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

Abstract

The utility model discloses a high frequency electromagnetic wave monitoring sensor used for partial discharge monitoring and a corresponding partial discharge monitoring device, the sensor comprises a dielectric substrate and an electromagnetic coupling plate, the dielectric substrate has a first surface and a second surface which are opposite to each other, the first surface is used for being attached to an over-current component of a power system, and the second surface is used for being attached to an over-current component of the power system. The second surface is fixedly attached to the electromagnetic coupling plate, one side edge of the electromagnetic coupling plate is provided with a signal output contact, and the over-current component, the dielectric substrate and the electromagnetic coupling plate form a capacitor structure with high-frequency response, so that when a high-frequency electromagnetic wave signal is generated on the over-current component of the power body system, the over-current component can generate the high-frequency electromagnetic wave signal. And a high-frequency induction signal is generated on the electromagnetic coupling plate. The utility model has the advantages of better high-frequency response characteristic, high precision, difficulty in interference and convenience in installation.

Description

Technical Field

[0001] The utility model belongs to the technical field of fault detection of electric power systems, and in particular relates to a high-frequency electromagnetic wave monitoring sensor for partial discharge monitoring, and a monitoring device using the high-frequency electromagnetic wave monitoring sensor. Background Art

[0002] Partial discharge and temperature anomalies are the main manifestations of power equipment failure or safety hazards. Partial discharge is one of the important manifestations of the loss of insulation performance of power equipment. Among all types of faults in the power system, partial discharge performance accounts for more than 80%. Partial discharge is also the main 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 equipment failures such as overload, short circuit, insulation aging or damage, cooling system failure, etc., the equipment temperature will be abnormal. Power equipment working in abnormal temperature state for a long time 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 partial discharge sensors and non-contact partial discharge sensors. The contact partial discharge sensors mainly include capacitive coupling partial discharge sensors and inductive sensing partial discharge sensors. However, the existing capacitive coupling partial discharge sensors and inductive sensing partial discharge sensors require wired connections and wired power supply. This type of system collects the signals of the front-end sensors through wires, and then analyzes the partial discharge data to determine the partial discharge status of the equipment. Therefore, the application of this type of sensor is limited in most power systems.

[0005] For example, Figure 1 As shown, a partial discharge detection method is proposed in the patent specification with the publication number CN114814497A, which is applied to the detection system. The detection system includes a broadband voltage sensor, an electric power device and a detection device. A coupling capacitor is formed between the broadband voltage sensor and the high-voltage busbar of the electric power device, and a conductive path is formed between the coupling capacitor and the broadband voltage sensor. The broadband voltage sensor includes a low-voltage arm capacitor, and the capacitance value of the low-voltage arm capacitor is within a preset interval. However, the broadband voltage sensor is arranged in the external space of the electric power device, and the dielectric between the broadband voltage sensor and the high-voltage busbar is the air in the electric power device. The dielectric constant is greatly affected by the temperature, humidity and particulate matter of the air itself, making the detection signal unstable; and the broadband voltage sensor is greatly affected by the change of the distributed capacitance of the electric power device during operation, making the detection signal accuracy low; in addition, the broadband voltage sensor needs to be connected and powered by wire, which is not convenient for installation.

[0006] Existing non-contact partial discharge sensors mainly monitor the three types of partial discharge signals generated by partial discharge: ultra-high frequency (UHF), ultrasonic wave (AE), and TEV (earth electric wave). The installation position of the partial discharge sensor is usually a certain distance away from the partial discharge point, so that the monitored data is the signal data of the partial discharge signal after a series of spatial propagation. The signal data will be interfered and affected by other signals in the environment during the propagation process, resulting in false alarms in the monitoring data. In addition, non-contact partial discharge sensors usually have a long installation distance, so for the same monitoring target or monitoring point, when monitoring temperature and partial discharge at the same time, the partial discharge sensor and the temperature sensor need to be completely separated, which will increase the complexity of the monitoring system and the installation workload.

[0007] In addition, the existing sensors that use UHF, AE, and TEV signals for partial discharge detection are powered by wires or industrial batteries, and do not achieve true passive power supply. As a result, in some scenarios, the batteries need to be replaced regularly, which will affect the normal operation of power equipment (such as equipment shutdown). Summary of the invention

[0008] 1. Technical issues to be resolved

[0009] The utility model mainly solves at least one of the following technical problems: the existing capacitive coupling partial discharge sensor is greatly affected by the distributed capacitance of the medium and the electrical equipment itself, and the accuracy is not high; the existing capacitive coupling partial discharge sensor requires wired connection and power supply due to the electrical equipment, which is inconvenient to install; the existing capacitive coupling partial discharge sensor system performs online monitoring, and the system involves many devices and the system structure is complex; the existing sensors for partial discharge detection through three types of signals, namely UHF, AE, and TEV, are usually far away from the partial discharge source, and the long-distance propagation of partial discharge signals in space is easily seriously interfered, resulting in large measurement errors; the existing sensors for partial discharge detection through three types of signals, namely UHF, AE, and TEV, do not achieve true passive power supply, and batteries need to be replaced regularly; the existing partial discharge sensors are large in size and cannot be mounted on the surface of the current-carrying components, and the local detection of the partial discharge source and the simultaneous monitoring of the partial discharge and temperature of the current-carrying body are not achieved.

[0010] (II) Technical solution

[0011] In order to solve the above technical problems, the utility model proposes, on the one hand, a high-frequency electromagnetic wave monitoring sensor for partial discharge monitoring, including a dielectric substrate and an electromagnetic coupling plate; the dielectric substrate has a first surface and a second surface relative to each other, the first surface is used to be attached to the current-carrying component of the power system, and the second surface is fixedly attached to the electromagnetic coupling plate; one side of the electromagnetic coupling plate has a signal output contact; the current-carrying component, the dielectric substrate and the electromagnetic coupling plate form a capacitor structure with a high-frequency response, so that when a high-frequency electromagnetic wave signal is generated on the current-carrying component, a high-frequency induction signal is generated on the electromagnetic coupling plate.

[0012] Another aspect of the utility model provides a monitoring device for partial discharge monitoring, comprising: the aforementioned high-frequency electromagnetic wave monitoring sensor; a circuit board having an input terminal and a signal processing circuit, the signal processing circuit being used to process the high-frequency induction signal so as to output and / or store the high-frequency induction signal; and a signal line being used to connect the input terminal of the circuit board to the output contact of the electromagnetic coupling board.

[0013] According to a preferred embodiment of the utility model, the monitoring device for partial discharge monitoring further comprises a housing, and the housing accommodates the high-frequency electromagnetic wave monitoring sensor, the circuit board and the signal line.

[0014] According to a preferred embodiment of the utility model, the first surface of the dielectric substrate of the high-frequency electromagnetic wave monitoring sensor is exposed from the opening so as to be attached to the current-carrying component of the power system.

[0015] According to a preferred embodiment of the utility model, the monitoring device for partial discharge monitoring also includes a temperature sensor, 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 to measure the temperature of the current-carrying component and generate a temperature signal.

[0016] According to a preferred embodiment of the utility model, the monitoring device for partial discharge monitoring also includes a power extraction module; the power extraction module can undergo electromagnetic induction with the power-passing components of the power system to generate induced electrical energy, so as to provide electrical energy for other components or circuits in the partial discharge monitoring device.

[0017] According to a preferred embodiment of the utility model, the power extraction module includes a power extraction element and an energy storage element; the power extraction element is used to generate induced electric energy by electromagnetic induction with the power transmission component of the power system; and the energy storage element is used to store the induced electric energy.

[0018] According to a preferred embodiment of the utility model, the power-taking element includes a magnetic ring surrounding the current-carrying component of the power system and a power-taking coil wound on the magnetic ring; the magnetic ring undergoes electromagnetic induction with the current-carrying component of the power system to generate an alternating electromagnetic field, and the alternating electromagnetic field generates an induced current and an induced voltage in the power-taking coil, thereby generating the induced electric energy.

[0019] According to a preferred embodiment of the utility model, the magnetic conductive ring is in the shape of a strip and is provided with a buckle structure, wherein the buckle structure is used to connect and fix the strip end to end so as to surround the current-carrying component of the power system.

[0020] According to a preferred embodiment of the utility model, the magnetic conductive ring passes through the shell, so that the part of the magnetic conductive ring wound by the power taking coil is also located in the shell.

[0021] According to a preferred embodiment of the utility model, the high-frequency electromagnetic wave monitoring sensor, the circuit board, and the power collection coil are sequentially stacked and fixed in the shell.

[0022] According to a preferred embodiment of the present utility model, two openings are arranged opposite to each other on both sides of the shell, so that the magnetic conductive ring can pass through the two openings and enter the shell.

[0023] According to a preferred embodiment of the present utility model, the circuit board includes an industrial frequency signal extraction element, which is used to detect the alternating electromagnetic field and generate an industrial frequency signal.

[0024] According to a preferred embodiment of the utility model, the circuit board further includes a UHF signal extraction element for extracting the UHF signal generated during partial discharge.

[0025] (III) Beneficial effects

[0026] The capacitive coupling structure of the utility model can adopt a ceramic substrate with good insulation performance and a high dielectric constant to isolate low-frequency electromagnetic signals with large energy, thereby protecting the internal circuit of the sensor from damage by external high voltage electricity. At the same time, it has good high-frequency response characteristics and can couple to high-frequency electromagnetic signals of local discharge, with the advantages of high precision and low interference.

[0027] The utility model has the functions of self-power collection and wireless communication, does not require wiring and power supply, truly realizes wireless passive partial discharge sensing detection, and is suitable for various application scenarios of power systems.

[0028] The utility model has a compact structure and can realize multi-mode partial discharge detection in one device, which is convenient for users to use.

[0029] The utility model can be mounted on the surface of a current-carrying component to detect partial discharge, can be mounted close to a partial discharge source, has high monitoring accuracy, and is less affected by environmental interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of an application scenario of a partial discharge detection system proposed in the patent specification with publication number CN114814497A.

[0031] Figure 2 It is a cross-sectional structure and principle diagram of the high-frequency electromagnetic wave monitoring sensor of the utility model.

[0032] Figure 3 It is a schematic diagram of the equivalent capacitive coupling structure of the high-frequency electromagnetic wave monitoring sensor of the utility model.

[0033] Figure 4 It is a three-dimensional structural schematic diagram of an embodiment of the high-frequency electromagnetic wave monitoring sensor of the utility model.

[0034] Figure 5 yes Figure 4 The schematic diagram of the component decomposition of the high-frequency electromagnetic wave monitoring sensor of the embodiment shown.

[0035] Figure 6 It is a schematic cross-sectional structure diagram of the first embodiment of the partial discharge monitoring device of the utility model.

[0036] Figure 7 yes Figure 6 Schematic diagram of component decomposition of a partial discharge monitoring device of an embodiment.

[0037] Figure 8 It is a cross-sectional structural diagram of the second embodiment of the partial discharge monitoring device of the utility model.

[0038] Fig. 9 yes Figure 8 Schematic diagram of component decomposition of a partial discharge monitoring device of an embodiment.

[0039] Fig.10 It is a cross-sectional structural diagram of a third embodiment of the partial discharge monitoring device of the utility model.

[0040] Fig.11 yes Fig.10 Schematic diagram of component decomposition of a partial discharge monitoring device of an embodiment.

[0041] Fig.12 yes Fig.10 and Fig.11 A schematic diagram of the three-dimensional structure of a partial discharge monitoring device according to a third embodiment of the present invention.

[0042] Fig.13It is a diagram of electronic components of an embodiment of a circuit board of a partial discharge monitoring device of the utility model.

[0043] Fig.14 yes Fig.13 The circuit structure diagram of one embodiment of a circuit board of a partial discharge monitoring device of the utility model is shown. DETAILED DESCRIPTION

[0044] In order to solve at least one of the above technical problems, the utility model proposes a high-frequency electromagnetic wave monitoring sensor for monitoring the high-frequency electromagnetic wave signals generated by the power system when partial discharge (PD) occurs. The sensor is an electromagnetic coupling board mounted 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 partial discharge occurs on high-voltage power conductors or contacts.

[0045] It should be noted that the high frequency referred to in the present invention refers to a frequency range between 300MHz and 3GHz. The local discharge high frequency electromagnetic wave signal of 300MHz to 3GHz is a transient signal in the time domain and an ultra-wideband signal in the frequency domain.

[0046] In the scheme of the present utility model, the dielectric substrate has a first surface and a second surface relative to each other, the first surface is attached to the current-carrying component of the power system, and the current-carrying component is, for example, an electric wire, an adapter, an electric contact, etc. The second surface is attached to the electromagnetic coupling plate. Thus, the current-carrying component, the dielectric substrate and the electromagnetic coupling plate form a capacitor structure with a high-frequency response, so that when a local discharge high-frequency electromagnetic wave signal is generated on the current-carrying component, a high-frequency voltage and current signal corresponding to the high-frequency electromagnetic wave signal is generated on the electromagnetic coupling plate. The high-frequency voltage and current signal is referred to as a high-frequency induction signal in the present utility model.

[0047] The utility model preferably uses a ceramic substrate as a dielectric substrate, because the ceramic substrate has good insulation properties and a high dielectric constant. This makes the "capacitor" structure have good high-frequency response characteristics and isolates low-frequency electromagnetic signals with large energy. At the same time, the ceramic substrate also has good thermal conductivity, which is also conducive to directly installing the temperature sensor on the ceramic substrate. Although the partial discharge signal as a high-frequency electromagnetic wave signal propagates and decays quickly on the over-current component, the high-frequency electromagnetic wave monitoring sensor of the utility model can be installed at key locations where partial discharge is prone to occur, such as the contacts of the power conductor, so that the distance between it and the point where partial discharge is prone to occur is even only a few centimeters. Even if the high-frequency electromagnetic wave propagates and decays severely in the power conductor, a higher partial discharge electromagnetic wave signal can still be monitored within the short-distance monitoring range.

[0048] Moreover, since a 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 components of the electrical equipment, which can improve the accuracy of signal measurement and frequency response characteristics. At the same time, since the high-frequency electromagnetic wave monitoring sensor of the utility model can be installed in an area very close to the over-current component, its working environment such as working temperature is consistent with the working environment of the power system, and it is less affected by the external environment, which is conducive to the analysis and research of the relationship between the detected partial discharge signal and the electrical equipment.

[0049] Figure 2 This is a cross-sectional structure and principle diagram of the high-frequency electromagnetic wave monitoring sensor of the utility model. Figure 2 As shown, the electric power system has a current-carrying component S. The high-frequency electromagnetic wave monitoring sensor of the utility model is used to monitor the high-frequency electromagnetic wave signal W generated by the electric power system during partial discharge. The sensor includes a dielectric substrate 1 and an electromagnetic coupling plate 2. The dielectric substrate 1 has a first surface (an upper surface in the figure) and a second surface (a lower surface in the figure) relative to each other. The first surface is used to attach to the current-carrying component S of the electric power system, while the second surface is fixedly attached to the electromagnetic coupling plate 2. That is to say, as a component of a component, 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 current-carrying component S of the electric power system. The current-carrying component referred to in the utility model refers to a component in the electric power system that can conduct electrical signals, and is also a component that can propagate high-frequency electromagnetic wave signals W when partial discharge occurs in the electric power system, such as wires, connectors, contacts, etc. of the electric power system.

[0050] Figure 3 It is a schematic diagram of the equivalent capacitive coupling structure of the high-frequency electromagnetic wave monitoring sensor of the utility model. Figure 3 The dashed box in Figure 2 Corresponding to the above, the current passing component S, the dielectric substrate 1 and the electromagnetic coupling plate 2 form a capacitor structure with a high-frequency response, so that when a high-frequency electromagnetic wave signal is generated on the current passing component, a high-frequency induction signal is generated on the electromagnetic coupling plate.

[0051] The dielectric substrate 1 of the utility model should have high insulation performance, or have a high dielectric constant, and preferably adopts a material with 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 100W / m*K. For example, the dielectric substrate is preferably made of ceramic.

[0052] As a preferred embodiment of the present invention, when the dielectric substrate is made of ceramic material, considering comprehensive factors such as capacitive coupling performance, material manufacturing process, cost, etc., the thickness of the ceramic is preferably 0.5-2.0 mm.

[0053] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0054] Figure 4 1 is a three-dimensional structural diagram of an embodiment of the high-frequency electromagnetic wave monitoring sensor of the utility model. In this embodiment, the element is in a roughly rectangular sheet shape. Figure 4 In the viewing direction, the upper part is a ceramic plate with a thickness of 1.2 to 1.4 mm, which serves as a dielectric substrate 1, and the lower part is a copper plate with a thickness of 0.2 to 0.4 mm, which serves as an electromagnetic coupling plate 2. The ceramic plate and the copper plate are closely attached to each other. A signal output contact 21 is provided on one side of the copper plate.

[0055] The high-frequency electromagnetic wave monitoring sensor of this embodiment can be used as an independent partial discharge detection element or partial discharge sensor to monitor the high-frequency electromagnetic wave signal generated by the power system during partial discharge. When in use, the ceramic plate is placed close to the joints of the switch cabinet of the power system and other over-current components. The over-current components, the ceramic plate and the copper plate form a capacitor structure with a high-frequency response, so that when a high-frequency electromagnetic wave signal is generated on the over-current component, a high-frequency induction signal is generated on the electromagnetic coupling plate. The output contact 21 on the side of the copper plate can be connected to a signal line to transmit the high-frequency induction signal to the outside through the signal line.

[0056] Figure 5 yes Figure 4 The schematic diagram of the component decomposition of the high-frequency electromagnetic wave monitoring sensor of the embodiment shown in the figure shows that the copper plate used as the electromagnetic coupling plate 2 has two notches on its side, and the output contact 21 is formed in the portion between the notches.

[0057] In the above embodiments, 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 invention is not limited to the shapes of the two, nor is it limited to the ratio of the areas of the main surfaces of the two. That is to say, in other embodiments, the sizes and shapes of the ceramic plate and the copper plate may be different, as long as the two and the electric components can form a capacitor structure suitable for sensing high-frequency electromagnetic wave signals.

[0058] Meanwhile, the materials used as the dielectric substrate 1 and the electromagnetic coupling substrate 2 are not limited to ceramics and copper, and they can also be composed of other insulating materials and other metal materials, respectively.

[0059] Figure 6 FIG. 1 is a cross-sectional structural diagram of the first embodiment of the partial discharge monitoring device of the utility model. Figure 6 As shown, the partial discharge monitoring device of this embodiment includes Figure 2In addition to the high-frequency electromagnetic wave monitoring sensor shown, a circuit board 3 is also included. The circuit board 3 maintains a certain distance from the electromagnetic coupling board 2 of the high-frequency electromagnetic wave monitoring sensor. The circuit board 3 has an input terminal and a signal processing circuit composed of circuit elements, and the signal processing circuit is used to process the high-frequency induction signal so as to output or store the high-frequency induction signal. In order to connect the high-frequency induction signal to the circuit board 3, the input terminal of the circuit board 3 is connected to the output contact 21 of the copper plate serving as the electromagnetic coupling board through the signal line 31.

[0060] The processing of the high-frequency induction signal includes gain control, filtering, analog-to-digital conversion, partial discharge feature extraction and storage, etc. Therefore, the circuit board 3 should have electronic components for performing the processing, such as a gain controller, a filter, an analog-to-digital converter, a memory, a processor, etc. The types and functions of the specific components on the circuit board 3 may be further described in the embodiments described below.

[0061] In addition, in order to maintain a certain distance between the circuit board 3 and the copper plate, support members 32 are provided between the circuit board 3 and the copper plate and around and / or in the middle of the circuit board. The utility model is not limited to the number of support members, but it is better to have multiple support members so that the circuit board 3 will not contact the copper plate serving as the electromagnetic coupling plate 2 at any position.

[0062] See also Figure 6 In this embodiment, the partial discharge monitoring device further comprises a shell 4 with an opening at one end. Figure 6 The opening of the shell 4 is upward so that the upper surface of the ceramic board serving as the dielectric substrate 1 faces the outside of the shell, and the electromagnetic coupling board 2 attached to the lower surface of the ceramic board and the circuit board 3 supported on the electromagnetic coupling board 2 are located inside the shell.

[0063] The housing 4 is used to protect the components on the dielectric substrate 1, the electromagnetic coupling board 2 and the circuit board 3 from the influence of the external environment. On the other hand, it also serves as a structural component to support and fix the devices and components inside. Figure 6 As shown, the lower surface of the circuit board is also fixed to the housing 4 through the support member 32. The housing 4 and the support member 32 are generally made of insulating materials, such as plastic, rubber, etc.

[0064] Figure 7 yes Figure 6 Schematic diagram of component decomposition of a partial discharge monitoring device according to an embodiment of the present invention. Figure 7As shown, the housing 4 of the partial discharge monitoring device of this embodiment is in the shape of a square box as a whole. Inside the housing 4, a circuit board 3 and a high-frequency electromagnetic wave monitoring sensor are stacked in sequence from the inside to the outside, and the two are isolated and fixed to each other by a support member (not shown) inside the housing. The high-frequency electromagnetic wave monitoring sensor is formed by attaching a protective dielectric substrate 1 and an electromagnetic coupling plate 2 to each other, which has been described in the previous text.

[0065] Figure 8 FIG. 2 is a cross-sectional structural diagram of the second embodiment of the partial discharge monitoring device of the utility model. Figure 8 As shown, the difference between this embodiment and the first embodiment is that a temperature sensor 33 is also provided on the circuit board 3 for measuring the temperature of the power supply component of the power system and generating a temperature signal. Therefore, the temperature signal obtained by the temperature sensor 33 can be directly transmitted to the signal processing circuit on the circuit board 3.

[0066] It is particularly important to note that, unlike the prior art, the temperature sensor 33 of the present invention is also attached to the high-frequency electromagnetic wave monitoring sensor. Since the high-frequency electromagnetic wave monitoring sensor is directly attached to the current-carrying component of the power system, and the high-frequency electromagnetic wave monitoring sensor is very 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 current-carrying component. Therefore, the present invention realizes the dual monitoring of partial discharge and temperature in one monitoring device.

[0067] Furthermore, the temperature sensor 33 can be attached to the dielectric substrate 1 of the high-frequency electromagnetic wave monitoring sensor, or to the electromagnetic coupling plate. In order to reduce the impact on the capacitive coupling structure, the utility model preferably attaches the temperature sensor 33 to the dielectric substrate 1.

[0068] See also 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. Fig. 9 yes Figure 8 Schematic diagram of component decomposition of a partial discharge monitoring device according to an embodiment of the present invention. Fig. 9 As shown, in order to prevent the electromagnetic coupling plate 2 from blocking 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 plate 2 of the second embodiment is slightly smaller than the main surface area of ​​the dielectric substrate 1, so that the temperature sensor 33 is attached to the area of ​​the dielectric substrate 1 that is not covered by the electromagnetic coupling plate 2.

[0069] Fig.10It is a cross-sectional structural diagram of the third embodiment of the partial discharge monitoring device of the utility model. The difference between the third embodiment and the previous two embodiments is that it also includes a power-collecting element, which can generate induced electric energy by electromagnetic induction with the over-current component, so as to provide electric energy for other components or circuits in the partial discharge monitoring device. The power-collecting element includes a power-collecting coil 5 and a magnetic ring 6, the magnetic ring 6 surrounds the over-current component, and the power-collecting coil 5 is wound on the magnetic ring 6. The magnetic ring 6 generates an alternating electromagnetic field by electromagnetic induction with the over-current component S, and the alternating electromagnetic field generates an induced current and an induced voltage in the power-collecting coil 5, thereby generating the induced electric energy. The material of the magnetic ring 6 can be Permalloy or silicon steel sheet, and the material of the power-collecting coil 5 can be copper.

[0070] The power system's current-carrying components usually carry a 50Hz industrial frequency current, which has the strongest electromagnetic wave energy. Permalloy or silicon steel sheets are good magnetic conductive materials, and can couple the alternating electromagnetic field generated by the alternating current in the power conductor through electromagnetic induction. At the same time, when the Permalloy or silicon steel sheets pass through the energy collection coil 5 and the electromagnetic field in the magnetic conductive ring 6 changes, the alternating electromagnetic field can induce electrical energy in the energy collection coil 5.

[0071] As a preferred embodiment, the circuit board 4 is also provided with an energy storage element, such as a supercapacitor energy storage device, whereby the electric energy generated by induction is stored by the energy storage element on the circuit board 4, thereby realizing a passive power supply function in the partial discharge monitoring device.

[0072] Fig.11 yes Fig.10 Schematic diagram of component decomposition of a partial discharge monitoring device according to an embodiment of the present invention. Fig.11 The magnetic ring 6 and the current-carrying component S are not shown. Fig.10 and Fig.11 It can be found that the third embodiment sets the power taking coil 5 below the circuit board 3 in the housing 4. The power taking coil 5 is wound into a flat ring with a through hole 51 in the middle to allow the flat strip-shaped magnetic ring 6 to pass through. At the same time, there are openings 41 at the positions corresponding to the through hole 51 on the two opposite sides of the housing to facilitate the magnetic ring 6 to pass in and out. That is to say, Fig.11 In the third embodiment, the magnetic conductive ring 6 passes through the housing 4 , so that the portion of the magnetic conductive ring 6 wound by the power taking coil 5 is also located in the housing 4 .

[0073] Fig.12 yes Fig.10 and Fig.11 A schematic diagram of the three-dimensional structure of the partial discharge monitoring device of the third embodiment. Figure 6As shown, the housing 4 is in the shape of a square box, and one of its top surfaces exposes the dielectric substrate 1 of the high-frequency electromagnetic wave monitoring sensor. The magnetic conductive ring passes through a side surface of the partial discharge monitoring device close to the bottom surface. The magnetic conductive ring 6 includes a strip 61 formed of a permalloy material, a protective cover 62 is sleeved on the outer side of the strip 61, and the strip 61 is joined at both ends by a buckle structure 63. That is, the buckle structure 63 is used to connect and fix the strip 61 end to end so as to surround the current-passing component S of the power system.

[0074] Fig.13 : This is an electronic component diagram of an embodiment of the circuit board 4 of the partial discharge monitoring device of the utility model. As mentioned above, the circuit board 3 has an input terminal and a signal processing circuit composed of circuit elements, and the signal processing circuit is used to process the high-frequency induction signal. However, the circuit board can also have other functional electronic components to enable the partial discharge monitoring device to achieve more functions and realize multi-modal detection. Fig.13 In the illustrated embodiment, in addition to the electronic components for processing high-frequency sensing signals, the circuit board 4 also includes other electronic components such as sensors, memories, and energy storage components.

[0075] First, if Fig.13 As shown, 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 terminal connected to the signal line 31, and perform automatic gain control, filtering and detection on the high-frequency induction signal from the high-frequency electromagnetic wave monitoring sensor, respectively. The high-frequency electromagnetic wave monitoring sensor preferentially passes the collected high-frequency induction signal through the first automatic gain controller 341, and the first automatic gain controller 341 automatically detects whether the intensity of the collected high-frequency induction signal is too high or too low. For electromagnetic waves with too high signal energy, automatic attenuation processing is performed to prevent damage to the back-end circuit; for electromagnetic waves with low signal intensity, automatic gain processing is performed to facilitate analysis and processing of subsequent circuits.

[0076] The high frequency induction signal generated by the partial discharge enters the filter 342 after passing through the first automatic gain controller 341. The filter 342 is preferably an adjustable filter, which can be configured according to different partial discharge equipment and partial discharge types and the electromagnetic setting process of the on-site environment, so as to reduce or isolate the entry of interference signals.

[0077] The high-frequency induction signal generated by the partial discharge is input into the detection circuit 343 after passing through the filter 342, and the relative power value of the high-frequency induction signal is directly output.

[0078] Secondly, see 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 board 2 of the high-frequency electromagnetic wave monitoring sensor, and will not be described in detail here.

[0079] Third, the circuit board 4 is also provided with a second automatic gain controller 35. The partial discharge monitoring device proposed in the utility model can perform phase extraction on the power frequency signal of the monitored target power system. Since partial discharge is closely related to the power frequency phase, correlation analysis between the partial discharge signal and the power frequency signal in the partial discharge monitoring application can eliminate the influence of environmental interference signals and distinguish the types of partial discharges. Therefore, the magnetic conductive ring 6 of the embodiment uses materials with good magnetic permeability such as Permalloy or silicon steel sheets, and has good low-frequency electromagnetic wave response characteristics. In this way, the 50Hz power frequency AC signal in the overcurrent component is also the strongest 50Hz signal in the electromagnetic signal induced in the magnetic conductive ring 6. After the 50Hz induced electromagnetic signal passes through the second automatic gain controller 35, the energy is adjusted to meet the processing requirements of subsequent electronic components.

[0080] Fourthly, a voiceprint sensor 36 is also configured on the circuit board 4, for example, a MIC voiceprint sensor is used, and the voiceprint sensor 36 can collect voiceprint signals in the frequency range of 20 Hz to 80 kHz. Thus, the voiceprint signals generated when partial discharge occurs can be collected together.

[0081] Fifth, the circuit board 4 is also provided with a UHF signal detection processor 39, which is used to perform adaptive gain control, signal filtering, and high-frequency signal detection functions on the UHF signal generated when partial discharge occurs.

[0082] Sixth, the circuit board 4 is also equipped with a microprocessor (MCU) 40 and a memory 37. The high-frequency induction signal generated by the partial discharge is collected by the analog-to-digital converter inside the microprocessor 40 after passing through the filter 342, and is stored in the memory 37. The microprocessor 40 is also used to perform fusion processing on the high-frequency induction signal after detection 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.

[0083] Finally, as mentioned above, the circuit board 4 is also provided with an energy storage element 38, such as a supercapacitor energy storage device, whereby the electric energy generated by induction is stored by the energy storage element 38 on the circuit board 4, thereby realizing a passive power supply function in the partial discharge monitoring device.

[0084] Fig.14 yes Fig.13 The circuit structure diagram of an embodiment of the circuit board 4 of the partial discharge monitoring device of the utility model is shown. Fig.14As shown, in addition to being connected to the memory and the wireless communication unit, the microprocessor 40 is also connected to the detection circuit, the UHF signal detection processor, the second automatic gain controller, the temperature sensor and the voiceprint sensor. Thus, the microprocessor 40 can store and process the UHF signal, the power frequency signal, the temperature signal and the voiceprint signal.

[0085] For example, the analog-to-digital converter in the microprocessor 40 also processes the gain-controlled 50 Hz power frequency signal from the second gain controller 35 to obtain the phase information of the 50 Hz power frequency signal in the power conductor.

[0086] To sum up, the partial discharge monitoring device of the utility model is based on a capacitive coupling structure and can use a ceramic substrate as a dielectric medium to have excellent insulation performance and a high dielectric constant to isolate low-frequency electromagnetic signals with large energy and protect the internal circuit of the sensor from damage by external high voltage electricity. At the same time, it has good high-frequency response characteristics and can be coupled to the high-frequency electromagnetic signals of partial discharge, with the advantages of high precision and low interference.

[0087] The utility model has the functions of self-power collection and wireless communication, does not require wiring and power supply, truly realizes wireless passive sensing detection, and is suitable for various scene applications of the power system.

[0088] The utility model has a compact structure and can realize multi-mode partial discharge detection in one device, which is convenient for users to use.

[0089] The utility model can be mounted on the surface of a current-carrying component to detect partial discharge, can be mounted close to a partial discharge source, has high monitoring accuracy, and is less affected by environmental interference.

[0090] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-frequency electromagnetic wave monitoring sensor for partial discharge monitoring, characterized in that: including a dielectric substrate and an electromagnetic coupling plate; The dielectric substrate has a first surface and a second surface opposite to each other, the first surface is used to be attached to the current-passing component of the power system, and the second surface is fixedly attached to the electromagnetic coupling plate; One side of the electromagnetic coupling plate has a signal output contact; The current passing component, the dielectric substrate and the electromagnetic coupling plate form a capacitor structure with high-frequency response, so that when a high-frequency electromagnetic wave signal is generated on the current passing component, a high-frequency induction signal is generated on the electromagnetic coupling plate.

2. A monitoring device for partial discharge monitoring, characterized in that: include: The high-frequency electromagnetic wave monitoring sensor according to claim 1; A circuit board having an input terminal and a signal processing circuit, wherein the signal processing circuit is used to process the high-frequency induction signal so as to output and / or store the high-frequency induction signal; A signal line is used to connect the input terminal of the circuit board to the output contact of the electromagnetic coupling board.

3. The monitoring device for partial discharge monitoring according to claim 2, characterized in that: It also includes a shell, which accommodates the high-frequency electromagnetic wave monitoring sensor, the circuit board and the signal line.

4. The monitoring device for partial discharge monitoring according to claim 3, characterized in that: The shell has an opening, and the first surface of the dielectric substrate of the high-frequency electromagnetic wave monitoring sensor is exposed from the opening so as to be attached to the current-carrying component of the power system.

5. The monitoring device for partial discharge monitoring according to claim 3, characterized in that: It also includes a temperature sensor, 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 to measure the temperature of the current-carrying component and generate a temperature signal.

6. The monitoring device for partial discharge monitoring according to claim 3, characterized in that: The monitoring device for partial discharge monitoring also includes a power extraction module; The power extraction module can generate electromagnetic induction with the current-carrying components of the power system to generate induced electric energy, so as to provide electric energy for other components or circuits in the monitoring device for partial discharge monitoring.

7. The monitoring device for partial discharge monitoring according to claim 6, characterized in that: The power taking module includes a power taking element and an energy storage element; The power-taking element is used to generate induced electric energy by electromagnetic induction with the power-passing component of the power system; The energy storage element is used to store the induced electrical energy.

8. The monitoring device for partial discharge monitoring according to claim 7, characterized in that: The power-collecting element comprises a magnetic conductive ring surrounding the power-passing component of the power system and a power-collecting coil wound around the magnetic conductive ring; The magnetic conductive ring generates electromagnetic induction with the current-carrying component of the power system to generate an alternating electromagnetic field, and the alternating electromagnetic field generates an induced current and an induced voltage in the power taking coil, thereby generating the induced electric energy.

9. The monitoring device for partial discharge monitoring according to claim 8, characterized in that: The magnetic conductive ring is in the shape of a strip and is provided with a buckle structure, wherein the buckle structure is used to connect and fix the strip end to end so as to surround the current-carrying component of the power system.

10. The monitoring device for partial discharge monitoring according to claim 8, characterized in that: The magnetic conductive ring passes through the shell, so that the part of the magnetic conductive ring wound by the power taking coil is also located in the shell.

11. The monitoring device for partial discharge monitoring according to claim 8, characterized in that: The high-frequency electromagnetic wave monitoring sensor, the circuit board, and the power collection coil are stacked in sequence and fixed in the shell.

12. The monitoring device for partial discharge monitoring according to claim 10, characterized in that: The two sides of the shell are provided with two openings which are arranged opposite to each other, so that the magnetic conductive ring can pass through the two openings and penetrate into the shell.

13. The monitoring device for partial discharge monitoring according to claim 2, characterized in that: The circuit board comprises an industrial frequency signal extraction element, which is used for detecting the alternating electromagnetic field and generating an industrial frequency signal.

14. The monitoring device for partial discharge monitoring according to claim 2, characterized in that: The circuit board also includes a UHF signal extraction element for extracting the UHF signal generated during partial discharge.

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