Ring main unit partial discharge inspection positioning device

Abstract

The utility model relates to the technical field of power equipment state detection, and discloses a ring main unit partial discharge routing inspection positioning device, a magnetic attraction assembly is arranged on the partial discharge routing inspection positioning device, the partial discharge routing inspection positioning device is attracted to a ring main unit, and detection work can be achieved only by one tester; the ring main unit grounding and the ring main unit partial discharge inspection positioning device grounding wire are connected together in a magnetic attraction mode, signal ground connection is achieved, the safety of testers is guaranteed, meanwhile, one grounding wire is reduced through magnet connection, and field operation is facilitated.

Description

Technical Field

[0001] This application relates to the technical field of power equipment status detection, and particularly to a local discharge inspection and positioning device for a ring main unit. Background Art

[0002] The ring main unit has a simple structure, reliable and safe operation, and small maintenance volume, and is widely used in the power distribution network of the power system. The main cause of internal faults in the ring main unit is insulation faults, and there are mainly two reasons for the damage of the cabinet insulation. First, if there are process problems in the early manufacturing or installation process, it will lead to uneven electric field distribution in some areas of the insulation system, and the uneven electric field distribution will damage the insulation system. Second, during operation, if affected by factors such as strong vibration, high and low temperature, and abnormal humidity, the insulation system of the cabinet will show aging in some areas. In a high-voltage system, the insulation weak positions caused by the above two reasons are extremely prone to partial discharge phenomena.

[0003] The technologies for detecting partial discharges in ring main units mainly include the ultra-high frequency method, the ultrasonic method, and the transient earth voltage method. The three detection methods have the same equipment architecture, including four parts: a sensor, a signal conditioning circuit, a signal acquisition circuit, and a human-computer interaction terminal. There are mainly two detection methods for partial discharges in ring main units. One is the live inspection detection technology, and the other is the on-line monitoring technology. Live inspection detection means that the detection personnel carry the detection equipment to regularly inspect the ring main unit, find problems and record them. On-line monitoring means installing a local discharge detection device in the ring main unit to conduct real-time monitoring, find faults and upload them in real time.

[0004] However, in the traditional local discharge detection work of the ring main unit, two test personnel are required to cooperate. First, the handheld local discharge detection device is connected to the ring main unit through a grounding wire. Then, one test personnel needs to hold the handheld local discharge detection device, and the other test personnel needs to stand at a distance and conduct detection through a handheld terminal communicatively connected to the handheld local discharge detection device, which has the defect of complicated operation, thus resulting in low detection work efficiency. Utility Model Content

[0005] The utility model provides a local discharge inspection and positioning device for a ring main unit, which solves the technical problem of the complicated operation in the traditional local discharge detection work of the ring main unit, thus resulting in low detection work efficiency.

[0006] This application provides a local discharge inspection and positioning device for a ring main unit, including a device housing;

[0007] A magnetic attraction component is arranged on the device housing for adsorbing the local discharge inspection and positioning device on the ring main unit;

[0008] The magnetic attraction component includes a steel sleeve and a magnet;

[0009] The steel sleeve is sleeved outside the magnet, and the magnet is fixed to the surface of the device housing by fixing screws;

[0010] A three-phase signal processing system is provided inside the device housing;

[0011] The three-phase signal processing system is connected to a handheld terminal.

[0012] Optionally, a rubber protection pad is provided between the magnet and the steel sleeve.

[0013] Optionally, the material of the device housing is aluminum alloy.

[0014] Optionally, three signal input interfaces are provided on the outer shell bottom plate of the device housing for electrically connecting to the three-phase phase discrimination holes of the live indicator of the ring main unit;

[0015] Among them, the three signal input interfaces are respectively an A-phase signal input interface, a B-phase signal input interface, and a C-phase signal input interface.

[0016] Optionally, the outer shell bottom plate is made of insulating material.

[0017] Optionally, the three-phase signal processing system includes a three-phase main control module, a high-speed AD module, an FPGA module, and a communication module that are electrically connected in sequence;

[0018] The FPGA module is electrically connected to the three-phase main control module;

[0019] The FPGA module is communicatively connected to the handheld terminal through the communication module.

[0020] Optionally, the three-phase main control module includes three main control modules respectively used for receiving partial discharge signals of each phase;

[0021] The three main control modules are respectively connected in one-to-one correspondence with the three signal input interfaces;

[0022] The three main control modules are all electrically connected to the high-speed AD module;

[0023] The three main control modules are all electrically connected to the FPGA module.

[0024] Optionally, the main control module includes an impedance matching module and a programmable gain filtering module that are electrically connected in sequence;

[0025] The output end of the programmable gain filtering module is electrically connected to the high-speed AD module;

[0026] The output end of the programmable gain filtering module is electrically connected to the FPGA module.

[0027] Optionally, the impedance matching module is an impedance matching circuit;

[0028] The impedance matching circuit includes an analog switch, a capacitor bank, and a resistor bank;

[0029] The first end of the capacitor bank is electrically connected to the three-phase phase comparison holes of the live indicator;

[0030] The second end of the capacitor bank is electrically connected to the analog switch;

[0031] The third end of the capacitor bank is electrically connected to the first end of the resistor bank;

[0032] The analog switch is electrically connected to the second end of the resistor bank;

[0033] The analog switch is electrically connected to the FPGA module;

[0034] The third end of the resistor bank is connected to a ground wire;

[0035] The ground wire is connected to the outer shell of the ring main unit through the magnet.

[0036] Optionally, the programmable gain filtering module includes a programmable amplifier, a first filter, a second filter, an amplifier, and a comparator;

[0037] The input end of the programmable amplifier is electrically connected to the output end of the impedance matching module;

[0038] The input ends of the first filter and the second filter are both electrically connected to the output of the programmable amplifier;

[0039] The output end of the first filter is electrically connected to the amplifier;

[0040] The output end of the second filter is electrically connected to the comparator.

[0041] It can be seen from the above technical solutions that the embodiments of the present invention have the following advantages:

[0042] The present invention discloses a partial discharge inspection and positioning device for a ring main unit. By providing a magnetic attraction component on the partial discharge inspection and positioning device, the partial discharge inspection and positioning device is adsorbed on the ring main unit, and only one tester is required to complete the detection work; by using the magnetic attraction method, the grounding of the ring main unit is connected to the ground wire of the partial discharge inspection and positioning device of the ring main unit to realize the connection of the signal ground, ensuring the safety of the tester. At the same time, one ground wire is reduced by connecting with a magnet, which is convenient for on-site operation. Description of the Drawings

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0044] Figure 1 It is a schematic structural diagram of a partial discharge inspection and positioning device for a ring main unit in an embodiment of the present invention;

[0045] Figure 2 It is a schematic diagram of a three-phase signal processing system of a partial discharge inspection and positioning device for a ring main unit in an embodiment of the present invention;

[0046] Figure 3 It is a schematic diagram of an impedance matching module in an embodiment of the present invention;

[0047] Figure 4 It is a schematic diagram of a programmable gain filtering module in an embodiment of the present invention.

[0048] Among them, the reference numerals are as follows:

[0049] 1. Device housing; 2. Signal input interface; 3. Outer shell bottom plate; 4. Main control module; 41. Impedance matching module; 411. Analog switch; 412. Capacitor bank; 413. Resistor bank; 42. Programmable gain filtering module; 421. Programmable amplifier; 422. First filter; 423. Second filter; 424. Amplifier; 425. Comparator; 5. High-speed AD module; 6. FPGA module; 7. Communication module; 8. Handheld terminal; 9. Magnetic attraction component; 91. Steel sleeve; 92. Magnet; 93. Fixing screw. Specific implementation manners

[0050] The embodiment of the present invention provides a partial discharge inspection and positioning device for a ring main unit, which is used to solve the technical problem that the existing partial discharge detection devices based on the three methods of the ultra-high frequency method, the ultrasonic method, and the transient earth voltage method cannot perform different measurements on three phases, and it is difficult to distinguish between-phase signals, thereby making it difficult to achieve between-phase positioning of partial discharge sources.

[0051] In order to make the utility model purpose, features and advantages of the present utility model more obvious and understandable, the following will clearly and completely describe the technical solutions in the embodiments of the present utility model with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the embodiments described below are only a part of the embodiments of the present utility model, rather than all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the protection scope of the present utility model.

[0052] Currently, there are the following problems in the on-site application of detection devices based on the three methods of ultra-high frequency method, ultrasonic method and transient earth voltage method:

[0053] 1) In the on-line monitoring application scenario, the cabinet needs to be modified. The corresponding detection device needs to be equipped with corresponding sensors, and the sensors need to be installed inside the ring main unit or on the surface of the metal shell to obtain the ultra-high frequency signal, ultrasonic signal and transient earth voltage signal generated during partial discharge. When using the on-line monitoring technology method, the cabinet needs to be modified to adapt to the installation of the sensors.

[0054] 2) The detection performance is reduced due to excessive investment cost. Since the quantity of ring main units is huge, the investment cost of installing on-line monitoring devices on the operating ring main units is too high. In order to reduce costs, the current on-line monitoring devices reduce the configuration of the monitoring terminal, delete the detection function of the partial discharge PRPD (phase-resolved partial discharge) pattern data, and only upload the partial discharge signal intensity and the number of discharges.

[0055] 3) It is impossible to intuitively reflect the severity of partial discharge in the ring main unit. These three methods are indirect detection methods, which are inconsistent with the detection results of the standard "GB / T7354 High-voltage test techniques - Partial discharge measurement", and it is impossible to directly judge the partial discharge situation.

[0056] 4) It is difficult to achieve the fault location function. In the application scenario of inspection equipment, the detection equipment of the ultra-high frequency method is difficult to be applied in the ring main unit shielded by a metal shell. The ultrasonic signal can only overflow to the outside of the cabinet from the gap, resulting in signal overflow as long as there is a gap, and it is impossible to accurately obtain the interval and phase where the discharge occurs. The transient earth voltage signal will be generated on the metal shells of all intervals, and it is also impossible to effectively locate the position where the partial discharge occurs.

[0057] The utility model provides a ring main unit partial discharge inspection and positioning device adapted to the ring main unit, which realizes the inspection and maintenance detection of the ring main unit partial discharge and the positioning of the partial discharge source under the energized operation condition, obtains the partial discharge situation of each time interval in the distribution ring main unit, and performs phase-to-phase positioning of the partial discharge source through the intensity of the partial discharge signal of each phase and the phase information of the PRPD spectrum, thus laying a foundation for the safe and stable operation of the ring main unit.

[0058] The utility model uses the charged indication device of the ring main unit as a detection sensor, obtains the three-phase partial discharge signal through the core phase hole of the charged indication device, develops a handheld inspection device for the detection and analysis of the three-phase partial discharge signal, and realizes the detection of the PRPD spectrum and the phase-to-phase positioning of the partial discharge source.

[0059] The utility model has the following advantages:

[0060] (1) The magnetic attraction component 9 of the device is designed to attach the partial discharge inspection and positioning device to the ring main unit by arranging the magnetic attraction component 9 on the partial discharge inspection and positioning device. Only one tester is required to perform the inspection. The ring main unit grounding wire and the ring main unit partial discharge inspection and positioning device grounding wire are connected together by magnetic attraction to realize the connection of the signal ground, thereby ensuring the safety of the tester. At the same time, one grounding wire is reduced by connecting the magnet 92, which is convenient for on-site operation.

[0061] (2) The overall structural design of the device. The overall structural design realizes the consistency of the coupling path of the partial discharge signal and the coordination of the propagation of the same signal source in the three phases ABC. The difference from the existing partial discharge inspection device of the ring main unit is that: 1) The detection device is based on the ultra-high frequency method, ultrasonic method and transient ground wave method. The sensor cannot guarantee the consistency of the coupling path of the signal during each measurement, and cannot perform horizontal comparison between the ring main units and between each interval. 2) The existing device cannot perform different measurements of the three phases, cannot distinguish the phase signals, and reduces the ability to detect faults.

[0062] (3) Positioning operation process. Through the workflow proposed in the utility model, the local discharge source is positioned in the specific scenario of the ring main unit. With current technology, whether it is online monitoring equipment or inspection equipment, it is difficult to achieve phase-to-phase positioning of the local discharge source under the ring main unit.

[0063] See also Figure 1 and Figure 2 , the utility model provides a ring main unit partial discharge inspection and positioning device, comprising a device housing;

[0064] The device housing is provided with a magnetic attraction component 9 for adsorbing the partial discharge inspection and positioning device on the ring main unit;

[0065] The magnetic attraction component 9 includes a steel sleeve 91 and a magnet 92;

[0066] The steel sleeve 91 is sleeved outside the magnet 92, and the magnet 92 is fixed to the surface of the device housing by fixing screws 93;

[0067] A three-phase signal processing system is provided inside the device housing 1, which is used to receive three-phase partial discharge signals and perform analysis to generate analysis data;

[0068] The three-phase signal processing system is connected to a handheld terminal 8, which is used to determine a positioning result based on the analysis data.

[0069] It should be noted that by providing the magnetic attraction component 9 on the partial discharge inspection and positioning device, the partial discharge inspection and positioning device is adsorbed on the ring main unit, and only one tester is required to complete the detection work; by using the magnetic attraction method, the grounding of the ring main unit is connected to the grounding wire of the partial discharge inspection and positioning device of the ring main unit to achieve the connection of the signal ground, ensuring the safety of the tester. At the same time, by connecting with the magnet 92, one grounding wire is reduced, which is convenient for on-site operation.

[0070] It is worth mentioning that since the housing of the ring main unit is made of metal, the partial discharge inspection and positioning device is adsorbed on the ring main unit by providing the magnetic attraction component 9 on the device housing 1; the magnetic attraction component 9 includes a steel sleeve 91 and a magnet 92; the steel sleeve 91 is sleeved outside the magnet 92, and the magnet 92 is fixed to the surface of the device housing 1 by fixing screws 93. During the test, there is no need for a tester to hold the partial discharge inspection and positioning device by hand. Only one tester with a handheld terminal 8 is required to complete the detection work. By using the magnetic attraction method, the built-in grounding wire of the partial discharge inspection and positioning device is connected to the outer shell of the ring main unit through the magnet 92, and the grounding of the ring main unit is connected to the grounding wire of the partial discharge inspection and positioning device of the ring main unit to achieve the connection of the signal ground, ensuring the safety of the tester. At the same time, by connecting with the magnet 92, one grounding wire is reduced, which is convenient for on-site operation.

[0071] It should be noted that a rubber protection pad is provided between the magnet 92 and the steel sleeve 91, and the rubber protection pad plays a role in protecting the magnet 92.

[0072] It should be noted that the magnet 92 uses a neodymium iron boron magnet 92 with a steel sleeve 91. The side with the steel sleeve 91 is installed on the outer shell of the partial discharge inspection and positioning device of the ring main unit through fixing screws 93. The side of the magnet 92 is adsorbed on the housing of the ring main unit. Using the magnet 92 with a steel sleeve 91 can solve the brittleness problem of the neodymium iron boron magnet 92.

[0073] The magnetic attraction component 9 has two functions:

[0074] One is to adsorb the partial discharge inspection and positioning device of the ring main unit on the ring main unit to facilitate on-site operation;

[0075] The second is to realize the electrical connection between the partial discharge inspection and positioning device of the ring main unit and the ring main unit through the magnet 92, connect the grounding of the ring main unit and the grounding wire of the partial discharge inspection and positioning device of the ring main unit together to realize the connection of the signal ground. At the same time, it also protects the safety of the test personnel. Connecting through the magnet 92 reduces one grounding wire and facilitates on-site operation.

[0076] Both sides of the device housing 1 are designed with a rounded corner structure, which is convenient for single-handed grasping on site and ensures that the operation process meets the requirements of single-handed operation for electrical operations.

[0077] The device housing 1 is made of aluminum alloy material, and the fixing screw 93 for fixing the magnet 92 can realize the electrical conduction between the outer shell of the ring main unit and the outer shell of the device.

[0078] Please refer to Figure 1 , a partial discharge inspection and positioning device for a ring main unit provided by the present utility model. Three signal input interfaces 2 are arranged on the outer shell bottom plate 3 of the device housing 1, which are used for electrically connecting with the three-phase phase-checking holes of the live indicator of the ring main unit to transmit the three-phase partial discharge signals to the three-phase signal processing system;

[0079] Among them, the three signal input interfaces 2 are respectively an A-phase signal input interface, a B-phase signal input interface, and a C-phase signal input interface.

[0080] It should be noted that three signal input interfaces 2 are arranged on the outer shell bottom plate 3 of the device housing 1, which are used for electrically connecting with the three-phase phase-checking holes of the live indicator of the ring main unit to transmit the three-phase partial discharge signals to the three-phase signal processing system; among them, the three signal input interfaces 2 are respectively an A-phase signal input interface, a B-phase signal input interface, and a C-phase signal input interface, and each signal input interface 2 corresponds to accessing the three-phase phase-checking holes of the live indicator. For example, the A-phase signal input interface is electrically connected to the A-phase phase-checking hole of the live indicator through a signal wire, the B-phase signal input interface is electrically connected to the B-phase phase-checking hole of the live indicator through a signal wire, and the C-phase signal input interface is electrically connected to the C-phase phase-checking hole of the live indicator through a signal wire.

[0081] It is worth mentioning that the signal input interface 2 adopts a banana connector seat with a diameter of 4 mm so as to be consistent with the size of the phase-checking hole of the live indicator and facilitate on-site wiring.

[0082] It should be noted that as a device for locating partial discharge of ring main unit, the three-phase partial discharge signal is obtained from the core phase hole of the charged indicator of the ring main unit, which ensures the consistency of the installation position and signal coupling mode of the sensor for each interval detection of the ring main unit in space, provides a consistent standard for partial discharge intensity analysis, and improves the accuracy of positioning. The synchronous measurement of ABC three-phase signals ensures the coordination of partial discharge signals in time and provides a consistent signal source for the intensity comparison of the three-phase PRPD spectrum. The consistency and coordination in space and time ensure the accuracy of phase-to-phase positioning of partial discharge signals based on the PRPD spectrum.

[0083] See also Figure 1 The utility model provides a local discharge inspection and positioning device for a ring main unit, wherein the bottom plate 3 of the shell is made of insulating material.

[0084] It should be noted that the shell bottom plate 3 of the device shell 1 is made of a plate made of insulating material, such as epoxy resin, silicone rubber, etc.; it has two functions: first, the insulating plate can achieve insulation isolation between signal input ports; second, when the communication mode adopts the wireless mode, it can ensure the effective transmission of wireless signals.

[0085] See also Figures 2-4 The utility model provides a ring main unit partial discharge inspection and positioning device, the three-phase signal processing system includes a three-phase main control module, a high-speed AD module 5, an FPGA module 6 and a communication module 7 which are electrically connected in sequence;

[0086] The FPGA module 6 is electrically connected to the three-phase main control module;

[0087] The FPGA module 6 is connected to the handheld terminal 8 for communication via the communication module 7 .

[0088] It should be noted that the partial discharge inspection and positioning device mainly includes a three-phase main control module, a high-speed AD (Analog-to-Digital) module, an FPGA (Field Programmable Gate Array) module, a communication module 7 and a handheld terminal 8.

[0089] Communication module 7: can use wired and wireless modes to realize the communication between handheld terminal 8 and FPGA. For example: USB interface, serial interface, network port, Bluetooth, WIFI and other types of communication module 7. Function: to realize the upload of FPGA module 6 detection results and the issuance of handheld terminal 8 instructions.

[0090] Handheld terminal 8: Devices such as smartphones, tablets, and laptop computers can be used. Its functions are: installing control software to achieve data parsing, drawing, and displaying the partial discharge PRPD patterns of three phases A, B, and C, sending control instructions, and locating partial discharge sources, etc.

[0091] It is worth mentioning that in this utility model, the electrical connection is specifically achieved by using electric wires.

[0092] Please refer to Figures 2-4 , for a partial discharge inspection and positioning device for a ring main unit provided by this utility model, the three-phase main control module includes three main control modules 4 respectively used for receiving partial discharge signals of each phase;

[0093] The three main control modules 4 are respectively and correspondingly connected to the three signal input interfaces 2 one by one;

[0094] The three main control modules 4 are all electrically connected to the high-speed AD module 5;

[0095] The three main control modules 4 are all electrically connected to the FPGA module 6.

[0096] It should be noted that the three-phase main control module includes three main control modules 4 respectively used for receiving partial discharge signals of each phase. The three main control modules 4 are respectively and correspondingly connected to the three signal input interfaces 2 one by one. The three main control modules 4 are respectively the A-phase main control module, the B-phase main control module, and the C-phase main control module; they are respectively and correspondingly connected to the A-phase signal input interface, the B-phase signal input interface, and the C-phase signal input interface one by one. The three main control modules 4 are all electrically connected to the high-speed AD module 5, and the three main control modules 4 are all electrically connected to the FPGA module 6.

[0097] Please refer to Figures 2-4 , for a partial discharge inspection and positioning device for a ring main unit provided by this utility model, the main control module 4 includes an impedance matching module 41 and a programmable gain and filtering module 42 that are electrically connected in sequence;

[0098] The impedance matching module 41 is used to respond to the switch control signal of the FPGA module 6, adjust the setting parameters suitable for the live indicator of the ring main unit, and receive the partial discharge signals of phase A / phase B / phase C;

[0099] The programmable gain and filtering module 42 is used to process the received partial discharge signals of phase A / phase B / phase C to generate three-phase partial discharge amplified analog signals and square wave analog signals;

[0100] The output end of the programmable gain and filtering module 42 is electrically connected to the high-speed AD module 5;

[0101] The high-speed AD module 5 is used to perform analog-to-digital conversion on the three-phase partial discharge amplified analog signals and square wave analog signals to generate three-phase partial discharge amplified digital signals and square wave digital signals;

[0102] The output end of the programmable amplification and filtering module 42 is electrically connected to the FPGA module 6.

[0103] It should be noted that the internal structures of the three main control modules 4 are the same. Each of the three main control modules 4 internally includes an impedance matching module 41 and a programmable amplification and filtering module 42 that are electrically connected in sequence. The impedance matching module 41 is used to respond to the switch control signal of the FPGA module 6, adjust the set parameters suitable for the live indicator of the ring main unit, and receive the partial discharge signals of phase A / phase B / phase C. The programmable amplification and filtering module 42 is used to process the received partial discharge signals of phase A / phase B / phase C to generate three-phase partial discharge amplified analog signals and square wave analog signals. Among them, the three-phase partial discharge signals include the partial discharge signal of phase A, the partial discharge signal of phase B, and the partial discharge signal of phase C. For example, when the main control module is the phase A main control module, it receives the partial discharge signal of phase A transmitted from the live indicator. The programmable amplification and filtering module 42 is used to process the received partial discharge signal of phase A to generate three-phase partial discharge amplified analog signals and square wave analog signals. The other phase main control modules are similar and will not be elaborated here. The output end of the programmable amplification and filtering module 42 is electrically connected to the high-speed AD module 5. The high-speed AD module 5 is used to perform analog-to-digital conversion on the three-phase partial discharge amplified analog signals and square wave analog signals output by the programmable amplification and filtering module 42 to generate three-phase partial discharge amplified digital signals and square wave digital signals. Among them, the high-speed AD module 5 can be two ADM9226 dual-channel high-speed AD modules 5. The output end of the programmable amplification and filtering module 42 is electrically connected to the FPGA module 6. The programmable amplification and filtering module 42 is used to transmit the square wave digital signal to the FPGA module 6. The high-speed AD module 5: Its function is to collect the analog signals output by the programmable amplification and filtering module 42, with a sampling frequency not lower than 10MS / s, and the sampling results are transmitted to the FPGA module 6.

[0104] Please refer to Figure 3 , for a partial discharge inspection and positioning device of a ring main unit provided by the present utility model, the impedance matching module 41 is an impedance matching circuit;

[0105] The impedance matching circuit includes an analog switch 411, a capacitor bank 412, and a resistor bank 413;

[0106] The first end of the capacitor bank 412 is electrically connected to the three-phase phase discrimination holes of the live indicator;

[0107] The second end of the capacitor bank 412 is electrically connected to the analog switch 411;

[0108] The third end of the capacitor bank 412 is electrically connected to the first end of the resistor bank 413;

[0109] The analog switch 411 is electrically connected to the second end of the resistor bank 413;

[0110] The third end of the resistor bank 413 is connected to an internal ground wire;

[0111] The analog switch 411 is electrically connected to the FPGA module 6;

[0112] The analog switch 411 is configured to respond to the received switch control signal and regulate the capacitance value and resistance value of the impedance matching circuit to adapt to the ring main unit at the work site;

[0113] The resistor bank 413 is connected to the housing of the ring main unit through a built-in ground wire.

[0114] It should be noted that the impedance matching module 41 is an impedance matching circuit. The impedance matching circuit includes an analog switch 411, a capacitor bank 412, and a resistor bank 413, which are composed of a series circuit of the analog switch 411, the capacitor bank 412, and the resistor bank 413. The first end of the capacitor bank 412 is electrically connected to the three-phase phase comparison holes of the live indicator; the second end of the capacitor bank 412 is electrically connected to the analog switch 411; the third end of the capacitor bank 412 is electrically connected to the first end of the resistor bank 413; the analog switch 411 is electrically connected to the second end of the resistor bank 413; the third end of the resistor bank 413 is connected with a built-in ground wire; the analog switch 411 is electrically connected to the FPGA module 6; the analog switch 411 is configured to respond to the received switch control signal and regulate the capacitance value and resistance value of the impedance matching circuit to adapt to the ring main unit at the work site; the resistor bank 413 is connected to the housing of the ring main unit through a built-in ground wire.

[0115] It is worth mentioning that the control signal of the analog switch 411 is provided by the FPGA module 6 to adjust the setting parameters suitable for the live indicator of the ring main unit. The setting parameters include the resistance value and the capacitance value. There are certain differences in the live indicators and bushing parameters used in ring main units of different manufacturers. The impedance matching module 41 needs to be adjusted in cooperation with the bushing parameters to obtain partial discharge signals to the greatest extent. By switching the resistance value and the capacitance value, it can adapt to more types of ring main units.

[0116] Please refer to Figure 4 , for a partial discharge inspection and positioning device for a ring main unit provided by the present utility model, the programmable gain filter module 42 includes a programmable amplifier 421, a first filter 422, a second filter 423, an amplifier 424, and a comparator 425;

[0117] The input end of the programmable amplifier 421 is electrically connected to the output end of the impedance matching module 41;

[0118] The input ends of the first filter 422 and the second filter 423 are both electrically connected to the output of the programmable amplifier 421;

[0119] The output end of the first filter 422 is electrically connected to the amplifier 424;

[0120] An amplifier 424 is used to amplify the three-phase partial discharge signal to generate a three-phase amplified analog partial discharge signal;

[0121] The output end of the second filter 423 is electrically connected to the comparator 425;

[0122] A comparator 425 is used to shape the power frequency signal to generate a square wave analog signal.

[0123] It should be noted that the programmable amplification and filtering module 42 includes a programmable amplifier 421, a first filter 422, a second filter 423, an amplifier 424, and a comparator 425. The input end of the programmable amplification and filtering module 42 is connected to the output end of the impedance matching module 41. The control signal of the programmable amplification and filtering module 42 is provided by the FPGA module 6. Among them, the first filter 422 is a programmable filter, and its frequency band can be adjusted in the range of 10 kHz - 10 MHz. The parameter adjustment of the programmable filter is provided by the FPGA module 6. The initial bandwidth of the filter 32 is generally set to 100 kHz - 400 kHz. The second filter 423 is a low-pass filter with a frequency band range of 0 - 100 Hz to filter the power frequency signal. The amplifier 424 is a non-inverting proportional amplifier to further amplify the partial discharge signal, and the comparator 425 shapes the power frequency signal into a square wave.

[0124] Although the preferred embodiments of the embodiments of the present application have been described, those skilled in the art can make additional changes and modifications once they learn the basic creative concepts. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present application.

[0125] Finally, it should also be noted that in this article, relational terms such as first and second

[0126] are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or terminal device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or terminal device including the said element.

[0127] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than limiting them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions recorded in the embodiments of the present application.

Claims

1. A partial discharge inspection and positioning device for a ring main unit, characterized in that, It includes a device housing; A magnetic attraction component is provided on the device housing for attracting the partial discharge inspection and positioning device to the ring main unit; The magnetic attraction component includes a steel sleeve and a magnet; The steel sleeve is sleeved outside the magnet, and the magnet is fixed to the surface of the device housing by fixing screws; A three-phase signal processing system is provided inside the device housing; The three-phase signal processing system is connected to a handheld terminal.

2. The partial discharge inspection and positioning device for the ring main unit according to claim 1, wherein A rubber protection pad is provided between the magnet and the steel sleeve.

3. The partial discharge inspection and positioning device for the ring main unit according to claim 1, characterized in that, The material of the device housing is aluminum alloy.

4. The partial discharge inspection and positioning device for the ring main unit according to claim 1, wherein Three signal input interfaces are provided on the outer shell bottom plate of the device housing for electrically connecting to the three-phase phase-checking holes of the live indicator of the ring main unit; Among them, the three signal input interfaces are respectively an A-phase signal input interface, a B-phase signal input interface, and a C-phase signal input interface.

5. The partial discharge inspection and positioning device for the ring main unit according to claim 4, wherein, The outer shell bottom plate is made of insulating material.

6. The partial discharge inspection and positioning device for the ring main unit according to claim 4, wherein, The three-phase signal processing system includes a three-phase main control module, a high-speed AD module, an FPGA module, and a communication module that are electrically connected in sequence; The FPGA module is electrically connected to the three-phase main control module; The FPGA module is communicatively connected to the handheld terminal through the communication module.

7. The partial discharge inspection and positioning device for the ring main unit according to claim 6, wherein The three-phase main control module includes three main control modules respectively used for receiving partial discharge signals of each phase; The three main control modules are respectively connected to the three signal input interfaces in one-to-one correspondence; The three main control modules are all electrically connected to the high-speed AD module; The three main control modules are all electrically connected to the FPGA module.

8. The partial discharge inspection and positioning device for the ring main unit according to claim 7, wherein The main control module includes an impedance matching module and a programmable gain and filtering module that are electrically connected in sequence; The output end of the programmable gain and filtering module is electrically connected to the high-speed AD module; The output end of the programmable gain and filtering module is electrically connected to the FPGA module.

9. The partial discharge inspection and positioning device for the ring main unit according to claim 8, characterized in that, The impedance matching module is an impedance matching circuit; The impedance matching circuit includes an analog switch, a capacitor bank, and a resistor bank; The first end of the capacitor bank is electrically connected to the three-phase phase-checking holes of the live indicator; The second end of the capacitor bank is electrically connected to the analog switch; The third end of the capacitor bank is electrically connected to the first end of the resistor bank; The analog switch is electrically connected to the second end of the resistor bank; The analog switch is electrically connected to the FPGA module; A grounding wire is connected to the third end of the resistor bank; The grounding wire is connected to the outer shell of the ring main unit through the magnet.

10. The partial discharge inspection and positioning device for the ring main unit according to claim 8, characterized in that, The programmable gain and filtering module includes a programmable amplifier, a first filter, a second filter, an amplifier, and a comparator; The input end of the programmable amplifier is electrically connected to the output end of the impedance matching module; The input ends of the first filter and the second filter are both electrically connected to the output of the programmable amplifier; The output end of the first filter is electrically connected to the amplifier; The output end of the second filter is electrically connected to the comparator.

Images