Partial discharge fusion temperature monitoring system of switch cabinet

Abstract

The invention relates to the technical field of electric power, in particular to a partial discharge fusion temperature monitoring system of a switch cabinet, which comprises the switch cabinet and a monitoring terminal, and is characterized in that an A-phase insulator, a B-phase insulator, a C-phase insulator and a first static contact box are arranged in the switch cabinet; after an A-phase busbar, a B-phase busbar and a C-phase busbar in the switch cabinet are fixed to an A-phase insulator, a B-phase insulator and a C-phase insulator through fixing pieces respectively, the A-phase busbar, the B-phase busbar and the C-phase busbar are electrically connected with static contacts of the first static contact box in a one-to-one correspondence mode respectively. The A-phase insulator, the B-phase insulator and the C-phase insulator are respectively provided with a signal interface, and the fixing pieces are respectively provided with a first temperature sensor; the monitoring terminal is electrically connected with partial discharge signal lines and first temperature receiving antennas, the partial discharge signal lines are electrically connected with the signal interfaces in a one-to-one correspondence manner, and the first temperature receiving antennas are in wireless communication connection with the first temperature sensors in a one-to-one correspondence manner; the problems of incomplete and inaccurate partial discharge and temperature monitoring in the switch cabinet are solved.

Description

Technical Field

[0001] The invention relates to the technical field of electric power, in particular to a partial discharge fusion temperature monitoring system of a switch cabinet. Background Art

[0002] In the power system, switch cabinets often cause partial discharge and potential faults due to long-term operation due to factors such as material aging, poor contact, and current overload. Therefore, it is necessary to monitor partial discharge of the switch cabinet to improve the safety and reliability of the switch cabinet.

[0003] At present, due to the different models and specifications of switch cabinets, the existing switch cabinet partial discharge monitoring is usually carried out through transient ground voltage (ie, TEV signal), ultrasound, temperature, etc., and the installation method is adsorption outside the cabinet, which has the following defects:

[0004] (1) Through transient ground voltage (TEV signal) monitoring, the discontinuity of the switchgear shielding layer is the prerequisite for detecting the TEV signal. If the shielding layer is complete, the TEV signal cannot be monitored outside the switchgear. This limits the use of TEV signal to monitor partial discharge and is not applicable to all switchgear.

[0005] (2) Ultrasonic monitoring cannot accurately locate the discharge point, and in some cases may be interfered by environmental noise, affecting the accuracy of monitoring. In addition, the propagation of ultrasonic signals will be affected by the equipment structure and material properties. When the internal structure of the switch cabinet is complex or limited by the material, the monitoring will fail, so ultrasonic monitoring cannot be applied to all switch cabinets.

[0006] (3) Temperature monitoring usually has few monitoring points and no restrictions on the location of the monitoring points. It is often necessary to wait until the partial discharge is serious or even the switch cabinet is burned before monitoring. The error is very large and it cannot be used as the main monitoring method for partial discharge monitoring of switch cabinets. Summary of the invention

[0007] In view of the above-mentioned defects, the purpose of the present invention is to propose a partial discharge fusion temperature monitoring system for a switch cabinet, which solves the problem of incomplete and inaccurate partial discharge and temperature monitoring inside the switch cabinet.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] A partial discharge fusion temperature monitoring system for a switch cabinet, comprising a switch cabinet and a monitoring terminal, wherein an A-phase insulator, a B-phase insulator, a C-phase insulator and a first static contact box are arranged in the switch cabinet; after the A, B and C three-phase busbars in the switch cabinet are respectively fixed to the A-phase insulator, the B-phase insulator and the C-phase insulator by fixing members, the A, B and C three-phase busbars are respectively electrically connected to the static contacts of the first static contact box in a one-to-one correspondence;

[0010] The A-phase insulator, the B-phase insulator and the C-phase insulator are respectively provided with a signal interface, and the fixing parts are each provided with a first temperature sensor;

[0011] The monitoring terminal is electrically connected to a partial discharge signal line and a first temperature receiving antenna, the partial discharge signal line and the signal interface are electrically connected in a one-to-one correspondence, and the first temperature receiving antenna and the first temperature sensor are wirelessly connected in a one-to-one correspondence.

[0012] Furthermore, the switch cabinet includes a busbar room, a cable room, a trolley room and an instrument room; the A-phase insulator, the B-phase insulator, the C-phase insulator and the first static contact box are all arranged in the busbar room, the monitoring terminal is arranged in the instrument room, and the partial discharge signal line and the first temperature receiving antenna are laid from the instrument room to the busbar room along the inner shell wall of the switch cabinet;

[0013] The cable chamber is provided with a second static contact box, and the cables in the cable chamber are electrically connected to the static contacts of the second static contact box one by one;

[0014] The trolley room is provided with a circuit breaker device, and the moving contacts in the circuit breaker device are respectively arranged in one-to-one correspondence with the static contacts of the first static contact box and the static contacts of the second static contact box; the moving contacts are each provided with a second temperature sensor;

[0015] The monitoring terminal is also electrically connected to a second temperature receiving antenna, which is laid along the inner shell wall of the switch cabinet from the instrument room to the trolley room. The second temperature receiving antenna and the second temperature sensor are wirelessly connected in a one-to-one correspondence.

[0016] Furthermore, the monitoring terminal includes a signal phase selection switching circuit, a partial discharge sampling circuit, a microcontroller, an antenna transceiver module and three signal access circuits; the input end of the signal access circuit is electrically connected to the signal interface, the output ends of the three signal access circuits are electrically connected to the three input ends of the phase selection switching circuit, the output end of the signal phase selection switching circuit is electrically connected to the input end of the partial discharge sampling circuit, the output end of the partial discharge sampling circuit is electrically connected to the microcontroller, the data end of the antenna transceiver module is electrically connected to the microcontroller, and the multiple communication ends of the antenna transceiver module are electrically connected to the first temperature receiving antenna and the second temperature receiving antenna in a one-to-one correspondence.

[0017] The three signal access circuits receive single-phase partial discharge signals respectively and transmit them to the signal phase selection switching circuit. The signal phase selection switching circuit collects the three single-phase partial discharge signals in a time-sharing manner and transmits them to the partial discharge sampling circuit. The partial discharge sampling circuit obtains partial discharge features from the single-phase partial discharge signals and transmits them to the microcontroller for identification.

[0018] The antenna transceiver module receives a first temperature signal from the first temperature sensor through the first temperature receiving antenna; the antenna transceiver module receives a second temperature signal from the second temperature sensor through the second temperature receiving antenna.

[0019] Furthermore, the signal access circuit includes a decoupling capacitor module, a high-pass filter module and a clamping module; the input end of the decoupling capacitor module is used as the input end of the signal access circuit, and the output end of the clamping module is used as the output end of the signal access circuit;

[0020] The output end of the decoupling capacitor module is electrically connected to the input end of the high-pass filter module, and the output end of the high-pass filter module is electrically connected to the input end of the clamping module;

[0021] The decoupling capacitor module is provided with at least one decoupling capacitor, and the high-pass filter module is provided with at least one first-order high-pass filter.

[0022] Furthermore, the signal phase selection switching circuit includes a multi-channel multiplexing chip U1 and an electronic switch; the channel input end of the multi-channel multiplexing chip U1 is used as the input end of the signal phase selection switching circuit, and the channel output end of the multi-channel multiplexing chip U1 is used as the output end of the signal phase selection switching circuit;

[0023] The electronic switch is electrically connected to the control terminal of the multi-channel multiplexing chip U1; the electronic switch may be electrically connected to the microcontroller;

[0024] The electronic switch is used to set the time-sharing acquisition rule of the multi-channel multiplexing chip U1.

[0025] Furthermore, the signal access circuit, the signal phase selection switching circuit, the partial discharge sampling circuit, the microcontroller and the antenna transceiver module are integrated into a first electronic control board, the partial discharge sampling circuit is integrated into a second electronic control board, and the second electronic control board is packaged into a plug-in and plugged into the first electronic control board.

[0026] Furthermore, the first temperature sensor is a tuning fork temperature sensor, the second temperature sensor is a contact temperature sensor, the antenna transceiver module is an RFID module, and the first temperature receiving antenna and the second temperature receiving antenna are both RFID antennas.

[0027] Further, the decoupling capacitor module includes a capacitor C11 and a capacitor C12; the capacitance values ​​of the capacitor C11 and the capacitor C12 are not equal;

[0028] One end of the capacitor C12 is used as the input end and the output end of the decoupling capacitor module;

[0029] One end of the capacitor C11 is electrically connected to one end of the capacitor C12, and the other end of the capacitor C11 and the other end of the capacitor C12 are both connected to the PE ground terminal.

[0030] Further, the high-pass filter module includes a capacitor C7, a capacitor C8, a capacitor C9, a capacitor C10, a resistor R3 and a resistor R4; one end of the capacitor C9 is used as an input end of the high-pass filter module, and one end of the capacitor C10 is used as an output end of the high-pass filter module;

[0031] One end of the capacitor C7 is electrically connected to one end of the capacitor C9, the other end of the capacitor C7, the other end of the capacitor C9, one end of the capacitor C8, and one end of the resistor R3 are all electrically connected to the other end of the capacitor C10, the other end of the capacitor C8 and one end of the resistor R4 are all electrically connected to one end of the capacitor C10, and the other end of the resistor R3 and the other end of the resistor R4 are both connected to the GND ground terminal.

[0032] Furthermore, an insulating wire trough is provided along the inner shell wall of the switch cabinet to the busbar room and the trolley room, and the partial discharge signal line, the first temperature receiving antenna and the second temperature receiving antenna are all laid in the insulating wire trough.

[0033] The technical solution provided by the present invention may include the following beneficial effects: based on the internal structure of the switch cabinet, the partial discharge signal line of the monitoring terminal and the first temperature receiving antenna are led out, so that the partial discharge signal line and the signal interface are electrically connected one-to-one, and the first temperature receiving antenna and the first temperature sensor are wirelessly connected one-to-one (non-core judgment basis, the use of wireless communication can avoid the influence of wire routing on indoor layout), forming one-to-one partial discharge monitoring and temperature monitoring, dual monitoring of partial discharge and temperature, solving the problems of unstable monitoring of transient ground voltage (ie, TEV signal) and inaccurate ultrasonic detection positioning, and also solving the problem of incomplete temperature detection. It is compatible with all types of switch cabinets and is not affected by the internal structure and materials of the switch cabinet.

[0034] It should be noted that, because ceramic insulators are necessary high-voltage busbar fixed insulation devices for switch cabinets, their upper and lower ends are high voltage and earth respectively. They can be understood as the main insulating devices of the primary circuit in the switch cabinet and are often used for high-voltage live display. Therefore, when the insulators or other equipment in the switch cabinet age, local discharge generally occurs first at the insulators. Therefore, the monitoring terminal collects the signal at the insulator as the local discharge judgment standard. Compared with the strong local discharge signal that generates electromagnetic waves or ultrasonic waves to be detected by TEV sensors and ultrasonic sensors, it is more forward-looking. It only needs to provide signal interfaces on the A-phase insulator, the B-phase insulator and the C-phase insulator respectively, and they can be directly connected through the local discharge signal line. There is no need to add external equipment such as sensors for monitoring, which is more accurate and convenient.

[0035] Taking into account that when partial discharge occurs, high-temperature current will flow through the busbar to generate heat, a first temperature sensor is provided on the fixing parts of each phase busbar, which can monitor the temperature changes of each phase accordingly, thereby indirectly knowing whether partial discharge occurs, which serves as reference data for partial discharge monitoring, making the judgment more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a structural schematic diagram of a partial discharge fusion temperature monitoring system for a switch cabinet according to one embodiment of the present invention.

[0037] Figure 2 Yes Figure 1 The schematic diagram of the monitoring terminal is shown.

[0038] Figure 3 Yes Figure 2 The internal circuit schematic diagram of the monitoring terminal is shown.

[0039] Figure 4 Yes Figure 2 A schematic diagram of one embodiment of a partial discharge sampling circuit is shown.

[0040] Figure 5Yes Figure 2 The circuit diagram shows one phase (phase B) signal being connected to the circuit.

[0041] Figure 6 Yes Figure 2 The circuit schematic diagram of the signal phase selection switching circuit shown.

[0042] Among them: switch cabinet 6, busbar room 1, cable room 2, trolley room 3, instrument room 4, A phase insulator 11, B phase insulator 12, C phase insulator 13, first static contact box 14, fixing part 15, second static contact box 21, circuit breaker device 31, moving contact 32, monitoring terminal 5, signal interface 16, first temperature sensor 17, second temperature sensor 33, partial discharge signal line 51, first temperature receiving antenna 52, second temperature receiving antenna 53, signal phase selection switching circuit 55, partial discharge sampling circuit 56, microcontroller 57, antenna receiving module 58, signal access circuit 54, decoupling capacitor module 541, high-pass filter module 542, clamping module 543, multi-channel multiplexing chip U1, electronic switch 551, capacitor C11, capacitor C12, capacitor C7, capacitor C8, capacitor C9, capacitor C10, resistor R3, resistor R4, voltage regulator diode D2, insulating wire trough 59. DETAILED DESCRIPTION

[0043] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0044] In the description of the present invention, it should be understood that the terms "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation of the present invention. In addition, features defined as "first" or "second" may explicitly or implicitly include one or more of the features, and are used to distinguish and describe features, without distinction of order or importance.

[0045] In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0046] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0047] Combine the following Figures 1 to 6 , describing a partial discharge fusion temperature monitoring system for a switch cabinet according to an embodiment of the present invention.

[0048] A partial discharge fusion temperature monitoring system for a switch cabinet comprises a switch cabinet 6 and a monitoring terminal 5. An A-phase insulator 11, a B-phase insulator 12, a C-phase insulator 13 and a first static contact box 14 are arranged in the switch cabinet 6. After the A-phase, B-phase and C-phase busbars in the switch cabinet 6 are respectively fixed to the A-phase insulator 11, the B-phase insulator 12 and the C-phase insulator 13 by fixing members 15, the A-phase, B-phase and C-phase busbars are respectively electrically connected to the static contacts of the first static contact box 14 in a one-to-one correspondence.

[0049] The A phase insulator 11, the B phase insulator 12 and the C phase insulator 13 are respectively provided with a signal interface 16, and the fixing member 15 is provided with a first temperature sensor 17;

[0050] The monitoring terminal 5 is electrically connected to a partial discharge signal line 51 and a first temperature receiving antenna 52 . The partial discharge signal line 51 and the signal interface 16 are electrically connected in a one-to-one correspondence. The first temperature receiving antenna 52 and the first temperature sensor 17 are wirelessly connected in a one-to-one correspondence.

[0051] The present invention proposes a preferred embodiment of a partial discharge monitoring system for a switch cabinet 6, such as Figures 1 to 2 As shown, the A, B, and C three-phase busbars in the switch cabinet 6 are fixed to the A-phase insulator 11, the B-phase insulator 12, and the C-phase insulator 13 by fixing parts 15 (such as clamps fixed by screws), and the insulators play a supporting role for the busbars. Subsequently, the A, B, and C three-phase busbars are electrically connected to the static contacts of the first static contact box 14 one by one.

[0052] Based on the internal structure of the above-mentioned switch cabinet 6, the partial discharge signal line 51 and the first temperature receiving antenna 52 of the monitoring terminal 5 are led out, so that the partial discharge signal line 51 and the signal interface 16 are electrically connected one by one, and the first temperature receiving antenna 52 and the first temperature sensor 17 are wirelessly connected one by one (non-core judgment basis, the use of wireless communication can avoid the influence of wire routing on indoor layout), forming a one-to-one partial discharge monitoring and temperature monitoring, dual monitoring of partial discharge and temperature, solving the problems of unstable monitoring of transient ground voltage (ie, TEV signal) and inaccurate ultrasonic detection positioning, and also solving the problem of incomplete temperature detection. It is compatible with all types of switch cabinets 6 and is not affected by the internal structure and materials of the switch cabinet 6.

[0053] It should be noted that, because the ceramic insulator is a necessary high-voltage busbar fixed insulating device for the switch cabinet 6, its upper and lower ends are high voltage and the earth respectively. It can be understood as the main insulating device of the primary circuit in the switch cabinet 6, and is often used for high-voltage live display. Therefore, when the insulator or other equipment of the switch cabinet 6 ages, local discharge generally occurs first at the insulator. Therefore, the monitoring terminal 5 collects the signal at the insulator as the local discharge judgment standard. Compared with the strong local discharge signal that generates electromagnetic waves or ultrasonic waves to be detected by the TEV sensor and ultrasonic sensor, it is more forward-looking. It only needs to be provided with a signal interface 16 on the A phase insulator 11, the B phase insulator 12 and the C phase insulator 13 respectively, and it can be directly connected through the partial discharge signal line 51. There is no need to add external equipment such as sensors for monitoring, which is more accurate and convenient.

[0054] Taking into account that when partial discharge occurs, high-temperature current will flow through the busbar to generate heat, a first temperature sensor 17 is provided on the fixing part 15 of each phase busbar, which can monitor the temperature change of each phase accordingly, thereby indirectly knowing whether partial discharge occurs, which serves as reference data for partial discharge monitoring, making the judgment more accurate.

[0055] Furthermore, the switch cabinet 6 includes a busbar room 1, a cable room 2, a trolley room 3 and an instrument room 4; the A-phase insulator 11, the B-phase insulator 12, the C-phase insulator 13 and the first static contact box 14 are all arranged in the busbar room 1, the monitoring terminal 5 is arranged in the instrument room 4, and the partial discharge signal line 51 and the first temperature receiving antenna 52 are laid from the instrument room 4 to the busbar room 1 along the inner shell wall of the switch cabinet 6;

[0056] The cable chamber 2 is provided with a second static contact box 21, and the cables in the cable chamber 2 are electrically connected to the static contacts of the second static contact box 21 one by one;

[0057] The trolley room 3 is provided with a circuit breaker device 31, and the moving contacts 32 in the circuit breaker device 31 are respectively arranged in one-to-one correspondence with the static contacts of the first static contact box 14 and the static contacts of the second static contact box 21; the moving contacts 32 are each provided with a second temperature sensor 33;

[0058] The monitoring terminal 5 is also electrically connected to a second temperature receiving antenna 53 , which is laid along the inner wall of the switch cabinet 6 from the instrument room 4 to the trolley room 3 . The second temperature receiving antenna 53 and the second temperature sensor 33 are wirelessly connected in a one-to-one correspondence.

[0059] In this embodiment, the interior of the switch cabinet 6 is usually composed of a busbar room 1, a cable room 2, a trolley room 3 and an instrument room 4. The monitoring terminal 5 (including its power supply) is arranged in the instrument room 4, which is isolated from the strong electric field and strong interference areas of other rooms to ensure that the monitoring of the monitoring terminal 5 is not affected; at the same time, based on the three-phase bus entering from the busbar room 1, the A-phase insulator 11, the B-phase insulator 12, the C-phase insulator 13 and the first static contact box 14 are all arranged in the busbar room 1, so that the insulator can fix the A, B, and C three-phase busbars, and after the A, B, and C three-phase busbars are electrically connected to the static contacts of the first static contact box 14 one by one, The cables in the cable chamber 2 are electrically connected to the static contacts of the second static contact box 21 in one-to-one correspondence, and finally a circuit breaker device 31 is arranged in the trolley chamber 3, so that the moving contacts 32 in the circuit breaker device 31 are arranged in one-to-one correspondence with the static contacts of the first static contact box 14 and the static contacts of the second static contact box 21, so that the moving and static contacts form a movable contact matching relationship. When the circuit breaker device 31 is closed, the moving and static contacts are closed, and the busbar of the busbar chamber 1 and the cable of the cable chamber 2 are electrically connected to form an energized circuit. When the circuit breaker device 31 is opened, the moving and static contacts are disconnected, and the busbar of the busbar chamber 1 and the cable of the cable chamber 2 are disconnected.

[0060] Based on the internal structure of the switch cabinet 6, when the local discharge phenomenon occurs, the power circuit formed by the busbar and the cable will flow through the high-temperature current to generate heat, especially when the circuit breaker device 31 is opened, a high-temperature arc will be generated between the moving and static contacts. Therefore, a second temperature sensor 33 is provided on all moving contacts 32. This arrangement can, firstly, comprehensively judge the temperature data of the first temperature sensor 17 and the second temperature sensor 33, and more comprehensively monitor the temperature change of the power circuit inside the switch cabinet 6, so as to indirectly know whether the local discharge phenomenon occurs, which serves as an important evidence for the local discharge monitoring and makes the judgment more accurate; secondly, the second temperature sensor 33 can also be used to monitor whether the arc is extinguished when the moving and static contacts are disconnected. If the temperature continues to rise, it can be used to warn the circuit breaker device 31 of arc extinguishing failure.

[0061] It should be noted that the partial discharge signal line 51 and the first temperature receiving antenna 52 are laid along the inner shell wall of the switch cabinet 6 from the instrument room 4 to the busbar room 1, the partial discharge signal line 51 and the signal interface 16 are electrically connected one-to-one, and the first temperature receiving antenna 52 and the first temperature sensor 17 are wirelessly connected one-to-one (non-core judgment basis, using wireless communication can avoid the wire routing affecting the indoor layout); the second temperature receiving antenna 53 is laid along the inner shell wall of the switch cabinet 6 from the instrument room 4 to the trolley room 3, and the second temperature receiving antenna 53 and the second temperature sensor 33 are wirelessly connected one-to-one (non-core judgment basis, using wireless communication can avoid the wire routing affecting the indoor layout); the core components in each sub-room can be avoided, so that the laid lines are as far away from interference sources as possible.

[0062] Further, the monitoring terminal 5 includes a signal phase selection switching circuit 55, a partial discharge sampling circuit 56, a microcontroller 57, an antenna transceiver module 58 and three signal access circuits 54; the input end of the signal access circuit 54 is electrically connected to the signal interface 16, the output ends of the three signal access circuits 54 are electrically connected to the three input ends of the phase selection switching circuit 55, the output end of the signal phase selection switching circuit 55 is electrically connected to the input end of the partial discharge sampling circuit 56, the output end of the partial discharge sampling circuit 56 is electrically connected to the microcontroller 57, the data end of the antenna transceiver module 58 is electrically connected to the microcontroller 57, and the multiple communication ends of the antenna transceiver module 58 are electrically connected to the first temperature receiving antenna 52 and the second temperature receiving antenna 53 in a one-to-one correspondence;

[0063] The three signal access circuits 54 receive the single-phase partial discharge signals respectively and transmit them to the signal phase selection switching circuit 55. The signal phase selection switching circuit 55 collects the three single-phase partial discharge signals in time division and transmits them to the partial discharge sampling circuit 56. The partial discharge sampling circuit 56 obtains the partial discharge characteristics from the single-phase partial discharge signals and transmits them to the microcontroller 57 for identification.

[0064] The antenna transceiver module 58 receives the first temperature signal from the first temperature sensor 17 through the first temperature receiving antenna 52 ; the antenna transceiver module 58 receives the second temperature signal from the second temperature sensor 33 through the second temperature receiving antenna 53 .

[0065] In this embodiment, Figure 3As shown, the monitoring terminal 5 is electrically connected to a microcontroller 57 (such as MCU) in sequence by a signal access circuit 54, a signal phase selection switching circuit 55 and a partial discharge sampling circuit 56 to realize partial discharge monitoring. The signal phase selection switching circuit 55 collects three-phase partial discharge signals through three signal access circuits 54 in a time-sharing manner, and transmits them to the local sampling circuit 56 to logarithmically detect the single-phase partial discharge signal (high-frequency current signal or high-frequency AC signal) to a specific frequency to obtain the corresponding partial discharge characteristics. The microcontroller 57 can process the partial discharge characteristics into a partial discharge spectrum and characteristic information, so that the staff can understand the comprehensive partial discharge situation of the switch cabinet 6 in a more concrete way. It should be noted that the partial discharge sampling circuit 56 can have a variety of sampling methods, such as the HFCT direct sampling solution (such as Figure 4 As shown in the figure, the high pulse signal generated by partial discharge (the signal frequency band is generally between 300KHz-30MHz) is directly sampled using a high-speed ADC, which is not limited here.

[0066] The monitoring terminal 5 realizes temperature monitoring by the antenna transceiver module 58. The antenna transceiver module 58 can select a wireless transceiver module (such as an RFID module, an NFC module, etc.) according to actual application conditions, which is not limited here.

[0067] Furthermore, the signal access circuit 54 includes a decoupling capacitor module 541, a high-pass filter module 542 and a clamping module 543; the input end of the decoupling capacitor module 541 is used as the input end of the signal access circuit 54, and the output end of the clamping module 543 is used as the output end of the signal access circuit 54;

[0068] The output end of the decoupling capacitor module 541 is electrically connected to the input end of the high-pass filter module 542, and the output end of the high-pass filter module 542 is electrically connected to the input end of the clamping module 543;

[0069] The decoupling capacitor module 541 includes at least one decoupling capacitor, and the high-pass filter module 542 includes at least one first-order high-pass filter.

[0070] In this embodiment, based on the fact that the single-phase partial discharge signal received by the signal access circuit 54 is a high-frequency AC signal or a high-frequency current signal, it is composed of a decoupling capacitor module 541, a high-pass filter module 542 and a clamping module 543. Figure 5 As shown (taking the signal access circuit 54 of the B phase insulator 12 as an example), the signal is shaped and filtered to facilitate sampling by the partial discharge sampling circuit 56; wherein at least one decoupling capacitor is set by the decoupling capacitor module 541 to provide charge for current buffering; then at least one first-order high-pass filter is set through the high-pass filter module 542 to perform at least one high-pass filtering on the signal to filter the high-frequency signal; finally, the clamping module 543 is used for signal clamping to ensure that the signal voltage is within a controllable range.

[0071] Specifically, the clamping module 543 includes a Zener diode D2, the cathode of the Zener diode D2 is used as the input and output ends of the clamping module 543, the anode of the Zener diode D2 is connected to the GND ground terminal, and the clamping module 543 achieves voltage clamping by the Zener diode D2.

[0072] Furthermore, the signal phase selection switching circuit 55 includes a multi-channel multiplexing chip U1 and an electronic switch 551; the channel input end of the multi-channel multiplexing chip U1 is used as the input end of the signal phase selection switching circuit 55, and the channel output end of the multi-channel multiplexing chip U1 is used as the output end of the signal phase selection switching circuit 55;

[0073] The electronic switch 551 is electrically connected to the control terminal of the multi-channel multiplexing chip U1; the electronic switch 551 can be electrically connected to the microcontroller 57;

[0074] The electronic switch 551 is used to set the time-sharing acquisition rule of the multi-channel multiplexing chip U1.

[0075] In this embodiment, Figure 6 As shown, the signal phase selection switching circuit 55 is mainly composed of a multi-channel multiplexing chip U1 and its peripheral circuits to realize time-sharing acquisition. The multi-channel multiplexing chip U1 takes ADG704BRM4-REEL as an example. The channel input terminals are S1 to S4 terminals, the channel output terminal is D terminal, and the control terminals are A0, A1 and EN terminals. Switching one of the three inputs to the channel output terminal (or common output terminal) is determined by the two-bit binary address (A1, A0) and the enable terminal (EN terminal, set to 1 to turn on the multi-channel multiplexing chip U1). Therefore, the time-sharing acquisition rules of the multi-channel multiplexing chip U1 can be set by connecting the electronic switch 551 to the control terminal.

[0076] It should be noted that the electronic switch 551 can be a level circuit with a set two-bit binary address cyclic output rule, for example, the electronic switch 551 is composed of a level shift chip (such as TXS0102) and its peripheral circuits, which can cyclically select three inputs to switch to the channel output end. The electronic switch 551 can also be a digital logic circuit, which is controlled by the microcontroller 57 to determine the two-bit binary address, so that the microcontroller 57 selects which phase to switch to the channel output end.

[0077] Furthermore, the signal access circuit 54, the signal phase selection switching circuit 55, the partial discharge sampling circuit 56, the microcontroller 57 and the antenna receiving and transmitting module 58 are integrated into the first electronic control board, the partial discharge sampling circuit 56 is integrated into the second electronic control board, and the second electronic control board is packaged into a plug-in and plugged into the first electronic control board.

[0078] In this embodiment, due to different application environments of the switch cabinet 6 and the wiring inside the cabinet, basic noise signals may be generated when there is no local discharge. Therefore, the monitoring terminal 5 separates the local discharge sampling circuit 56 into a plug-in connection form, so that the monitoring terminal 5 supports replacing the local discharge sampling circuit 56 plug-in (or processing card) according to different environmental noises to adjust the hardware threshold, thereby being compatible with the basic noise signal and avoiding misjudgment as a local discharge phenomenon.

[0079] Furthermore, the first temperature sensor 17 is a tuning fork temperature sensor, the second temperature sensor 33 is a contact temperature sensor, the antenna transceiver module 58 is an RFID module, and the first temperature receiving antenna 52 and the second temperature receiving antenna 53 are both RFID antennas.

[0080] In this embodiment, in order to improve the accuracy and reliability of temperature monitoring, the first temperature sensor 17 is preferably a tuning fork temperature sensor. The working principle of the tuning fork temperature sensor is based on the thermal sensitivity of the piezoelectric resonator to temperature. It belongs to a thermosensitive piezoelectric resonant sensor. It uses the close correlation between the resonant frequency of the quartz crystal and the temperature. The temperature sensor designed and manufactured according to the frequency-temperature characteristics of the quartz crystal is arranged near the busbar to effectively resist the strong electric field and strong interference of the busbar. The second temperature sensor 33 is preferably a contact temperature sensor, which is a wireless passive temperature sensor dedicated to the contact and is more suitable for the monitoring environment at the moving contact 32. Based on the fact that both the tuning fork temperature sensor and the contact temperature sensor use wireless sensors, and considering that RFID communication can read a large number of RFID tags in batches compared to other wireless communications, one RFID antenna can receive multiple temperature tag signals in the same room, reducing the number of antennas laid and saving costs. Therefore, the antenna receiving and transmitting module 58 is preferably an RFID module, and the corresponding first temperature receiving antenna 52 and the second temperature receiving antenna 53 are both RFID antennas.

[0081] Furthermore, the decoupling capacitor module 541 includes a capacitor C11 and a capacitor C12; the capacitance values ​​of the capacitor C11 and the capacitor C12 are not equal;

[0082] One end of the capacitor C12 is used as the input end and the output end of the decoupling capacitor module 541;

[0083] One end of the capacitor C11 is electrically connected to one end of the capacitor C12, and the other end of the capacitor C11 and the other end of the capacitor C12 are both connected to the PE ground terminal.

[0084] In this embodiment, the decoupling capacitor module 541 is preferably composed of two capacitors, capacitor C11 and capacitor C12, which can provide sufficient charge for current buffering, and the smaller capacitor can also be used to filter out high-frequency interference and ripple signals.

[0085] Furthermore, the high-pass filter module 542 includes a capacitor C7, a capacitor C8, a capacitor C9, a capacitor C10, a resistor R3, and a resistor R4; one end of the capacitor C9 is used as an input end of the high-pass filter module 542, and one end of the capacitor C10 is used as an output end of the high-pass filter module 542;

[0086] One end of capacitor C7 is electrically connected to one end of capacitor C9, the other end of capacitor C7, the other end of capacitor C9, one end of capacitor C8, and one end of resistor R3 are electrically connected to the other end of capacitor C10, the other end of capacitor C8 and one end of resistor R4 are electrically connected to one end of capacitor C10, and the other end of resistor R3 and the other end of resistor R4 are connected to the GND ground terminal.

[0087] In this embodiment, the high-pass filter module 542 is preferably set to a second-order high-pass filter. Capacitor C7, capacitor C9 and resistor R3 constitute a first-order high-pass filter to filter out field noise. Capacitor C8, capacitor C10 and resistor R4 constitute a second-order high-pass filter to filter high-frequency signals again, making the frequency response smoother and the boundary between the passband and the stopband more obvious.

[0088] Furthermore, an insulating wire trough 59 is provided along the inner shell wall of the switch cabinet 6 to the busbar chamber 1 and the trolley chamber 3 , and the partial discharge signal line 51 , the first temperature receiving antenna 52 and the second temperature receiving antenna 53 are all laid in the insulating wire trough 59 .

[0089] In this embodiment, in order to reduce the interference of the switch cabinet 6 on the laying line during the laying process, the partial discharge signal line 51 , the first temperature receiving antenna 52 and the second temperature receiving antenna 53 are preferably laid in the insulating wire trough 59 .

[0090] Other structures and operations of the partial discharge monitoring system for a switch cabinet according to the embodiment of the present invention are known to those skilled in the art and will not be described in detail here.

[0091] In the description of this specification, the description with reference to the terms "embodiment", "example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0092] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A partial discharge fusion temperature monitoring system for a switch cabinet, characterized in that: The invention comprises a switch cabinet and a monitoring terminal, wherein the switch cabinet is provided with an A-phase insulator, a B-phase insulator, a C-phase insulator and a first static contact box; after the A, B and C three-phase busbars in the switch cabinet are respectively fixed to the A-phase insulator, the B-phase insulator and the C-phase insulator by fixing members, the A, B and C three-phase busbars are respectively electrically connected to the static contacts of the first static contact box in a one-to-one correspondence; The A-phase insulator, the B-phase insulator and the C-phase insulator are respectively provided with a signal interface, and the fixing parts are each provided with a first temperature sensor; The monitoring terminal is electrically connected to a partial discharge signal line and a first temperature receiving antenna, the partial discharge signal line and the signal interface are electrically connected in a one-to-one correspondence, and the first temperature receiving antenna and the first temperature sensor are wirelessly connected in a one-to-one correspondence.

2. The partial discharge fusion temperature monitoring system for a switch cabinet according to claim 1, characterized in that: The switch cabinet includes a busbar room, a cable room, a trolley room and an instrument room; the A-phase insulator, the B-phase insulator, the C-phase insulator and the first static contact box are all arranged in the busbar room, the monitoring terminal is arranged in the instrument room, and the partial discharge signal line and the first temperature receiving antenna are laid from the instrument room to the busbar room along the inner shell wall of the switch cabinet; The cable chamber is provided with a second static contact box, and the cables in the cable chamber are electrically connected to the static contacts of the second static contact box one by one; The trolley room is provided with a circuit breaker device, and the moving contacts in the circuit breaker device are respectively arranged in one-to-one correspondence with the static contacts of the first static contact box and the static contacts of the second static contact box; the moving contacts are each provided with a second temperature sensor; The monitoring terminal is also electrically connected to a second temperature receiving antenna, which is laid along the inner shell wall of the switch cabinet from the instrument room to the trolley room. The second temperature receiving antenna and the second temperature sensor are wirelessly connected in a one-to-one correspondence.

3. The partial discharge fusion temperature monitoring system for a switch cabinet according to claim 2, characterized in that: The monitoring terminal includes a signal phase selection switching circuit, a partial discharge sampling circuit, a microcontroller, an antenna transceiver module and three signal access circuits; the input end of the signal access circuit is electrically connected to the signal interface, the output ends of the three signal access circuits are electrically connected to the three input ends of the phase selection switching circuit, the output end of the signal phase selection switching circuit is electrically connected to the input end of the partial discharge sampling circuit, the output end of the partial discharge sampling circuit is electrically connected to the microcontroller, the data end of the antenna transceiver module is electrically connected to the microcontroller, and the multiple communication ends of the antenna transceiver module are electrically connected to the first temperature receiving antenna and the second temperature receiving antenna in a one-to-one correspondence. The three signal access circuits receive single-phase partial discharge signals respectively and transmit them to the signal phase selection switching circuit. The signal phase selection switching circuit collects the three single-phase partial discharge signals in a time-sharing manner and transmits them to the partial discharge sampling circuit. The partial discharge sampling circuit obtains partial discharge features from the single-phase partial discharge signals and transmits them to the microcontroller for identification. The antenna transceiver module receives a first temperature signal from the first temperature sensor through the first temperature receiving antenna; the antenna transceiver module receives a second temperature signal from the second temperature sensor through the second temperature receiving antenna.

4. The partial discharge fusion temperature monitoring system for a switch cabinet according to claim 3 is characterized in that: The signal access circuit includes a decoupling capacitor module, a high-pass filter module and a clamping module; The input end of the decoupling capacitor module is used as the input end of the signal access circuit, and the output end of the clamping module is used as the output end of the signal access circuit; The output end of the decoupling capacitor module is electrically connected to the input end of the high-pass filter module, and the output end of the high-pass filter module is electrically connected to the input end of the clamping module; The decoupling capacitor module is provided with at least one decoupling capacitor, and the high-pass filter module is provided with at least one first-order high-pass filter.

5. The partial discharge fusion temperature monitoring system for a switch cabinet according to claim 3, characterized in that: The signal phase selection switching circuit includes a multi-channel multiplexing chip U1 and an electronic switch; the channel input end of the multi-channel multiplexing chip U1 is used as the input end of the signal phase selection switching circuit, and the channel output end of the multi-channel multiplexing chip U1 is used as the output end of the signal phase selection switching circuit; The electronic switch is electrically connected to the control terminal of the multi-channel multiplexing chip U1; the electronic switch may be electrically connected to the microcontroller; The electronic switch is used to set the time-sharing acquisition rule of the multi-channel multiplexing chip U1.

6. The partial discharge fusion temperature monitoring system for a switch cabinet according to claim 3, characterized in that: The signal access circuit, the signal phase selection switching circuit, the partial discharge sampling circuit, the microcontroller and the antenna transceiver module are integrated into a first electric control board, the partial discharge sampling circuit is integrated into a second electric control board, and the second electric control board is packaged into a plug-in and plugged into the first electric control board.

7. The partial discharge fusion temperature monitoring system for a switch cabinet according to claim 3, characterized in that: The first temperature sensor is a tuning fork temperature sensor, the second temperature sensor is a contact temperature sensor, the antenna transceiver module is an RFID module, and the first temperature receiving antenna and the second temperature receiving antenna are both RFID antennas.

8. The partial discharge fusion temperature monitoring system for a switch cabinet according to claim 4, characterized in that: The decoupling capacitor module includes a capacitor C11 and a capacitor C12; the capacitance values ​​of the capacitor C11 and the capacitor C12 are not equal; One end of the capacitor C12 is used as the input end and the output end of the decoupling capacitor module; One end of the capacitor C11 is electrically connected to one end of the capacitor C12, and the other end of the capacitor C11 and the other end of the capacitor C12 are both connected to the PE ground terminal.

9. The partial discharge fusion temperature monitoring system for a switch cabinet according to claim 4, characterized in that: The high-pass filter module includes a capacitor C7, a capacitor C8, a capacitor C9, a capacitor C10, a resistor R3 and a resistor R4; one end of the capacitor C9 is used as an input end of the high-pass filter module, and one end of the capacitor C10 is used as an output end of the high-pass filter module; One end of the capacitor C7 is electrically connected to one end of the capacitor C9, the other end of the capacitor C7, the other end of the capacitor C9, one end of the capacitor C8, and one end of the resistor R3 are all electrically connected to the other end of the capacitor C10, the other end of the capacitor C8 and one end of the resistor R4 are all electrically connected to one end of the capacitor C10, and the other end of the resistor R3 and the other end of the resistor R4 are both connected to the GND ground terminal.

10. The partial discharge fusion temperature monitoring system for a switch cabinet according to claim 2, characterized in that: An insulating wire trough is provided along the inner shell wall of the switch cabinet to the busbar room and the trolley room, and the partial discharge signal line, the first temperature receiving antenna and the second temperature receiving antenna are all laid in the insulating wire trough.

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