Partial discharge measurement method using acoustic camera and reference signal generation apparatus, partial discharge measurement system, and computer-readable recording medium

Abstract

A partial discharge measurement system is disclosed. The present system comprises: a reference signal generation apparatus that is located in a real space and outputs a reference signal for phase correction; and an acoustic camera that measures partial discharge on the basis of a partial discharge acoustic signal generated from a target to be measured. The acoustic camera includes: an acoustic signal reception unit that receives the partial discharge acoustic signal generated from the target being measured; and a data processing unit that generates partial discharge acoustic data for the partial discharge acoustic signal and phase-corrects the partial discharge acoustic data on the basis of a phase difference between the reference signal and the partial discharge acoustic signal, so as to generate phase-corrected partial discharge acoustic data.

Description

Partial discharge measurement method using an acoustic camera and a reference signal generation device, a partial discharge measurement system, and a computer-readable recording medium

[0001] The present invention relates to a technology for performing phase calibration of partial discharge acoustic data collected by an acoustic camera using a reference signal of a reference signal generating device, and analyzing phase resolved partial discharge (PRPD) based on the phase-corrected partial discharge acoustic data.

[0002] Partial discharge (PD) is a local discharge phenomenon that occurs within an electrical insulation system. It is an electrical discharge that occurs in a local area without destroying the insulation of the entire system.

[0003] In general, partial discharge can be classified into external discharge, internal discharge, surface discharge, and floating discharge.

[0004] External discharges include arc discharge, a type of insulation breakdown that occurs continuously in the gas between electrodes due to a potential difference generated at the electrodes, and corona discharge, a discharge phenomenon that occurs when gas particles on the electrode surface are ionized due to the high voltage applied between two electrodes.

[0005] Internal discharge is the most common discharge that occurs when there is a defect in the solid insulation of cables, bushings, or GIS joint insulation.

[0006] Surface discharge is the most dangerous type of discharge, and is a discharge that occurs on the surface of an insulator when the voltage applied to the dielectric increases and exceeds a certain value.

[0007] Floating discharge is a partial discharge that occurs when there is a conductor that is floating at an unstable potential, such as due to poor grounding, poor connection, or insulation cracks.

[0008] As an example of the partial discharge described above, power equipment deteriorates as it is used outdoors for a long period of time, and in particular, as deterioration progresses, cracks develop inside the insulators of the power equipment, and moisture penetrates into these cracks, and as wet and dry states are repeated, contaminants penetrate inside, creating conductive paths, and electric fields are concentrated on these conductive paths, causing partial discharge.

[0009] Partial discharge causes electrical and mechanical vibrations and releases discharge energy in the form of electromagnetic waves, ultrasound, and sound. Therefore, detecting discharge energy in power equipment can diagnose deterioration of the power equipment.

[0010] Previously, there was an acoustic camera that measured ultrasonic waves generated at the time of partial discharge to determine whether a partial discharge occurred or what type of partial discharge occurred.

[0011] These acoustic cameras provide a Phase Resolved Partial Discharge Graph (PRPD graph) for partial discharge analysis, and in order to produce a PRPD graph from an acoustic camera, ① the power line frequency of the measurement target equipment (typically 50 Hz or 60 Hz) and synchronization information of the AC voltage signal applied to the operating equipment, and ② time-domain sound pressure data are essential.

[0012] At this point, the reason why the commercial frequency of the measurement target equipment must be known is for phase locking. A PRPD graph decomposes a constant signal into phases ranging from 0 to 360 degrees and displays them as points. Without phase locking, it is difficult to obtain an accurate PRPD graph.

[0013] Figure 25 is a diagram showing PRPD graphs according to Poor Phase Lock and Good Phase Lock, respectively. In the PRPD graph, the X-axis represents the phase value (degree) in the range of 0 to 360 degrees, the Y-axis represents the partial discharge magnitude, and the color / density of the points in the graph indicates the number of partial discharge occurrences.

[0014] If a PRPD graph is visualized without obtaining accurate phase information, a PRPD graph may be drawn in which the points of the graph are distributed over the entire phase rather than concentrated in a specific phase, as in the example of Poor Phase Lock in Fig. 24(a), making it difficult to distinguish what type of partial discharge it is. However, if a PRPD graph is visualized with accurate phase information, a PRPD graph may be drawn in which the points of the graph are concentrated in a specific phase, as in the example of Good Phase Lock in Fig. 24(b), making it possible to distinguish what type of partial discharge it is.

[0015] Conventional HFCT sensors or TEV sensors that measure partial discharge using electromagnetic waves can measure the commercial frequency and phase of operating equipment, enabling the calculation of accurate PRPD graphs.

[0016] However, since it is difficult for an acoustic camera to accurately measure the commercial frequency and phase information of a facility, the PRPD graph is drawn after setting the commercial frequency and phase to arbitrary values. Accordingly, there was a problem in that it was difficult for a conventional acoustic camera to produce an accurate PRPD graph.

[0017] Additionally, the conventional inaccurate PRPD graph had the problem of causing inaccurate partial discharge analysis results for users using acoustic cameras.

[0018] The present invention has been conceived in accordance with the above-described needs, and an object of the present invention is to provide a partial discharge measurement method, a partial discharge measurement system, and a computer-readable recording medium that enable an acoustic camera to accurately measure the commercial frequency and phase information of a measurement target using a reference signal output from a reference signal generating device.

[0019] An object of the present invention is to provide a partial discharge measuring method, a partial discharge measuring system, and a computer-readable recording medium for generating phase-corrected partial discharge sound data by phase-correcting partial discharge sound data collected by an acoustic camera using a reference signal of a reference signal generating device.

[0020] In addition, an object of the present invention is to provide a partial discharge measurement method, a partial discharge measurement system, and a computer-readable recording medium for generating a PRPD graph based on phase-corrected partial discharge acoustic data.

[0021] In order to achieve the above-described object, a partial discharge measurement system according to an embodiment of the present invention includes a reference signal generating device located in a real space and outputting a reference signal for phase correction, and an acoustic camera for measuring partial discharge based on a partial discharge acoustic signal generated from a measurement target, wherein the acoustic camera includes an acoustic signal receiving unit for receiving the partial discharge acoustic signal generated from the measurement target, and a data processing unit for generating partial discharge acoustic data for the partial discharge acoustic signal, and for phase-correcting the partial discharge acoustic data based on a phase difference between the reference signal and the partial discharge acoustic signal to generate phase-corrected partial discharge acoustic data.

[0022] In addition, the reference signal generating device may include a power supply connected to an external power source in the same environment as the environment in which the measurement target is located.

[0023] In addition, the reference signal generating device can generate and output a signal synchronized with an AC voltage signal applied through the power supply.

[0024] In addition, the reference signal generating device may include a phase detection unit that detects a predetermined phase position of an AC voltage signal applied through the power supply unit, and a reference signal output unit that generates a predetermined pulse at the position of the detected phase and outputs it as the reference signal.

[0025] Additionally, the reference signal may include at least one of an RF (Radio Frequency) signal and an ultrasonic acoustic signal.

[0026] And, when the reference signal is an ultrasonic reference signal, the reference signal output unit can adjust at least one of the cycle and number of times of outputting the ultrasonic reference signal.

[0027] In addition, the data processing unit can calculate a phase difference between the reference signal and the partial discharge sound signal, convert the calculated phase difference into a number of samples, and correct the sound data by the number of converted samples to generate the phase-corrected partial discharge sound data.

[0028] In addition, the data processing unit can produce a phase-resolved partial discharge (PRPD) graph using phase-corrected partial discharge acoustic data.

[0029] In addition, it may further include an output section that outputs the phase-resolved partial discharge graph.

[0030] And, the reference signal generating device may be located within a predetermined distance from the measurement target or within a predetermined distance from the acoustic camera.

[0031] Meanwhile, in a partial discharge measurement method according to an embodiment of the present invention for achieving the above-described purpose, a reference signal generating device is positioned in a real space and includes a step of outputting a reference signal for phase correction, and an acoustic camera includes a step of receiving a partial discharge acoustic signal generated from a measurement target, generating partial discharge acoustic data for the partial discharge acoustic signal, and performing phase correction on the partial discharge acoustic data based on a phase difference between the reference signal and the partial discharge acoustic signal to generate phase-corrected partial discharge acoustic data.

[0032] And, the power supply unit of the reference signal generating device may further include a step of connecting to an external power supply in the same environment as the environment in which the measurement target is located, and the step of outputting the reference signal may generate and output a signal synchronized with an AC voltage signal applied through the power supply unit.

[0033] Additionally, the reference signal may include at least one of an RF reference signal and an ultrasonic reference signal.

[0034] And, in the case of the RF reference signal, the step of generating the phase-corrected partial discharge sound data may include the step of calculating the phase difference between the RF reference signal and the partial discharge sound signal, the step of converting the calculated phase difference into a number of samples, and the step of correcting the partial discharge sound data by the converted number of samples to generate the phase-corrected partial discharge sound data.

[0035] In addition, in the case of the ultrasonic reference signal, the step of generating the phase-corrected partial discharge sound data may include the steps of distinguishing ultrasonic reference sound data corresponding to the ultrasonic reference signal and the partial discharge sound data, calculating a phase difference between the ultrasonic reference signal and the partial discharge sound signal, converting the calculated phase difference into a number of samples, and correcting the partial discharge sound data by the converted number of samples to generate the phase-corrected partial discharge sound data.

[0036] Meanwhile, an acoustic camera according to an embodiment of the present invention for achieving the above-described purpose may include an acoustic receiving unit that receives a partial discharge acoustic signal generated from a measurement target and an ultrasonic reference signal generated from a reference signal generating device that outputs a reference signal for phase correction, and a data processing unit that phase-corrects partial discharge acoustic data based on a phase difference between the ultrasonic reference signal and the partial discharge acoustic signal to generate phase-corrected partial discharge acoustic data.

[0037] In addition, an acoustic camera according to an embodiment of the present invention for achieving the above-described purpose includes an acoustic receiving unit that receives a partial discharge acoustic signal generated from a measurement target, an RF receiving unit that receives an RF reference signal generated from a reference signal generating device that outputs a reference signal for phase correction, and a data processing unit that phase-corrects partial discharge acoustic data based on a phase difference between the RF reference signal and the partial discharge acoustic signal to generate phase-corrected partial discharge acoustic data.

[0038] In addition, a computer-readable recording medium according to an embodiment of the present invention for achieving the above-described purpose may record a program for executing the above-described partial discharge measurement method.

[0039] In addition, a computer program stored in a computer-readable recording medium according to an embodiment of the present invention for achieving the above-described purpose may include a program code for executing the above-described partial discharge measurement method.

[0040] According to various embodiments of the present invention, by correcting the phase of partial discharge sound data collected by an acoustic camera using a reference signal of a reference signal generating device and generating phase-corrected partial discharge sound data, an accurate PRPD graph can be drawn through phase lock.

[0041] Additionally, according to various embodiments of the present invention, it is possible to enable accurate partial discharge analysis by a user using an acoustic camera through an accurate PRPD graph.

[0042] FIG. 1 is a conceptual diagram showing a partial discharge measurement system according to one embodiment of the present invention.

[0043] FIG. 2 is a block diagram showing a partial discharge measurement system according to one embodiment of the present invention.

[0044] FIG. 3 is a block diagram showing an RF reference signal generating device that generates an RF reference signal according to one embodiment of the present invention.

[0045] FIG. 4 is a diagram showing an AC voltage signal and an RF reference signal generated by a reference signal generating device in an environment in which a measurement target is installed according to one embodiment of the present invention.

[0046] FIG. 5 is a block diagram showing an ultrasonic reference signal generating device that generates an ultrasonic reference signal according to one embodiment of the present invention.

[0047] FIG. 6 is a drawing for explaining the operation of a phase detection unit and an ultrasonic reference signal output unit according to one embodiment of the present invention.

[0048] FIG. 7 is a drawing showing an example of controlling at least one of the period and number of times of outputting an ultrasonic reference signal according to one embodiment of the present invention.

[0049] FIG. 8 is a block diagram showing a reference signal generation device that generates an ultrasonic reference signal and an RF reference signal according to one embodiment of the present invention.

[0050] FIG. 9 is a drawing showing an implementation example of a reference signal generating device according to one embodiment of the present invention.

[0051] FIG. 10 is a block diagram showing an acoustic camera according to one embodiment of the present invention.

[0052] FIG. 11 is a flowchart illustrating a method for generating acoustic data through beam forming according to an embodiment of the present invention.

[0053] FIG. 12 is a drawing for explaining a method for time alignment and synthesis of an audio signal according to an embodiment of the present invention.

[0054] FIG. 13 is a flowchart illustrating a method for phase correction of partial discharge acoustic data using an ultrasonic reference signal according to an embodiment of the present invention.

[0055] FIG. 14 is a drawing for explaining a phase difference calculation and phase correction method according to one embodiment of the present invention.

[0056] FIG. 15 is a diagram for explaining a partial discharge acoustic data phase correction method according to one embodiment of the present invention.

[0057] FIG. 16 is a block diagram showing an acoustic camera according to another embodiment of the present invention.

[0058] FIG. 17 is a flowchart illustrating a method for phase correction of partial discharge acoustic data using an RF reference signal according to an embodiment of the present invention.

[0059] FIG. 18 is a drawing showing an example of an implementation of an acoustic camera according to one embodiment of the present invention.

[0060] Figure 19 is a conceptual diagram showing a scenario in which a reference signal generation device is installed close to a measurement target to measure partial discharge of the measurement target.

[0061] Figure 20 is a conceptual diagram showing a scenario in which a reference signal generation device is installed close to an acoustic camera to measure partial discharge of a measurement target.

[0062] Fig. 21 is a flowchart showing the operation of the system when implemented as an ultrasonic reference signal generating device in the example of Fig. 19.

[0063] Fig. 22 is a flowchart showing the operation of the system when implemented as an ultrasonic reference signal generating device in the example of Fig. 20.

[0064] Fig. 23 is a flowchart showing the operation of the system when implemented as an RF reference signal generation device in the example of Fig. 19.

[0065] Fig. 24 is a flowchart showing the operation of the system when implemented as an RF reference signal generation device in the example of Fig. 20.

[0066] Figure 25 is a diagram showing PRPD graphs according to bad phase lock and good phase lock, respectively.

[0067] Fig. 26 is a drawing showing a PRPD graph of a corona discharge according to one embodiment of the present invention.

[0068] FIG. 27 is a drawing showing an optical-acoustic coupling image according to one embodiment of the present invention.

[0069] Fig. 28 is a block diagram showing the configuration of a data processing unit according to one embodiment of the present invention.

[0070] Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. The following detailed description is provided to facilitate a comprehensive understanding of the methods, devices, and / or systems described herein. However, these are merely examples and the present invention is not limited thereto.

[0071] In describing embodiments of the present invention, detailed descriptions of known technologies related to the present invention will be omitted if they are deemed to unnecessarily obscure the gist of the invention. Furthermore, the terms described below are defined based on their functions within the present invention and may vary depending on the intent or custom of the user or operator. Therefore, their definitions should be based on the overall content of this specification.

[0072] The terminology used in this detailed description is for the purpose of describing embodiments of the present invention only and should not be construed as limiting. Unless expressly stated otherwise, singular forms include plural forms.

[0073] In this description, expressions such as "including" or "having" are intended to indicate certain features, numbers, steps, operations, elements, portions or combinations thereof, and should not be construed to exclude the presence or possibility of one or more other features, numbers, steps, operations, elements, portions or combinations thereof other than those described.

[0074] Additionally, in describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only intended to distinguish the components from other components, and the nature, order, or sequence of the components are not limited by the terms.

[0075]

[0076] FIG. 1 is a conceptual diagram illustrating a partial discharge measurement system according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a partial discharge measurement system according to an embodiment of the present invention. Referring to FIGS. 1 and 2, the partial discharge measurement system (1000) includes a reference signal generation device (100), an acoustic camera (200), and a measurement target (300).

[0077] The reference signal generation device (100) is a device that outputs a reference signal for phase correction and may include a power supply unit (110) and a reference signal generation unit (120, 130).

[0078] The power supply (110) can be connected to an external power supply (102) in the same environment as the environment in which the measurement target (300) is located. The external power supply can be a ground power supply, and an AC voltage of commercial frequency can be applied through the ground power supply.

[0079] Commercial frequency refers to the frequency of alternating current supplied by power companies, and can be 50 Hz or 60 Hz. For reference, the commercial frequency in Korea is 60 Hz, and in Germany it is 50 Hz.

[0080] The reference signal generation unit (120, 130) can generate and output a signal synchronized with the AC voltage signal applied through the power supply unit (110). At this time, the reference signal (101) can include at least one of an RF (Radio Frequency) signal and an ultrasonic sound signal.

[0081] The measurement target (300) is a device, apparatus, facility, etc. that is a target of partial discharge measurement, such as external discharge, internal discharge, surface discharge, floating discharge, etc. According to a non-limiting example of the present invention, the measurement target (300) may be a power facility such as a high-voltage cable, transformer, motor, insulator, bushing, condenser, reactor, etc.

[0082] The measurement target (300) can emit a partial discharge acoustic signal (301) when partially discharging. Here, the partial discharge acoustic signal can be an ultrasonic acoustic signal.

[0083] The acoustic camera (200) can receive a partial discharge acoustic signal (301) generated when a measurement target (300) partially discharges, generate partial discharge acoustic data, and phase-correct the partial discharge acoustic data based on the phase difference between the reference signal and the partial discharge acoustic signal to generate phase-corrected partial discharge acoustic data. Here, the acoustic camera (200) can include a signal receiving unit (210, 220), a data processing unit (230), and an output unit (240).

[0084] Here, the reference signal generating device (100) may be installed at a short distance from the measurement target (300) or the reference signal generating device (100) may be installed at a short distance from the acoustic camera (200). At this time, the short distance may preferably be within a radius of 1 meter from the measurement target (300) or the acoustic camera (200), but is not limited thereto.

[0085] As explained above, in order to produce an accurate PRPD graph using the collected data of the acoustic camera (200), it is necessary to know the commercial frequency of the measurement target (300) and the synchronization information of the AC voltage signal applied to the operating equipment. In the present invention, the reference signal generation device (100) generates a reference signal including the commercial frequency of the measurement target (300) and the synchronization information of the AC voltage signal applied to the operating equipment, and transmits the signal to the acoustic camera (200), thereby enabling accurate PRPD analysis.

[0086]

[0087] FIG. 3 is a block diagram illustrating an RF reference signal generation device that generates an RF reference signal according to an embodiment of the present invention. Referring to FIG. 3, the RF reference signal generation device (100-1) includes a power supply unit (110) and an RF reference signal generation unit (120).

[0088] The power supply (110) can be connected to an external power supply in the same environment as the environment in which the measurement target (300) is located. The external power supply can be a ground power supply, and an AC voltage of commercial frequency can be applied through the ground power supply.

[0089] Additionally, the power supply (110) may include an internal power source, such as a battery, for operation of the device in situations where connection to an external power source is not possible.

[0090] The RF reference signal generation unit (120) includes a phase detection unit (121) and an RF reference signal output unit (122). The phase detection unit (121) can detect a predetermined phase position of an AC voltage signal applied through a power supply unit (110). For example, the phase detection unit (121) can be implemented as a zero-cross detector that detects 180 degrees and 360 degrees, which are phase positions, of the zero point of the AC voltage signal applied through the power supply. In addition, the RF reference signal output unit (122) can generate a predetermined pulse at the phase position of the detected point and output it as an RF reference signal.

[0091] At this time, the generated RF reference signal is an electromagnetic wave signal, and the frequency of the RF reference signal can be determined by synchronizing with the commercial frequency of the power source grounded in the environment where the measurement target (300) is located. In addition, the generated RF reference signal can be synchronized with the AC voltage signal applied through the power supply (110).

[0092]

[0093] FIG. 4 is a diagram showing an AC voltage signal in an environment where a measurement target is installed and an RF reference signal generated by a reference signal generating device according to an embodiment of the present invention. FIG. 4(a) shows a case where the commercial frequency of the AC voltage signal in an environment where a measurement target (300) is installed is 60 Hz. Referring to FIG. 4(a), the phase detection unit (121) can detect the positions (41-1, 41-3, 41-5) of the 180-degree phase, which are zero-cross points of the AC voltage signal, and the positions (41-2, 41-4) of the 360-degree phase.

[0094] And, FIG. 4(b) shows an RF reference signal. Referring to FIG. 4(b), the RF reference signal output unit (122) can generate a predetermined pulse (42-1, 42-2, 42-3, 42-4, 42-5) at the detected 180-degree phase positions (41-1, 41-3, 41-5) and 360-degree phase positions (41-2, 41-4) and output the pulse as an RF reference signal. For example, since the commercial frequency of the power source grounded in the environment where the measurement target (300) is installed is 60 Hz, the pulse period at the 180-degree phase positions (41-1, 41-3, 41-5) and 360-degree phase positions (41-2, 41-4) can be 8.35 ms. The RF reference signal generator (100-1) can output an RF reference signal having periodic peaks at 180 and 360 degree phase positions.

[0095]

[0096] Fig. 5 is a block diagram illustrating an ultrasonic reference signal generating device that generates an ultrasonic reference signal according to one embodiment of the present invention. Referring to Fig. 5, the ultrasonic reference signal generating device (100-2) includes a power supply unit (110) and an ultrasonic reference signal generating unit (130).

[0097] Here, the function of the power supply (110) is the same as that described above in Fig. 3, so a detailed description thereof is omitted.

[0098] The ultrasonic reference signal generation unit (130) includes a phase detection unit (131) and an ultrasonic reference signal output unit (132). For example, the phase detection unit (131) can detect a predetermined phase position of an AC voltage signal applied through the power supply unit (110). For example, the phase detection unit (131) can be implemented to detect the phase of a point of maximum magnitude of the AC voltage signal applied through the power supply, for example, a position of a 90 degree phase. In addition, the ultrasonic reference signal output unit (132) can generate a predetermined pulse at the phase position of the detected point and output it as an ultrasonic reference signal.

[0099] At this time, the generated ultrasonic reference signal is an acoustic signal, and the frequency of the ultrasonic reference signal can be determined by synchronizing with the commercial frequency of the power source grounded to the environment where the measurement target (300) is located. In addition, the generated ultrasonic reference signal can be synchronized with the AC voltage signal applied through the power supply (110).

[0100] FIG. 6 is a diagram showing an ultrasonic reference signal according to an embodiment of the present invention. Referring to FIG. 6(a), when the commercial frequency of the power source grounded in the environment where the measurement target (300) is installed is 60 Hz, the phase detection unit (131) detects the position of the 90-degree phase, which is the maximum value point of the AC voltage signal (61), and the ultrasonic reference signal output unit (132) can generate an ultrasonic reference signal (62) by generating a constant pulse at the detected 90-degree phase position and output the generated ultrasonic reference signal. For example, when the commercial frequency of the power source grounded in the environment where the measurement target (300) is installed is 60 Hz, one cycle of the AC voltage signal (61) can be 0.0167 seconds, and the ultrasonic reference signal generation device (100-2) can output an ultrasonic reference signal (62) in which a periodic peak occurs at the 90-degree phase position.

[0101] Referring to Fig. 6(b), when the commercial frequency of the power source grounded in the environment where the measurement target (300) is installed is 50 Hz, one cycle of the AC electric signal (63) can be 0.02 seconds, and the ultrasonic reference signal generating device (100-2) can output an ultrasonic reference signal (64) in which a periodic peak occurs at a 90 degree phase position.

[0102] Meanwhile, in the examples of FIGS. 3 to 6 described above, the phase detection unit (121) of the RF reference signal generation unit (120) detects the zero cross point, and the phase detection unit (131) of the ultrasonic reference signal generation unit (130) detects the phase of the maximum value point of the AC voltage signal. However, this is only an example of implementation and is not limited thereto. According to another example of implementation of the present invention, each phase detection unit (121, 131) may be implemented to detect a phase position different from the example described above.

[0103] In addition, although the examples of FIGS. 3 to 6 described above have described generating a reference signal in the form of an impulse having a peak value at a detected phase position, the present invention is not limited thereto. According to another implementation example of the present invention, the reference signal generating unit (120, 130) may be implemented to generate a pulse having a value of "0" in the range of 0 to 180 degrees, which is the zero cross phase position, and having a predetermined value (e.g., a value of "1") in the range of 180 to 360 degrees.

[0104]

[0105] Meanwhile, since both the partial discharge acoustic signal generated when the measurement target (300) partially discharges and the ultrasonic reference signal generated from the ultrasonic reference signal generating device (100-2) are acoustic signals in the ultrasonic band, a method is needed to enable the acoustic camera (200) receiving them to distinguish between the partial discharge acoustic signal and the ultrasonic reference signal. Accordingly, the ultrasonic reference signal generating device (100-2) according to the present invention can enable the acoustic camera (200) receiving them to distinguish between the partial discharge acoustic signal and the ultrasonic reference signal by controlling at least one of the cycle and the number of times the ultrasonic reference signal is output.

[0106] FIG. 7 is a diagram showing an example of controlling the output cycle of an ultrasonic reference signal according to an embodiment of the present invention. FIG. 7(a) is an example of operating the output cycle of the ultrasonic reference signal generating device (100-2) to be the same as the commercial frequency of 60 Hz, and it can be confirmed that the ultrasonic reference signal generating device (100-2) generates an ultrasonic reference signal in which a total of 10 peaks periodically occur at a 90-degree phase position for 10 cycles, which is 0.167 seconds. However, in this case, the timing of the partial discharge acoustic signal generated when the measurement target (300) partially discharges and the ultrasonic reference signal generated from the ultrasonic reference signal generating device (100-2) may be the same, and it may be difficult for the acoustic camera (200) to distinguish between the partial discharge acoustic signal and the ultrasonic reference signal.

[0107] Fig. 7(b) shows that the output cycle of the ultrasonic reference signal generator (100-2) is set to 10%, and the ultrasonic reference signal generator (100-2) generates an ultrasonic reference signal in which a total of one peak periodically occurs at a 90-degree phase position for 10 cycles, which is 0.167 seconds. In this case, the timing of the partial discharge acoustic signal generated when the measurement target (300) partially discharges and the ultrasonic reference signal generated from the ultrasonic reference signal generator (100-2) are different, so that it is easy to distinguish the partial discharge acoustic signal and the ultrasonic reference signal from the acoustic camera (200) side.

[0108]

[0109] Meanwhile, the above-described reference signal generation device (100-3) may be implemented to include both an RF reference signal generation unit (120) and an ultrasonic reference signal generation unit (130). Fig. 8 is a block diagram showing a reference signal generation device that generates an ultrasonic reference signal and an RF reference signal according to an embodiment of the present invention. Here, the functions of the power supply unit (110), the RF reference signal generation unit (120), and the ultrasonic reference signal generation unit (130) are the same as those described above with reference to Figs. 3 and 5, and therefore, a detailed description thereof will be omitted.

[0110] The switching unit (140) can select either the generation and output of an RF reference signal through the RF reference signal generation unit (120) or the generation and output of an ultrasonic reference signal through the ultrasonic reference signal generation unit (130) depending on the position of the measurement target (300) or the measurement environment.

[0111] In the case of the RF method, since the acoustic camera (200) can receive a constant reference signal with relatively little delay in an environment where a line of sight is secured regardless of the measurement distance, it may be desirable to select and operate the RF reference signal generator (120) in that environment.

[0112] In the case of the ultrasonic method, since correction must be performed at a relatively close distance, it may be desirable to select and operate an ultrasonic reference signal generator (130) in that environment.

[0113] Meanwhile, the reference signal generator (100-3) may be implemented to simultaneously emit RF reference signals and ultrasonic reference signals for distance estimation. In this case, the acoustic camera (200), which will be described later, can calculate the distance between the acoustic camera (200) and the reference signal generator (100-3) by using the time difference between the received RF reference signals and ultrasonic reference signals.

[0114]

[0115] FIG. 9 is a drawing showing an example of an implementation of a reference signal generating device according to an embodiment of the present invention. The reference signal generating device (100) may include a speaker (132) for outputting an ultrasonic reference signal generated by an ultrasonic reference signal generating unit (130), a volume knob (151) for adjusting the size of the ultrasonic reference signal, a power supply unit (110) for receiving power from an external power source through a power connection line (111) for connecting to the ground power of the external power source, and a mode selection switch (152). Although not shown in FIG. 9, the reference signal generating device (100) may include an RF reference signal generating unit (120) therein.

[0116] Here, the mode selection switch (152) is a switch for selecting the frequency of the reference signal output from the reference signal generation device (100), and the user can select an operation mode as at least one of “frequency 50 Hz mode”, “frequency 60 Hz mode”, and “external power connection mode” through the switch (152).

[0117] The "50Hz frequency mode" is a mode selected when the reference signal generation device (100) is not connected to an external power line (111) and operates on its own with an internal power source such as a battery, and the reference signal generation device (100) can generate and output a 50Hz RF reference signal and / or a 50Hz ultrasonic reference signal. However, in the "50Hz frequency mode", the AC voltage of the commercial frequency is not applied from an external power source, so the reference signal generated in the "50Hz frequency mode" is a signal that is not synchronized with the AC voltage signal of the external power source.

[0118] The "60Hz frequency mode" is a mode selected when the reference signal generation device (100) is not connected to an external power line (111) and operates on its own with an internal power source such as a battery, and the reference signal generation device (100) can generate and output a 60Hz RF reference signal and / or a 60Hz ultrasonic reference signal. However, in the "60Hz frequency mode", the AC voltage of the commercial frequency is not applied from an external power source, so the reference signal generated in the "60Hz frequency mode" is a signal that is not synchronized with the AC voltage signal of the external power source.

[0119] The “external power connection mode” is a mode selected when the reference signal generation device (100) is connected to a power connection line (111) and operates on an external power source, and the reference signal generation device (100-3) has a frequency that is the same as the commercial frequency of 50 Hz or 60 Hz of the AC voltage signal applied from the external power source (111), and can generate and output an RF reference signal and / or an ultrasonic reference signal synchronized with the AC voltage signal.

[0120] The above-described "frequency 50 Hz mode" and "frequency 60 Hz mode" may be suitable for an environment in which the user checks the commercial frequency (e.g., 60 Hz in Korea, 50 Hz in Germany) and directly sets the frequency to operate in an environment in which the reference signal generator (100) cannot be used by connecting it to an external power source. However, in the "frequency 50 Hz mode" and the "frequency 60 Hz mode", the reference signal output from the reference signal generator (100) is not synchronized with the AC voltage signal applied to the measurement target (300), so although the accuracy of the PRPD analysis can be increased compared to when the reference signal generator (100) is not present, there is a limitation in that accurate PRPD analysis is difficult compared to when an external power source is connected to the power supply (110).

[0121] However, the above-described "external power connection mode" may be suitable in an environment where the reference signal generation device (100) can be used by connecting it to an external power source. In this case, the reference signal output from the reference signal generation device (100) is synchronized with the AC voltage signal applied to the measurement target (300), so that accurate PRPD analysis may be possible.

[0122]

[0123] Fig. 10 is a block diagram showing an acoustic camera according to an embodiment of the present invention. The acoustic camera (200-1) illustrated in Fig. 10 is an implementation example that includes only an acoustic signal receiving unit (210) without an RF signal receiving unit, and can be used to measure partial discharge of a measurement target (300) in conjunction with an ultrasonic reference signal generating device (100-2) illustrated in Fig. 5 having an ultrasonic signal generating unit (130) or an RF and ultrasonic reference signal generating device (100-3) illustrated in Fig. 8.

[0124] Referring to FIG. 10, the acoustic camera (200) may include an acoustic signal receiving unit (210), an optical signal receiving unit (220), a data processing unit (230), and an output unit (240).

[0125] The acoustic signal receiving unit (210) can receive an acoustic signal from an acoustic scene, and can be configured as an acoustic sensor array in which a plurality of acoustic sensors (210-1, 210-2, . . . 210-n) are arranged in a regular or irregular manner. In this case, the acoustic sensors (210-1, 210-2, . . . 210-n) can be implemented as MEMS (Micro-Electro-Mechanical Systems) microphones.

[0126] An acoustic scene may be a space in the real world where a sound source that generates sound is located. In other words, the acoustic scene may be a scene in a real space (or real world) where a measurement target (300) and a reference signal generation device (100-2, 100-3) are located.

[0127] Here, the acoustic signal of the sound scene may include audible sounds, ultrasound, infrasound, etc. Accordingly, the acoustic signal may include an audible acoustic signal in the range of 20 Hz to 20 kHz, which is the frequency of sound waves that can be heard by the human ear, and an inaudible acoustic signal outside the audible range (e.g., an ultrasound band).

[0128] Accordingly, when a partial discharge acoustic signal is generated due to partial discharge at a measurement target (300) located in an acoustic scene, the acoustic signal receiving unit (210) can receive the partial discharge acoustic signal generated at the measurement target (300). In addition, when an ultrasonic reference signal is generated at a reference signal generating device (100-2, 100-3) located in an acoustic scene, the acoustic signal receiving unit (210) can receive the ultrasonic reference signal generated at the reference signal generating device (100-2, 100-3).

[0129] In addition, the acoustic signal receiving unit (210) can transmit the received partial discharge acoustic signal and ultrasonic reference signal to the data processing unit (230).

[0130] The optical signal receiving unit (220) may be implemented as an optical camera comprising a lens, an image sensor, and the like. Specifically, the optical signal receiving unit (220) may receive an optical signal from an optic scene. Here, the optic scene may be a scene of a real space (or the real world) where a measurement target (300) and a reference signal generating device (100-2, 100-3) are located, similar to an acoustic scene.

[0131] And, the optical signal receiving unit (220) can transmit an optical signal to the data processing unit (230).

[0132] The data processing unit (230) can generate partial discharge sound data for a partial discharge sound signal and ultrasonic reference sound data for an ultrasonic reference signal. In addition, the data processing unit (230) can phase-correct the partial discharge sound data based on the phase difference between the ultrasonic reference signal and the partial discharge sound signal, thereby generating phase-corrected partial discharge sound data. The operation of this data processing unit (230) will be described in detail with reference to the drawings below.

[0133] The output unit (240) can display at least one of the presence or absence of partial discharge of the measurement target (300), the location of the partial discharge, and the type of partial discharge (corona discharge, surface discharge, floating discharge, etc.) through an optical-acoustic combined image. Specifically, the data processing unit (230) can generate an acoustic image through beam forming of a partial discharge acoustic signal, generate an optical image for an optical signal received by the optical signal receiving unit (220), and generate an optical-acoustic combined image by combining the optical image and the acoustic image. The optical-acoustic combined image is an image that visualizes the presence or absence of partial discharge and the location of the partial discharge by combining acoustic information with an optical image. This optical-acoustic combined image can also be expressed as an acoustic map, an acoustic spectrum image, an acoustic heatmap, an acoustic beamforming visualization, etc.

[0134] Additionally, the output unit (240) can output the PRPD graph produced by the data processing unit (230).

[0135]

[0136] Figure 11 is a flowchart illustrating a method for generating acoustic data through beamforming according to one embodiment of the present invention. Here, beamforming is a signal processing technology that utilizes a microphone array to enhance acoustic signals generated from a specific direction and suppress unnecessary noise to increase the signal-to-noise ratio (SNR).

[0137] Referring to FIG. 11, the data processing unit (230) can receive an acoustic signal from the acoustic signal receiving unit (210) (S1001). In the case of the acoustic camera (200-1) illustrated in FIG. 10, the data processing unit (230) can receive a partial discharge acoustic signal and an ultrasonic reference signal from the acoustic signal receiving unit (210).

[0138] In addition, the data processing unit (230) can remove noise from the sound signal by setting a frequency detection band of a predetermined range (S1002).

[0139] Furthermore, the data processing unit (230) can perform time alignment and synthesis of the acoustic signals (S1003). Since the time it takes for acoustic signals coming from specific directions to reach each microphone differs, it is necessary to calculate the time difference between the arrival of the acoustic signals at each microphone and perform delay compensation to time-align the ultrasonic acoustic signals. This will be described in detail with reference to FIG. 12.

[0140] FIG. 12 is a drawing for explaining a method for time alignment and synthesis of an audio signal according to an embodiment of the present invention. The data processing unit (230) calculates the distances between the acoustic sensors (210-1, 210-2, .. . . 210-n) and the virtual plane points (410-1, 410-2, .. . 410-n) using the coordinates (Xs, Ys) of each of the acoustic sensors (210-1, 210-2, .. . 210-n) constituting the acoustic signal receiving unit (210), the coordinates (Xg, Yg) of the virtual plane (Source surface) set in the real-world acoustic scene, and the distance (L) between the acoustic sensor array plane (Array surface) and the virtual plane (Source surface), and calculates the delay distances for each point (410-1, 410-2, .. . 410-n) of the virtual plane based on the calculated distances, and applies time delay correction to each of the acoustic signals using the calculated delay distances, and adds them up to obtain the sound source value of each of the virtual plane points (410-1, 410-2, .. . 410-n). And, by dividing the produced sound source value by the number of sound sensors (210-1, 210-2, . . . 210-n) constituting the sound signal receiving unit (210), the sound pressure level of each virtual plane point (410-1, 410-2, . . . 410-n) can be produced.

[0141] Here, the virtual plane is a virtual space where sound pressure levels are calculated from a real-world acoustic scene, and at least one virtual plane can be set. Furthermore, the size of the virtual plane can vary depending on the beamforming field of view.

[0142] In this way, the data processing unit (230) can receive only the acoustic signals generated in the beam forming field of view through beam forming, and remove the acoustic signals generated in areas other than the beam forming field of view. Through this, the data processing unit (230) can intensively capture the ultrasonic acoustic signals generated from each of the measurement target (300) and the ultrasonic reference signal generating device (100-2, 100-3) and remove the unwanted ultrasonic acoustic signals.

[0143] Referring to FIG. 11, the data processing unit (230) can generate acoustic data corresponding to an acoustic signal (S1004). In the case of the acoustic camera (200-1) illustrated in FIG. 10, the data processing unit (230) can generate partial discharge acoustic data corresponding to a partial discharge acoustic signal and ultrasonic reference acoustic data corresponding to an ultrasonic reference signal.

[0144]

[0145] FIG. 13 is a flowchart illustrating a method for phase correction of partial discharge acoustic data using an ultrasonic reference signal according to an embodiment of the present invention.

[0146] Referring to FIG. 13, the data processing unit (230) can distinguish between ultrasonic reference acoustic data and partial discharge acoustic data (S110). Unlike the RF method, in the ultrasonic method, both the module for receiving the ultrasonic reference signal and the module for receiving the partial discharge acoustic signal are the same as the acoustic signal receiving unit (210), so an algorithm for distinguishing between the ultrasonic reference signal and the partial discharge acoustic signal must be additionally provided. The ultrasonic reference signal generating unit (130) can adjust at least one of the period and the number of times the ultrasonic reference signal is output, and the data processing unit (230) can distinguish between the ultrasonic reference acoustic data and the partial discharge acoustic data based on at least one of the period and the number of times.

[0147] The data processing unit (230) can calculate the phase difference between the ultrasonic reference signal and the partial discharge acoustic signal (S120).

[0148] Fig. 14 is a diagram for explaining a phase difference calculation and phase correction method according to an embodiment of the present invention. Fig. 14(a) shows a partial discharge acoustic signal before phase correction. Referring to Fig. 14(a), the pulse of the reference signal (73) is located at a 90-degree phase position of the AC voltage signal (71) in the environment where the measurement target (300) is installed, but the pulse of the partial discharge acoustic signal (72) is located at a phase position of about 200 degrees, so it can be confirmed that there is a phase difference between the reference signal (73) and the acoustic signal (72). At this time, the phase difference may mean a delay time in another expression.

[0149] When a PRPD graph is calculated based on partial discharge acoustic data in a situation where a phase difference exists, as in Fig. 14(a), an accurate PRPD graph cannot be calculated.

[0150] The data processing unit (230) according to the present invention can calculate the phase difference between a reference signal (73) and a partial discharge sound signal (72) as in Fig. 14(a), and correct the phase of the partial discharge sound data based on the calculated phase difference to generate phase-corrected partial discharge sound data. At this time, the phase-corrected partial discharge sound signal corresponding to the phase-corrected partial discharge sound data can be as in Fig. 14(b).

[0151] To this end, the data processing unit (230) can convert the calculated phase difference into a number of samples (S130). Then, the data processing unit (230) can correct the partial discharge sound data by the converted number of samples to generate phase-corrected partial discharge sound data (S140).

[0152] FIG. 15 is a diagram illustrating a method for phase correction of partial discharge acoustic data according to an embodiment of the present invention. FIG. 15(a) shows partial discharge acoustic data before phase correction, and FIG. 15(b) shows ultrasonic reference acoustic data. Referring to FIGS. 15(a) and (b), it can be confirmed that there is a phase difference (delay time) between the partial discharge acoustic signal before phase correction and the ultrasonic reference signal.

[0153] In this case, the data processing unit (230) can convert the phase difference into the number of samples (81) of partial discharge sound data before phase correction, as shown in Fig. 15(c), and cut out the partial discharge sound data by the converted number of samples to generate phase-corrected sound data. At this time, data collection / analysis is performed by pulling forward or delaying the time point by the number of samples (81) according to the correction of the partial discharge sound data by the number of samples (e.g., adding or cutting data), and the peak position of the phase-corrected partial discharge sound signal can be located at the pulse of the reference signal.

[0154] As described above, after phase correction is performed once using the reference signal generating device (100) in the environment where the measurement target (300) according to the present invention is located, the AC voltage signal in which the measurement target (300) operates in that environment and the partial discharge acoustic signal collected by the acoustic camera (200) are mutually synchronized, so subsequent phase correction may not be necessary unless the measurement location or measurement environment changes.

[0155] Meanwhile, the data processing unit (230) can generate a PRPD graph using phase-corrected acoustic data (S150). Then, the data processing unit (230) can output the generated PRPD graph through the output unit (240).

[0156] This data processing unit (230) may be installed inside the acoustic camera (200-1). However, the installation location is only an example of one implementation, and it may be implemented by being installed outside the acoustic camera (200-1).

[0157]

[0158] Fig. 16 is a block diagram showing an acoustic camera according to another embodiment of the present invention. The acoustic camera (200-2) illustrated in Fig. 16 is an implementation example that includes both an RF signal receiving unit (250) and an acoustic signal receiving unit (210), and can be used to measure partial discharge of a measurement target (300) in conjunction with an RF reference signal generating device (100-1) illustrated in Fig. 3 or an ultrasonic and RF reference signal generating device (100-3) illustrated in Fig. 8.

[0159] Referring to FIG. 16, the acoustic camera (200-2) may include an acoustic signal receiving unit (210), an optical signal receiving unit (220), a data processing unit (230), an output unit (240), and an RF receiving unit (250). Here, the function of the acoustic camera (200-2) illustrated in FIG. 16 is different from the acoustic camera (200-1) illustrated in FIG. 10 in that it receives and uses an RF reference signal generated from an RF reference signal generating device (100-1, 100-3) through an RF signal receiving unit (250) to correct the phase of a partial discharge acoustic signal generated from a measurement target (300). Therefore, in describing FIG. 16, overlapping content with FIG. 10 will be omitted and the differences will be mainly described.

[0160] In the case of the RF method, the RF receiver (250) that receives the RF reference signal and the acoustic receiver (210) that receives the partial discharge acoustic signal can be separated into different modules, and accordingly, the step of distinguishing between the RF reference signal and the partial discharge acoustic signal may be unnecessary.

[0161] The RF receiver (250) can receive an RF reference signal generated from an RF reference signal generator (100-1, 100-3).

[0162] The data processing unit (230) can generate partial discharge sound data for a partial discharge sound signal. In addition, the data processing unit (230) can phase-correct the partial discharge sound data based on the phase difference between the RF reference signal and the partial discharge sound signal to generate phase-corrected partial discharge sound data.

[0163] In addition, the data processing unit (230) can receive the RF reference signal and the ultrasonic reference signal emitted from the RF and ultrasonic reference signal generating device (200-3) through the RF signal receiving unit (250) and the acoustic signal receiving unit (210), respectively, and calculate the distance between the acoustic camera (200-2) and the reference signal generating device (200-3).

[0164] Specifically, since the RF reference signal travels at the speed of light, it will be received almost immediately by the RF signal receiver (250), but on the other hand, since the ultrasonic reference signal travels much more slowly than the RF reference signal, it takes time to arrive at the acoustic signal receiver (210). The data processing unit (230) can calculate the time difference between the reception time of the RF reference signal and the reception time of the ultrasonic reference signal, and multiply the calculated time difference by the speed of the ultrasonic signal (for example, the speed of the ultrasonic signal passing through the air is about 340 m / s) to calculate the distance between the acoustic camera (200-2) and the reference signal generating device (200-3).

[0165] FIG. 17 is a flowchart illustrating a method for phase correction of partial discharge acoustic data using an RF reference signal according to an embodiment of the present invention.

[0166] Referring to FIG. 17, the data processing unit (230) can calculate the phase difference between the RF reference signal and the partial discharge acoustic signal (S210). Here, the phase difference calculation process of the processor (230) can be easily derived by those skilled in the art based on FIG. 14, so a detailed description thereof will be omitted.

[0167] In addition, the data processing unit (230) can convert the calculated phase difference into a number of samples (S220). In addition, the data processing unit (230) can correct the partial discharge sound data by the converted number of samples to generate phase-corrected partial discharge sound data (S230).

[0168] And, the data processing unit (230) can produce a PRPD graph using the phase-corrected acoustic data (S240). Here, the acoustic data phase correction process of the data processing unit (230) can be easily derived by those skilled in the art based on FIG. 15, so a detailed description thereof will be omitted.

[0169]

[0170] Fig. 18 is a drawing showing an example of an implementation of an acoustic camera according to an embodiment of the present invention. Referring to Fig. 18, the acoustic camera may be implemented as a portable acoustic camera that can be carried by a user. Fig. 18(a) shows the front of the acoustic camera, and a grip portion (260) for a user to hold is formed on both sides of the acoustic camera, and an acoustic signal receiving portion (210) may be formed on the front of the acoustic camera. The acoustic receiving portion (210) may have a sound wave inlet hole (211) formed therein for sound wave introduction, and a microphone array may be formed therein.

[0171] Fig. 18(b) shows the rear of the acoustic camera, and an output unit (240) for user confirmation may be formed on the rear of the acoustic camera.

[0172] Meanwhile, in Fig. 18, the acoustic camera is implemented as a portable type, but it is not limited thereto. According to another embodiment of the present invention, the acoustic camera may be implemented as a fixed acoustic camera fixedly installed at a predetermined point, or may be implemented as a fixed acoustic camera that operates in conjunction with a CCTV fixedly installed at a predetermined point. Alternatively, according to another embodiment of the present invention, the acoustic camera may be implemented as a mobile acoustic camera installed on a mobile platform capable of autonomous or non-autonomous driving (e.g., a robot, a vehicle, a motorcycle, etc.).

[0173]

[0174] Below, a partial discharge measurement scenario of a partial discharge measurement system (1000) consisting of a reference signal generation device (100), an acoustic camera (200), and a measurement target (300) is specifically described.

[0175] Fig. 19 is a conceptual diagram illustrating a scenario in which a reference signal generation device is installed close to a measurement target to measure a partial discharge of the measurement target. Fig. 19 illustrates a scenario in which a user can access the measurement target (300), and the reference signal generation device (100) may be installed at a short distance from the measurement target (300). In this case, according to an unrestricted implementation example of the short distance, the distance may be within 1 meter from the measurement target (300).

[0176] Fig. 20 is a conceptual diagram illustrating a scenario in which a reference signal generation device is installed close to an acoustic camera to measure partial discharge of a measurement target. Fig. 20 illustrates a scenario in which a user has difficulty accessing the measurement target (300), and the reference signal generation device (100) may be installed at a short distance from the acoustic camera (200). In this case, according to an unrestricted implementation example of the short distance, the distance may be within 1 meter from the acoustic camera (200).

[0177] Fig. 21 is a flowchart illustrating the operation of a system implemented as an ultrasonic reference signal generating device in the example of Fig. 19. Referring to Fig. 21, the reference signal generating device (100-2, 100-3) may be installed at a short distance from the measurement target (300) as in the implementation example of Fig. 19 (S11), and the reference signal generating device (100-2, 100-3) may be connected to an external power source (102). In this case, the reference signal generating device (100-2, 100-3) may output an ultrasonic reference signal (101).

[0178] And, the acoustic camera (200-1) can receive an ultrasonic reference signal (101) (S14).

[0179] In addition, when a partial discharge acoustic signal is output according to the partial discharge of the measurement target (300) (S15), the acoustic camera (200-1) can receive the partial discharge acoustic signal (S16).

[0180] In addition, the acoustic camera (200-1) can generate phase-corrected partial discharge acoustic data by phase-correcting the partial discharge acoustic data based on the phase difference between the ultrasonic reference signal and the partial discharge acoustic signal (S17).

[0181] In addition, the acoustic camera (200-1) can perform phase-resolved partial discharge analysis using phase-corrected acoustic data to produce a PRPD graph (S18). In addition, the acoustic camera (200-1) can output the produced PRPD graph (S19).

[0182] In the example of Fig. 21, since the reference signal generating device (100-2, 100-3) and the measurement target (300) are positioned adjacent to each other, the first distance between the acoustic camera (200-1) and the reference signal generating device (100-2, 100-3) and the second distance between the acoustic camera (200-1) and the measurement target (300) are almost the same. In addition, both the ultrasonic reference signal (101), which is the output of the reference signal generating device (100-2, 100-3), and the partial discharge acoustic signal generated by the partial discharge of the measurement target (300) are sound waves having the same physical characteristics. Therefore, in the scenario of Fig. 21, distance compensation considering the signal delay due to the distance difference between the first distance and the second distance is unnecessary for the acoustic camera (200-1).

[0183]

[0184] Fig. 22 is a flowchart illustrating the operation of a system implemented as an ultrasonic reference signal generating device in the example of Fig. 20. Referring to Fig. 22, the reference signal generating device (100-2, 100-3) may be installed at a short distance from the acoustic camera (200) as in the implementation example of Fig. 20 (S41), and the reference signal generating device (100-2, 100-3) may be connected to an external power source (102) (S42). In this case, the reference signal generating device (100-2, 100-3) may output an ultrasonic reference signal (101) (S43).

[0185] And, the acoustic camera (200-1) can receive an ultrasonic reference signal (101) (S44).

[0186] In addition, when a partial discharge acoustic signal is output according to the partial discharge of the measurement target (300) (S45), the acoustic camera (200-1) can receive the partial discharge acoustic signal (S46).

[0187] In addition, the acoustic camera (200-1) can generate phase-corrected partial discharge acoustic data by phase-correcting the partial discharge acoustic data based on the phase difference between the ultrasonic reference signal and the partial discharge acoustic signal (S47).

[0188] Meanwhile, in the example of Fig. 22, since the reference signal generation device (100-2, 100-3) is positioned adjacent to the acoustic camera (200-1), there is a large difference between the first distance between the acoustic camera (200-1) and the reference signal generation device (100-2, 100-3) and the second distance between the acoustic camera (200-1) and the measurement target (300). Therefore, in the scenario of Fig. 22, distance compensation is required that takes into account the signal delay due to the distance difference.

[0189] For this purpose, the acoustic camera (200-1) can measure the distance between the acoustic camera (200-1) and the measurement target (300) (S48).

[0190] In addition, the acoustic camera (200-1) can calculate the delay according to the distance and then apply distance correction to the phase-corrected partial discharge acoustic data (S49). Here, the sample delay for distance correction can be calculated based on the following mathematical expression 1.

[0191] [Mathematical Formula 1]

[0192] Sample delay for distance compensation = (distance between acoustic camera and measurement target) / (transmission speed of sound source of measurement target)

[0193] In addition, the application of distance correction can be performed by converting the sample delay into the number of samples, as in the example of Fig. 15 described above, and correcting the phase-corrected partial discharge acoustic data by the number of converted samples. In this case, if the distance between the acoustic camera (200-1) and the measurement target (300) changes, the distance correction described above must be performed again.

[0194] In addition, the acoustic camera (200-1) can perform phase-resolved partial discharge analysis using phase-corrected acoustic data to produce a PRPD graph (S18). In addition, the acoustic camera (200-1) can output the produced PRPD graph.

[0195]

[0196] Fig. 23 is a flowchart illustrating the operation of a system implemented as an RF reference signal generation device in the example of Fig. 19. Referring to Fig. 23, the reference signal generation device (100-1, 100-3) may be installed at a short distance from the measurement target (300) as in the implementation example of Fig. 19 (S21), and the reference signal generation device (100-1, 100-3) may be connected to an external power source (102) (S22). In this case, the reference signal generation device (100-1, 100-3) may output an RF reference signal (101) (S23).

[0197] And, the acoustic camera (200-2) can receive the RF reference signal (101) (S24).

[0198] In addition, when a partial discharge acoustic signal is output according to the partial discharge of the measurement target (300) (S25), the acoustic camera (200-2) can receive the partial discharge acoustic signal (S26).

[0199] In addition, the acoustic camera (200-2) can generate phase-corrected partial discharge acoustic data by phase-correcting the partial discharge acoustic data based on the phase difference between the RF reference signal and the partial discharge acoustic signal (S27).

[0200] Meanwhile, in the example of Fig. 23, the physical characteristic of the RF reference signal (101), which is the output of the reference signal generating device (100-1, 100-3), is an electromagnetic wave, and the physical characteristic of the partial discharge acoustic signal generated by the partial discharge of the measurement target (300) is a sound wave, which are different from each other. Therefore, in the scenario of Fig. 23, distance compensation is required that takes into account the signal delay due to the difference in the physical characteristics of the signal.

[0201] To this end, the acoustic camera (200-2) can measure the distance between the acoustic camera (200-2) and the measurement target (300) (S28). Furthermore, the acoustic camera (200-2) can calculate a delay based on the distance and then apply distance correction to the phase-corrected partial discharge acoustic data (S29). Here, the sample delay for distance correction can be calculated based on the mathematical expression 1 described above.

[0202] In addition, the acoustic camera (200-2) can perform phase-resolved partial discharge analysis using phase-corrected partial discharge acoustic data to produce a PRPD graph (S30). In addition, the acoustic camera (200-2) can output the produced PRPD graph (S31).

[0203]

[0204] Fig. 24 is a flowchart illustrating the operation of a system implemented as an RF reference signal generation device in the example of Fig. 20. Referring to Fig. 24, the reference signal generation device (100-1, 100-3) may be installed at a short distance from the acoustic camera (200-2) as in the implementation example of Fig. 20 (S61), and the reference signal generation device (100-1, 100-3) may be connected to an external power source (102) (S62). In this case, the reference signal generation device (100-1, 100-3) may output an RF reference signal (101) (S63).

[0205] And, the acoustic camera (200-2) can receive the RF reference signal (101) (S64).

[0206] In addition, when a partial discharge acoustic signal is output (S65) according to the partial discharge of the measurement target (300), the acoustic camera (200-2) can receive the partial discharge acoustic signal (S66).

[0207] In addition, the acoustic camera (200-2) can generate phase-corrected partial discharge acoustic data by phase-correcting the partial discharge acoustic data based on the phase difference between the RF reference signal and the partial discharge acoustic signal (S67).

[0208] Meanwhile, in the example of Fig. 24, the physical characteristic of the RF reference signal (101), which is the output of the reference signal generating device (100-1, 100-3), is an electromagnetic wave, and the physical characteristic of the partial discharge acoustic signal generated by the partial discharge of the measurement target (300) is a sound wave, which are different from each other. Therefore, in the scenario of Fig. 24, distance compensation is required that takes into account the signal delay due to the difference in the physical characteristics of the signal.

[0209] To this end, the acoustic camera (200-2) can measure the distance between the acoustic camera (200-2) and the measurement target (300) (S68). Furthermore, the acoustic camera (200-2) can calculate a delay based on the distance and then apply distance correction to the phase-corrected partial discharge acoustic data (S69). Here, the sample delay for distance correction can be calculated based on the mathematical expression 1 described above.

[0210] In addition, the acoustic camera (200-2) can perform phase-resolved partial discharge analysis using phase-corrected partial discharge acoustic data to produce a PRPD graph (S70). In addition, the acoustic camera (200-2) can output the produced PRPD graph (S71).

[0211]

[0212] Fig. 26 is a diagram showing a PRPD graph of a corona discharge according to an embodiment of the present invention. Referring to Fig. 26, by phase-correcting the partial discharge sound data collected by the acoustic camera using the reference signal of the reference signal generating device (100) to generate phase-corrected partial discharge sound data, an accurate PRPD graph can be drawn through phase lock.

[0213] Through this, users using acoustic cameras can perform accurate partial discharge analysis by checking the PRPD graph.

[0214]

[0215] Fig. 27 is a diagram showing an optical-acoustic combined image according to an embodiment of the present invention. Referring to Fig. 27, the output unit (240) can display at least one of an acoustic map (2701) indicating the presence or absence of partial discharge and the location of the partial discharge and a phase-corrected PRPD graph (2702) through an optical-acoustic combined image.

[0216] Through this, a user using an acoustic camera can easily determine whether a partial discharge exists, where the partial discharge occurs, and at least one of the types of partial discharge (corona discharge, surface discharge, floating discharge, etc.).

[0217]

[0218] Fig. 28 is a block diagram showing the configuration of a data processing unit according to an embodiment of the present invention. Referring to Fig. 28, the data processing unit (230) may include a processor (234), an input / output I / O (231), a memory (232), an interface (233), and a bus (235). The processor (234), the input / output device (231), the memory (232), and / or the interface (233) may be connected to each other via the bus (235). The bus (235) corresponds to a path through which data is transferred.

[0219] Specifically, the processor (234) may include at least one of a CPU (Central Processing Unit), an MPU (Micro Processor Unit), an MCU (Micro Controller Unit), a GPU (Graphics Processing Unit), a microprocessor, a digital signal processor, a microcontroller, an application processor (AP), and logic elements capable of performing functions similar thereto.

[0220] The input / output device (231) may include at least one of a keypad, a keyboard, a touchscreen, and a display device. The memory device (122) may store data and / or programs, etc.

[0221] The interface (233) may perform a function of transmitting data to or receiving data from a communication network. The interface (233) may be wired or wireless. For example, the interface (233) may include an antenna or a wired / wireless transceiver. The memory (232) may enhance the operation of the processor (234), but may further include high-speed DRAM and / or SRAM as a volatile operating memory.

[0222] Additionally, the memory (234) stores programming and data configurations that provide the functionality of some or all of the modules described herein. For example, it may include logic that causes selected aspects of the methods described above to be performed.

[0223] A program or application is loaded as a set of instructions including each step of performing the aforementioned method stored in memory (232) and the processor (234) is enabled to perform each step.

[0224] The present invention has been described so far, focusing on preferred embodiments thereof. All embodiments and conditional examples disclosed herein are intended to assist those skilled in the art in understanding the principles and concepts of the present invention. Those skilled in the art will appreciate that the present invention can be implemented in modified forms without departing from its essential characteristics.

[0225] Therefore, the disclosed embodiments should be considered illustrative rather than restrictive. The scope of the present invention is determined by the claims, not the foregoing description, and all differences within the scope equivalent thereto should be construed as being encompassed by the present invention.

[0226] Meanwhile, the methods for the various embodiments of the present invention described above can be implemented as programs and provided to servers or devices. Accordingly, each device can access the server or device where the program is stored and download the program.

[0227] In addition, the methods according to the various embodiments of the present invention described above may be implemented as programs and stored and provided on various non-transitory computer-readable media. A non-transitory computer-readable medium refers to a medium that permanently stores data and can be read by a device, rather than a medium that stores data for a short period of time, such as a register, cache, or memory. Specifically, the various applications or programs described above may be stored and provided on non-transitory computer-readable media, such as a CD, DVD, hard disk, Blu-ray disk, USB, memory card, or ROM.

[0228] In addition, although the preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above, and various modifications can be made by a person having ordinary skill in the art to which the present invention pertains without departing from the gist of the present invention claimed in the claims, and such modifications should not be understood individually from the technical idea or prospect of the present invention.

Claims

1. In the partial discharge measurement system, A reference signal generating device located in real space and outputting a reference signal for phase correction; and An acoustic camera for measuring partial discharge based on a partial discharge acoustic signal generated from a measurement target; The above acoustic camera, An acoustic signal receiving unit for receiving a partial discharge acoustic signal generated from the above measurement target; and A partial discharge measurement system comprising a data processing unit that generates partial discharge sound data for the partial discharge sound signal and phase-corrects the partial discharge sound data based on the phase difference between the reference signal and the partial discharge sound signal to generate phase-corrected partial discharge sound data.

2. In paragraph 1, The above reference signal generating device is, A partial discharge measurement system characterized by including a power supply unit connected to an external power supply in the same environment as the environment in which the measurement target is located.

3. In paragraph 2, The above reference signal generating device is, A partial discharge measurement system characterized in that it generates and outputs a signal synchronized with an AC voltage signal applied through the above power supply.

4. In paragraph 2, The above reference signal generating device is, A phase detection unit that detects a predetermined phase position of an AC voltage signal applied through the above power supply unit; A partial discharge measurement system including a reference signal output unit that generates a predetermined pulse at the position of the detected phase and outputs it as the reference signal.

5. In paragraph 4, The above reference signal is, A partial discharge measurement system characterized by including at least one of an RF (Radio Frequency) signal and an ultrasonic acoustic signal.

6. In paragraph 5, A partial discharge measurement system characterized in that, when the reference signal is an ultrasonic reference signal, the reference signal output unit controls at least one of the cycle and number of times of outputting the ultrasonic reference signal.

7. In paragraph 1, The above data processing unit, A partial discharge measurement system characterized in that it calculates the phase difference between the reference signal and the partial discharge sound signal, converts the calculated phase difference into a number of samples, and corrects the sound data by the number of converted samples to generate the phase-corrected partial discharge sound data.

8. In paragraph 1, The above data processing unit, A partial discharge measurement system characterized by producing a phase-resolved partial discharge (PRPD) graph using phase-corrected partial discharge acoustic data.

9. In paragraph 8, A partial discharge measurement system further comprising an output section for outputting the phase-resolved partial discharge graph.

10. In paragraph 1, A partial discharge analysis system, characterized in that the reference signal generating device is located within a predetermined distance from the measurement target or within a predetermined distance from the acoustic camera.

11. In the method of measuring partial discharge, The reference signal generating device is, A step of positioning in real space and outputting a reference signal for phase correction; The sound camera is, A step of receiving a partial discharge acoustic signal generated from a measurement target; A partial discharge measurement method comprising the steps of generating partial discharge sound data for the partial discharge sound signal, and phase-correcting the partial discharge sound data based on the phase difference between the reference signal and the partial discharge sound signal to generate phase-corrected partial discharge sound data.

12. In paragraph 11, Further comprising a step of connecting the power supply unit of the reference signal generating device to an external power supply in the same environment as the environment in which the measurement target is located; A partial discharge measurement method characterized in that the step of outputting the above reference signal generates and outputs a signal synchronized with the AC voltage signal applied through the power supply.

13. In paragraph 11, The above reference signal is, A partial discharge measurement method characterized by including at least one of an RF reference signal and an ultrasonic reference signal.

14. In paragraph 13, In the case of the above RF reference signal, the step of generating the phase-corrected partial discharge acoustic data is: A step of calculating a phase difference between the RF reference signal and the partial discharge acoustic signal; A step of converting the above-mentioned calculated phase difference into a number of samples; and A partial discharge measurement method, characterized by comprising a step of generating the phase-corrected partial discharge sound data by correcting the partial discharge sound data by the number of converted samples.

15. In paragraph 13, In the case of the above ultrasonic reference signal, the step of generating the phase-corrected partial discharge acoustic data is as follows: A step of distinguishing between ultrasonic reference acoustic data corresponding to the ultrasonic reference signal and the partial discharge acoustic data; A step of calculating a phase difference between the ultrasonic reference signal and the partial discharge acoustic signal; A step of converting the above-mentioned calculated phase difference into a number of samples; and A partial discharge measurement method, characterized by comprising a step of generating the phase-corrected partial discharge sound data by correcting the partial discharge sound data by the number of converted samples.

16. In the sound camera, An acoustic receiver that receives a partial discharge acoustic signal generated from a measurement target and an ultrasonic reference signal generated from a reference signal generating device that outputs a reference signal for phase correction; and An acoustic camera comprising a data processing unit for generating phase-corrected partial discharge acoustic data by phase-correcting partial discharge acoustic data based on the phase difference between the ultrasonic reference signal and the partial discharge acoustic signal.

17. In the sound camera, An acoustic receiver for receiving a partial discharge acoustic signal generated from a measurement target; An RF receiver for receiving an RF reference signal generated from a reference signal generator that outputs a reference signal for phase correction; and An acoustic camera comprising a data processing unit for generating phase-corrected partial discharge acoustic data by phase-correcting partial discharge acoustic data based on the phase difference between the RF reference signal and the partial discharge acoustic signal.

18. A computer-readable recording medium having recorded thereon a program for executing a partial discharge measurement method described in any one of claims 11 to 15.

19. A computer program stored on a computer-readable recording medium including a program code for executing a partial discharge measurement method described in any one of Articles 11 to 15.

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