JPH03233374A - Abnormality searching device for overhead transmission line and equipment thereof - Google Patents

Abstract

PURPOSE:To distinctly search an abnormality of overhead transmission line, etc., by measuring a radio wave from the overhead transmission line, etc., with a measuring antenna and analyz ing the frequency in a low frequency band after a distance correction is made on the measured radio wave according to the distance measured by a distance measuring means. CONSTITUTION:A helicopter mounted with a searching device is made to fly, and the radio waves (50Hz - approximately 10kHz) emitted from the overhead transmission line and the equipment thereof are received by the measuring antenna 10, and the distance to a measuring object is measured by a radio wave distance meter 12. The measured radio wave signal and distance signal are amplified 16, 18 and subjected to an A/D conversion 20, 22 then impressed on a distance correcting and analyzing circuit 24. The output of a position fixing marker 14 settled on the ground is also impressed on the circuit 24. In the circuit 24, the distance correction is made on the measured radio wave signal by the measured distance, and the analysis is made by dividing the signal to frequency components (indicating the defective grounding resistance of a steel tower) of the fundamental wave (50/60Hz) and fre quency components indicating a breaking of element wire or a corrosion, then the result is outputted as numerical values. Plural outputs 24a-24e of the circuit 24 are subjected to the A/D conversion respectively and impressed in a chart recorder 29 and plotted on paper with individual pens.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an apparatus for detecting abnormalities in overhead power transmission lines and their equipment, and more specifically, a device for detecting abnormalities in overhead power transmission lines and their equipment using corona discharge. related to a device for

[Prior art] A method and device for detecting abnormalities in overhead power transmission lines and their equipment by corona discharge is disclosed in Patent Application Publication No. 5 in 1988.
No. 03324 (PCT/CH36100066). The method disclosed in this publication involves flying a helicopter along an aerial overhead wire, receiving radio waves in the band of 20 MHz to 200 MHz using an antenna for detecting corona discharge mounted on the helicopter, and measuring the waveform on an oscilloscope (the same publication). 5 to 9) to determine and detect the defective location.

[Problem to be solved by the invention] However, in the above conventional example, the measurement frequency band is mainly 20MHz.
z to 200 MHz, which is extremely high, and therefore has the drawback that high-speed and expensive circuit elements must be used in each part.

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 with such a determination method, it is difficult to quantitatively and objectively determine the content of the abnormality. It is also difficult to locate. For example, if a part of the wire of an overhead power transmission line is 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.

Furthermore, in the conventional example, it is not possible to compare and contrast the current measured value with the preceding measured value, and it is also not possible to graph changes in the measured value. The disadvantage is that it is not possible to detect parts that are changing.

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems and provide an abnormality detection device that can clearly detect abnormalities in overhead power transmission lines and their equipment.

[Means for Solving the Problems] An exploration device according to the present invention includes a measuring antenna that receives radio waves from an overhead power transmission line and its equipment, and a distance measuring antenna that measures the distance to the overhead power transmission line and its equipment to be explored. a measuring means, a distance correcting means for correcting the distance of the radio wave measured by the measuring antenna, based on the distance measured by the distance measuring means, and an analysis for frequency-analyzing the radio signal whose distance has been corrected by the distance correcting means in a low frequency band. It is characterized by consisting of means.

The present invention also provides a measurement antenna that receives radio waves from overhead power transmission lines and their equipment, a level control means that controls the level of the radio waves measured by the measurement antenna so that the level of the fundamental wave component is constant, and It is characterized by comprising an analysis means for frequency-analyzing the measurement radio wave signal whose level has been controlled by the level control means in a low frequency band.

[Operation] Since the existence and content of an abnormality can be determined using radio waves in a low frequency band, for example, a low frequency of up to 10 KHz, each processing circuit can be manufactured at low cost, and therefore an abnormality can be detected at a very low cost. In addition, distance correction based on the measured distance value or level control that keeps the fundamental wave level constant eliminates the need to maintain a precisely constant distance to the overhead power line during measurement, making data collection easier. . This also helps reduce costs.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.

In overhead power transmission lines and their equipment (steel towers, insulators, sleeves, dampers, etc.), corona discharge occurs due to defects or abnormalities such as corrosion, dirt, or breakage of the wires, and radio waves and Radio waves due to the propagating power are radiated to the surroundings. This point is stated in the above-mentioned publication, but through several experiments conducted by the inventor, the above defects or abnormalities were detected using relatively low frequency radio waves (up to about 10KH2 at most) from overhead power transmission lines and their equipment. It turns out it can be done. .

In other words, overhead power transmission lines and their equipment have defects that exist over long distances due to corrosion or aging of the overhead power transmission lines, as well as defects in specific parts such as poor insulation in steel towers, broken wires, and poor insulation in insulators. There are malfunctions and abnormalities that occur.

The former appears as a low-frequency noise component that is superimposed on the 50 or 60 Hz fundamental wave over a certain length along the overhead power transmission line in the measured radio signal, and the latter
It appears as a sudden wave that is superimposed at a position corresponding to a failure or abnormality, or as a fluctuation component over a short period. As a result of the observation,
Such noise components imply corrosion or deterioration of overhead power transmission lines, and it has been found that they have a frequency band around 4 KHz or 5 to 6 KHz, and it is sufficient to measure up to 10 KH2 at most.

Further, the frequency of radio waves caused by electric power propagating through overhead power transmission lines matches the frequency of the electric power (50 Hz or 60 Hz, hereinafter referred to as fundamental wave), and the amplitude of received radio wave power 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. As a result, it was found that it is possible to determine the presence or absence of a malfunction in a steel tower and its degree from the amplitude of the fundamental wave component of radio waves from overhead power transmission lines and their equipment.

FIG. 3 shows an example of output actually measured by this example. In FIG. 3, the A and H portions of the fundamental wave indicate poor grounding resistance of the tower, and the noise portion C1D indicates corrosion or staining of the wire. A sudden wave in the sudden wave detection results suggests that there is a sleeve or spacer at that position, or that there is a wire breakage. Note that the reference position is a line indicating the location of an object whose ground position is known, such as a steel tower.

FIG. 1 shows a schematic block diagram of the basic configuration of an embodiment of the present invention. The equipment shown in Figure 1 is mounted on a helicopter,
A helicopter is flown along overhead power lines to detect abnormalities. In FIG. 1, reference numeral 10 denotes a measurement antenna that receives the radio waves radiated from overhead power transmission lines and their equipment. In this embodiment, the measurement antenna 10 has 50 to 60
Any antenna can be used as long as it can receive radio waves from the fundamental wave of Hz to about 10KH2 at most.

12 is a radio distance meter that measures the distance to the measurement target (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, 3GH.
The distance to the object is measured based on the time it takes to emit a pulsed radio wave of z to the object and receive the reflected radio wave 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.

Reference numeral 14 denotes a position fixed marker that generates a fixed mark signal for 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 fixing marker 14 is equipped with a plurality of switches that individually generate different voltages so that the plurality of fixation points can be later distinguished.

The position fixed marker 16 makes it easy to confirm the ground position of the abnormal location in the graph for analyzing the measured data.

The measurement radio wave signal output from the measurement antenna 10 and the distance signal to the power transmission line output from the distance meter 12 are each transmitted through an amplifier 16.1 with an anti-aliasing filter.
8, converted into a digital signal by A/D converters 20 and 22, and applied to the distance correction/analysis circuit 24. The distance correction/analysis circuit 24 is composed of a digital signal processing circuit called a DSP, but it may also be one that operates a general-purpose microcomputer with a program. The output of the fixed position marker 14 is also applied to a distance correction and analysis circuit 24 .

Measuring antenna 10. Distance meter 12 and position fixed marker 14
It is preferable that the output is recorded on a recording medium such as a magnetic tape by the data recorder 26 for later analysis.

Although details will be described later with reference to FIG. 2, the distance correction/analysis circuit 24 corrects the measured radio wave signal by the measured distance (distance to the power transmission line), and detects the frequency component of the fundamental wave and the breakage of the wire. and frequency components that indicate corrosion, and output the analysis results as numerical values. D/A converter 28 in FIG.
is a plurality of outputs 24a to 24 of the distance correction/analysis circuit 24.
It is equipped with a D/A conversion circuit that individually converts the signals e into analog signals, and each output thereof is applied to the chart recorder 29. The chart recorder 29 draws each input signal on paper using a separate pen.

In addition, although not shown, it is preferable to mount a well-known GPS (Global Positioning System) device that can confirm the flight position of the helicopter.

A helicopter equipped with the equipment shown in FIG. 1 is flown at a constant speed as much as possible along the overhead power transmission line on which an 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 IO measures radio waves from overhead power transmission lines and their equipment. The measurer operates the fixed position marker 14 at the position of the steel tower, etc.
A corresponding mark signal is generated. These signals are analyzed by a distance correction/analysis circuit 24, and the analysis results are drawn on paper by a chart recorder 29.

Although it is desirable that the distance between the helicopter and the overhead power transmission line be constant, as will be described later, in this embodiment, radio wave attenuation due to distance is corrected, so the distance between the helicopter and the overhead power transmission line may vary. It is possible to appropriately determine and detect abnormalities even when

FIG. 2 shows a block diagram of the circuit configuration of the distance correction/analysis circuit 24. In FIG. 2, 30 is a distance value (specifically, A /D converter 22 output) to correct the value to a constant distance value. Even if a helicopter were to fly parallel to overhead power lines, it is practically impossible to maintain a constant distance to the overhead power lines.

The radio waves emitted from overhead power lines and their equipment are theoretically 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 applied to a low pass filter (LPF) 32 and a band pass filter (BPF) 34. LPF32
has a cutoff frequency of about 80Hz, and the fundamental wave (5
The BPF 34 is a digital filter that extracts the 0 Hz or 60 Hz) component, and the BPF 34 is a digital filter with a passband of 80 Hz to 10 KHz. BPF34
Also narrower, 3,5KHz~4,5
The BPF may have a pass band of KHz or 5 to 6 KHz.
The output of 34 is also converted into an absolute value by an absolute value conversion circuit 38. The output of the absolute value conversion circuit 36 indicates the amplitude of the fundamental wave, and the output of the absolute value conversion circuit 38 indicates frequency components other than the fundamental wave (i.e.,
Indicates the amplitude of noise (on the fundamental wave and sudden waves). The output of the absolute value conversion circuit 36 is smoothed by a smoothing circuit 40,
The signal is applied to the D/A converter 28 via the output signal line 24a.

The output of the smoothing circuit 40 is also applied to the divisor input of the division circuit 42, and the output of the absolute value circuit 38 is applied to the dividend input of the division circuit 42. That is, the output of the division circuit 42 indicates the ratio of the noise component to the fundamental wave. The index conversion circuit 44 converts the division result of the division circuit 42 into, for example, 1. 2.
3. 4, and a numerical value indicating the corresponding classification is output as an evaluation index of the degree of abnormality. 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. The output of the indexing circuit 44 is time-adjusted by the delay circuit 45 and applied to the D/A converter 28 via the output signal line 24b.

The output of the absolute value converting circuit 38 is also smoothed by a smoothing circuit 46 for the purpose of graphically displaying the intensity of frequency components other than the fundamental wave, that is, noise components, and is output to the D/D via the signal line 24c.
is applied to the A converter 28.

The degree of corrosion and deterioration of the wire can be determined based on the strength of the noise component.

The sudden wave detection circuit 48, based on the output of the smoothing circuit 46,
A sudden wave is detected from the output of the absolute value conversion circuit 38. The delay circuit 50 adjusts the time of the output of the sudden wave detection circuit 48 and supplies it to the D/A converter 28 via the signal line 24d. The output of the sudden wave detection circuit 48 is drawn by the chart recorder 29 as shown in FIG.

Further, the output of the position fixed marker 14 is output from the pulse generation circuit 52.
is applied to The pulse generation circuit 52 is the position fixed marker 1
A short pulse of voltage corresponding to the type of mark signal from 4 is generated. The output of the pulse generation circuit 52 is time-adjusted by a delay circuit 54 and sent to the D/A converter 28 via a signal line 24e.
is applied to

This indicates a fixed line, that is, a reference position whose position is known, on the graph produced by the chart recorder 29. For example, the pulse generation circuit 52 may be a circuit that generates a pulse signal only in response to a mark signal for a steel tower, and in such a case, the output of the delay circuit 54 may be passed through the D/A converter 28. It is sufficient to apply the signal directly to the chart recorder 29 without any need.

Regardless of the distance correction by the distance correction circuit 30, the reason why the amplitude of the fundamental wave component fluctuates greatly is because the grounding resistance of the tower of the overhead power transmission line is inappropriate, as explained earlier in FIG. Ru. According to this embodiment, this is the signal line 24a.
signal (A in Figure 3).

It is obvious from B).

As a result of field observation, the relationship between abnormalities or defects in overhead power transmission lines and their equipment and the analysis results of measured radio waves is summarized as follows. That is, if the wires of the power transmission line are corroded or dirty, the noise component increases depending on the degree of corrosion or dirt. If there is a break in the wire, a sharp sudden wave will be generated depending on the degree of breakage. Furthermore, if the ground resistance of the steel tower is poor, the level of the fundamental wave changes, and the levels of frequency components other than the fundamental wave also change. Therefore, by looking at the output graph of the chart recorder 29, the location and degree of abnormality in the overhead power transmission line and its equipment can be determined on the spot.

In the embodiment shown in FIGS. 1 and 2, the intensity of the radio waves received by the measurement antenna was corrected based on the measured distance value measured by the distance meter 12. However, poor insulation in steel towers is a phenomenon that occurs in a limited manner when towers are installed or when they become obsolete. The intensity of the radio waves received by the measurement antenna may be feedback-controlled so that the

That is, in FIG. 2, the output of the smoothing circuit 40 is input to the distance correction control input of the distance correction circuit 30 instead of the output of the A/D converter 22, so that the output of the smoothing circuit 40 is kept constant. Feedback control. In this way, it is not necessary to equip the radio range finder 12. In this case, even if there is a defect in the insulation of the steel tower, the amplitude of the components other than the fundamental wave, that is, the noise component, will shift to a different value over a considerable distance, so it will not be possible to determine the defective insulation of the steel tower. can.

Furthermore, it is possible to determine whether the grounding resistance of the power transmission line tower is good or bad by using only the signal on the output signal line 24a of the distance correction/analysis circuit 24 (FIG. 2).

Although an example has been described in which the distance correction/analysis circuit 24 is configured with a digital arithmetic circuit, it goes without saying that part or all of it can be realized by program processing, and further, part or all of the present invention can be configured with an analog circuit. You may.

[Effects of the Invention] As can be easily understood from the above description, according to the present invention, it is possible to precisely detect defects in overhead power transmission lines and their equipment, as well as their contents and locations in real time.

Since the measured value is distance-corrected based on the measurement distance to the measurement target, there is no need to keep the measuring device at a strict distance from the overhead power transmission line and its equipment to be measured, making it possible to more accurately determine the nature and extent of the problem. It becomes possible to judge objectively. In addition, the entire circuit only needs to be able to process signals of about 1 kHz at most, so it can be manufactured at a very low cost.
I can prepare it.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the configuration of an embodiment of the present invention, FIG. 2 is a block diagram of the circuit configuration of the distance correction/analysis circuit 24 shown in FIG. 1, and FIG. 3 is an example of output of actual measurement results. 10: Measurement antenna 12: Radio distance meter 14: Fixed position marker 16, 18: Amplification circuit 20° 22: A
/D converter 24: Distance correction/analysis circuit 26: Data/
Recorder 28: D/A converter 29: Chart recorder 30: Distance correction circuit 32: LPF 3
4: BPF 36, 38: Absolute value circuit 40: Smoothing circuit 42: Division circuit 44: Delay circuit 46: Smoothing circuit 48: Sudden wave detection circuit 50: Delay circuit 5
2: Pulse generation circuit 54: Delay circuit

Claims (8)

[Claims] (1) A device for detecting abnormalities in overhead power transmission lines and their equipment, which includes a measurement antenna that receives radio waves from the overhead power transmission lines and their equipment, and the distance to the overhead power transmission lines and equipment to be investigated. A distance measuring means for measuring a distance, a distance correcting means for correcting the distance of a measured radio wave by the measuring antenna by the distance measured by the distance measuring means, and a radio wave signal whose distance has been corrected by the distance correcting means in a low frequency band. An apparatus for detecting abnormalities in overhead power transmission lines and their equipment, characterized by comprising an analysis means for analyzing. (2) The analysis means compares the intensity of the fundamental wave and the frequency band not including the fundamental wave with the frequency separation means that separates the frequency band into a fundamental wave and a frequency band that does not include the fundamental wave, and An apparatus for detecting an abnormality in an overhead power transmission line and its equipment according to claim (1), characterized in that it is equipped with an index output means for outputting an index value indicating the proportion of a frequency band that does not contain waves. . (3) The analysis means includes means for detecting sudden waves.
An abnormality detection device for overhead power transmission lines and their equipment as described in item 2). (4) An abnormality in the overhead power transmission line and its equipment as set forth in claim (1), wherein the analysis means comprises means for outputting a signal obtained by converting the fundamental wave into an absolute value and smoothing it. Location detection device. (5) Claim (1) further comprising an output means for outputting the analysis result of the analysis means in a graph.
An apparatus for detecting abnormalities in an overhead power transmission line and its equipment according to any one of paragraphs to (4). (6) A device for detecting abnormalities in overhead power transmission lines and their equipment, which includes a measurement antenna that receives radio waves from the overhead power transmission lines and their equipment, and a measurement antenna that measures the level of the radio waves measured by the measurement antenna, including the fundamental wave component. An overhead power transmission line and its equipment characterized by comprising a level control means for controlling the level to be constant, and an analysis means for frequency-analyzing the measured radio wave signal level-controlled by the level control means in a low frequency band. Abnormal location detection device. (7) An abnormality in the overhead power transmission line and its equipment as set forth in claim (6), wherein the analysis means comprises means for outputting a signal obtained by converting the fundamental wave into an absolute value and smoothing it. Location detection device. (8) Claim (6) characterized by comprising an output means for outputting the analysis result of the analysis means in a graph.
An abnormality location detection device for overhead power transmission lines and their equipment as described in paragraph (7).