Inspection system, inspection device, inspection method and inspection program

Abstract

In an inspection system according to one embodiment, one of the received signals calculated by a phase calculation unit is delayed so that time fluctuations of the received signals calculated by the phase calculation unit on the basis of the distances between high-voltage electrical equipment and electromagnetic wave receivers match each other as much as possible upon comparison, the amplitude ratio of each received signal for which the reception time has been shifted by the delay difference is calculated, when the calculated amplitude ratio exceeds a predetermined threshold, the phase of each received signal is corrected to specify the phase of the period, without adding or subtracting the signals for which the phase of each received signal is an integer multiple of the period, the position of the source of electromagnetic waves received by the plurality of electromagnetic wave receivers is estimated on the basis of the variance of the corrected phase residual of each received signal, and where a source determination unit determines that the source of electromagnetic waves is high-voltage electrical equipment, the presence or absence of an abnormality or state of the abnormality in the high-voltage electrical equipment is determined on the basis of signal characteristics such as the frequency, level fluctuations, and duration of occurrence of the received signals received by each electromagnetic wave receiver.

Description

[Technical Field]

[0001] The present invention relates to an inspection system, an inspection device, an inspection method, and an inspection program for inspecting high-voltage electrical equipment. [Background technology]

[0002] It is desirable to be able to inspect high-voltage electrical equipment, such as wind power generation equipment, for abnormalities and their status while the equipment is in operation. For example, in the stator of a generator installed in wind power generation equipment, mechanical stress is applied to the dielectric between the electrodes over a long period of operation, causing many small voids (impurities). This makes it easier for partial discharges, such as air gap discharges and void discharges, to occur in the dielectric between the electrodes, resulting in the emission of electromagnetic waves.

[0003] For example, in order to inspect high-voltage electrical equipment such as a generator for abnormalities while the equipment is running, known technologies include measuring and diagnosing the timing of discharge radio waves (discharge electromagnetic waves) emitted from the generator, and receiving discharge radio waves using multiple antennas and receivers to estimate the location of the source of the discharge radio waves.

[0004] Furthermore, a technique for diagnosing partial discharge (PD) in power equipment using a drone by the UHF method is known (see, for example, Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Hiroki Obara and two others, "2.4GHz-Band Drone Communication Wave Removal Characteristics of Frequency Filters for Partial Discharge Radiation Electromagnetic Wave Detection and Evaluation of Detected Waveforms by Cross-Correlation Method," Kyushu Branch Joint Conference of Electrical and Information Engineering Societies, 2018, 06-2P-03, p. 444 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when estimating the location of the source of discharge radio waves to inspect for abnormalities in high-voltage electrical equipment, if the accuracy of estimating the location of the source of discharge radio waves is reduced by external noise such as atmospheric noise caused by lightning discharge, there is a problem in that the accuracy of inspecting for abnormalities in the high-voltage electrical equipment being inspected is reduced.

[0007] The present invention has been made in consideration of the above-mentioned problems, and aims to provide an inspection system, an inspection device, an inspection method, and an inspection program that can accurately inspect the presence or absence of abnormalities in high-voltage electrical equipment or the state of the abnormality even when external noise may be present. [Means for solving the problem]

[0008] An inspection system according to one embodiment of the present invention includes a plurality of electromagnetic wave receiving units that move toward high-voltage electrical equipment and receive electromagnetic waves as reception signals at different positions, and an inspection device that inspects the high-voltage electrical equipment for abnormalities based on the reception signals received by each of the electromagnetic wave receiving units. The inspection device includes a phase calculation unit that calculates the phase and amplitude of each of the reception signals received by each of the electromagnetic wave receiving units, a delay unit that delays one of the reception signals calculated by the phase calculation unit based on the distance between the high-voltage electrical equipment and each of the electromagnetic wave receiving units so that the amplitude of each of the reception signals calculated by the phase calculation unit can be compared for each period, and a delay unit that calculates an amplitude ratio of each of the reception signals whose one side has been delayed by the delay unit, and when the calculated amplitude ratio exceeds a predetermined threshold, detects the position of each of the reception signals. The electromagnetic wave receiving device is characterized by comprising: a phase correction unit that corrects the phase of each received signal to identify the phase of one period without adding or subtracting a signal whose phase is an integer multiple of the period; a residual calculation unit that calculates the phase residual of each received signal for the period whose phase has been corrected by the phase correction unit; a position estimation unit that estimates the position of a source of the electromagnetic waves received by a plurality of the electromagnetic wave receiving units based on the variance of the phase residual of each received signal calculated by the residual calculation unit; a source determination unit that determines whether the source of the electromagnetic waves is the high-voltage electrical equipment based on the position of the source of the electromagnetic waves estimated by the position estimation unit; and a determination unit that, when the source determination unit determines that the source of the electromagnetic waves is the high-voltage electrical equipment, determines whether there is an abnormality or an abnormal state of the high-voltage electrical equipment based on the received signals received by each of the electromagnetic wave receiving units.

[0009] Furthermore, an inspection device according to one embodiment of the present invention is an inspection device that inspects high-voltage electrical equipment for abnormalities based on reception signals received by a plurality of electromagnetic wave receiving units that move toward the high-voltage electrical equipment and receive electromagnetic waves as reception signals at different positions, the inspection device comprising: a phase calculation unit that calculates the phase and amplitude of each reception signal received by each of the electromagnetic wave receiving units; a delay unit that delays one of the reception signals calculated by the phase calculation unit based on the distance between the high-voltage electrical equipment and each of the electromagnetic wave receiving units so that the amplitude of each reception signal calculated by the phase calculation unit can be compared for each period; and a delay unit that calculates an amplitude ratio of each of the reception signals whose one is delayed, and when the calculated amplitude ratio exceeds a predetermined threshold, outputs a signal whose phase in each reception signal is an integer multiple of the period. The electromagnetic wave receiving device is characterized by comprising a phase correction unit that corrects the phase of each received signal so as to identify the phase of a period without addition or subtraction; a residual calculation unit that calculates the phase residual of each received signal for the period whose phase has been corrected by the phase correction unit; a position estimation unit that estimates the position of a source of the electromagnetic waves received by a plurality of the electromagnetic wave receiving units based on the variance of the phase residual of each received signal calculated by the residual calculation unit; a source determination unit that determines whether the source of the electromagnetic waves is the high-voltage electrical equipment based on the position of the source of the electromagnetic waves estimated by the position estimation unit; and a determination unit that, when the source determination unit determines that the source of the electromagnetic waves is the high-voltage electrical equipment, determines whether there is an abnormality or an abnormal state of the high-voltage electrical equipment based on the received signals received by each of the electromagnetic wave receiving units.

[0010] Furthermore, an inspection method according to one embodiment of the present invention is an inspection method for inspecting high-voltage electrical equipment for abnormalities based on reception signals received by a plurality of electromagnetic wave receiving units that move toward the high-voltage electrical equipment and receive electromagnetic waves as reception signals at different positions, the inspection method comprising: a phase calculation step of calculating the phase and amplitude of each reception signal received by each of the electromagnetic wave receiving units; a delay step of delaying one of the reception signals based on the distance between the high-voltage electrical equipment and each of the electromagnetic wave receiving units so that the amplitudes of each reception signal calculated by the phase calculation step can be compared for each period; and a delay step of calculating an amplitude ratio of each of the reception signals whose one side is delayed by the delay step, and adding or subtracting a signal whose phase in each reception signal is an integer multiple of the period when the calculated amplitude ratio exceeds a predetermined threshold. a residual calculation step of calculating a phase residual of each of the received signals for the period whose phase has been corrected by the phase correction step; a position estimation step of estimating positions of sources of the electromagnetic waves received by the plurality of electromagnetic wave receiving units based on the variance of the phase residuals of each of the received signals calculated by the residual calculation step; a source determination step of determining whether the source of the electromagnetic waves is the high-voltage electrical equipment based on the positions of the sources of the electromagnetic waves estimated by the position estimation step; and a determination step of determining whether or not there is an abnormality or an abnormal state of the high-voltage electrical equipment based on the received signals received by each of the electromagnetic wave receiving units when it is determined by the source determination step that the source of the electromagnetic waves is the high-voltage electrical equipment. [Effects of the Invention]

[0011] According to the present invention, even when external noise may be present, it is possible to accurately inspect whether or not there is an abnormality in high-voltage electrical equipment, or whether the abnormality is present. [Brief explanation of the drawings]

[0012] [Figure 1] 1A is a diagram showing an overview of an inspection system according to an embodiment, and FIG. 1B is a graph illustrating an example of an operation of an inspection system according to an embodiment to inspect whether or not there is an abnormality in high-voltage electrical equipment. [Figure 2] 1A is a diagram showing an overview of another example of the configuration of an inspection system according to an embodiment, and FIG. 1B is a graph showing an example of the operation of an inspection system according to an embodiment to identify the source of discharge radio waves in order to inspect high-voltage electrical equipment for abnormalities. [Figure 3] FIG. 1 is a diagram illustrating a specific configuration example of an inspection system according to an embodiment. [Figure 4] FIG. 1 is a diagram illustrating an example of the configuration of a drone control device. [Figure 5] FIG. 1 is a diagram illustrating an example of the configuration of a drone. [Figure 6] FIG. 1 is a diagram illustrating a configuration example of an inspection device according to an embodiment. [Figure 7] 10 is a graph illustrating an example of the change over time in amplitude of each of the received signals calculated by each of the phase calculation units. [Figure 8] 10 is a graph illustrating the results of delaying one of the amplitude changes over time of a received signal by a delay unit. [Figure 9] 1 is a graph illustrating an example of the amplitude ratio of each electromagnetic wave. [Figure 10] 10 is a graph illustrating a process in which a phase correcting unit corrects the phase of an electromagnetic wave. [Figure 11] 10 is a graph showing the results of phase correction by a phase correction unit. [Figure 12] 12(a) is a graph showing the time variation φ31(t−τ) of the corrected phase at drone 3-1 with a delay difference τ, and the time variation φ32(t) of the received and corrected phase at drone 3-2. FIG. 12(b) is a graph showing the time variation of the residual φ31(t+τ)−φ32(t). [Figure 13] FIG. 2 is a diagram illustrating an example of a hardware configuration of an inspection device according to an embodiment. [Figure 14] 10 is a flowchart illustrating an example of the operation of the inspection system according to an embodiment. [Figure 15](a) is a diagram showing the relative positions of high-voltage electrical equipment and drones. (b) is a graph showing the frequency characteristics of the filter used by the drone to receive electromagnetic waves. (c) is a graph showing the residual phase dispersion when the drone's signal-to-noise ratio is 10 dB. DETAILED DESCRIPTION OF THE INVENTION

[0013] First, an overview of the operation of an inspection system according to an embodiment for inspecting high-voltage electrical equipment will be described. Fig. 1 is a diagram showing an example of the operation of an inspection system according to an embodiment for inspecting high-voltage electrical equipment. Fig. 1(a) is a diagram showing an overview of the inspection system according to an embodiment. Fig. 1(b) is a graph illustrating the operation of an inspection system according to an embodiment for inspecting high-voltage electrical equipment for abnormalities.

[0014] The high-voltage electrical equipment 100 to be inspected, such as a wind power generation facility, is housed behind switchgear or the like to prevent radio wave interference to the surrounding area, and the strength of the radio waves transmitted to the surrounding area is weakened. Therefore, inspection is carried out by approaching the high-voltage electrical equipment 100 to be inspected and receiving the discharge radio waves. When the high-voltage electrical equipment 100 is a wind power generation facility, it is difficult for people to approach the high-voltage electrical equipment 100 directly.

[0015] Therefore, in one embodiment of the inspection system, a drone A1 equipped with an electromagnetic wave receiving unit flies near a high-voltage electrical equipment 100, and the electromagnetic waves received by the drone A1 are relayed to the inspection device B1 via a wireless line between the drone and the inspection device, such as a telemeter, and are received by the inspection device B1.

[0016] For example, as shown in Figure 1(b), if the level of the received electromagnetic waves remains at a level stronger than a predetermined threshold for a predetermined time, or if the difference between the received level and the previously acquired value is greater than a predetermined value, the inspection device B1 determines that the high-voltage electrical equipment 100 is emitting partial discharge electromagnetic waves, and inspects (diagnoses) the signal characteristics to determine whether the high-voltage electrical equipment 100 is normal or abnormal.

[0017] More specifically, for example, for electromagnetic waves at a level stronger than a threshold, the inspection device B1 determines whether the frequency characteristics, occurrence frequency, duration, power, etc. are outliers compared to normal values ​​(for example, being more than three times the standard deviation value from the average), or the size of the difference from previously obtained values, and inspects (diagnoses) whether the high-voltage electrical equipment 100 is normal or abnormal.

[0018] Fig. 2 is a diagram showing an overview of an inspection method using another configuration of an inspection system according to an embodiment. Fig. 2(a) is a diagram showing an overview of another configuration example of an inspection system according to an embodiment. Fig. 2(b) is a graph showing an example of the operation of an inspection system according to an embodiment to identify the source of discharge radio waves in order to inspect high-voltage electrical equipment for abnormalities.

[0019] 2(a), in another configuration example of an inspection system according to one embodiment, drones A1 and A2, each equipped with an electromagnetic wave receiving unit and a drone-to-inspection device wireless line communication unit, are flown at distances D1 and D2, respectively, from high-voltage electrical equipment 100, and the electromagnetic waves received by drones A1 and A2 are received by inspection device B2 via the drone-to-inspection device wireless line. Inspection device B2 only needs to know the distance between each drone and the high-voltage power supply equipment to be inspected using a rangefinder or the like, and may be configured so that a single drone moves and uses electromagnetic waves of different levels received at different positions.

[0020] For example, as shown in FIG. 2(b), if the calculated value (for example, in the case of free space loss, the reception level of drone A1 multiplied by (D1 squared) is equal to the reception level of drone A2 multiplied by (D2 squared)) matches the measured value for two reception levels that differ depending on the distance from the high-voltage electrical equipment 100, the inspection device B2 determines that the radio waves are emitted by the high-voltage electrical equipment 100 that is the object of inspection. Specifically, the inspection device B2 1A1 ×D1 2 =P 1A2 ×D2 2 , and P 2A1 ×D1 2 =P 2A2 ×D2 2The inspection device B2 then inspects (diagnoses) whether the high voltage electrical equipment 100 is normal or abnormal based on the frequency characteristics, occurrence frequency, power, etc. of the discharge radio waves.

[0021] Furthermore, the inspection device B2 may be configured to measure the amplitude and phase of the electromagnetic waves received by the drones A1 and A2, and based on the amplitude ratio of the received electromagnetic waves, correct the phase by setting it to zero if the amplitude ratio is large. In this case, if the time difference in phase matches the reception time difference due to distance, the inspection device B2 determines that the radio waves are emitted by the high-voltage electrical equipment 100 being inspected. The inspection device B2 may then inspect (diagnose) whether the high-voltage electrical equipment 100 is normal or abnormal based on the frequency characteristics, occurrence frequency, power, etc. of the discharge radio waves.

[0022] The frequency characteristics of the electromagnetic waves caused by partial discharges emitted from the high-voltage electrical equipment 100 are broadband. In the inspection system according to one embodiment, the receiving frequency may be determined arbitrarily, or the frequency (wavelength λ) to be received may be assumed to be known in advance.

[0023] The propagation characteristics of the electromagnetic waves caused by partial discharge radiated from the high-voltage electrical equipment 100 are uniform in space. r ) depends only on the distance from the radiation source (φ r =D / λ×(2π)), phase difference (φ 12 ) depends only on the distance difference and wavelength (φ 12 =(D1-D2) / λ×(2π)).

[0024] Furthermore, the amplitude of the electromagnetic waves received by the drone is inversely proportional to the distance from the radiation source. Furthermore, there is an uncertainty of 2π×n when measuring the phase difference of the electromagnetic waves. When an inspection system according to one embodiment corrects the phase of the electromagnetic waves, if the amplitude ratio of the electromagnetic waves received between drones A1 and A2 is N times or more or less than M times the distance ratio, it is considered that the level of external noise is high, and the phase cannot be measured correctly due to the influence of the external noise. This value is used as a threshold, and the uncertainty when the phase difference of the electromagnetic waves is an integer multiple of the period is set to zero.

[0025] Next, an inspection system according to one embodiment will be described in more detail. Fig. 3 is a diagram showing a specific configuration example of an inspection system 1 according to one embodiment. As shown in Fig. 3, the inspection system 1 according to one embodiment includes, for example, a drone control device 2, drones 3-1 and 3-2, and an inspection device 4 in order to inspect high-voltage electrical equipment 100 such as wind power generation equipment.

[0026] The drone control device 2 controls the flight of the drones 3-1 and 3-2. The drones 3-1 and 3-2 each have an electromagnetic wave receiving unit 34 that receives radiated electromagnetic waves associated with discharges, which will be described later, and fly close to the high-voltage electrical equipment 100 to receive the electromagnetic waves as received signals, which are then relayed and transferred to the inspection device 4 via a wireless line between the drone and the inspection device. Hereinafter, when there is no need to specify one of multiple configurations, such as drones 3-1 and 3-2, they will be simply referred to as drone 3, etc.

[0027] The inspection device 4 has a control unit 40, an antenna 41, a wireless line communication unit 42, a data separation unit 43, a correlator 44, an analyzer 45, and a distance measurement unit 46, and analyzes the received signals transferred by the drones 3-1 and 3-2 to inspect the presence or absence of an abnormality or the state of the abnormality in the high-voltage electrical equipment 100. Details of the inspection device 4 will be described later using FIG. 6 etc.

[0028] Fig. 4 is a diagram showing an example configuration of the drone control device 2. As shown in Fig. 4, the drone control device 2 includes, for example, an antenna 20, a drone control communication unit 22, and a command unit 24. The command unit 24 transmits commands to control the drones 3-1 and 3-2 via the drone control communication unit 22 and the antenna 20.

[0029] Fig. 5 is a diagram showing an example of the configuration of the drone 3. As shown in Fig. 5, the drone 3 has, for example, a drone main body 30, a wireless line communication unit 32, and an electromagnetic wave receiving unit (discharge radio wave receiver) 34, and performs flight, communication, etc. according to the control of the drone control device 2.

[0030] The drone body 30 includes, for example, an antenna 301, a drone control communication unit 302, a flight control unit 303, four motor units 304, for example, and four rotors 305.

[0031] The drone control communication unit 302 communicates wirelessly with the drone control device 2 via the antenna 301. The flight control unit 303 controls the flight of the drone 3 by controlling four motor units 304 to rotate four rotors 305.

[0032] The wireless line communication unit 32 has, for example, an antenna 320, a MOD (modulator) 321, an amplifier 322, an amplifier 323, and a DEM (demodulator) 324, and performs wireless communication with the inspection device 4. For example, the wireless line communication unit 32 transmits a signal input from the electromagnetic wave receiving unit 34 to the inspection device 4, and performs settings on the electromagnetic wave receiving unit 34.

[0033] The electromagnetic wave receiving unit 34 has an antenna 340, a reference signal source 341, a frequency setting unit 342, a multiplier unit 343, a filter 344, an amplifier 345, a mixer 346, and a filter 347, and receives electromagnetic waves emitted due to partial discharge in high-voltage electrical equipment 100, etc., and outputs them to the wireless line communication unit 32.

[0034] The electromagnetic wave receiving unit 34 receives electromagnetic waves from the high-voltage electrical equipment 100 or the like via the antenna 340 and inputs them to a mixer 346 via a filter 344 and an amplifier 345. The electromagnetic wave receiving unit 34 also multiplies a reference signal oscillated by a reference signal source 341 to a frequency set by a frequency setting unit 342 using a multiplication unit 343 to generate a local signal, and inputs the local signal to the mixer 346.

[0035] Mixer 346 multiplies and mixes the input signals, and for the signals of the frequency that have passed through filter 344, which are the sum and difference of the frequencies of the local signals, filter 347 removes unnecessary frequency component signals, extracts signals of desired frequency components, and outputs the signals to wireless line communication unit 32, performing frequency conversion while retaining the phase information of the received signal. Wireless line communication unit 32 relays and transfers the signals input from filter 347 to the inspection device. At this time, modulator 321 modulates the signals by, for example, making the transmission frequencies different between drones so that the inspection device can have multiple access from drone 3-1 and drone 3-2.

[0036] Fig. 6 is a diagram showing an example of the configuration of an inspection device 4 according to one embodiment. As shown in Fig. 6, the inspection device 4 has a control unit 40, an antenna 41, a wireless line communication unit 42, a data separation unit 43, a correlator 44, an analyzer 45, and a distance measurement unit 46, and inspects the high-voltage electrical equipment 100 for abnormalities based on signals received from the drones 3-1 and 3-2. The distance measurement unit 46 measures the distance between each of the drones 3-1 and 3-2 and the high-voltage electrical equipment 100 and outputs the measurement result to the analyzer 45, but the distance between each of the drones 3-1 and 3-2 and the high-voltage electrical equipment 100 may be determined in advance.

[0037] The control unit 40 controls the wireless line communication device, the frequency setting unit 342 that sets the frequency of the receiver of the discharge electromagnetic waves in the drone, and each unit that constitutes the inspection device 4. The control unit 40 also controls to perform two-way wireless communication with the drones 3-1 and 3-2 via the wireless line communication unit 42 and the antenna 41.

[0038] The antenna 41 receives signals received and transferred by the drones 3-1 and 3-2 and outputs the signals to the wireless line communication unit 42. It also transmits signals to the drones 3-1 and 3-2.

[0039] The wireless line communication unit 42 has a filter 421, an amplifier 422, a DEM 423, a MOD 424, and an amplifier 425, and performs two-way wireless communication with the drones 3-1 and 3-2.

[0040] The data separator 43 separates the signals received by the inspection device 4 from the drones 3-1 and 3-2 to enable multiple access, and outputs them to the inspection device 4, respectively.

[0041] The correlator 44 has, for example, an oscillator 440, a 90-degree phase change unit 441, phase processing units 442-1, 442-2, a delay unit 443, a phase correction unit 444, and a residual calculation unit 445, and performs correlation processing to adjust and integrate the delay time and phase amount of the signal from drone 3-1 and the signal from drone 3-2.

[0042] Oscillator 440 outputs the oscillated signal to 90-degree phase shifter 441, phase processor 442-1, and phase processor 442-2.

[0043] 90-degree phase shifter 441 shifts the phase of the signal input from oscillator 440 by 90 degrees, and outputs the signal to phase processors 442-1 and 442-2.

[0044] The phase processing unit 442-1 has two multiplication units 446, two integrator units 447, and a phase calculation unit 448, and processes the signal input from the data separation unit 43 to calculate the phase, and outputs the calculated phase to the correlator 44.

[0045] Like the phase processing unit 442-1, the phase processing unit 442-2 has two multiplication units 446, two integration units 447, and a phase calculation unit 448, and processes the signal input from the data separation unit 43 to calculate the phase and output it to the delay unit 443.

[0046] For example, each phase calculation unit 448 calculates and outputs the phase and amplitude of each received signal received by each electromagnetic wave receiving unit 34 of the drone 3 using the principle of quadrature detection. That is, for example, when an input signal S = A·cos(ωt-φ) and a local oscillation signal Lc = B·cos(ωt) with a frequency of ω / (2π) are input to a mixer, the mixer output Mc can be expressed as the product of both signals, Mc = A·cos(ωt-φ) × B·cos(ωt). This calculation yields Mc = AB / 2·cos(2ωt-φ) + AB / 2·cos(φ). To remove the AC component of this signal and extract the DC component, for example, the integrator 447 integrates it every π / ω and divides the result by the π / ω period. Therefore, integrator 447 obtains Ic=ω / π∫[0→π / ω]Mc dt=ω / π∫[0→π / ω]{AB / 2cos(2ωt-φ)+AB / 2cos(φ)} dt=AB / 2·cos(φ). Meanwhile, the mixer output Ms with the local oscillation signal Ls=B·sin(ωt) that is phase shifted by 90 degrees is Ms=1 / 2sin(2ωt+φ)+1 / 2sin(φ), as above, and integrator 447 obtains output Is=AB / 2·sin(φ). From the output values ​​from the two integrators, φ can be calculated as φ=arctan(Is / Ic). The phase φ can be uniquely determined from the signs of Is and Ic. When (Is, Ic) = (+, +), 0 < φ < π / 2 (first quadrant); when (Is, Ic) = (+, -), π / 2 < φ < π (second quadrant); when (Is, Ic) = (-, -), π < φ < 3π / 2 (third quadrant); and when (Is, Ic) = (-, +), 3π / 2 < φ < 2π (fourth quadrant). Furthermore, from the above, the amplitude of the received signal can be calculated using 2Ic / {Bcos(φ)} or 2Is / {Bsin(φ)}, or the following equation (1). In this way, the phase and amplitude are calculated every fixed time (Δt).

[0047]

number

[0048] Figure 7 is a graph illustrating the change over time in the amplitude of each discharge radio wave reception signal for each drone calculated by each phase calculation unit 448. As shown in Figure 7, each phase calculation unit 448 calculates the amplitude of the electromagnetic waves received by each drone 3-1, 3-2 as described above. If the amplitudes at time t are S31(t) and S32(t), respectively, the change over time (reception time) in the amplitude of the electromagnetic waves received by drone 3-1 differs from the change over time in the amplitude of the electromagnetic waves received by drone 3-2 due to a reception time difference (delay difference τ) and amplitude ratio (Ar) caused by the distance from the radio wave emission source, and the result is S32(t) = Ar · S32(t - τ).

[0049] The phase processing sections 442-1 and 442-2 may be configured integrally, and are not limited to the configuration shown in FIG.

[0050] The delay unit 443 (FIG. 6) delays one of the time fluctuations in the amplitude of the received signals calculated by the phase calculation unit 448 so as to obtain an amplitude ratio (Ar) due to the delay difference in the reception time of each of the received signals calculated by the phase calculation unit 448 based on the distance between the high-voltage electrical equipment 100 and each of the electromagnetic wave receiving units 34, and outputs the delayed time fluctuation of the amplitude to the correlator 44. In other words, the delay unit 443 delays one of the received signals calculated by the phase calculation unit 448 so that the amplitudes of each of the received signals calculated by the phase calculation unit 448 can be compared for each period.

[0051] Fig. 8 is a graph illustrating the results of delaying one of the time changes in the amplitude of the received signal of the radio waves emitted by the drone by the delay unit 443. As shown in Fig. 8, even when the delay unit 443 processes the amplitudes of the two received signals so that they can be compared, there is a residual difference.

[0052] The phase correction unit 444 calculates the amplitude ratio (Ar) of each of the received signals, one of which has been delayed by the delay unit 443, and when the calculated amplitude ratio exceeds a predetermined threshold, corrects the phase of each of the received signals so as to identify the phase of the period without adding or subtracting a signal whose phase in each of the received signals is an integer multiple of the period, and outputs the corrected phase to the residual calculation unit 445.

[0053] For example, the phase correction unit 444 calculates the amplitude ratio (Ar) of the two received signals shown in FIG. 8, and when the amplitude ratio falls outside the range of a predetermined threshold as shown in FIG. 9, it sets the uncertainty of the integer multiple of the electromagnetic wave to zero, and sets the phase at that time to the phase found in the range of 0 to 2π radians as described above.

[0054] 10 is a graph illustrating the process of correcting the phase of the electromagnetic wave by the phase corrector 444. The phase corrector 444 corrects the uncertainty of an integer multiple of 2π for the phase of the electromagnetic wave so that the fluctuation of the electromagnetic wave becomes continuous.

[0055] Specifically, the phase correction unit 444 adds 2π radians to the change in Δt of the phase (φ(t) is the phase at time t) calculated every Δt when (A) φ(t) is in the third quadrant and φ(t+Δt) changes to the first quadrant and the amount of change (φ(t+Δt)-φ(t)) is -π radians or less, (B) there is a change from the fourth quadrant to the first quadrant, or (C) there is a change from the fourth quadrant to the second quadrant and the amount of change (φ(t+Δt)-φ(t)) is -π radians or less, correcting the phase to φ(t+Δt) = φ(t+Δt) + 2π.

[0056] Furthermore, the phase correction unit 444 subtracts 2π radians and corrects φ(t+Δt) to φ(t+Δt)=φ(t+Δt)-2π if (D) φ(t) changes to the first quadrant and φ(t+Δt) changes to the fourth quadrant, (E) there is a change from the second quadrant to the fourth quadrant and the amount of change (φ(t+Δt)-φ(t)) is π radians or more, or (F) there is a change from the first quadrant to the third quadrant and the amount of change (φ(t+Δt)-φ(t)) is π radians or more.

[0057] Furthermore, when external noise is large, the quality of the received signal deteriorates, and a phase error of 2π or more occurs due to the ambiguity of the integer multiple described above. Therefore, phase correction unit 444 sets the ambiguity of the integer multiple to zero, calculates the phase in the range of 0 to 2π radians as described above, and corrects the phase again every Δt.

[0058] Fig. 11 is a graph showing the result of phase correction by the phase correction unit 444 for the signal received by drone 3-1. As shown in Fig. 11, the inspection device 4 performs delay processing to compensate for the difference in reception time between drones 3-1 and 3-2 for signals received by drones close to high-voltage electrical equipment 100, which may be a source of electromagnetic waves, calculates the amplitude ratio of the received signals by comparing their amplitudes, and when the amplitude ratio (Ar) is outside a predetermined threshold range, determines that external noise is large, sets the uncertainty of the integer multiple described above to zero, and sets the phase found in the range of 0 to 2π radians as the phase at that time.

[0059] The residual calculation unit 445 (FIG. 6) calculates the time change of the phase corrected by the phase correction unit 444 when the delay difference is τ (time change of the phase of the signals received by the drone 3-1 and the drone 3-2 is φ 31 (t) and φ 32 (t)) residual φ 31 (t+τ)-φ 32 (t) to the analyzer 45. In other words, the residual calculation unit 445 calculates the phase residual of each received signal for the period in which the phase correction unit 444 corrected the phase.

[0060] The analyzer 45 includes a variance calculation unit 451 , a position estimation unit 452 , a source determination unit 453 , and a determination unit 454 .

[0061] The variance calculation unit 451 calculates the phase residual {φ 31 (n△t+τ)-φ 32 (n△t)} measurement time variance (=(φ 31 (t+τ)-φ 32 (t)) 2 / T: Here, T is the measurement time, or the following equation (2) is calculated, and the calculated variance value is output as a result to the position estimation unit 452 together with information indicating the distance input from the distance measurement unit 46.

[0062]

number

[0063] Figure 12 is a graph showing the time change of the phase and the time change of the residual. Figure 12(a) is a graph showing the time change of the corrected phase φ31(t-τ) at drone 3-1 with the delay difference τ, and the time change of the corrected phase φ32(t) received at drone 3-2. Figure 12(b) is a graph showing the time change of the residual φ31(t+τ)-φ32(t).

[0064] The position estimation unit 452 estimates the position of the source of the electromagnetic waves received by the electromagnetic wave receiving unit 34 of each drone 3-1, 3-2 based on the variance of the phase residual of each received signal calculated by the residual calculation unit 445, and outputs the estimation result to the source determination unit 453.

[0065] The source determination unit 453 determines whether the source of the electromagnetic waves is the high-voltage electrical equipment 100 based on the position of the source of the electromagnetic waves estimated by the position estimation unit 452, and outputs the determination result to the determination unit 454.

[0066] For example, the source determination unit 453 determines that the source of the electromagnetic waves is the high-voltage electrical equipment 100 when the level difference of the received signals received by each electromagnetic wave receiving unit 34 matches the level difference due to the difference in distance between the high-voltage electrical equipment 100 and each electromagnetic wave receiving unit 34, or when the phase time difference of the received signals received by each electromagnetic wave receiving unit 34 matches the reception time difference due to the difference in distance between the high-voltage electrical equipment 100 and each electromagnetic wave receiving unit 34.

[0067] When the source determination unit 453 determines that the source of the electromagnetic waves is the high-voltage electrical equipment 100, the determination unit 454 determines whether there is an abnormality or an abnormal state of the high-voltage electrical equipment 100 based on the received signals received by the electromagnetic wave receiving units 34 of each of the drones 3-1 and 3-2.

[0068] For example, the determining unit 454 determines that there is an abnormality in the high-voltage electrical equipment 100 when the reception signals received by the electromagnetic wave receiving units 34 are at a level stronger than a predetermined threshold.

[0069] The determining unit 454 may also determine whether the high-voltage electrical equipment 100 is in an abnormal state based on the frequency characteristics, occurrence frequency, power, etc. of the electromagnetic waves received by the electromagnetic wave receiving unit .

[0070] In addition, each function possessed by the inspection device 4 may be partially or entirely configured by hardware such as a PLD (Programmable Logic Device) or an FPGA (Field Programmable Gate Array), or may be configured as a program executed by a processor such as a CPU.

[0071] For example, the inspection device 4 can be realized using a computer and a program, and the program can be recorded on a storage medium or provided via a network.

[0072] Fig. 13 is a diagram showing an example of the hardware configuration of an inspection device 4 according to one embodiment. As shown in Fig. 12, the inspection device 4 has an input unit 90, an output unit 91, a communication unit 92, a CPU 93, a memory 94, and an HDD 95 connected via a bus 96, and has the functions of a computer. The inspection device 4 is also configured to be able to input and output data to and from a computer-readable storage medium 97.

[0073] The input unit 90 is, for example, a keyboard and a mouse, etc. The output unit 91 is, for example, a display device such as a display.

[0074] The communication unit 92 is a communication interface that performs wireless communication.

[0075] The CPU 93 controls each component of the inspection device 4 and performs predetermined processing, etc. The memory 94 and the HDD 95 store data, etc.

[0076] The storage medium 97 is capable of storing programs and the like that cause the inspection device 4 to execute the functions of the inspection device 4. Note that the architecture that configures the inspection device 4 is not limited to the example shown in FIG.

[0077] Next, an example of the operation of the inspection system 1 will be described. Fig. 14 is a flowchart showing an example of the operation of the inspection system 1 according to one embodiment. As shown in Fig. 14, in step 100 (S100), the drones 3-1 and 3-2 determine whether the level of the signal received by the electromagnetic wave receiving unit 34 is greater than a predetermined threshold. If the drones 3-1 and 3-2 determine that the level of the signal received by the electromagnetic wave receiving unit 34 is greater than the predetermined threshold (S100: Yes), they proceed to processing of S102, and if the drones 3-1 and 3-2 determine that the level of the signal received by the electromagnetic wave receiving unit 34 is equal to or less than the predetermined threshold (S100: No), they continue processing.

[0078] In step 102 (S102), the electromagnetic wave receiving unit 34 continues receiving electromagnetic waves (data) for a predetermined time.

[0079] In step 104 (S104), the analyzer 45 calculates the variance of the residual with respect to the phase difference Δτ.

[0080] In step 106 (S106), the analyzer 45 calculates the delay time t L Identify.

[0081] In step 108 (S108), the inspection device 4 measures the positions (distances) of the drones 3-1 and 3-2 and the high-voltage electrical equipment 100.

[0082] In step 110 (S110), the inspection device 4 sets the coordinates of the drones 3-1 and 3-2 and the high-voltage electrical equipment 100 to their respective positions. For example, the inspection device 4 sets (0,0,0) for the drone 3-1, (D,0,0) for the drone 3-2, and (Sx,Sy,Sz) for the high-voltage electrical equipment 100.

[0083] In step 112 (S112), the inspection device 4 performs the calculation of the equation shown in S112, where c is the speed of light.

[0084] In step 114 (S114), the inspection device 4 determines whether the equations shown in S112 are satisfied for each of the received electromagnetic waves and the positions of the drones 3-1, 3-2 and the high-voltage electrical equipment 100. If the inspection device 4 determines that the equations shown in S112 are not satisfied (S114: No), it proceeds to processing of S116, and if the inspection device 4 determines that the equations shown in S112 are satisfied (S114: Yes), it proceeds to processing of S118.

[0085] In step 116 (S116), the inspection device 4 determines that the electromagnetic waves received by the drone 3 are radio waves from a source other than the high-voltage electrical equipment 100 (other), and returns to the processing of S100.

[0086] In step 118 (S118), the inspection device 4 determines that the electromagnetic waves received by the drone 3 are radio waves from the high-voltage electrical equipment 100, which is the equipment to be inspected.

[0087] In step 120 (S120), the inspection device 4 stores the time when the drones 3-1 and 3-2 received the electromagnetic waves and the level of the electromagnetic waves.

[0088] In step 122 (S122), the inspection device 4 calculates the generation intervals of the stored electromagnetic waves.

[0089] In step 124 (S124), the inspection device 4 determines whether the calculated electromagnetic wave generation interval and level deviate from the normal values, and if they deviate (S126: Yes), proceeds to processing S126, and if they do not deviate (S126: No), proceeds to processing S128.

[0090] In step 126 (S126), the inspection device 4 determines that there is an abnormality in the high-voltage electrical equipment 100 (equipment abnormality), and returns to the processing of S100.

[0091] In step 128 (S128), the inspection device 4 determines that there is no abnormality in the high-voltage electrical equipment 100 (equipment is normal), and returns to the processing of S100.

[0092] Next, an example will be described in which the inspection system 1 inspects high-voltage electrical equipment 100. Fig. 15 is a diagram showing an example in which the inspection system 1 inspects high-voltage electrical equipment 100. Fig. 15(a) is a diagram showing the positional relationship between the high-voltage electrical equipment 100 and the drones 3-1 and 3-2. Fig. 15(b) is a graph showing the frequency characteristics of a filter used by the drone 3 when receiving electromagnetic waves. Fig. 15(c) is a graph showing the residual variance of the phase when the S / N ratio of the drone 3-1 is 10 dB.

[0093] Here, we conducted a numerical experiment by generating noise with a standard normal distribution using the Box-Muller method. As shown in Figure 14(a), the distance from high-voltage electrical equipment 100, which may be a radio wave source, to drone 3-1 is 1000 m, and the distance from high-voltage electrical equipment 100 to drone 3-2 is 1300 m. In other words, the distance difference between drones 3-1 and 3-2 is 300 m.

[0094] The electric field strength (the square root of the power or level) is inversely proportional to the distance, and the strength of the external noise is assumed to be the same for both drones 3-1 and 3-2. Drones 3-1 and 3-2 receive electromagnetic waves through receiving filters with the frequency characteristics shown in Figure 14(b) (a 3 dB bandwidth of 100 kHz centered at 1 MHz).

[0095] The inspection device 4 of the inspection system 1 changes the intensity of the external wave noise based on the intensity of the partial discharge radio waves received by the drone 3-1, and uses this as a parameter in the signal-to-noise ratio.

[0096] In addition, the inspection device 4 changed the delay time of the radio waves received by the drone 3-1 analyzed by the analyzer 45 using 10,000 sampling data (400 μs) with a sampling interval of 0.04 μs, and calculated the residual variance of the phase against the delay time.

[0097] Here, the variance was smallest when the delay time (delay difference) was 1 μs, and it was possible to deduce that the difference in distance between the discharge radio waves received by drones 3-1 and 3-2 was 300 m (=1 μs), which was consistent with the calculation model. In this way, it was demonstrated that the inspection system 1 according to one embodiment can estimate the position of the source of partial discharge radio waves more accurately than, for example, a comparative example that does not include the phase correction unit 444.

[0098] That is, the inspection system 1 can improve the accuracy of estimating the position of the source of the discharge radio waves, and therefore can improve the accuracy of inspecting the high-voltage electrical equipment 100 to be inspected for abnormalities.

[0099] In this way, in the inspection system 1 according to one embodiment, the delay unit 443 calculates the amplitude ratio of each of the phase-matched received signals, and when the calculated amplitude ratio exceeds a predetermined threshold, corrects the phase of each received signal to identify the phase of the period without adding a signal whose phase difference in each received signal is an integer multiple of the period. Therefore, even when external noise may be present, it is possible to accurately inspect the presence or absence of abnormalities in the high-voltage electrical equipment 100 or the state of the abnormality. [Explanation of symbols]

[0100] 1···Inspection system, 2···Drone control device, 3-1, 3-2, A1, A2···Drone, 4, B1, B2···Inspection device, 20···Antenna, 22···Drone control communication unit, 24···Command unit, 30···Drone main body, 32···Wireless line communication unit, 34···Electromagnetic wave receiving unit, 40···Control unit, 41···Antenna, 42···Wireless line communication unit, 43···Data separation unit, 44···Correlator, 45···Analyzer, 46···Ranging unit, 90···Input unit, 91···Output unit, 92···Communication unit, 93···CPU, 9 4. Memory, 95. HDD, 96. Bus, 97. Storage medium, 100. High-voltage electrical equipment, 301. Antenna, 302. Drone control communication unit, 303. Flight control unit, 304. Motor unit, 305. Rotor, 442-1, 442-2. Phase processing unit, 443. Delay unit, 444. Phase correction unit, 445. Residual calculation unit, 446. Multiplication unit, 447. Integration unit, 448. Phase calculation unit, 451. Variance calculation unit, 452. Position estimation unit, 453. Source determination unit, 454. Determination unit

Claims

1. An inspection system including a plurality of electromagnetic wave receiving units that move toward high-voltage electrical equipment and receive electromagnetic waves as reception signals at different positions, and an inspection device that inspects the high-voltage electrical equipment for abnormalities based on the reception signals received by each of the electromagnetic wave receiving units, The inspection device includes: a phase calculation unit that calculates the phase and amplitude of each of the received signals received by each of the electromagnetic wave receiving units; a delay unit that delays one of the received signals calculated by the phase calculation unit based on the distance between the high-voltage electrical equipment and each of the electromagnetic wave receiving units so that the amplitudes of the received signals calculated by the phase calculation unit can be compared for each period; a phase correcting unit that calculates an amplitude ratio of each of the received signals, one of which has been delayed by the delay unit, and corrects the phase of each of the received signals so as to specify a phase of the period without adding or subtracting a signal whose phase in each of the received signals is an integer multiple of the period, when the calculated amplitude ratio exceeds a predetermined threshold; a residual calculation unit that calculates a phase residual of each received signal for a period whose phase has been corrected by the phase correction unit; a position estimation unit that estimates positions of sources of electromagnetic waves received by the plurality of electromagnetic wave receiving units based on the variance of the phase residuals of the respective received signals calculated by the residual calculation unit; a source determination unit that determines whether the source of the electromagnetic waves is the high-voltage electrical equipment based on the position of the source of the electromagnetic waves estimated by the position estimation unit; a determination unit that determines whether or not there is an abnormality in the high-voltage electrical equipment or determines an abnormal state based on the reception signals received by each of the electromagnetic wave receiving units when the generation source determination unit determines that the source of the electromagnetic waves is the high-voltage electrical equipment; An inspection system comprising:

2. The determination unit When the received signals received by the electromagnetic wave receiving units are at a level stronger than a predetermined threshold, it is determined that there is an abnormality in the high-voltage electrical equipment. The inspection system according to claim 1 .

3. The generation source determination unit When the level difference of the received signals received by each of the electromagnetic wave receiving units matches the level difference due to the difference in distance between the high-voltage electrical equipment and each of the electromagnetic wave receiving units, or when the phase time difference of the received signals received by each of the electromagnetic wave receiving units matches the reception time difference due to the difference in distance between the high-voltage electrical equipment and each of the electromagnetic wave receiving units, it is determined that the source of the electromagnetic waves is the high-voltage electrical equipment.

3. The inspection system according to claim 1 or 2,

4. An inspection device that inspects high-voltage electrical equipment for abnormalities based on reception signals received by a plurality of electromagnetic wave receiving units that move close to the high-voltage electrical equipment and receive electromagnetic waves as reception signals at different positions, a phase calculation unit that calculates the phase and amplitude of each of the received signals received by each of the electromagnetic wave receiving units; a delay unit that delays one of the received signals calculated by the phase calculation unit based on the distance between the high-voltage electrical equipment and each of the electromagnetic wave receiving units so that the amplitudes of the received signals calculated by the phase calculation unit can be compared for each period; a phase correcting unit that calculates an amplitude ratio of each of the received signals, one of which has been delayed by the delay unit, and corrects the phase of each of the received signals so as to specify a phase of the period without adding or subtracting a signal whose phase in each of the received signals is an integer multiple of the period, when the calculated amplitude ratio exceeds a predetermined threshold; a residual calculation unit that calculates a phase residual of each received signal for a period whose phase has been corrected by the phase correction unit; a position estimation unit that estimates positions of sources of electromagnetic waves received by the plurality of electromagnetic wave receiving units based on the variance of the phase residuals of the respective received signals calculated by the residual calculation unit; a source determination unit that determines whether the source of the electromagnetic waves is the high-voltage electrical equipment based on the position of the source of the electromagnetic waves estimated by the position estimation unit; a determination unit that determines whether or not there is an abnormality in the high-voltage electrical equipment or determines an abnormal state based on the reception signals received by each of the electromagnetic wave receiving units when the generation source determination unit determines that the source of the electromagnetic waves is the high-voltage electrical equipment; An inspection device comprising:

5. The determination unit When the received signals received by the electromagnetic wave receiving units are at a level stronger than a predetermined threshold, it is determined that there is an abnormality in the high-voltage electrical equipment.

5. The inspection device according to claim 4, wherein:

6. The generation source determination unit When the level difference of the received signals received by each of the electromagnetic wave receiving units matches the level difference due to the difference in distance between the high-voltage electrical equipment and each of the electromagnetic wave receiving units, or when the phase time difference of the received signals received by each of the electromagnetic wave receiving units matches the reception time difference due to the difference in distance between the high-voltage electrical equipment and each of the electromagnetic wave receiving units, it is determined that the source of the electromagnetic waves is the high-voltage electrical equipment.

6. The inspection device according to claim 4 or 5,

7. 1. An inspection method for inspecting high-voltage electrical equipment for abnormalities based on reception signals received by a plurality of electromagnetic wave receiving units that move toward the high-voltage electrical equipment and receive electromagnetic waves as reception signals at different positions, comprising: a phase calculation step of calculating the phase and amplitude of each of the received signals received by each of the electromagnetic wave receiving units; a delaying step of delaying one of the received signals calculated in the phase calculating step based on the distance between the high-voltage electrical equipment and each of the electromagnetic wave receiving units so that the amplitudes of the received signals calculated in the phase calculating step can be compared for each period; a phase correction step of calculating an amplitude ratio of the received signals, one of which has been delayed by the delay step, and correcting the phase of each received signal so as to specify a phase of the period without adding or subtracting a signal whose phase is an integer multiple of the period in each received signal when the calculated amplitude ratio exceeds a predetermined threshold; a residual calculation step of calculating a phase residual for each of the received signals for the period whose phases have been corrected by the phase correction step; a position estimation step of estimating positions of sources of electromagnetic waves received by the plurality of electromagnetic wave receiving units based on the variance of the phase residuals of the respective received signals calculated in the residual calculation step; a source determination step of determining whether the source of the electromagnetic waves is the high-voltage electrical equipment based on the position of the source of the electromagnetic waves estimated in the position estimation step; a determination step of determining whether or not there is an abnormality in the high-voltage electrical equipment or the abnormal state based on the reception signals received by each of the electromagnetic wave receiving units when it is determined in the source determination step that the source of the electromagnetic waves is the high-voltage electrical equipment; An inspection method comprising:

8. An inspection program for causing a computer to function as each part of the inspection device according to claim 4.

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