Gas insulated switch vibration fault detection sensor and fault detection system

Abstract

The invention provides a gas insulated switch vibration fault detection sensor and a fault detection system.The sensor comprises a supporting part, a vibration pickup piezoelectric part, a balance weight part and a detection circuit, the vibration pickup piezoelectric part comprises an even number of vibration pickup beams arranged at equal intervals in the circumferential direction and corresponding piezoelectric modules, and the two ends of each vibration pickup beam are connected with the supporting part and the balance weight part respectively; in the middle, a straight plate type elastic beam is bent at a right angle to form a rectangular groove body with a radial opening, the resonant frequency of the vibration pickup beam is set to be within the vibration frequency range of the gas insulated switch in the normal working state, and the piezoelectric module comprises a plurality of piezoelectric plates stacked in the rectangular groove body in the axial direction; and the detection circuit outputs a two-bit binary gas insulated switch vibration fault detection result based on the amplitude of the piezoelectric signal output by the piezoelectric module. According to the technical scheme, different vibration states are converted into corresponding piezoelectric signals through the vibration pick-up piezoelectric part, and accurate detection of various vibration faults of the gas insulated switch is achieved.

Description

Technical Field

[0001] This application belongs to the field of power equipment condition monitoring technology, and relates to a fault detection technology applicable to gas-insulated switches. Specifically, it provides a vibration fault detection sensor and fault detection system for gas-insulated switches. Background Technology

[0002] Gas-insulated switchgear (GIS) is a medium- to high-voltage electrical device that uses SF6, N2, or a mixture of gases as the insulating medium. As a core component of modern power systems, it is widely used in high-voltage transmission networks due to its compactness and high reliability. During operation, GIS components such as gas pipelines, circuit breakers, busbars and joints, and disconnectors may experience loosening, poor contact, or aging. Therefore, continuous monitoring of its operating status is necessary to ensure the safe operation of the power system.

[0003] Due to the fully enclosed structure of GIS, internal faults are difficult to observe directly. Traditional monitoring methods, such as regular inspections, are insufficient for timely and comprehensive safety testing of GIS. As a result, hidden dangers such as mechanical loosening, aging, and poor contact are often only discovered after serious accidents such as insulation breakdown and gas leakage occur, leading to sudden power outages, equipment damage, or even safety incidents.

[0004] In recent years, various sensors capable of collecting parameters such as vibration frequency and amplitude have been deployed on the outside of GIS (metal casing) to detect gas-insulated switches using vibration characteristics. However, existing sensor equipment capable of collecting multiple vibration parameters is expensive and has demanding installation conditions, making it difficult to deploy and maintain in the numerous gas-insulated switches in the power grid. Summary of the Invention

[0005] This application provides a vibration fault detection sensor for a gas-insulated switch through embodiments, including a support part, a vibration-sensing piezoelectric part, a counterweight part, and a detection circuit; The support, the vibration-collecting piezoelectric part, and the counterweight are arranged sequentially along the axial direction. The vibration-collecting piezoelectric part includes an even number of vibration-collecting beams and corresponding piezoelectric modules arranged at equal intervals along the circumference. The two ends of the vibration-collecting beams are connected to the support and the counterweight, respectively. The middle part is a rectangular groove with a radial opening formed by bending a straight plate elastic beam at a right angle. The resonant frequency of the vibration-collecting beams is set to be within the vibration frequency range of the gas-insulated switch under normal operating conditions. The piezoelectric module includes a plurality of first piezoelectric sheets stacked axially in the rectangular groove. The detection circuit is connected to the electrical output terminal of the piezoelectric module, and outputs a two-bit binary gas insulation switch vibration fault detection result based on the amplitude of the piezoelectric signal output by the piezoelectric module.

[0006] Preferably, the number of the vibration pickup beams is two or four.

[0007] Preferably, the part where the piezoelectric module contacts with the two ends of the rectangular groove is provided with an elastic pad.

[0008] Preferably, the vibration pickup piezoelectric part further comprises a second piezoelectric sheet attached to the outer surface of the groove bottom of the rectangular groove of the vibration pickup beam.

[0009] Further, The detection circuit comprises a self-powered piezoelectric circuit and a state switching circuit. The self-powered piezoelectric circuit comprises a peak detector and a MOSFET rectifier bridge, the peak detector is connected between the electrical output end of the piezoelectric module and the MOSFET rectifier bridge, and is turned on when the voltage on both sides of the piezoelectric module reaches the peak value, the MOSFET rectifier bridge is used to convert the alternating piezoelectric signal output by the piezoelectric module and passing through the peak detector into a direct rectified signal and output through the positive output end thereof. The state switching circuit comprises an envelope extractor and a state signal switcher, the envelope extractor is connected between the electrical output end of the piezoelectric module and the state signal switcher, and is used to extract the envelope of the piezoelectric signal, the state signal switcher compares the relationship between the voltage amplitude of the piezoelectric signal and the preset lower limit and upper limit of the voltage through the amplitude of the envelope, and outputs corresponding high and low level signals through the first output end and the second output end thereof according to the comparison result. The positive output end of the MOSFET rectifier bridge is connected with the first output end of the state signal switcher and serves as the first state signal output end of the detection circuit, and the second output end of the state signal switcher serves as the second state signal output end of the detection circuit.

[0010] Further, The state signal switcher comprises three control lines, and a plurality of NMOS tubes and a control resistor are connected in series in each control line. The drain electrodes of the NMOS tubes in the first control line are all connected to the ground, and the gate electrodes thereof are all connected with the first output end of the envelope extractor, the drain electrodes of the NMOS tubes in the second control line are all connected to the ground, and the gate electrodes thereof are all connected with the source electrode of the NMOS tube farthest from the ground in the first control line, and the drain electrodes of the NMOS tubes in the third control line are all connected to the ground, and the gate electrodes thereof are all connected with the second output end of the envelope extractor. The non-grounded common connection end of the three control lines is used as a first output end of the state signal switcher, and the source of the NMOS transistor farthest from the ground end in the third control line is used as a second output end of the state signal switcher. The resistance of the control resistor connected in series in the first control line and the third control line is much larger than the resistance of the control resistor connected in series in the second control line.

[0011] The gas insulated switch vibration fault detection sensor provided by the application can effectively utilize the resonance characteristics to realize the piezoelectric signal with obviously different output amplitudes in different vibration modes, and can utilize the piezoelectric signal to supply power to the detection circuit and output corresponding two-bit binary detection results for each vibration mode. Compared with the dependence on external power supply of the conventional vibration sensor based on an accelerometer, the gas insulated switch vibration fault detection sensor provided by the application can output corresponding detection results for various vibration fault states without external separate power supply, thereby significantly reducing the difficulty of large-scale deployment and maintenance in the power grid.

[0012] The application further provides a gas insulated switch fault detection system through an embodiment, which comprises a shell, a coupling fixing seat, a measurement unit, a main control unit, a communication unit and a power supply unit. The shell is used for accommodating the measurement unit, the main control unit, the communication unit and the power supply unit. The bottom surface of the coupling fixing seat is in close contact with the outer surface of the gas pipeline of the gas insulated switch, and the top surface is used for rigidly bearing the shell. The coupling fixing seat is provided with a first through hole penetrating through the bottom surface and the top surface, and the shell is provided with a second through hole matched with the first through hole. The measurement unit comprises a temperature sensor and the aforementioned gas insulated switch vibration fault detection sensor. The temperature measurement structure of the temperature sensor is located in the first through hole, and the support part of the gas insulated switch vibration fault detection sensor is rigidly connected with the shell. The main control unit is used for receiving the measurement data of the measurement unit, and the measurement data comprises the temperature of the gas insulated switch and the two-bit binary vibration fault detection result. The communication unit is used for sending the measurement data. The power supply unit is used for supplying power to the temperature sensor, the main control unit and the communication unit.

[0013] Preferably, the coupling fixing seat is made of a material with high thermal conductivity and high mechanical rigidity.

[0014] Preferably, the bottom surface of the coupling fixing seat and the outer surface of the gas pipeline of the gas insulated switch, the top surface of the coupling fixing seat and the bottom surface of the shell, and the temperature measuring structure of the temperature sensor and the first through hole are all filled with heat-conducting silicone grease.

[0015] The gas insulated switch fault detection system provided by the embodiments of the present application detects the operation state of the gas insulated switch in a non-invasive manner, wherein the coupling fixing seat with high thermal conductivity, high mechanical rigidity and shape adaptation to the gas pipeline of the gas insulated switch is used for heat and vibration transmission, the temperature-vibration coupling connection between the measuring sensor and the surface of the measured gas insulated switch is realized, and the through hole is arranged in the coupling fixing seat to form a good closed environment for temperature measurement, so that the measurement results of the temperature and vibration can timely and accurately reflect the change of the operation state of the gas insulated switch. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A layout diagram of the gas insulated switch fault detection system provided by the embodiments of the present application is shown; Figure 2 A frame diagram of the gas insulated switch fault detection system provided by the embodiments of the present application is shown; Figure 3 An exploded view of the gas insulated switch fault detection system provided by the embodiments of the present application is shown; Figure 4 A side view of the coupling fixing seat provided by the embodiments of the present application is shown; Figure 5 An energy and signal transmission diagram of the gas insulated switch fault detection system provided by the embodiments of the present application is shown; Figure 6 A perspective view of the vibration power generation part of the vibration fault detection sensor of the gas insulated switch provided by the embodiments of the present application is shown; Figure 7 A specific structure diagram of the vibration piezoelectric part provided by the embodiments of the present application is shown; Figure 8 A vibration state distribution diagram of the vibration pickup beam in some embodiments is shown; Figure 9 A frame diagram of the detection circuit provided by the embodiments of the present application is shown; Figure 10 A schematic diagram of the detection circuit provided by the embodiments of the present application is shown; Figure 11 A state change diagram of the self-powered piezoelectric circuit in some embodiments is shown; Figure 12 A diagram of the open circuit voltage of the piezoelectric module and the displacement of the vibration pickup beam in some embodiments is shown; Figure 13 The schematic diagram of the state signal switcher provided by the embodiment of the application.

[0017] Reference numerals in the drawings The shell 100, the upper cover 101, the side wall 102, the lower cover 103, the second through hole 104, the coupling fixing seat 200, the bottom surface 201 of the coupling fixing seat, the top surface 202 of the coupling fixing seat, the first through hole 203, the fixing support 300, the first slot hole 301, the second slot hole 302, the vertical plate 303, the vibration power generation part 400, the support part 401, the vibration pickup piezoelectric part 402, the vibration pickup beam 4021, the piezoelectric module 4022, the first piezoelectric sheet 4022-1, the second piezoelectric sheet 4022-2, the elastic pad 4023, the counterweight part 403, the temperature sensing probe 500 of the temperature sensor, the circuit board 601, the solar panel 701, the energy storage module 702, the energy management module 703, the gas pipeline 810 of the gas insulated switch. DETAILED DESCRIPTION

[0018] Hereinafter, the application will be further described based on the preferred embodiments and with reference to the drawings.

[0019] In the description in the embodiments of the application, it should be noted that if the terms such as "upper", "lower", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the embodiments of the application is usually placed, and are only for the convenience of describing the application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application. In addition, in the description of the application, in order to distinguish different units, the first, second and the like are used in the specification, but these are not limited by the order of manufacture, and cannot be understood as indicating or implying relative importance, and the name thereof may be different in the detailed description and the claims of the application. In addition, in order to facilitate understanding, various components on the drawing are enlarged or reduced, but this practice is not intended to limit the protection scope of the application.

[0020] The words in the specification are used to illustrate the embodiments of the application, but are not intended to limit the application. It should be noted that, unless otherwise explicitly specified and limited, if the terms "provided", "connected", "connected" appear, they should be understood in a broad sense, for example, they can be fixedly connected, or can be detachably connected, or integrally connected; can be mechanically connected, can be directly connected, or indirectly connected through an intermediate medium, or the communication between two elements inside. For those skilled in the art, the specific meaning of the above terms in the application can be specifically understood.

[0021] The technical solutions of the application will be described in detail below with reference to the drawings.

[0022] Some embodiments of the present application provide a gas insulated switch fault detection system, which can be deployed at the gas pipe position of the gas insulated switch device, and collect vibration-temperature data of the device in real time to realize fault detection of the gas insulated switch. Figure 1 A layout schematic diagram of the gas insulated switch fault detection system provided according to some embodiments of the present application, Figure 2 A frame schematic diagram of the gas insulated switch detection system, Figure 3 An exploded view of the gas insulated switch detection system, Figure 4 A side view of the coupling fixing seat, Figure 5 An energy and signal transmission schematic diagram of the gas insulated switch fault detection system.

[0023] As shown in the above figures, the fault detection system is composed of a shell 100, a coupling fixing seat 200, a measurement unit, a master control unit, a communication unit and a power supply unit. The detection system is deployed on the outer surface of the gas pipe 810 (generally a metal shell) of the gas insulated switch, and realizes fault detection of the gas insulated switch device by collecting the temperature and vibration of the outer surface of the gas pipe 810.

[0024] The shell 100 is used to accommodate the measurement unit, the master control unit, the communication unit and the power supply unit. In some optional embodiments, as shown in Figure 1 , Figure 3 The shell 100 is in the form of a cuboid as a whole, which is surrounded by an upper cover 101, a lower cover 103 and a side wall 102 in the middle. The lower cover 103 can be fixedly connected with the top surface 202 of the coupling fixing seat 200 by bonding or other methods. The side wall 102 and the upper cover 101 and the lower cover 103 can be connected by a buckle or a screw-hole in a mutually matched manner. The interior is a space for accommodating the measurement unit, the master control unit and the communication unit.

[0025] The measurement unit includes a temperature sensor and a gas insulated switch vibration fault detection sensor described later. The temperature sensor is used to collect temperature data of the gas insulated switch. The gas insulated switch vibration fault detection sensor is used to obtain vibration fault detection results of the gas insulated switch. In the embodiments of the present application, the vibration fault detection results of the gas insulated switch are two-bit binary digital signals, such as [0, 0], [0, 1] and the like. Different binary digits respectively represent normal vibration states or different fault vibration states of the gas insulated switch. The specific meanings will be described in detail later.

[0026] The main control unit is used for receiving the measurement data of the measurement unit. In some optional embodiments, the main control unit can adopt various types of microcontroller (MCU) chips known to those skilled in the art, and receive the temperature data sent by the temperature sensor through the analog pins thereof (converted into digital quantities by the built-in analog-to-digital converter), and receive the two-bit binary vibration fault detection results output by the gas insulated switch vibration fault detection sensor through the GPIO pins.

[0027] The communication unit receives the measurement data sent by the main control unit, and sends the measurement data to devices such as the host computer and the main control center under the control of the main control unit. Those skilled in the art can adopt wired or wireless communication modes according to the specific communication range, and select appropriate communication modules as the communication unit. Preferably, a long-distance communication module supporting 4G / 5G communication protocol, such as an NB-IoT module (Narrow Band Internet of Things), can be used to realize long-distance low-power consumption transmission of the measurement data.

[0028] In some preferred embodiments, the chips of the main control unit and the communication unit and their peripheral circuits, and the detection circuit included in the gas insulated switch vibration fault detection sensor described below can be arranged on the circuit board 601 and fixed on the lower cover 103 as shown. Figure 3

[0029] The power supply unit is used for providing the main control unit, the communication unit and the temperature sensor with the electric energy required for normal operation. In some preferred embodiments, the power supply unit includes a solar panel 701 arranged outside the shell, and an energy storage module 702 and an energy management module 703 arranged inside the shell. The number of solar panels 701 is preferably two or more, which are respectively attached to different surfaces outside the side wall 102 to ensure that photoelectric conversion can be effectively realized in different sunlight directions. The energy storage module 702 can be a lithium battery or other charge-discharge storage device. The energy management module 703 is used for coordinating the power generation state of the solar panel 701 and the charge-discharge state of the energy storage module 702. For example, when the light condition is good, the solar panel 701 is controlled to directly supply power to the main control unit, the temperature sensor and the communication unit, and to charge the energy storage module 702. When the light condition is poor and at night, the energy storage module 702 is controlled to supply power to each device.

[0030] ​In some preferred embodiments, the inside of the shell 100 is provided with a fixing support 300, which is provided with a plurality of insertion slots and support structures, such as a first slot 301 for inserting the energy storage module 702, a second slot 302 for inserting the gas insulated switch vibration fault detection sensor, and a vertical plate 303 for supporting the energy management module 703, etc. In addition, a rectangular slot for accommodating the circuit board 601 is also provided on the fixing support 300.

[0031] The coupling fixing seat 200 is used to realize the coupling connection of the shell 100 and the gas pipeline 810 of the gas insulated switch device, so as to ensure that the temperature and vibration information of the gas insulated switch are accurately transmitted to the measurement unit. The manufacturing material thereof is preferably a material with high thermal conductivity and high mechanical rigidity, for example, in some specific embodiments, the coupling fixing seat 200 is made of pure copper material, which has excellent thermal conductivity and good mechanical rigidity: the thermal conductivity of pure copper material can reach about 400 W / (m·K), which can realize efficient heat transfer and ensure that the temperature sensor quickly and accurately obtains the shell temperature change; at the same time, the Young's modulus and density of copper are high, which can effectively transmit the structure vibration signal without significant attenuation, and is suitable for high-fidelity measurement of the vibration sensor. In addition, copper material is easy to process, easy to realize close metal contact with the shell, and can improve long-term stability through nickel plating or anti-oxidation treatment, so it is an ideal connection material selection in occasions that require simultaneous consideration of heat and vibration signal transmission.

[0032] As shown in FIGS. Figure 3 , Figure 4 In some preferred embodiments, the bottom surface 201 of the coupling fixing seat 200 is configured to have an arc shape that is adapted to the outer surface of the gas pipeline 810 of the gas insulated switch, and the close contact between the two can be realized by bonding or the like. The top surface 202 can be fixedly connected with the lower cover 103 of the shell 100 by bonding or the like. In some preferred embodiments, the top surface 202 of the coupling fixing seat 200 can be configured to have a groove that matches the lower cover 103 of the shell 100, so that the lower cover 103 is firmly inserted into the groove and then bonded, which can further improve the connection strength of the shell 100 and the coupling fixing seat 200.

[0033] It should be known that those skilled in the art can change or adjust the above connection mode without departing from the idea of the present application, for example, the connection mode of the coupling fixing seat 200 and the lower cover 103 is set as screw and screw hole connection, or a sliding groove with a limiting piece is further provided on the inner wall of the groove, and a sliding block that can slide in the sliding groove is formed on the lower cover 103, so as to realize the fixed connection of the lower cover 103 and the coupling fixing seat 200 in a sliding and limiting manner.

[0034] Further, asFigure 3 、 Figure 4 As shown in FIGS. 1 and 2, the coupling fixing seat 200 is provided with a first through hole 203 penetrating the bottom surface 201 and the top surface 202, and the size of the hole is matched with the size of the temperature measuring structure of the temperature sensor, such as the temperature measuring probe 500. In the corresponding part of the lower cover 103 of the shell 100, a second through hole 104 penetrating the lower cover is provided. After the coupling fixing seat 200 is installed, the overall temperature can quickly track the temperature change of the gas insulated switch by using the good heat conduction characteristics, and a closed temperature measuring area in the first through hole 203 is formed, which is not disturbed by the external temperature. After the shell 100 and the coupling fixing seat 200 are fixedly connected, the first through hole 203 is aligned with the second through hole 104, and the temperature measuring structure of the temperature sensor, such as the temperature measuring probe 500, can enter the temperature measuring area in the first through hole 203 through the second through hole 104, so that the temperature data of the gas insulated switch can be accurately obtained.

[0035] In this way, the problem that the temperature measuring structure of the temperature sensor and the arc surface of the gas pipeline 810 are not matched, the contact area between them is too small, and the temperature measuring environment is connected with the external environment, so that the temperature measurement result cannot accurately reflect the actual temperature of the gas pipeline 810 can be effectively solved.

[0036] In some preferred embodiments, the bottom surface 201 of the coupling fixing seat 200 and the outer surface of the gas pipeline 810 of the gas insulated switch, the top surface 202 of the coupling fixing seat 200 and the bottom surface of the shell 100 (i.e. the lower surface of the lower cover 103), and the temperature measuring probe 500 of the temperature sensor and the first through hole 203 are all filled with a heat-conducting silicone grease material. On the one hand, since the heat-conducting silicone grease material contains micron-sized heat-conducting fillers such as aluminum oxide and boron nitride, the heat-conducting coefficient can reach 0.8-5 W / (m·K), which is 30-200 times that of air. Coating the heat-conducting silicone grease material in the above-mentioned parts can fill the micron-sized microscopic air gaps between the connection parts, avoid the air remaining in these gaps from forming significant thermal resistance, and thus build a continuous and efficient heat transfer path, so as to ensure that the temperature sensor can capture the temperature fluctuation of the gas insulated switch shell in real time and meet the high-precision temperature measurement requirement. On the other hand, the semi-solid paste form of the silicone grease has low viscosity and low damping characteristics, and the attenuation rate of the vibration signal is only 5%-10%, which will not interfere with the vibration transmission advantage of pure copper “high Young's modulus + high density”. When the gas insulated switch vibrates, the vibration signal can be accurately transmitted to the gas insulated switch vibration fault detection sensor through the coupling fixing seat 200 of the silicone grease layer-pure copper-silicone grease layer-shell 100, which not only avoids the signal interruption caused by the air gap, but also does not cause high-frequency vibration distortion due to medium damping, thereby ensuring the high fidelity of vibration measurement.

[0037] As described above, in the fault detection system, the gas insulated switch vibration fault detection sensor is used to detect the vibration state of the gas insulated switch and output the vibration fault detection result in the form of a two-bit binary digital signal. Unlike the existing active power supply vibration detection sensors that measure vibration frequency and amplitude, the gas insulated switch vibration fault detection sensor provided by the embodiments of the present application can realize accurate detection of the vibration fault state in a self-powered manner, thereby effectively reducing the vibration state monitoring energy consumption and facilitating long-term monitoring of a large range of distributed gas insulated switches in the power grid.

[0038] Specifically, the gas insulated switch vibration fault detection sensor provided by the present application is composed of a vibration power generation part 400 and a detection circuit, wherein the vibration power generation part includes a support part 401, a vibration pickup piezoelectric part 402, and a counterweight part 403, which are sequentially arranged along the axial direction. By converting the mechanical energy of the vibration of the gas insulated switch into a piezoelectric signal, the sensor is self-powered, and the detection circuit is provided with piezoelectric signal amplitude information corresponding to different vibration states. The detection circuit can be arranged on a circuit board 601 together with a master control unit and a communication unit, and based on the amplitude information of the piezoelectric signal, a corresponding two-bit binary vibration state signal is generated.

[0039] Figure 6 A perspective view of the vibration power generation part of the gas insulated switch vibration fault detection sensor in some embodiments is shown, Figure 7 a specific structure of the vibration piezoelectric part is shown, Figure 8 a vibration state distribution diagram of the vibration pickup beam in the vibration piezoelectric part is shown, Figure 9 a frame diagram of the detection circuit electrically connected to the piezoelectric module in the vibration piezoelectric part is shown, Figure 10 a schematic diagram of the detection circuit provided according to a specific embodiment is shown, Figure 11 a schematic diagram of the state signal switcher in the detection circuit is shown. The specific implementation of the gas insulated switch vibration fault detection sensor will be described in detail below with reference to the accompanying drawings.

[0040] As shown in Figure 6 the lower part of the support part 401 is cylindrical, and the upper part gradually expands to form a circular truncated cone, which is used to bear the vibration pickup piezoelectric part 402 and the counterweight part 403, and to transmit the vibration of the gas insulated switch to the vibration pickup piezoelectric part 402 and the counterweight part 403 during vibration fault detection. During the detection process, the lower part of the support part 401 needs to ensure rigid connection with the gas pipeline 810 of the gas insulated switch. For example, as shown in Figure 3 the lower part of the support part 401 can be inserted into the second slot hole 302 of the fixed support 300, or other optional ways can be used to fixedly connect the lower part of the support part 401 with the shell 100.

[0041] The vibration pickup piezoelectric part 402 is arranged above the support part, and includes an even number of vibration pickup beams 4021 and corresponding piezoelectric modules 4022 arranged at equal intervals in the circumferential direction. The number of vibration pickup beams 4021 is preferably two or four. For example, when the number of vibration pickup beams 4021 is two, the two vibration pickup beams 4021 are arranged opposite each other, and for example, when the number of vibration pickup beams 4021 is four, the four vibration pickup beams 4021 have an included angle of 90 degrees between each other, are arranged opposite each other in pairs, and are distributed in the circumferential direction above the support part 401. Figure 6

[0042] The vibration pickup beam 4021 can be formed by a conventional straight plate type elastic beam that is bent at right angles, for example, as shown in FIG. 4B, a conventional straight plate of metal material is bent at right angles four times at the middle part, thereby forming a rectangular groove with a radial opening, and the opening faces the axis of the support part 401 and the counterweight part 403. Figure 7

[0043] The rectangular groove of each vibration pickup beam 4021 is provided with a piezoelectric module 4022 composed of a plurality of first piezoelectric sheets 4022-1, and the first piezoelectric sheets 4022-1 are stacked in the axial direction in the rectangular groove. The electrical terminals of each first piezoelectric sheet 4022-1 can be connected in parallel or in series, and finally two electrical output terminals are formed, which are connected to the alternating current input terminals of the detection circuit.

[0044] The counterweight part 403 is arranged above the vibration pickup piezoelectric part 402. Specifically, the lower end and the upper end of each vibration pickup beam 4021 are fixedly connected to the support part 401 and the counterweight part 403, respectively, by means of bonding, insertion or welding, and the upper part of the counterweight part 403 is in a freely movable state.

[0045] After the support part 401 of the power generation part 400 is rigidly connected to the gas pipeline 810 of the gas insulated switch, for example, in the fault detection system described above, the support part 401 is inserted into the second slot hole 302 of the fixed support 300, the vibration of the gas insulated switch is transmitted to the support part 401 through the coupling fixed seat 200-outer shell 100. Since the circumferentially spaced vibration pickup beams 4021 with elasticity form a flexible region that can elastically move between the support part 401 and the counterweight part 403, the vibration pickup beams 4021 will sway under the driving of the vibration of the gas insulated switch, causing the opening of the rectangular groove to shrink or expand, thereby generating a piezoelectric effect on the piezoelectric module 4022 stacked inside, and outputting an alternating piezoelectric signal to the detection circuit.

[0046] The first piezoelectric sheet 4022-1 can be made of various piezoelectric materials known to those skilled in the art, such as lead titanate (PZT), barium titanate (BaTiO3), etc. In some preferred embodiments, as shown in FIG. 4C, the first piezoelectric sheet 4022-1 is made of lead titanate (PZT). Figure 7 ​​As shown, an elastic pad 4023 made of rubber or other materials can be arranged at the position where the piezoelectric module 4022 contacts the two ends of the rectangular groove, which can exert an axial pre-tightening force on the piezoelectric module 4022 and protect the relatively fragile first piezoelectric sheet 4022-1 contacting the two ends of the rectangular groove.

[0047] In the embodiments of the present application, the vibration frequency and vibration amplitude of the gas insulated switch in the normal state can be measured in advance, and the vibration frequency range in the normal state is determined, for example, the lower limit of the frequency in the normal state is , and the upper limit of the frequency is Then, the structural parameters of the vibration pickup beam 4021 and the counterweight part 403 are adjusted, for example, the length and thickness of the rectangular groove in the vibration pickup beam 4021, and the length and mass of the counterweight part 403, so that the resonance frequency of the vibration pickup beam 4021 is within the vibration frequency range of the gas insulated switch in the normal working state Therefore, when the vibration frequency of the gas insulated switch is abnormal and deviates from , each vibration pickup beam 4021 will not resonate, and at this time the piezoelectric signal amplitude output by the piezoelectric module 4022 is extremely small; when the vibration frequency of the gas insulated switch is normal, the vibration pickup beam 4021 will produce obvious resonance, thereby outputting a piezoelectric signal with a higher amplitude to the detection circuit through the piezoelectric module 4022.

[0048] Since the distance between the two ends of the rectangular groove body will change when the vibration pickup beam 4021 vibrates, the groove bottom of the rectangular groove body will also be bent and deformed, therefore, in some preferred embodiments, as shown in Figure 7 , a second piezoelectric sheet 4022-2 is further arranged in the vibration pickup piezoelectric part 402, which is attached to the outer surface of the groove bottom of the rectangular groove body of the vibration pickup beam 4021 (i.e. the radially outward side), to further increase the strength of the collected piezoelectric signal. Figure 8 The change of the vibration amplitude of the vibration pickup beam 4021 (which can be characterized by the axial distance between the two ends of the opening of the rectangular groove) with the change of the vibration frequency and vibration amplitude of the gas insulated switch, and the state of the gas insulated switch reflected thereby are shown schematically.

[0049] Abnormal vibration frequency state: under the premise of ensuring that the resonance frequency of the vibration pickup beam 4021 is within the vibration frequency range of the gas insulated switch in the normal state (i.e. the frequency Figure 8 If the vibration frequency deviates, for example, the vibration frequency is less than , or the vibration frequency is greater than ​​​​When the resonance condition is not met, the vibration amplitude of the vibration-collecting beam 4021 is significantly reduced; that is, when the amplitude of the vibration-collecting beam 4021 is at... Figure 8 When the two red areas in the lower middle part are visible, it indicates that the gas-insulated switch is in an abnormal frequency state. Obviously, at this time, the pressure applied to the piezoelectric module 4022 by the two ends of the rectangular slot opening of the vibration pickup beam is small, the piezoelectric effect is weak, and the piezoelectric module 4022 only outputs a weak piezoelectric signal, or even no piezoelectric signal.

[0050] Abnormal vibration amplitude: When the gas-insulated switch becomes loose due to the loosening of certain fixing structures, another abnormal situation may occur. In this case, the vibration frequency remains within the normal frequency range, but the vibration amplitude abnormally increases. The vibration pickup beam 4021 is in a resonant state, and its amplitude is significantly amplified, exceeding the upper limit of the amplitude corresponding to the vibration pickup beam 4021 under normal vibration conditions of the gas-insulated switch (e.g., ...). Figure 8 In That is, when the amplitude of the vibration-collecting beam 4021 is at Figure 8 When the red area in the upper middle part is visible, it indicates that the vibration amplitude of the gas-insulated switch is in an abnormal state. Obviously, unlike the abnormal vibration frequency, the piezoelectric signal output by the piezoelectric module 4022 is relatively strong at this time.

[0051] Normal vibration state: When the vibration frequency of the gas-insulated switch is within its normal frequency range and its vibration amplitude is within the preset normal range, the vibration pickup beam 4021 resonates, and the vibration amplitude of the vibration pickup beam 4021 is also between the lower and upper limits of the amplitude corresponding to the normal vibration state of the gas-insulated switch (i.e., Figure 8 In ~ (between), that is, when the amplitude of the vibration-collecting beam 4021 is within Figure 8 When the green area is visible, it indicates that the gas-insulated switch is in normal vibration state. At this time, the intensity of the piezoelectric signal output by the piezoelectric module 4022 is greater than the piezoelectric signal intensity under abnormal vibration frequency conditions but less than the piezoelectric signal intensity under abnormal vibration amplitude conditions.

[0052] In the embodiments of this application, the detection of the different vibration states is performed by a detection circuit. Figure 9 The diagram illustrates the framework structure of a detection circuit connected to the electrical output of a piezoelectric module in some embodiments. Figure 10 A schematic diagram of a detection circuit according to a specific embodiment is shown. Figure 11 This is a schematic diagram illustrating the state changes during the operation of the self-powered voltage circuit in some embodiments; Figure 12 This is a schematic diagram showing the changes in open-circuit voltage across the piezoelectric module and displacement of the vibration pickup beam in some embodiments; Figure 13The schematic diagram of the state signal switcher provided according to one specific embodiment.

[0053] The specific implementation of the detection circuit is described in detail below with reference to the accompanying drawings.

[0054] The detection circuit is used to distinguish three vibration states (vibration frequency abnormal state, vibration amplitude abnormal state, normal vibration state) of the gas insulated switch without external power supply according to different amplitude AC piezoelectric signals output by the piezoelectric module, and output the result in the form of two-bit binary digital signals ([0, 0], [0, 1], [1, 0], [1, 1]). As shown in Figure 9 、 Figure 10 , the detection circuit includes a self-powered piezoelectric circuit and a state switching circuit, wherein the self-powered piezoelectric circuit converts the AC piezoelectric signal output by the piezoelectric module into a DC rectified signal to provide power supply for the entire detection circuit, and the state switching circuit extracts the envelope of the piezoelectric signal and switches the state signal through the amplitude of the envelope signal.

[0055] A. Self-powered piezoelectric circuit As shown in Figure 9 、 Figure 10 , the self-powered piezoelectric circuit includes a peak detector and a MOSFET rectifier bridge, wherein the peak detector is composed of an extreme value detection capacitor , two NPN triodes (first triode , third triode ) and two PNP triodes (second triode , fourth triode ) cross-coupled, which can be regarded as a switch that is only turned on when the voltage on both sides of the piezoelectric module reaches the peak value; the MOSFET rectifier bridge is used to convert the piezoelectric signal (AC) output by the piezoelectric module and passing through the peak detector into a rectified signal (DC), which is composed of two diodes (first diode , second diode ) and two NMOS tubes (first MOS tube , second MOS tube ) cross-coupled, which can be regarded as a controlled switch by using the controlled characteristics of N-MOSFET, and the power loss can be ignored when the NMOS tube is turned on. Compared with the conventional diode rectifier, the MOSFET rectifier bridge only flows through one diode when the current passes through, which can effectively reduce the loss of rectifying the AC input piezoelectric signal.

[0056] The specific connection mode of the peak detector and the MOSFET rectifier bridge is as follows: The base of the first triode , the base of the second triode the collector of the first transistor the collector of the third transistor the base of the first transistor is connected to the base of the fourth transistor, and the first transistor the collector of the second transistor is connected to the base of the fourth transistor the collector of the fourth transistor is connected to the base of the third transistor the collector of the third transistor is connected to the base of the first transistor the base of the first transistor is connected to the emitter of the fourth transistor the emitter of the fourth transistor is connected to the emitter of the first transistor the first end of the peak detection capacitor is connected to the emitter of the first transistor the second end of the peak detection capacitor is connected to the emitter of the second transistor the emitter of the second transistor is connected to the emitter of the third transistor and is connected to the first input end of the MOSFET rectifier bridge as the first output end of the peak detector the second end of the peak detection capacitor is connected to the second input end of the MOSFET rectifier bridge as the second output end of the peak detector the anode of the first diode is connected to the anode of the second diode the cathode of the first diode is connected to the cathode of the second diode the anode of the first diode is connected to the anode of the second diode as the first input end and the second input end of the MOSFET rectifier bridge, respectively, and is connected to the first output end and the second output end of the peak detector, respectively the cathode of the first diode is connected to the cathode of the second diode as the positive output end of the MOSFET rectifier bridge to output a rectified signal, and is connected to the first output end of the state signal switcher to be described later as the first state signal output end of the entire detection circuit the gate of the first MOS transistor is connected to the anode of the second diode the source of the second MOS transistor is connected to the anode of the second diode the gate of the second MOS transistor is connected to the cathode of the first diode the source of the first MOS transistor is connected to the anode of the first diode the drain of the first MOS transistor is connected to the drain of the second MOS transistor as the negative output end of the MOSFET rectifier bridge and is connected to the ground the first MOS transistor and the second MOS transistor are connected in parallel as the MOSFET rectifier bridge the first MOS transistor and the second MOS transistor are connected in parallel as the MOSFET rectifier bridge the first MOS transistor and the second MOS transistor are connected in parallel as the MOSFET rectifier bridge the first MOS transistor and the second MOS transistor are connected in parallel as the MOSFET rectifier bridge the first MOS transistor and the second MOS transistor are connected in parallel as the MOSFET rectifier bridge the first MOS transistor and the second MOS transistor are connected in parallel as the MOSFET rectifier bridge the first MOS transistor and the second MOS transistor are connected in parallel as the MOSFET rectifier bridge the first inductor is connected between the first output end of the peak detector and the first input end of the MOSFET rectifier bridge A second inductor is connected between the first and second input terminals of the MOSFET rectifier bridge. .

[0057] When the vibration pickup beam vibrates, the two ends of the rectangular groove periodically apply pressure to the piezoelectric module. Due to the piezoelectric effect, the electrical output terminal of the piezoelectric module will output AC voltage. The amplitude of the voltage depends on the vibration coupling between the vibration pickup beam and the gas-insulated switch.

[0058] When the vibration frequency of the gas-insulated switch deviates from its normal vibration frequency range, the vibration pickup beam cannot resonate, therefore the vibration state of the vibration pickup beam is in a state of... Figure 8 Within the two red areas in the lower middle, the piezoelectric signal generated by the piezoelectric module has an extremely small amplitude and cannot pass through the peak detector. Therefore, the positive output of the MOSFET rectifier bridge does not output a rectified signal. The output is low (i.e., binary 0).

[0059] If the vibration frequency of the gas-insulated switch is within its normal operating frequency range, the vibration pickup beam will experience a significant increase in amplitude due to resonance, and will enter... Figure 8 In the green area or the red area above, the self-powered voltage circuit will output a high-amplitude rectified signal. Since the self-powered voltage circuit operates on the same principle in both positive and negative oscillation cycles of sinusoidal excitation, only half of the oscillation cycle during its operation is selected as the research object. Its operation process can be divided into... Figure 11 The four stages shown also include, simultaneously, the open-circuit voltage across the piezoelectric module and the displacement of the vibration pickup beam during the operation of the self-powered voltage circuit. u(t) like Figure 12 As shown.

[0060] Ignore the internal resistance of the piezoelectric module R p The influence of the open-circuit voltage of the piezoelectric module. V oc It can be described as: (1), in, It is the peak current of the piezoelectric module as an equivalent current source. ω It is the angular velocity of the gas-insulated switch vibration. It is the internal capacitor of the piezoelectric module.

[0061] The period from time t3 to t4 is the natural charging phase, such as... Figure 11 As shown in section (a), the piezoelectric module moves in the positive direction, at which time the second transistor... Third transistor and the fourth transistor In the off state, equivalent current source ip for internal capacitor and peak detection capacitor When the pick-up beam reaches its positive displacement peak at time t4, the voltage across the piezoelectric module reaches its maximum value V max Since there is conduction loss, the voltage across the peak detection capacitor is (2), where is the base-emitter potential difference of the triode.

[0062] From time t4 to t5 is the extra open circuit phase, as shown in part (b) of FIG. 1, when the piezoelectric module moves positively to the peak point and starts to move negatively, the equivalent current source Figure 11 p reversely charges the internal capacitor i of the piezoelectric module, and the open circuit voltage decreases. At this time, all four triodes are in the off state, and the peak detection capacitor records the peak voltage across the piezoelectric module, and the voltage remains unchanged. At time t5, when the voltage difference between the piezoelectric module and the voltage of is , the voltage across the piezoelectric module can be expressed as: (3).

[0063] From time t5 to t6 is the energy extraction and charge reversal phase, as shown in part (c) of FIG. 1, as the open circuit voltage of the piezoelectric module decreases, when the voltage difference between the open circuit voltage and the voltage of Figure 11 is the base-emitter potential difference of the fourth triode be , the fourth triode V turns on, and then the third triode turns on. The internal capacitor of the piezoelectric module, the peak detection capacitor and the first inductor form an LC resonance circuit, and the current released by the piezoelectric sheet flows partly to the first inductor and partly to the second inductor . Since the voltage of is clamped to by the rectifier bridge (where is the conduction voltage drop of the diode, ​​The main control unit behind the detection circuit is regarded as the equivalent load. (voltage), at this time the second NMOS transistor The gate potential rises to meet the conduction requirement; ignoring the on-state voltage drop, it makes... The rate of change of current is limited, therefore current Growing at a relatively fast rate, through A portion of the current flows into The other part is output as rectified current through the rectifier bridge, realizing the first energy extraction. During this process... terminal voltage and current This can be expressed as: (4), (5).

[0064] At this point, the equivalent capacitance of the piezoelectric module C p It is always in a state of discharge, and its sum The current and voltage of the series circuit formed can be expressed as: (6), in It is a capacitor C p The terminal voltage, yes C p and extreme value detection capacitor The parallel equivalent capacitance, It is the first inductor The current.

[0065] neglect The conduction loss of voltage can be considered as , and The circuit formed satisfies: (7).

[0066] Since the inductor current cannot change abruptly, therefore We can obtain the first inductance during the time interval from t5 to t6. The current is: (8), in, It is the peak voltage across the piezoelectric element.

[0067] along with The gradual decrease and The gradual increase at time t6 and When the two are equal, the forward conduction of the rectifier bridge is cut off, and in this stage The electrical energy collected by the rectifier bridge is: (9).

[0068] In the time period t6 to t7, it is a secondary extraction stage, as shown in part (d) of FIG. 6, the electrical energy stored in Figure 6 and flows through the rectifier bridge into , , and gradually decreases over time until it is zero, and the voltage reversal process ends, according to the law of conservation of energy: (10), wherein, is the voltage of the piezoelectric module at the end of the secondary extraction stage. R L The electrical energy collected by the rectifier bridge, is the voltage of the piezoelectric module after 1 / 2 LC oscillation period in the time period t5 to t7.

[0069] Finally, the total electrical energy collected by the rectifier bridge in this half vibration period is: (11).

[0070] Therefore, when the vibration frequency of the gas insulated switch is within the vibration frequency range in its normal state, the positive output end of the MOSFET rectifier bridge will always output a higher rectified signal.

[0071] The self-powered voltage circuit provided by the embodiment of the application adopts a self-powered peak detection switch and a diode-MOSFET (MOSFET) cooperative rectifier circuit design, and can ensure that the rectifier module outputs different potential signals in the resonant state and the non-resonant state by using the voltage linear response characteristic of the MOSFET.

[0072] In some specific embodiments, a person skilled in the art can select various components in the self-powered piezoelectric circuit according to the energy output characteristics of the piezoelectric module in the resonant state, for example, the first diode and the second diode preferably use Zener diodes, and for example, the preferred value range of L is 4.7 mH~44 mH, , the ratio of C1 / C2 is preferably set to :​ =1~2.

[0073] B. State switching circuit It should be noted that although the output of the rectified signal by the MOSFET rectifier bridge can preliminarily judge whether the gas insulated switch is in the abnormal state of the vibration frequency, when the vibration frequency of the gas insulated switch is not greatly deviated from the normal frequency range, the self-supply voltage circuit still has a certain probability of outputting a certain amplitude of the rectified signal. If the rectified signal is directly used as the state signal of the gas insulated switch, it may appear that the main control unit misrecognizes the rectified signal as a high-level signal (i.e., binary digital 1). In order to avoid such misjudgment, it is necessary to enhance the judgment accuracy of the frequency deviation.

[0074] In addition, it can be known from the foregoing that if the vibration frequency of the gas insulated switch is in the vibration frequency range in the normal state, the vibration of the vibration pickup beam will be in the Figure 8 green region and the red region above, that is, in the case that the self-supply voltage circuit outputs a high-level rectified signal, the detected device may be in an abnormal state in which the vibration frequency is in the normal range but the vibration amplitude is significantly large.

[0075] It can be seen that at least two binary digital signals are needed to distinguish three different vibration states. Therefore, in the embodiment of the present application, the self-supply voltage circuit needs to cooperate with the state switching circuit, wherein the state switching circuit includes two output ends, the first output end of which is connected with the positive output end of the self-supply voltage circuit, and together serves as the first state signal output end of the entire detection circuit , and the second output end thereof serves as the second state signal output end of the entire detection circuit . When the gas insulated switch is in the abnormal state of the vibration frequency, whether the self-supply voltage circuit outputs or does not output the rectified signal, the first output end of the state switching circuit is pulled low in potential, so that remains low (i.e., binary digital 0); when the gas insulated switch is in the state in which the vibration frequency is normal but the vibration amplitude is abnormal, causing the vibration amplitude of the vibration pickup beam to be in the Figure 8 red region above, is high (i.e., binary digital 1), but is low (i.e., binary digital 0); when the vibration frequency of the gas insulated switch is in the normal range of Figure 8 , ~, and the vibration amplitude is also in the preset normal range, so that the vibration amplitude of the vibration pickup beam in the resonance state is in the Figure 8 , ~, green region.(i.e., the area where the green zone is located) It is a high level (i.e., a binary digit 1), and at the same time It is also a high level (i.e., binary 1). Therefore, it is possible to effectively distinguish the normal vibration state of the gas-insulated switch from the abnormal vibration frequency state and the abnormal vibration amplitude state.

[0076] Specifically, the state switching circuit includes an envelope extractor and a state signal switcher. The envelope extractor is used to extract the envelope of the piezoelectric signal output by the piezoelectric module in real time. The state signal switcher determines the voltage amplitude of the piezoelectric signal output by the piezoelectric module based on the amplitude of the envelope. The lower limit of the piezoelectric signal corresponding to the amplitude of the gas-insulated switch in its normal state. With voltage upper limit The relationship between the piezoelectric signal and the corresponding high / low level signals are output through the first and second output terminals based on the comparison results: when the piezoelectric signal envelope amplitude is used to determine... satisfy When the gas-insulated switch vibrates abnormally, both its first and second output terminals output high-level signals; when the gas-insulated switch vibrates abnormally, causing... At this time, its first output terminal outputs a low-level signal to pull it low. The potential, when the vibration frequency of the gas-insulated switch is normal but the vibration amplitude is abnormally increased, leads to At that time, its second output terminal outputs a low-level signal to pull it low. The potential.

[0077] The envelope extractor can be constructed using various sinusoidal signal envelope extraction circuits known to those skilled in the art, for example, in some alternative embodiments, such as Figure 10 As shown, through the third diode First resistor Second resistor and the first capacitor Composition, in which the third diode The anode is connected to the first output terminal of the piezoelectric equivalent circuit, and the cathode is connected to the first capacitor. The first end is connected to the first capacitor. The second terminal is grounded, and the third diode... cathode and first resistor The first terminal is connected and serves as the first output terminal of the envelope extractor, and the voltage of this first output terminal is... First resistor The second end and the second resistor The first terminal is connected and serves as the second output terminal of the envelope extractor, and the voltage of the second output terminal is... Second resistor The second end of the first resistor is grounded.

[0078] In some specific embodiments, each component in the extractor can be selected according to the actual need of judging the amplitude of the piezoelectric signal output by the piezoelectric module. Preferably, the first resistor and the second resistor have a value range of 10 MΩ-50 MΩ. The specific ratio of can be determined by equation (15) below. The first capacitor has a value range of 1 uF-2 uF.

[0079] The state signal switch compares the amplitudes of the envelope signals , judges the relationship between the voltage amplitude of the piezoelectric signal and the preset lower limit of voltage and the upper limit of voltage , and according to the comparison result, keeps or pulls down the potential of the rectified signal through the first output end, thereby switching the potential high and low, and switching the potential high and low through the second output end.

[0080] In some preferred embodiments, the state signal switch includes three control lines, and each control line is connected in series with a plurality of NMOS tubes and a control resistor. Preferably, the resistance value of the control resistor connected in series in the first control line and the third control line is much larger than that of the control resistor connected in series in the second control line.

[0081] Specifically, the drain of each NMOS tube in the first control line is connected to the ground, and the gate is connected to the first output end of the envelope extractor; the drain of each NMOS tube in the second control line is connected to the ground, and the gate is connected to the source of the NMOS tube farthest from the ground in the first control line; the drain of each NMOS tube in the third control line is connected to the ground, and the gate is connected to the second output end of the envelope extractor.

[0082] Further, the common connection end of the three control lines not connected to the ground is the first output end of the state signal switch, which is connected to the positive output end of the MOSFET rectifier bridge to serve as the first state signal output end of the entire detection circuit ; the source of the NMOS tube farthest from the ground in the third control line is the second output end of the state signal switch, which also serves as the second state signal output end of the entire detection circuit .

[0083] The following will be described by Figure 10 and Figure 13The working principle of the state signal switch is described in detail in the embodiment.

[0084] Figure 10 The working principle of the state signal switch is described in detail in the embodiment. Figure 13 The state signal switch in the embodiment is composed of eight NMOS tubes (the third NMOS tube , the fourth NMOS tube , the fifth NMOS tube , the sixth NMOS tube , the seventh NMOS tube , the eighth NMOS tube , the ninth NMOS tube , and the tenth NMOS tube ) and three control resistors (the third resistor , the fourth resistor , and the fifth resistor ).

[0085] The three NMOS tubes (the third NMOS tube , the fourth NMOS tube , and the fifth NMOS tube ) and the resistor (the third resistor ) are connected in series in the first control line, the drain electrodes of the three NMOS tubes are connected to the ground, and the gate electrodes are connected to the first output end of the envelope extractor; the two NMOS tubes (the sixth NMOS tube and the seventh NMOS tube ) and the resistor (the fourth resistor ) are connected in series in the second control line, the drain electrodes of the two NMOS tubes are connected to the ground, and the gate electrodes are connected to the source electrode of the NMOS tube (the third NMOS tube ) farthest from the ground in the first control line; the three NMOS tubes (the eighth NMOS tube , the ninth NMOS tube , and the tenth NMOS tube ) and the resistor (the fifth resistor ) are connected in series in the third control line, the drain electrodes of the three NMOS tubes are connected to the ground, and the gate electrodes are connected to the second output end of the envelope extractor.

[0086] The common connection end (non-ground end) of the three control lines serves as the first output end of the state signal switch and is connected to the positive output end of the MOSFET rectifier bridge output rectification signal, thereby forming the first state signal output end of the entire detection circuit, and the tenth NMOS tube farthest from the ground among the three NMOS tubes in the third control lineThe second output end of the state signal switcher and the second state signal output end of the whole detection circuit , With Further connect with the I / O pin of the master unit to send the gas insulated switch vibration fault detection result in the form of two-bit binary to the master unit.

[0087] During the whole working process, the envelope extractor outputs And Are: (12), (13), The upper limit and the lower limit of the voltage for which the state signal switcher switches signals And Are: (14), (15), Among them, The on threshold voltage of the N-MOSFET.

[0088] From formulas (14) and (15), when the voltage across the piezoelectric sheet Satisfies , the device is in a normal working state, when the voltage across the piezoelectric sheet Satisfies , the device is in a vibration frequency abnormal fault state. When the voltage across the piezoelectric sheet Satisfies , the device is in a vibration amplitude abnormal increase fault state.

[0089] When the gas insulated switch is in a normal state, its vibration frequency is consistent with the resonance frequency of the vibration amplifier, and the amplitude is in a preset normal range, the peak value of the voltage across the piezoelectric sheet is between the preset lower limit of voltage And the upper limit of voltage , , , The control signal voltage of the N-MOSFET Is greater than its on threshold Therefore , , Conducts, And The gate potential is 0, so , Because the gate voltage is insufficient to close, , And This is because of the control signal voltage. Insufficient to close. Because... The resistance is relatively large (typically in the megaohm range), therefore at this time , All remain at a high level, i.e., the vibration state detection result is output in the range of [1,1].

[0090] When the equipment malfunctions due to abnormal vibration frequency, the piezoelectric module cannot reach a resonant state because of the frequency change. At this time, the peak voltage across the piezoelectric module decreases. When the voltage across the piezoelectric module meets the condition... hour, , , , , and Because of the control signal voltage and Insufficient to close, at this time , When the gate potential and drain potential are the same and the conduction condition is met, then... It is connected in parallel at the output of the self-powered voltage circuit, and The resistance is low (typically in the range of hundreds to thousands of ohms), causing the power supply signal voltage output by the self-powered voltage circuit to be pulled down. Keep low level, The level of the signal is affected by the amplitude of the envelope signal and may be high or low, that is, the vibration state detection result is output as [0,0] or [0,1].

[0091] When a gas-insulated switch is in an abnormal state where the vibration frequency is normal but the vibration amplitude is abnormally increased, the peak voltage across the piezoelectric module increases due to the increased amplitude. When the voltage across the piezoelectric module satisfies... At that time, control signal voltage Increase to reach , and The conduction requirements, thus Switch to low level, and at the same time because , The resistance is relatively large. Maintain a high level, i.e., output the vibration state detection result [1,0].

[0092] In some specific embodiments, the vibration frequency range and vibration amplitude range of the gas-insulated switch under normal conditions can be measured in advance. Based on this, the resonance characteristics of the vibration pickup beam can be determined, and its structural and electrical parameters can be designed. Finally, the lower limit of the piezoelectric signal output by the piezoelectric module under normal conditions can be determined. and lower voltage limit ;according to 、 Further, the envelope extractor outputs and and the condition of triggering state change, and determines the value range of the resistance 、 and . In some preferred embodiments, the resistance of is 1 MΩ~2 MΩ, is 100Ω~1000Ω, is 1 MΩ~2 MΩ, that is, the resistance of the control resistance connected in series in the first control line and the third control line is much larger than the resistance of the control resistance connected in series in the second control line (the difference is three to four orders of magnitude).

[0093] The reason for using multiple NMOS tubes connected in series in the control line is that, on the one hand, the NMOS tube can be regarded as an equivalent resistance when it is turned off, especially in a small current state. Since the loop resistance where the NMOS tube is located is very large, the equivalent resistance when it is turned off must be large, otherwise it is easy to appear a situation that cannot be turned off to generate a voltage division. Therefore, the use of multiple NMOS tubes connected in series increases the equivalent resistance when it is turned off. On the other hand, too many NMOS tubes connected in series in the control line will result in a longer turn-off time and a larger delay. Therefore, in some preferred embodiments, the number of NMOS tubes connected in series in each control line is between 2 and 4.

[0094] In some preferred embodiments, the model and parameters of the NMOS tubes connected in series in each control line are consistent.

[0095] The state switching circuit composed of the envelope extractor and the state signal switcher can automatically detect various vibration faults of the gas insulated switch and output a two-bit binary detection result without any external power supply according to the change of the voltage generated on both sides of the piezoelectric module. At the same time, the sampling control signal of the envelope extractor only acts on the gate control of each NMOS tube, which maximizes the avoidance of the coupling effect between the detection control circuit and the self-powered voltage circuit.

[0096] Considering that there may be a phase difference in the piezoelectric signals output by different piezoelectric modules, in some optional embodiments, a corresponding detection circuit is connected for each piezoelectric module. For example, when the gas insulated switch vibration fault detection sensor is provided with four groups of piezoelectric modules, four detection circuits are simultaneously provided, four two-bit binary detection results are output, and the eight I / O pins are received by the host control unit. The host control unit can consider the detection result of one detection circuit or comprehensively consider the detection results of multiple or even all detection circuits to comprehensively judge the vibration state of the gas insulated switch in each direction.

[0097] The specific embodiments of the present application have been described above in detail, and those skilled in the art will understand that the application can make a number of modifications and improvements without departing from the principles of the application. These modifications and improvements are also within the scope of the application.

Claims

1. A vibration fault detection sensor for gas-insulated switches, characterized in that, include: It includes a support section, a vibration-sensing piezoelectric section, a counterweight section, and a detection circuit; The support, the vibration-collecting piezoelectric part, and the counterweight are arranged sequentially along the axial direction. The vibration-collecting piezoelectric part includes an even number of vibration-collecting beams and corresponding piezoelectric modules arranged at equal intervals along the circumference. The two ends of the vibration-collecting beams are connected to the support and the counterweight, respectively. The middle part is a rectangular groove with a radial opening formed by bending a straight plate elastic beam at a right angle. The resonant frequency of the vibration-collecting beams is set to be within the vibration frequency range of the gas-insulated switch under normal operating conditions. The piezoelectric module includes a plurality of first piezoelectric sheets stacked axially in the rectangular groove. The detection circuit is connected to the electrical output terminal of the piezoelectric module, and outputs a two-bit binary gas insulation switch vibration fault detection result based on the amplitude of the piezoelectric signal output by the piezoelectric module.

2. The gas-insulated switch vibration fault detection sensor according to claim 1, characterized in that, The number of vibration-collecting beams is two or four.

3. The gas-insulated switch vibration fault detection sensor according to claim 2, characterized in that, Elastic pads are provided at the points where the piezoelectric module contacts both ends of the rectangular groove.

4. The gas-insulated switch vibration fault detection sensor according to claim 3, characterized in that, The vibration-harvesting piezoelectric part also includes a second piezoelectric sheet, which is attached to the outer surface of the bottom of the rectangular groove of the vibration-harvesting beam.

5. The gas-insulated switch vibration fault detection sensor according to claim 1, characterized in that, The detection circuit includes a self-powered voltage circuit and a state switching circuit; The self-powered voltage circuit includes a peak detector and a MOSFET rectifier bridge. The peak detector is connected between the electrical output terminal of the piezoelectric module and the MOSFET rectifier bridge. It conducts when the voltage on both sides of the piezoelectric module reaches its peak value. The MOSFET rectifier bridge is used to convert the AC piezoelectric signal output by the piezoelectric module and passing through the peak detector into a DC rectified signal and output it through its positive output terminal. The state switching circuit includes an envelope extractor and a state signal switcher. The extractor is connected between the electrical output terminal of the piezoelectric module and the state signal switcher to extract the envelope of the piezoelectric signal. The state signal switcher compares the voltage amplitude of the piezoelectric signal with a preset lower voltage limit and a preset upper voltage limit based on the amplitude of the envelope, and outputs corresponding high and low level signals through its first and second output terminals according to the comparison result. The positive output terminal of the MOSFET rectifier bridge is connected to the first output terminal of the state signal switch and serves as the first state signal output terminal of the detection circuit, while the second output terminal of the state signal switch serves as the second state signal output terminal of the detection circuit.

6. The gas-insulated switch vibration fault detection sensor according to claim 5, characterized in that, The status signal switcher includes three control lines, each of which has several NMOS transistors and a control resistor connected in series. In the first control circuit, the drains of each NMOS transistor are all facing the ground terminal, and the gates of each NMOS transistor are all connected to the first output terminal of the envelope extractor. In the second control circuit, the drains of each NMOS transistor are all facing the ground terminal, and the gates of each NMOS transistor are all connected to the source of the NMOS transistor in the first control circuit that is farthest from the ground terminal. In the third control circuit, the drains of each NMOS transistor are all facing the ground terminal, and the gates of each NMOS transistor are all connected to the second output terminal of the envelope extractor. The common non-grounded connection terminal of the three control lines serves as the first output terminal of the state signal switcher, and the source of the NMOS transistor in the third control line that is farthest from the ground terminal serves as the second output terminal of the state signal switcher. The resistance values ​​of the control resistors connected in series in the first and third control lines are much greater than the resistance value of the control resistor connected in series in the second control line.

7. A fault detection system for gas-insulated switches, characterized in that, include: The system includes a housing, a coupling mount, a measurement unit, a main control unit, a communication unit, and a power supply unit. The housing is used to house the measurement unit, main control unit, communication unit, and power supply unit; The bottom surface of the coupling fixing base is in close contact with the outer surface of the gas pipeline of the gas-insulated switch, and the top surface is used to rigidly support the housing. The coupling fixing base is provided with a first through hole penetrating the bottom surface and the top surface, and the housing is provided with a second through hole that mates with the first through hole. The measuring unit includes a temperature sensor and a gas-insulated switch vibration fault detection sensor as described in claim 1, wherein the temperature measuring structure of the temperature sensor is located in the first through hole, and the support part of the gas-insulated switch vibration fault detection sensor is rigidly connected to the outer shell. The main control unit is used to receive the measurement data from the measurement unit, including the temperature of the gas-insulated switch and the vibration fault detection result of two binary bits; The communication unit is used to transmit the measurement data; The power supply unit is used to power the temperature sensor, main control unit and communication unit.

8. The gas-insulated switch fault detection system according to claim 7, characterized in that, The coupling fixture is made of a material with high thermal conductivity and high mechanical rigidity.

9. The gas-insulated switch fault detection system according to claim 7, characterized in that, Thermally conductive silicone grease is filled between the bottom surface of the coupling fixing base and the outer surface of the gas pipe of the gas-insulated switch, between the top surface of the coupling fixing base and the bottom surface of the housing, and between the temperature measuring structure of the temperature sensor and the first through hole.

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