by the average value of the entire measurement range, as in the case of defective insulators,
It is possible to objectively identify soiled insulators. In addition, to obtain an evaluation value with defective insulators removed, for example, the average value of CH2
The value divided by the average value of 4 may be used.

The evaluation value calculation circuit 102 performs arithmetic processing on the measured values recorded in the large-capacity data recording device 49, and outputs the evaluation value. If the evaluation value exceeds a predetermined constant value, it can be estimated that a defective or contaminated insulator exists.

The present invention is not limited to the configuration of the above embodiment. For example, it is easy to realize some or all of the circuit blocks illustrated in the drawings using one or separate digital processing devices, and it goes without saying that this is also within the technical scope of the present invention.

Although the evaluation value calculation circuit 102 calculates the evaluation value for judgment by calculating the measurement value once recorded on the recording medium, it may of course be output in real time.

[0050]

As can be easily understood from the above explanation, according to the present invention, defective and/or contaminated insulators can be objectively detected. Therefore, it becomes possible to automatically detect defective/contaminated insulators, and it becomes possible to investigate them more easily and in a shorter time.

[Brief explanation of the drawing]

FIG. 1 is a configuration block diagram of onboard equipment mounted on a helicopter.

FIG. 2 is a configuration block diagram of an analysis plotting device installed on the ground.

3 is a circuit configuration block diagram of an abnormality degree determination circuit 46 in FIG. 2. FIG.

FIG. 4 is an example of plotting the sudden wave detection results and each frequency component of the received radio wave.

FIG. 5 is a circuit configuration block diagram of the sudden wave detection circuit 36.

6 is an analog signal waveform diagram at each processing stage within the sudden wave detection circuit 36. FIG.

7 shows the frequency band of the output channel of the fast Fourier transform circuit 34. FIG.

[Figure 8] Defective and healthy insulators for each channel
FIG. 3 is a diagram of maximum measured values of a soiled insulator.

FIG. 9 is a diagram of evaluation values S1 of defective/stained insulators.

[Figure 10] Field test results.

[Explanation of symbols]

10: Measuring antenna 12: Radio distance meter 14: Ground speed meter 16: Fixed position marker 18: Interface circuit 20: Data recorder 22: Magnetic tape 24: Playback device 26: Statistical processing circuit
28: Voltage conversion circuit 30: Distance correction circuit 32
: Buffer memory 34: Fast Fourier transform circuit (
FFT) 36: Sudden wave detection circuit 38: Mark extraction circuit 42: Statistical processing circuit 44: Voltage conversion circuit 46: Abnormality degree determination circuit 48: Plotting device 49
: Data recording device 50: Adder 52: Division circuit 54: Indexing circuit 60: LPF 62: HP
F64: Peak detection circuit 66: Absolute value circuit 68
:Statistical processing circuit 70:Noise cut circuit 72
: Absolute value circuit 74: Delay circuit 76: Sudden wave calculation circuit 78: Fundamental wave height calculation circuit 80: Output circuit 9
0: Computer 92, 94, 96: Amplifier 9
8: Low-pass filter 100: Pulse generation circuit
102: Evaluation value calculation circuit

Claims (4)

[Claims] [Claim 1] A method for detecting defective/contaminated insulators in overhead power transmission equipment, characterized in that defective/contaminated insulators are determined based on measured values in a band of about 1 KHz of radio waves emitted from overhead power transmission equipment. A method for detecting defective/contaminated insulators. [Claim 2] In a method for detecting defects and insulators in overhead power transmission equipment, the difference between the maximum value and the average value of the measured values of the radio waves emitted from the overhead power transmission equipment in a band of approximately 1 KHz is determined when an abnormal wave occurs. A method for detecting a defective insulator, characterized in that a defective insulator is determined by a value divided by the fundamental wave height of the insulator. 3. A method for detecting defective insulators in overhead power transmission equipment, characterized in that the soiled insulator is determined based on a measured value of approximately 200 Hz of radio waves emitted from the overhead power transmission equipment. . 4. A method for detecting a soiled insulator, characterized in that the determination is made based on the ratio of a measured value of approximately 200 Hz to a measured value of approximately 1 KHz.