High-frequency electromagnetic wave monitoring sensor and partial discharge monitoring device

Abstract

The present invention provides a high-frequency electromagnetic wave monitoring sensor and a corresponding partial discharge monitoring device, for use in monitoring high-frequency electromagnetic wave signals generated by power systems during partial discharge. The high-frequency electromagnetic wave monitoring sensor comprises a dielectric substrate and an electromagnetic coupling plate attached to each other, and the electromagnetic coupling plate is attached to a current-carrying component of a power system. The current-carrying component, the dielectric substrate, and the electromagnetic coupling plate form a capacitive structure having a high-frequency response. When a high-frequency electromagnetic wave signal is generated on the current-carrying component, the electromagnetic coupling plate generates a high-frequency induced signal. Moreover, in addition to the high-frequency electromagnetic wave monitoring sensor, the partial discharge monitoring device further comprises a signal processing circuit, a temperature sensor, a voiceprint MIC, an energy harvesting module, etc. so as to realize multi-modal partial discharge detection. The present invention has good high-frequency response characteristics and high accuracy, is less susceptible to interference, and is convenient to install.

Description

High-frequency electromagnetic wave monitoring sensor and partial discharge monitoring device TECHNICAL FIELD

[0001] The present application belongs to the technical field of fault detection of power systems, and particularly relates to a high-frequency electromagnetic wave monitoring sensor for power systems and a partial discharge monitoring device using the same. BACKGROUND

[0002] Partial discharge and temperature anomaly are main manifestations of faults or safety hazards of power equipment. Partial discharge is one of the important performance characteristics of the insulation performance of power equipment. In various faults of power systems, the performance of partial discharge accounts for more than 80%. Partial discharge is also a major factor affecting the insulation performance of power equipment. Each partial discharge will cause the insulation performance of power equipment to decline to varying degrees.

[0003] When the power system has faults such as overload, short circuit, insulation aging or damage, cooling system failure, etc., the temperature of the equipment will be abnormal. Long-term operation of power equipment in an abnormal temperature state poses a serious threat to the service life, operation safety and operation efficiency of the equipment. In order to ensure the stable, safe and efficient operation of the power system, it is necessary to monitor the partial discharge and temperature of the power equipment online.

[0004] The existing partial discharge sensors commonly used in power systems include contact-type partial discharge sensors and non-contact-type partial discharge sensors. The contact-type partial discharge sensors mainly include capacitive coupling partial discharge sensors and inductive induction partial discharge sensors. However, the existing capacitive coupling partial discharge sensors and inductive induction partial discharge sensors need to be connected and powered by wires. Such systems collect signals from the front-end sensors by the rear-end high-speed collector through wires, and then analyze the partial discharge data to determine the partial discharge condition of the equipment. Therefore, such sensors are limited in application in most power systems.

[0005] For example, as shown in FIG. 1, a partial discharge detection method is proposed in a patent specification with publication number CN114814497A, which is applied to a detection system including a wide-frequency voltage sensor, a power device, and a detection device. The wide-frequency voltage sensor forms a coupling capacitor with the high-voltage bus of the power device, and a conductive path is formed between the coupling capacitor and the wide-frequency voltage sensor. The wide-frequency voltage sensor includes a low-voltage arm capacitor, and the capacitance value of the low-voltage arm capacitor is within a preset interval range. However, the wide-frequency voltage sensor is arranged in the external space of the power device, and the dielectric between the wide-frequency voltage sensor and the high-voltage bus is air in the electrical equipment. The dielectric constant is greatly affected by the temperature, humidity, and particulate matter of the air itself, making the detection signal unstable. Moreover, the wide-frequency voltage sensor is greatly affected by the change of the distributed capacitance of the power device during operation, resulting in low detection signal accuracy. In addition, the wide-frequency voltage sensor needs to be connected and powered by wires, which is not convenient for installation.

[0006] The existing non-contact partial discharge sensor mainly monitors three types of partial discharge signals: ultra-high frequency (UHF), ultrasonic wave (AE), and TEV (ground electric wave). The installation position of the partial discharge sensor is usually a certain distance away from the partial discharge point, so the monitored data is the signal data after a series of spatial propagation of the partial discharge signal. The signal data is disturbed and affected by other signals in the environment during propagation, resulting in false positives in the monitoring data. In addition, the non-contact installed partial discharge sensor usually has a long installation distance, so for the same monitoring target or monitoring point, when temperature and partial discharge are monitored simultaneously, the partial discharge sensor and the temperature sensor need to be completely separated, which increases the complexity of the monitoring system and the installation engineering quantity.

[0007] In addition, the existing sensors that detect partial discharge through UHF, AE, and TEV signals are powered by wires or industrial batteries, and do not achieve true passive power supply, which requires regular battery replacement in some scenarios, affecting the normal operation of the power device (such as device downtime). SUMMARY

[0008] The technical problems solved by the present application are at least one of the following: the existing capacitive coupling partial discharge sensor is greatly affected by the distributed capacitance of the medium and the electrical equipment itself, and has low accuracy; the existing capacitive coupling partial discharge sensor needs wired connection and power supply of the electrical equipment, and is inconvenient to install; the existing capacitive coupling partial discharge sensor system is used for online monitoring, and the system involves many devices and has a complex structure; the sensor for detecting partial discharge by using UHF, AE and TEV signals is usually far away from the partial discharge source, the long-distance propagation of the partial discharge signal in space is easily interfered, and the measurement error is large; the existing sensor for detecting partial discharge by using UHF, AE and TEV signals cannot realize true passive power supply, and needs to replace the battery regularly; the existing partial discharge sensor has a large size, cannot be mounted on the surface of the live part, cannot realize nearby detection of the partial discharge source, and cannot realize synchronous monitoring of the partial discharge and temperature of the live part.

[0009] To solve the above technical problems, the present application provides a high-frequency electromagnetic wave monitoring sensor for monitoring high-frequency electromagnetic wave signals generated by the partial discharge of an electrical power system, which comprises a dielectric substrate and an electromagnetic coupling plate, the dielectric substrate has opposite first and second surfaces, the first surface is used for attaching to a live part of the electrical power system, and the second surface is fixedly attached to the electromagnetic coupling plate; the live part, the dielectric substrate and the electromagnetic coupling plate form a capacitive structure with high-frequency response, so that when the high-frequency electromagnetic wave signals are generated on the live part, high-frequency induction signals are generated on the electromagnetic coupling plate.

[0010] According to a preferred embodiment of the present application, the dielectric substrate is composed of ceramic.

[0011] The present application also provides a partial discharge monitoring device, which comprises the high-frequency electromagnetic wave monitoring sensor and a signal processing circuit, the signal processing circuit is used for processing the high-frequency induction signals, so as to output and / or store the high-frequency induction signals.

[0012] According to a preferred embodiment of the present application, the partial discharge monitoring device further comprises a temperature monitoring element, which is attached to the second surface of the dielectric substrate of the high-frequency electromagnetic wave monitoring sensor or attached to the electromagnetic coupling plate, and is used for measuring the temperature of the live part and generating a temperature signal.

[0013] According to a preferred embodiment of the present application, the processing of the high-frequency induction signals by the signal processing circuit comprises at least one of the following: filtering, gain control, partial discharge feature extraction and analog-to-digital conversion.

[0014] According to a preferred embodiment of the present application, the partial discharge monitoring device further comprises a power taking module; the power taking module is capable of generating induced power through electromagnetic induction with the live part of the power system, so as to provide power for other elements or circuits in the partial discharge monitoring device.

[0015] According to a preferred embodiment of the present application, the power taking module comprises a power taking element and an energy storage element; the power taking element is used to generate induced power through electromagnetic induction with the live part of the power system; the energy storage element is used to store the induced power.

[0016] According to a preferred embodiment of the present application, the power taking element comprises a magnetic conductive ring surrounding the live part of the power system and a power taking coil wound on the magnetic conductive ring; the magnetic conductive ring generates an alternating electromagnetic field through electromagnetic induction with the live part of the power system, and the alternating electromagnetic field generates induced current and induced voltage in the power taking coil, thereby generating the induced power.

[0017] According to a preferred embodiment of the present application, the partial discharge monitoring device further comprises a power frequency signal extraction element for detecting the alternating electromagnetic field and generating a power frequency signal.

[0018] According to a preferred embodiment of the present application, the signal processing circuit is further used to process the power frequency signal, so as to output and / or store the power frequency signal.

[0019] According to a preferred embodiment of the present application, the processing of the power frequency signal by the signal processing circuit comprises at least one of the following: filtering, gain control, partial discharge feature extraction and analog-to-digital conversion.

[0020] According to a preferred embodiment of the present application, the partial discharge monitoring device further comprises a UHF signal extraction element for extracting a UHF signal generated during partial discharge.

[0021] According to a preferred embodiment of the present application, the signal processing circuit is further used to process the UHF signal, so as to output or store the UHF signal.

[0022] According to a preferred embodiment of the present application, the magnetic conductive ring is in the shape of a strip and is provided with a buckle structure for connecting the head and tail of the strip and fixing them, so as to surround the live part of the power system.

[0023] According to a preferred embodiment of the present application, the partial discharge monitoring device further comprises a housing; the housing contains the high-frequency electromagnetic wave monitoring sensor, the temperature monitoring element, the signal processing circuit, the power taking coil and the energy storage element; the magnetic conductive ring passes through the housing, so that the part of the magnetic conductive ring wound by the power taking coil is also located in the housing.

[0024] According to a preferred embodiment of the present application, the shell has an opening, and a first surface of a dielectric substrate of the high-frequency electromagnetic wave monitoring sensor is exposed from the opening to be attached to the live part of the power system.

[0025] According to a preferred embodiment of the present application, the signal processing circuit, the temperature sensing element and the energy storage element are all formed on one circuit board, and the high-frequency electromagnetic wave monitoring sensor, the circuit board and the power taking coil are sequentially stacked and fixed in the shell.

[0026] According to a preferred embodiment of the present application, the shell has two openings arranged oppositely on two sides thereof, so that the magnetic conducting ring is inserted into the shell through the two openings.

[0027] The capacitive coupling structure of the present application can adopt a ceramic substrate to have good insulation performance and a high dielectric constant to isolate low-frequency electromagnetic signals with large energy, so as to protect the internal circuit of the sensor from damage by external high voltage, while having good high-frequency response characteristics, being able to couple to high-frequency electromagnetic signals of partial discharge, and having the advantages of high precision and being not easy to be disturbed.

[0028] The present application has the functions of self-power collection and wireless communication, and does not need wiring and power supply, and truly realizes wireless and passive partial discharge sensor detection, and is suitable for various scene applications of the power system.

[0029] The present application has a compact structure, and can realize multi-modal partial discharge detection in one device, and is convenient for users to use.

[0030] The present application can be attached to the surface of a live part to detect partial discharge, can be attached near the partial discharge source, has high monitoring accuracy and is less disturbed by the environment. BRIEF DESCRIPTION OF DRAWINGS

[0031] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description of example embodiments thereof, taken in conjunction with the accompanying drawings. The drawings described below are only some embodiments of the present disclosure, and other drawings can be obtained according to these drawings without creative labor for those skilled in the art.

[0032] Fig. 1 is a schematic diagram of an application scene of a partial discharge detection system proposed in the patent specification CN114814497A.

[0033] Fig. 2 is a schematic diagram of the cross-sectional structure and principle of the high-frequency electromagnetic wave monitoring sensor of the present application.

[0034] Fig. 3 is a schematic diagram of the equivalent capacitive coupling structure of the high-frequency electromagnetic wave monitoring sensor of the present application.

[0035] Fig. 4 is a perspective structural schematic diagram of one embodiment of the high frequency electromagnetic wave monitoring sensor of the present application.

[0036] Fig. 5 is an exploded schematic diagram of the high frequency electromagnetic wave monitoring sensor of the embodiment shown in Fig. 4.

[0037] Fig. 6 is a cross-sectional structural schematic diagram of a first embodiment of the partial discharge monitoring device of the present application.

[0038] Fig. 7 is an exploded schematic diagram of the partial discharge monitoring device of the embodiment of Fig. 6.

[0039] Fig. 8 is a cross-sectional structural schematic diagram of a second embodiment of the partial discharge monitoring device of the present application.

[0040] Fig. 9 is an exploded schematic diagram of the partial discharge monitoring device of the embodiment of Fig. 8.

[0041] Fig. 10 is a cross-sectional structural schematic diagram of a third embodiment of the partial discharge monitoring device of the present application.

[0042] Fig. 11 is an exploded schematic diagram of the partial discharge monitoring device of the embodiment of Fig. 10.

[0043] Fig. 12 is a perspective structural schematic diagram of the partial discharge monitoring device of the third embodiment of Figs. 10 and 11.

[0044] Fig. 13 is an electronic component diagram of one embodiment of the circuit board of the partial discharge monitoring device of the present application.

[0045] Fig. 14 is a circuit structural diagram of one embodiment of the circuit board of the partial discharge monitoring device of the present application shown in Fig. 13. Best Mode for Carrying Out the Invention

[0046] Example embodiments now will be described more fully hereinafter with reference to the accompanying drawings; however, these embodiments should not be construed as limiting the present disclosure, but merely exemplification thereof. Like reference numerals in different drawings denote like elements, and thus repetitive descriptions thereof will be omitted.

[0047] Furthermore, described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the disclosure. One skilled in the relevant art will recognize, however, that the aspects of the disclosure can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, devices, implementations, or operations are not shown or described in detail to avoid obscuring aspects of the disclosure.

[0048] The block diagrams shown in the drawings are merely functional entities, and do not necessarily have to correspond to physically independent entities. That is, the functional entities can be implemented in the form of software, or in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0049] The flowcharts shown in the drawings are merely exemplary illustrations, and do not necessarily include all contents and operations / steps, nor are they necessarily executed in the order described. For example, some operations / steps can be further divided, and some operations / steps can be combined or partially combined, so the actual execution order can be changed according to actual conditions.

[0050] It should be understood that although the terms first, second, third, etc. can be used herein to describe various components, these components should not be limited by these terms. These terms are used to distinguish one component from another. Therefore, the first component discussed below can be called the second component without departing from the teachings of the present disclosure concept. As used herein, the term "and / or" includes any one of the associated listed items and one or more of all combinations thereof.

[0051] Those skilled in the art can understand that the modules or flows in the drawings are only schematic diagrams of exemplary embodiments, and are not necessarily required for implementing the present disclosure, and therefore cannot be used to limit the protection scope of the present disclosure.

[0052] To solve at least one of the foregoing technical problems, the present application proposes a high-frequency electromagnetic wave monitoring sensor for monitoring high-frequency electromagnetic wave signals generated by a power system when partial discharge (PD) occurs. The sensor is equipped with an electromagnetic coupling plate on a high-performance insulating material (or dielectric substrate) such as a ceramic substrate, to collect high-frequency electromagnetic wave signals generated and propagated after PD occurs on a high-voltage power conductor or contact.

[0053] It should be noted that the high frequency referred to in the present application refers to a frequency range of 300 MHz to 3 GHz. The PD high-frequency electromagnetic wave signal of 300 MHz to 3 GHz is a transient signal in the time domain and a super-wideband signal in the frequency domain.

[0054] In the scheme of the present application, the dielectric substrate has opposite first and second surfaces, the first surface is attached to an electrically stressed component of the power system, such as an electric conductor, a transfer joint, an electrical contact, etc. The second surface is attached to the electromagnetic coupling plate. Thus, the electrically stressed component, the dielectric substrate and the electromagnetic coupling plate form a capacitive structure with high-frequency response, so that when a PD high-frequency electromagnetic wave signal is generated on the electrically stressed component, a high-frequency voltage and current signal corresponding to the PD high-frequency electromagnetic wave signal is generated on the electromagnetic coupling plate. This high-frequency voltage and current signal is referred to as a high-frequency induced signal in the present application.

[0055] The application preferably adopts a ceramic substrate as the dielectric substrate, because the ceramic substrate has good insulation performance and high dielectric constant. This makes the "capacitor" structure have good high-frequency response characteristics and insulate low-frequency electromagnetic signals with large energy. At the same time, the ceramic substrate also has good heat conduction performance, which is also conducive to directly installing a temperature sensor on the ceramic substrate. Although the propagation of partial discharge signals as high-frequency electromagnetic wave signals on the overvoltage component attenuates quickly, the high-frequency electromagnetic wave monitoring sensor of the application can be installed at a key position where partial discharge is prone to occur, such as a contact of the power conductor, so that the distance between the sensor and the point where partial discharge is prone to occur is even only a few centimeters. Even if the propagation of high-frequency electromagnetic waves in the power conductor attenuates severely, in the short monitoring range, a relatively high partial discharge electromagnetic wave signal can still be monitored.

[0056] In addition, since the dielectric substrate is used as the dielectric of the "capacitor", the dielectric constant, thickness, surface area and other physical indicators of the dielectric are stable during use, so that the "capacitor" value is less affected by the distributed capacitance of other elements of the electrical equipment, and the signal measurement accuracy and frequency response characteristics can be improved. At the same time, since the high-frequency electromagnetic wave monitoring sensor of the application can be installed in a region very close to the overvoltage component, the working temperature and other working environments of the sensor remain consistent with the working environment of the power system, and are less affected by the external environment, which is conducive to analyzing and researching the relationship between the detected partial discharge signal and the electrical equipment.

[0057] Fig. 2 is a schematic diagram of the cross-sectional structure and principle of the high-frequency electromagnetic wave monitoring sensor of the application. As shown in Fig. 2, the power system has an overvoltage component S, and the high-frequency electromagnetic wave monitoring sensor of the application is used to monitor the high-frequency electromagnetic wave signal W generated by the power system when partial discharge occurs. The sensor includes a dielectric substrate 1 and an electromagnetic coupling plate 2. The dielectric substrate 1 has opposite first and second surfaces (the upper surface in the figure and the lower surface in the figure), the first surface is used to attach to the overvoltage component S of the power system, and the second surface is fixedly attached to the electromagnetic coupling plate 2. That is, as a component part, the dielectric substrate 1 and the electromagnetic coupling plate 2 are fixedly attached to each other, and one side of the dielectric substrate 1 is used to attach to the overvoltage component S of the power system. The overvoltage component referred to in the application refers to a component in the power system that can conduct electrical signals and also propagate high-frequency electromagnetic wave signals W when partial discharge occurs in the power system, such as a conductor, a joint, a contact, etc. of the power system.

[0058] Fig. 3 is a schematic diagram of the equivalent capacitive coupling structure of the high-frequency electromagnetic wave monitoring sensor of the application. The dashed box in Fig. 3 corresponds to that in Fig. 2. The overvoltage component S, the dielectric substrate 1 and the electromagnetic coupling plate 2 form a capacitive structure with high-frequency response, so that when a high-frequency electromagnetic wave signal is generated on the overvoltage component, a high-frequency induced signal is generated on the electromagnetic coupling plate.

[0059] The dielectric substrate 1 of the present application should have high insulation properties, or have a high dielectric constant, and preferably use a material having a large dielectric constant and good thermal conductivity. As a preferred embodiment, the dielectric constant of the dielectric substrate should be greater than 5, and the thermal conductivity should be greater than 100 W / m*K, for example, the dielectric substrate is preferably made of ceramic.

[0060] As a preferred embodiment of the present application, when the dielectric substrate uses a ceramic material, considering the comprehensive factors of capacitive coupling performance, material manufacturing process, cost, etc., the thickness of the ceramic is preferably 0.5-2.0 mm.

[0061] In order to make the purpose, technical scheme and advantages of the present application more clear and obvious, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0062] Fig. 4 is a perspective structural schematic diagram of an embodiment of the high-frequency electromagnetic wave monitoring sensor of the present application. In this embodiment, the element is in the form of a generally rectangular sheet. In the viewing direction of Fig. 4, the upper part is a ceramic plate with a thickness of 1.2-1.4 mm, which serves as the dielectric substrate 1, and the lower part is a copper plate with a thickness of 0.2-0.4 mm, which serves as the electromagnetic coupling plate 2. The ceramic plate and the copper plate are tightly attached to each other. The copper plate has a signal output contact 21 on one side edge.

[0063] The high-frequency electromagnetic wave monitoring sensor of this embodiment can be used as a local discharge detection element or a local discharge sensor with independent function, for monitoring the high-frequency electromagnetic wave signals generated by the power system when local discharge occurs. In use, the ceramic plate is tightly attached to the overvoltage components such as the joints of the switch cabinet of the power system, and the overvoltage components, the ceramic plate and the copper plate form a capacitive structure with high-frequency response, so that when high-frequency electromagnetic wave signals are generated on the overvoltage components, high-frequency induction signals are generated on the electromagnetic coupling plate. The output contact 21 on the side edge of the copper plate can be connected to a signal line to transmit the high-frequency induction signals to the outside through the signal line.

[0064] Fig. 5 is an exploded schematic diagram of the elements of the high-frequency electromagnetic wave monitoring sensor of the embodiment shown in Fig. 4. As can be seen from this figure, the side edge of the copper plate serving as the electromagnetic coupling plate 2 has two notches, and the part between the notches forms the output contact 21.

[0065] In the above embodiment, the shapes and areas of the main surfaces (upper and lower surfaces) of the ceramic plate and the copper plate are substantially the same. However, the present application is not limited to the shapes of the two, nor to the area ratio of the main surfaces of the two. That is, in other embodiments, the sizes and shapes of the ceramic plate and the copper plate can be different, as long as they can form a capacitive structure suitable for induction of high-frequency electromagnetic wave signals with the overvoltage components.

[0066] Meanwhile, the materials of the dielectric substrate 1 and the electromagnetic coupling substrate 2 are not limited to ceramic and copper, respectively, but can be composed of other insulating materials and other metal materials, respectively.

[0067] Fig. 6 is a schematic diagram of a sectional structure of a first embodiment of the partial discharge monitoring device according to the present application. As shown in Fig. 6, the partial discharge monitoring device of this embodiment comprises, in addition to the high-frequency electromagnetic wave monitoring sensor shown in Fig. 2, a circuit board 3. The circuit board 3 is kept at a certain distance from the electromagnetic coupling plate 2 of the high-frequency electromagnetic wave monitoring sensor. The circuit board 3 has input terminals and a signal processing circuit composed of circuit elements for processing the high-frequency induction signal for output or storage of the high-frequency induction signal. In order to connect the high-frequency induction signal to the circuit board 3, the input terminals of the circuit board 3 are connected to the output contacts 21 of the copper plate as electromagnetic coupling plate by means of signal lines 31.

[0068] The processing of the high-frequency induction signal includes gain control, filtering, analog-digital conversion, partial discharge feature extraction and storage, etc. Thus, the circuit board 3 should have electronic elements for performing the processing, such as gain controllers, filters, analog-digital converters, memories, processors, etc. The type and function of the specific elements on the circuit board 3 can be further described in the embodiments described below.

[0069] In addition, in order to keep the circuit board 3 at a certain distance from the copper plate, supports 32 are provided between the circuit board 3 and the copper plate and around and / or in the middle of the circuit board. The present application is not limited to the number of supports, but preferably a plurality of supports are provided so that the circuit board 3 does not come into contact with the copper plate as electromagnetic coupling plate 2 at any point.

[0070] Referring again to Fig. 6, in this embodiment, the partial discharge monitoring device also has a housing 4 which is open at one end. The opening of the housing 4 in Fig. 6 is upwardly directed so that the upper surface of the ceramic plate as dielectric substrate 1 faces the outside of the housing, the electromagnetic coupling plate 2 attached to the lower surface of the ceramic plate and the circuit board 3 supported on the electromagnetic coupling plate 2 are located inside the housing.

[0071] The housing 4 serves on the one hand to protect the elements on the dielectric substrate 1, the electromagnetic coupling plate 2 and the circuit board 3 from the outside environment and on the other hand as a structural component to support and fix the devices and elements inside. For example, as shown in Fig. 6, the lower surface of the circuit board is also fixed to the housing 4 by means of the supports 32. The housing 4 and the supports 32 are generally composed of insulating materials, such as plastic, rubber, etc.

[0072] Figure 7 is an exploded view of the partial discharge monitoring device of the embodiment of Figure 6. As shown in Figure 7, the housing 4 of the partial discharge monitoring device of this embodiment is in the shape of a square box. Inside the housing 4, the circuit board 3 and the high-frequency electromagnetic wave monitoring sensor are stacked one on top of the other from inside to outside, and are isolated and fixed from each other by a support (not shown in the figure) inside the housing. The high-frequency electromagnetic wave monitoring sensor is formed by the protective dielectric substrate 1 and the electromagnetic coupling board 2 being attached to each other, as described above.

[0073] Figure 8 is a cross-sectional view of a second embodiment of the partial discharge monitoring device of the present application. As shown in Figure 8, the difference between this embodiment and the first embodiment is that the circuit board 3 of this embodiment is further provided with a temperature sensor 33 for measuring the temperature of the live part of the power system and generating a temperature signal. Thus, the temperature signal obtained by the temperature sensor 33 can be directly transmitted to the signal processing circuit on the circuit board 3.

[0074] It is particularly important to note that, unlike the prior art, the temperature sensor 33 of the present application is also attached to the high-frequency electromagnetic wave monitoring sensor. Since the high-frequency electromagnetic wave monitoring sensor is directly attached to the live part of the power system, and the high-frequency electromagnetic wave monitoring sensor is thin and has good thermal conductivity, the temperature of the high-frequency electromagnetic wave monitoring sensor detected by the temperature sensor 33 can be directly regarded as the temperature of the live part. Thus, the present application achieves dual monitoring of partial discharge and temperature in one monitoring device.

[0075] Further, the temperature sensor 33 can be attached to the dielectric substrate 1 of the high-frequency electromagnetic wave monitoring sensor, or can be attached to the electromagnetic coupling board. In order to reduce the impact on the capacitive coupling structure, the present application preferably attaches the temperature sensor 33 to the dielectric substrate 1.

[0076] Referring again to Figure 8, in this second embodiment, the temperature sensor 33 is attached to the lower surface of the dielectric substrate 1 of the high-frequency electromagnetic wave monitoring sensor. Figure 9 is an exploded view of the partial discharge monitoring device of the embodiment of Figure 8. As shown in Figure 9, in order to allow the electromagnetic coupling board 2 not to block the temperature sensor 33 from being attached to the dielectric substrate 1 of the high-frequency electromagnetic wave monitoring sensor, the area of the main surface of the electromagnetic coupling board 2 of this second embodiment is slightly smaller than the area of the main surface of the dielectric substrate 1, so that the temperature sensor 33 is attached to the dielectric substrate 1 in a place not covered by the electromagnetic coupling board 2.

[0077] Figure 10 is a schematic diagram of a third embodiment of the partial discharge monitoring device of the present application. The third embodiment differs from the first two embodiments in that it further comprises a power taking element capable of generating induced power by electromagnetic induction with the live part, so as to supply power to other elements or circuits in the partial discharge monitoring device. The power taking element comprises a power taking coil 5 and a magnetic conducting ring 6, the magnetic conducting ring 6 being wrapped around the live part, and the power taking coil 5 being wound around the magnetic conducting ring 6. The magnetic conducting ring 6 generates an alternating electromagnetic field by electromagnetic induction with the live part S, and the alternating electromagnetic field generates induced current and induced voltage in the power taking coil 5, thereby generating the induced power. The material of the magnetic conducting ring 6 can be permalloy or silicon steel sheet, and the material of the power taking coil 5 can be copper.

[0078] The live part of the power system usually carries 50 Hz power frequency current, and the electromagnetic wave energy at this frequency is the strongest. Permalloy or silicon steel sheet is a good magnetic conducting material, and can generate induced power in the power taking coil 5 by electromagnetic induction coupling with the alternating electromagnetic field generated by the alternating current in the power line. Meanwhile, the permalloy or silicon steel sheet passes through the power taking coil 5, so that when the electromagnetic field in the magnetic conducting ring 6 changes, the alternating electromagnetic field can induce power in the power taking coil 5.

[0079] As a preferred embodiment, the circuit board 4 is further provided with an energy storage element, such as a super capacitor energy storage device. Thus, the induced power is stored by the energy storage element on the circuit board 4, thereby realizing passive power supply function in the partial discharge monitoring device.

[0080] Figure 11 is an exploded view of the partial discharge monitoring device of the embodiment of Figure 10. The magnetic conducting ring 6 and the live part S are not shown in Figure 11. As can be seen from Figures 10 and 11, in the third embodiment, the power taking coil 5 is arranged below the circuit board 3 in the housing 4. The power taking coil 5 is wound into a flat ring shape, and has a through hole 51 in the middle to allow the flat strip-shaped magnetic conducting ring 6 to pass through. Meanwhile, the housing has openings 41 on the opposite two sides corresponding to the through hole 51, to facilitate the magnetic conducting ring 6 to pass in and out. That is, in the third embodiment of Figure 11, the magnetic conducting ring 6 passes through the housing 4, so that the part of the magnetic conducting ring 6 wound by the power taking coil 5 is also located inside the housing 4.

[0081] Figure 12 is a schematic diagram of the partial discharge monitoring device of the third embodiment of Figures 10 and 11. As shown in Figure 6, the housing 4 is a square box shape, and one of the top surfaces exposes the dielectric substrate 1 of the high frequency electromagnetic wave monitoring sensor. The magnetic conducting ring passes through one of the sides close to the bottom of the partial discharge monitoring device. The magnetic conducting ring 6 comprises a strip 61 formed of permalloy material, the outer side of the strip 61 is sleeved with a protective sleeve 62, and the strip 61 is joined at both ends by a buckle structure 63. That is, the buckle structure 63 is used to join and fix the strip 61 end to end, so as to wrap around the live part S of the power system.

[0082] Fig. 13 is an electronic component diagram of one embodiment of the circuit board 4 of the partial discharge monitoring device. As mentioned above, the circuit board 3 has input terminals and a signal processing circuit composed of electronic components for processing the high-frequency induction signal. However, the circuit board can also have other functional electronic components to enable the partial discharge monitoring device to have more functions and to achieve multi-modal detection. In the embodiment shown in Fig. 13, the circuit board 4 is provided with electronic components other than those for processing the high-frequency induction signal, including other sensors, memory, energy storage components, etc.

[0083] First, as shown in Fig. 13, the circuit board 4 is provided with a first automatic gain controller 341, a filter 342, and a detection circuit 343. These three components are connected to the input terminals connected to the signal line 31 and perform automatic gain control, filtering, and detection of the high-frequency induction signal from the high-frequency electromagnetic wave monitoring sensor, respectively. The high-frequency induction signal collected by the high-frequency electromagnetic wave monitoring sensor is first passed through the first automatic gain controller 341, which automatically detects whether the collected high-frequency induction signal is too high or too low in intensity. For electromagnetic waves with too high signal energy, automatic attenuation is performed to prevent damage to the backend circuit; for electromagnetic waves with low signal intensity, automatic gain processing is performed to facilitate analysis and processing by the subsequent circuit.

[0084] The high-frequency induction signal generated by partial discharge is passed through the first automatic gain controller 341 and then enters the filter 342. The filter 342 is preferably an adjustable filter to be configured according to the setting process of different partial discharge devices, partial discharge types, and on-site environmental electromagnetic conditions, thereby reducing or isolating the entry of interference signals.

[0085] The high-frequency induction signal generated by partial discharge is passed through the filter 342 and then input into the detection circuit 343, which directly outputs the relative power value of the high-frequency induction signal.

[0086] Second, referring again to Fig. 13, the circuit board 4 is also provided with a digital temperature sensor 33 to obtain a temperature signal. As mentioned above, the temperature sensor 33 is attached to the dielectric substrate 1 or the electromagnetic coupling plate 2 of the high-frequency electromagnetic wave monitoring sensor, which will not be described again here.

[0087] Thirdly, the second automatic gain controller 35 is also configured on the circuit board 4. The partial discharge monitoring device proposed in the present application can extract the phase of the power frequency signal of the target power system being monitored. Since the partial discharge is closely related to the power frequency phase, the correlation analysis of the partial discharge signal and the power frequency signal in the partial discharge monitoring application can exclude the influence of the environmental interference signal, and distinguish the partial discharge categories, etc. Therefore, the scheme of the magnetic conductive ring 6 in this embodiment applies materials with good magnetic conductivity, such as permalloy or silicon steel sheet, and has good low-frequency electromagnetic wave response characteristics. In this way, the 50Hz power frequency alternating current signal in the overvoltage component is also the strongest 50Hz signal in the electromagnetic signal induced in the magnetic conductive ring 6. After the second automatic gain controller 35, the energy is adjusted to meet the processing requirements of the subsequent electronic components.

[0088] Fourthly, the voiceprint sensor 36, for example, a MIC voiceprint sensor, is also configured on the circuit board 4. The voiceprint sensor 36 can collect voiceprint signals in the frequency band of 20Hz to 80kHz. Thus, the voiceprint signals generated when the partial discharge occurs can be collected together.

[0089] Fifthly, the UHF signal detection processor 39 is also configured on the circuit board 4. The UHF signal detection processor 39 is used for adaptive gain control, signal filtering, and high-frequency signal detection of the UHF signal generated when the partial discharge occurs.

[0090] Sixthly, the microprocessor (MCU) 40 and the memory 37 are also configured on the circuit board 4. The high-frequency induction signal generated by the partial discharge is collected by the analog-to-digital converter in the microprocessor 40 after the filter 342, and is stored by the memory 37. The microprocessor 40 is also used for fusion processing of the detected high-frequency induction signal and the signal after analog-to-digital conversion. Moreover, this processing can be performed locally, or sent to the back-end server through the wireless communication unit of the microprocessor.

[0091] Finally, as mentioned before, the energy storage element 38, for example, a super capacitor energy storage device, is also configured on the circuit board 4. Thus, the electric energy generated by induction is stored by the energy storage element 38 on the circuit board 4, so as to realize the passive power supply function in the partial discharge monitoring device.

[0092] FIG. 14 is a circuit structure diagram of one embodiment of the circuit board 4 of the partial discharge monitoring device of the present application shown in FIG. 13. As shown in FIG. 14, the microprocessor 40 is connected to the memory and the wireless communication unit, and is also connected to the detection circuit, the UHF signal detection processor, the second automatic gain controller, the temperature sensor, and the voiceprint sensor, respectively. Thus, the microprocessor 40 can store and process the UHF signal, the power frequency signal, the temperature signal, and the voiceprint signal.

[0093] For example, the analog-digital converter in the microprocessor 40 also processes the 50Hz power frequency signal which is gain-controlled by the second gain controller 35, and the phase information of the 50Hz power frequency signal in the power conductor can be obtained.

[0094] In summary, the partial discharge monitoring device based on the capacitive coupling structure can use a ceramic substrate as a dielectric medium, has good insulation performance, and has a high dielectric constant to isolate low-frequency electromagnetic signals with large energy, so as to protect the internal circuit of the sensor from damage by external high-voltage electricity, while having good high-frequency response characteristics, can be coupled to high-frequency electromagnetic signals of partial discharge, has the advantages of high precision and is not easy to be disturbed.

[0095] The present application has the functions of self-power collection and wireless communication, does not need wiring and power supply, and truly realizes wireless and passive sensing detection, and is suitable for various scene applications of the power system.

[0096] The present application has a compact structure, can realize multi-modal partial discharge detection in one device, and is convenient for users to use.

[0097] The present application can be attached to the surface of an overvoltage component to detect partial discharge, can be attached near the partial discharge source, has high monitoring accuracy, and is less disturbed by the environment.

[0098] The above specifically illustrates and describes the exemplary embodiments of the present disclosure. It should be understood that the present disclosure is not limited to the detailed structure, arrangement or implementation method described herein; on the contrary, the present disclosure is intended to cover various modifications and equivalent arrangements included in the spirit and scope of the appended claims.

Claims

1. A high-frequency electromagnetic wave monitoring sensor for monitoring high-frequency electromagnetic wave signals generated by a power system during partial discharge, comprising a dielectric substrate and an electromagnetic coupling plate; the dielectric substrate has opposite first and second surfaces, the first surface being configured to be attached to an electrically stressed component of the power system, and the second surface being configured to be fixedly attached to the electromagnetic coupling plate; the electrically stressed component, the dielectric substrate and the electromagnetic coupling plate form a capacitive structure having a high-frequency response, such that when the electrically stressed component generates high-frequency electromagnetic wave signals, the electromagnetic coupling plate generates high-frequency induced signals.

2. The high-frequency electromagnetic wave monitoring sensor according to claim 1, wherein the dielectric substrate is made of ceramic.

3. A partial discharge monitoring device comprising the high-frequency electromagnetic wave monitoring sensor according to claim 1 or 2 and a signal processing circuit, wherein, the signal processing circuit is configured to process the high-frequency induced signals so as to output and / or store the high-frequency induced signals.

4. The partial discharge monitoring device of claim 3, further comprising a temperature monitoring element attached to the second surface of the dielectric substrate of the high-frequency electromagnetic wave monitoring sensor or attached to the electromagnetic coupling plate, for measuring a temperature of the electrically stressed component and generating a temperature signal.

5. The partial discharge monitoring device of claim 4, wherein the processing of the high-frequency induced signals by the signal processing circuit comprises at least one of filtering, gain control, partial discharge feature extraction and analog-to-digital conversion.

6. The partial discharge monitoring device of claim 4, wherein the partial discharge monitoring device further comprises a power harvesting module; the power harvesting module is configured to generate induced power by electromagnetic induction with the electrically stressed component of the power system, so as to provide power for other elements or circuits in the partial discharge monitoring device.

7. The partial discharge monitoring device of claim 6, wherein the power harvesting module comprises a power harvesting element and an energy storage element; the power harvesting element is configured to generate induced power by electromagnetic induction with the electrically stressed component of the power system; the energy storage element is configured to store the induced power.

8. The partial discharge monitoring device of claim 7, wherein the power harvesting element comprises a magnetic conductive ring surrounding the electrically stressed component of the power system and a power harvesting coil wound around the magnetic conductive ring; the magnetic conductive ring is configured to generate an alternating electromagnetic field by electromagnetic induction with the electrically stressed component of the power system, and the alternating electromagnetic field generates induced current and induced voltage in the power harvesting coil, thereby generating the induced power.

9. The partial discharge monitoring device of claim 8, further comprising a power frequency signal extraction element configured to detect the alternating electromagnetic field and generate a power frequency signal.

10. The partial discharge monitoring device of claim 9, wherein the signal processing circuit is further configured to process the power frequency signal so as to output and / or store the power frequency signal.

11. The partial discharge monitoring device of claim 10, wherein the processing of the power frequency signal by the signal processing circuit comprises at least one of filtering, gain control, partial discharge feature extraction and analog-to-digital conversion.

12. The corrosion monitoring apparatus of claim 8, wherein, further comprising a UHF signal extraction element configured to extract UHF signals generated during partial discharge.

13. The partial discharge monitoring device of claim 12, wherein the signal processing circuit is further configured to process the UHF signals so as to output or store the UHF signals.

14. The partial discharge monitoring device of claim 8, wherein, the magnetic conducting ring is in a strip shape and is provided with a buckle structure for connecting and fixing the strip head to tail to surround the live part of the power system.

15. The partial discharge monitoring device of claim 8, wherein, the partial discharge monitoring device further comprises a housing; the housing contains the high frequency electromagnetic wave monitoring sensor, the temperature monitoring element, the signal processing circuit, the power taking coil and the energy storage element; the magnetic conducting ring passes through the housing so that the part of the magnetic conducting ring wound by the power taking coil is also located in the housing.

16. The corrosion monitoring apparatus of claim 15, wherein, the housing has an opening through which the first surface of the dielectric substrate of the high frequency electromagnetic wave monitoring sensor is exposed to be attached to the live part of the power system.

17. The corrosion monitoring apparatus of claim 15, wherein, the signal processing circuit, the temperature monitoring element and the energy storage element are formed on a circuit board, and the high frequency electromagnetic wave monitoring sensor, the circuit board and the power taking coil are sequentially stacked and fixed in the housing.

18. The corrosion monitoring apparatus of claim 15, wherein, the housing has two openings oppositely arranged on two sides of the housing through which the magnetic conducting ring passes into the housing.

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