Non-contact overvoltage measurement system and scale factor calibration method

Abstract

The invention relates to the technical field of power systems, in particular to a non-contact overvoltage measurement system and a scale factor calibration method. The non-contact overvoltage measurement system comprises a non-contact voltage sensing module, a synchronous trigger module, a high-speed data acquisition module and an upper computer, the non-contact voltage sensing module is used for acquiring bus voltage analog quantity signals, and the synchronous trigger module is used for sending out external trigger signals. The high-speed data acquisition module is used for responding to an external trigger signal and acquiring an acquired bus voltage analog quantity signal; and the upper computer is used for receiving the bus voltage analog quantity signal and processing and analyzing the bus voltage analog quantity signal. Measurement of broadband analog quantity signals is achieved through impedance conversion, the application scene of power frequency superposition impact is met, and meanwhile due to the fact that scale factors of low-frequency signals and scale factors of high-frequency signals are consistent, the scale factors of a non-contact overvoltage measurement system can be calibrated through power frequency voltage signals of a measured point position.

Description

Technical Field

[0001] The invention relates to the technical field of power systems, in particular to a non-contact overvoltage measurement system and a scale factor calibration method. Background Art

[0002] While various electrical equipment in the power system are subject to power frequency voltage, they are also subject to various forms of overvoltage, which in turn causes insulation damage to the electrical equipment and breakdown accidents, posing a serious threat to the safe operation of the power grid. Among them, switch equipment is more severe, not only facing the harm of power system from power frequency, operation and lightning overvoltage, but also the operation of switch equipment will cause rapid transient overvoltage. In long-term operation, with the frequent operation of switch equipment, rapid transient overvoltage will cause its insulation damage, and the maintenance difficulty and cost of switch equipment are high, so failure will bring greater losses to the stable operation of the power system.

[0003] Previously, although a large number of fault recording devices have been installed in the power system, the voltage transformer has good low-frequency response characteristics but poor high-frequency characteristics, which cannot meet the measurement requirements of fast transient overvoltages, and thus cannot accurately capture the complete transient voltage waveform. As a result, the research and mechanism analysis of overvoltages in power systems, especially fast transient overvoltages, mostly use numerical simulation methods. In recent years, researchers at home and abroad have conducted systematic research on the waveform measurement of fast transient overvoltages and proposed various overvoltage measurement methods. However, with the continuous increase in voltage levels, higher requirements are placed on the insulation design of voltage sensors.

[0004] Non-contact voltage sensing modules came into being, using stray capacitance to form a voltage divider to avoid contact with the high-voltage bus, so that the insulation level of the sensor can easily meet the requirements of field testing. However, when it is necessary to measure the power frequency voltage signal and the fast transient overvoltage signal at the same time, the non-contact voltage sensing module often has waveform distortion due to the small time constant. Therefore, how to solve the problem of broadening the measurement frequency band of this type of sensor has become the key to further promote its application. At the same time, since the stray capacitance changes with the structure, this type of sensor cannot complete the calibration of the scale factor consistent with the field application under laboratory conditions, and when the sensor is applied to different measurement points, the scale factor also changes accordingly. How to calibrate the scale factor of the non-contact voltage sensing module used in the test site has become another difficulty that restricts its development. Summary of the invention

[0005] The technical problem to be solved by the embodiments of the present invention is to provide a non-contact overvoltage measurement system and a scale factor calibration method to solve the problem in the prior art that in the process of transient overvoltage measurement in the power system, the stray capacitance value changes due to changes in the measured point, making it difficult to calibrate the scale factor.

[0006] The invention discloses a non-contact overvoltage measurement system, comprising: The non-contact voltage sensing module is connected to the device housing at the measured point and is used to obtain the bus voltage analog signal by forming a voltage divider through stray capacitance; The synchronous trigger module is used to convert the trigger level signal available on site into light through electrical processing and send out an external trigger signal with adjustable delay; A high-speed data acquisition module, electrically connected to the synchronous trigger module and the non-contact voltage sensing module, respectively, for receiving an external trigger signal sent in response to the synchronous trigger module, and acquiring a bus voltage analog signal acquired by the non-contact voltage sensing module; The host computer is connected to the high-speed data acquisition module for receiving the bus voltage analog signal uploaded by the high-speed data acquisition module and performing processing and analysis.

[0007] Optionally, the non-contact voltage sensing module includes a sensing electrode, a PCB capacitor plate and a low-voltage electrode plate, the sensing electrode is used to sense and obtain the bus voltage analog signal of the measured point, and the stray capacitance between the sensing electrode and the high-voltage bus at the measured point constitutes a high-voltage arm; The low-voltage electrode plate, the PCB capacitor plate and the sensing electrode are electrically connected in sequence, and the PCB capacitor plate is located between the low-voltage electrode plate and the sensing electrode to form a low-voltage arm, and the low-voltage electrode plate is electrically connected to the high-speed data acquisition module.

[0008] Optionally, the non-contact voltage sensing module further includes a switching electrode, and the sensing electrode is electrically connected to the PCB capacitor plate through the switching electrode.

[0009] Optionally, the non-contact voltage sensing module also includes an assembly flange, which is provided with an assembly end that matches the window on the housing of the measured point device, and the sensing electrode is arranged on the assembly end, and the assembly flange is provided with a connecting end opposite to the assembly end, the low-voltage electrode plate is arranged on the connecting end, and the high-speed data acquisition module is arranged on the low-voltage electrode plate, and the switching electrode and the PCB capacitor plate are both arranged in the assembly flange.

[0010] Optionally, an integrated channel penetrating the assembly end and the connection end is provided in the middle of the assembly flange, a matching insulating support is provided in the integrated channel at the assembly end, the low-voltage electrode plate is mounted on the end surface of the connection end, and a supporting portion is integrally provided on the low-voltage electrode plate, the supporting portion is matched and arranged in the integrated channel, and the inner end surface of the supporting portion is in close contact with the inner end surface of the insulating support; A first positioning groove is provided on the inner end surface of the insulating support, and the switching electrode and the PCB capacitor plate are both arranged in the first positioning groove. A second positioning groove is provided on the outer end surface of the insulating support, and the sensing electrode is embedded in the second positioning groove.

[0011] Optionally, a guide channel connecting the first positioning groove and the second positioning groove is further provided in the insulating support member, the switching electrode includes a first electrode portion and a second electrode portion which are integrally formed in a "T" shape, the first electrode portion is cooperatively arranged in the first positioning groove, the second electrode portion is cooperatively arranged in the guide channel, and an embedding groove is provided on the bottom end surface of the second electrode portion, the sensing electrode includes a third electrode portion and a fourth electrode portion which are integrally formed in a "T" shape, the third electrode portion is cooperatively arranged in the second positioning groove, and the fourth electrode portion is cooperatively embedded in the embedding groove along the guide channel.

[0012] Optionally, the high-speed data acquisition module includes a shielded shell, and a data acquisition card, a communication photoelectric unit, a trigger photoelectric unit and an impedance transformation unit arranged in the shielded shell, the data acquisition card is electrically connected to the communication photoelectric unit, the trigger photoelectric unit and the impedance transformation unit, respectively, the trigger photoelectric unit is electrically connected to the synchronous trigger module, and is used to receive an external trigger signal issued by the synchronous trigger module, the impedance transformation unit is electrically connected to the non-contact voltage sensing module, and is used to collect the bus voltage analog signal obtained by the non-contact voltage sensing module, and the communication photoelectric unit is communicatively connected to the host computer for data exchange.

[0013] Optionally, the high-speed data acquisition module further includes a power supply unit and a DC-DC conversion unit, and the power supply unit is electrically connected to the data acquisition card through the DC-DC conversion unit.

[0014] Optionally, the non-contact overvoltage measurement system includes multiple non-contact voltage sensing modules and high-speed data acquisition modules electrically connected to the multiple non-contact voltage sensing modules in a one-to-one correspondence. The multiple high-speed data acquisition modules are electrically connected to the synchronous trigger modules respectively so that the synchronous trigger unit sends multiple external trigger signals.

[0015] The present invention also discloses a scale factor calibration method, which uses the above-mentioned non-contact overvoltage measurement system. The scale factor calibration method includes: S1. When the non-contact overvoltage measurement system is in steady-state operation, the bus voltage information in the original voltage monitoring system and the analog signal obtained by the non-contact overvoltage measurement system are read simultaneously, and the average value of the preset number of readings is taken; S2, adjusting the non-contact overvoltage measurement system to different working voltage conditions, repeating step S1 to obtain data under at least five different working voltages, and drawing a fitting straight line, and determining that the slope of the fitting straight line is the scale factor of the non-contact overvoltage measurement system under the power frequency voltage measurement condition; S3, determining the scale factor of the non-contact overvoltage measurement system according to the scale factor obtained in step S2, and when changing the measuring point, repeating steps S1 to S2 to recalibrate the scale factor of the non-contact overvoltage measurement system.

[0016] Compared with the prior art, the non-contact overvoltage measurement system and scale factor calibration method provided by the embodiments of the present invention have the following beneficial effects: By setting a non-contact voltage sensing module, a synchronous trigger module, a high-speed data acquisition module and a host computer, the non-contact voltage sensing module is used to form a voltage division through stray capacitance to obtain the bus voltage analog signal, and the high-speed data acquisition module processes the bus voltage analog signal on the spot and transmits it to the host computer in real time. The synchronous trigger module is used to control the high-speed data acquisition module to capture the bus voltage analog signal at the required time, and the host computer can calculate, analyze, extract characteristic parameters and store the bus voltage analog signal. The non-contact overvoltage measurement system of the present invention uses impedance transformation to measure broadband analog signals, which meets the application scenario of power frequency superposition impact. At the same time, since the scale factors of low-frequency signals and high-frequency signals are consistent, the scale factor of the non-contact overvoltage measurement system can be calibrated using the power frequency voltage signal of the measured point, which effectively solves the problem that the scale factor of the technical route is difficult to calibrate due to the change of the stray capacitance value caused by the change of the measured point. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, in which: Figure 1 A schematic block diagram of the structure of a non-contact overvoltage measurement system provided by an embodiment of the present invention; Figure 2 A schematic diagram of the structure of a non-contact voltage sensing module provided by an embodiment of the present invention; Figure 3 A schematic diagram of the structure of a high-speed data acquisition module provided in an embodiment of the present invention.

[0018] The reference numerals in the figures are: 1. Non-contact voltage sensing module; 11. Sensing electrode; 111. Third electrode part; 112. Fourth electrode part; 12. PCB capacitor plate; 13. Low-voltage electrode plate; 131. Support part; 14. Transfer electrode; 141. First electrode part; 142. Second electrode part; 15. Assembly flange; 16. Insulating support; 2. Synchronous trigger module; 3. High-speed data acquisition module; 31. Shielding shell; 32. Data acquisition card; 33. Communication photoelectric unit; 34. Trigger photoelectric unit; 35. Impedance transformation unit; 36. Power supply unit; 37. DC-DC conversion unit; 4. Host computer. DETAILED DESCRIPTION

[0019] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. Now, in conjunction with the accompanying drawings, the preferred embodiments of the present invention are described in detail.

[0020] The invention discloses a non-contact overvoltage measurement system, comprising: The non-contact voltage sensing module 1 is connected to the device housing of the measured point and is used to obtain the bus voltage analog signal by forming a voltage divider through stray capacitance; Synchronous trigger module 2, used to convert the trigger level signal available on site into light through electrical conversion and send out an external trigger signal with adjustable delay; The high-speed data acquisition module 3 is electrically connected to the synchronous trigger module 2 and the non-contact voltage sensing module 1, respectively, and is used to receive and respond to the external trigger signal sent by the synchronous trigger module 2, and to collect the bus voltage analog signal obtained by the non-contact voltage sensing module 1; The host computer 4 is connected to the high-speed data acquisition module 3 for communication, and is used for receiving the bus voltage analog signal uploaded by the high-speed data acquisition module 3 and performing processing and analysis.

[0021] Through the implementation of the above-mentioned non-contact overvoltage measurement system embodiment, the non-contact voltage sensing module 1 is used to form a voltage division through stray capacitance to obtain the bus voltage analog signal, and the high-speed data acquisition module 3 processes the bus voltage analog signal on the spot and transmits it to the host computer 4 in real time. The synchronous trigger module 2 is used to control the high-speed data acquisition module 3 to capture the bus voltage analog signal at the required time, and the host computer 4 can calculate, analyze, extract characteristic parameters and store the bus voltage analog signal. The non-contact overvoltage measurement system of the present invention uses impedance transformation to measure broadband analog signals, meets the application scenario of power frequency superposition impact, and makes the scale factor of low-frequency signals consistent with that of high-frequency signals, so the scale factor of the non-contact overvoltage measurement system can be calibrated using the power frequency voltage signal of the measured point, which effectively solves the problem that the scale factor of the technical route is difficult to calibrate due to the change of the stray capacitance value caused by the change of the measured point.

[0022] Furthermore, the non-contact voltage sensing module 1 includes a sensing electrode 11, a PCB capacitor plate and a low-voltage electrode plate 13. The sensing electrode 11 is used to sense and obtain the bus voltage analog signal of the measured point, and the stray capacitance between the sensing electrode 11 and the high-voltage bus at the measured point constitutes a high-voltage arm. The low-voltage electrode plate 13, the PCB capacitor plate and the sensing electrode 11 are electrically connected in sequence, and the PCB capacitor plate is located between the low-voltage electrode plate 13 and the sensing electrode 11 to form a low-voltage arm, and the low-voltage electrode plate 13 is electrically connected to the high-speed data acquisition module 3.

[0023] Through the implementation of the above-mentioned non-contact overvoltage measurement system embodiment, the bus voltage is sensed by the sensing electrode 11, rather than directly contacting the high-voltage bus, which improves the anti-interference ability of the measurement system and makes the insulation design easier to meet the requirements. The sensing electrode 11 can accurately obtain the bus voltage analog signal of the measured point, and the stray capacitance between the sensing electrode 11 and the high-voltage bus of the measured point constitutes a high-voltage arm, and the low-voltage electrode plate 13, the PCB capacitor plate and the sensing electrode 11 are electrically connected in sequence, and the PCB capacitor plate is located between the low-voltage electrode plate 13 and the sensing electrode 11 to form a low-voltage arm, so that the high-voltage arm and the low-voltage arm form a capacitive voltage divider, so as to convert the high-voltage bus voltage signal into an analog signal within the amplitude range that the high-speed data acquisition module 3 can receive, which helps to reduce electromagnetic interference, improve the stability and reliability of signal transmission, realize the electrical isolation of the high-voltage and low-voltage parts, and prevent the high-voltage from damaging the low-voltage part. By connecting the low-voltage electrode plate 13 with the high-speed data acquisition module 3, the high-speed data acquisition module 3 can quickly and accurately collect the bus voltage analog signal, thereby improving the efficiency and real-time performance of data acquisition.

[0024] Furthermore, the non-contact voltage sensing module 1 further includes a switching electrode 14 , and the sensing electrode 11 is electrically connected to the PCB capacitor plate via the switching electrode 14 .

[0025] By implementing the above-mentioned non-contact overvoltage measurement system embodiment, the transfer electrode 14 is used as an intermediate connection component to safely transmit the signal sensed by the sensing electrode 11 to the low-voltage part, while isolating the high-voltage and low-voltage systems, further preventing the high voltage from damaging the low-voltage circuit. In addition, the transfer electrode 14 can also optimize the signal transmission path between the sensing electrode 11 and the PCB capacitor plate, reduce the attenuation of the signal during the transmission process, and ensure the signal quality.

[0026] Furthermore, the non-contact voltage sensing module 1 also includes an assembly flange 15. The assembly flange 15 is provided with an assembly end that matches the window on the housing of the measured point device, and the sensing electrode 11 is arranged on the assembly end. The assembly flange 15 is provided with a connection end opposite to the assembly end, the low-voltage electrode plate 13 is arranged on the connection end, and the high-speed data acquisition module 3 is arranged on the low-voltage electrode plate 13. The transfer electrode 14 and the PCB capacitor plate are both arranged in the assembly flange 15.

[0027] Through the implementation of the above-mentioned non-contact overvoltage measurement system embodiment, the non-contact voltage sensing module 1 is connected to the housing of the device at the measured point by using the setting of the assembly flange 15, but the sensing electrode 11 is non-contact with the high-voltage bus, and the assembly flange 15 is matched with the window of the housing of the device under test, providing a stable mechanical connection, reducing the displacement caused by vibration or temperature change, so as to ensure that the sensing electrode 11 can stably sense the bus voltage, thereby improving the anti-interference ability of the measurement system. At the same time, the sensing electrode 11 is set on the assembly end, which can accurately sense the high-voltage bus voltage of the measured point, and the high-speed data acquisition module 3 is directly set on the low-voltage electrode plate 13, which can quickly respond to and collect voltage data, thereby improving the efficiency of data processing.

[0028] Furthermore, an integrated channel that runs through the assembly end and the connection end is provided in the middle of the assembly flange 15. A matching insulating support 16 is provided at the assembly end in the integrated channel, and the low-voltage electrode plate 13 is mounted on the end face of the connection end, and a support portion 131 is integrally provided on the low-voltage electrode plate 13. The support portion 131 is provided in a matching manner in the integrated channel, and the inner end face of the support portion 131 is in close contact with the inner end face of the insulating support 16. A first positioning groove is provided on the inner end face of the insulating support 16, and the transfer electrode 14 and the PCB capacitor plate are both provided in a matching manner in the first positioning groove. A second positioning groove is provided on the outer end face of the insulating support 16, and the sensing electrode 11 is embedded in the second positioning groove.

[0029] Through the implementation of the above-mentioned non-contact overvoltage measurement system embodiment, the integrated channel is used to arrange the transfer electrode 14 and the PCB capacitor plate compactly in a limited space to optimize the internal space layout of the integrated channel. Through the setting of the insulating support 16, the first positioning groove and the second positioning groove, the PCB capacitor plate is fixed between the transfer electrode 14 and the low-voltage electrode plate 13 by the assembly flange 15 and the low-voltage electrode plate 13 through the positioning screws, so that it is tightly and reliably connected, ensuring the precise positioning and fixing of the sensing electrode 11, the transfer electrode 14 and the PCB capacitor plate, improving the installation accuracy of each device, and providing additional structural support for the sensing electrode 11, the transfer electrode 14, the PCB capacitor plate and the low-voltage electrode plate 13, enhancing the connection stability between the components, so as to ensure that the entire non-contact voltage sensing module 1 can stably obtain the bus voltage analog signal, avoiding the situation where the data acquisition is erroneous due to vibration or temperature changes. And the use of the insulating support 16 improves the overall insulation performance of the non-contact voltage sensing module 1, protecting the internal circuit from the influence of the external electric field.

[0030] Furthermore, a guide channel connecting the first positioning groove and the second positioning groove is also provided in the insulating support 16. The switching electrode 14 includes a first electrode portion 141 and a second electrode portion 142 which are integrally formed into a "T" shape. The first electrode portion 141 is arranged in the first positioning groove, and the second electrode portion 142 is arranged in the guide channel. An embedding groove is provided on the bottom end surface of the second electrode portion 142. The sensing electrode 11 includes a third electrode portion 111 and a fourth electrode portion 112 which are integrally formed into a "T" shape. The third electrode portion 111 is arranged in the second positioning groove, and the fourth electrode portion 112 is embedded in the embedding groove along the guide channel.

[0031] Through the implementation of the above-mentioned non-contact overvoltage measurement system embodiment, the setting of the guide channel helps to achieve a stable electrical connection between the transfer electrode 14 and the sensing electrode 11, reducing the contact resistance and signal attenuation. The "T"-shaped structure of the transfer electrode 14 and the "T"-shaped structure of the sensing electrode 11 are matched to enable the transfer electrode 14 and the sensing electrode 11 to be accurately aligned, ensuring that they are in contact at the correct position, which helps to improve the accuracy and stability of signal transmission between the sensing electrode 11 and the transfer electrode 14. In addition, by using the "T"-shaped structure and the groove position on the insulating support 16, additional mechanical support is provided for the sensing electrode 11 and the transfer electrode 14, the connection strength between the sensing electrode 11 and the transfer electrode 14 is enhanced, and the loose connection caused by external factors such as vibration or temperature changes is reduced. Its tight and reliable connection helps to reduce the contact resistance, thereby improving the transmission efficiency of the signal and the overall performance of the sensor, and can better resist external electromagnetic interference and maintain the stability of the sensing signal.

[0032] Furthermore, the high-speed data acquisition module 3 includes a shielding shell 31, and a data acquisition card 32, a communication photoelectric unit 33, a trigger photoelectric unit 34, and an impedance conversion unit 35 arranged in the shielding shell 31. The data acquisition card 32 is electrically connected to the communication photoelectric unit 33, the trigger photoelectric unit 34, and the impedance conversion unit 35, respectively. The trigger photoelectric unit 34 is electrically connected to the synchronous trigger module 2 to receive an external trigger signal sent by the synchronous trigger module 2. The impedance conversion unit 35 is electrically connected to the non-contact voltage sensing module 1 to collect the bus voltage analog signal obtained by the non-contact voltage sensing module 1, and the communication photoelectric unit 33 is connected to the host computer 4 for data exchange.

[0033] Through the implementation of the above-mentioned non-contact overvoltage measurement system embodiment, the shielding shell 31 can effectively prevent external electromagnetic interference, ensure the stability of the data acquisition card 32, the communication photoelectric unit 33, the trigger photoelectric unit 34 and the impedance transformation unit 35 in the shielding shell 31, and effectively enhance the anti-environmental interference ability of the entire high-speed data acquisition module 3. Therefore, the data acquisition card 32 is preferably a high-speed acquisition card, and the data acquisition card 32 receives the trigger signal sent by the synchronous trigger module 2 through the trigger photoelectric unit 34 to achieve the acquisition of the bus voltage signal at a specific time. The bus voltage analog signal obtained by the non-contact voltage sensing module 1 is collected by the data acquisition card 32 through the impedance transformation unit 35, and the impedance transformation unit 35 can achieve the voltage analog signal measurement frequency band covering the power frequency to 10MHz. Then the data acquisition card 32 interacts with the host computer 4 through the communication photoelectric unit 33. The data acquisition card 32 can process and transmit data in real time and at high speed, so that the data acquisition and processing process of the entire high-speed data acquisition module 3 is more efficient and can adapt to different application scenarios.

[0034] As described above, the data acquisition card 32, the communication photoelectric unit 33, the trigger photoelectric unit 34 and the impedance conversion unit 35 are encapsulated in the shielding shell 31, and assembled together with the low-voltage electrode plate 13 of the non-contact voltage sensing module 1, so that the length of the signal transmission line can be shortened as much as possible, thereby reducing its influence on the measurement of different frequency signals, and the analog signal can be processed on-site by the high-speed data acquisition module 3. Impedance conversion is used to improve the time constant of low-frequency measurement without affecting the high-frequency response, thereby realizing the measurement of broadband analog signals and meeting the application scenario of power frequency superposition impact.

[0035] Furthermore, the high-speed data acquisition module 3 further includes a power supply unit 36 ​​and a DC-DC conversion unit. The power supply unit 36 ​​is electrically connected to the data acquisition card 32 via the DC-DC conversion unit.

[0036] Through the implementation of the above-mentioned non-contact overvoltage measurement system embodiment, the power supply unit 36 ​​is used to provide a stable power supply for the data acquisition card 32, the communication photoelectric unit 33, the trigger photoelectric unit 34 and the impedance transformation unit 35, and the DC-DC conversion unit can convert the input power into a suitable voltage and current according to the specific needs of each device, so that inputs of different voltage levels can be processed to adapt to a variety of power supply environments, thereby increasing the versatility and flexibility of the high-speed data acquisition module 3.

[0037] Furthermore, the non-contact overvoltage measurement system includes a multi-channel non-contact voltage sensing module 1, and a high-speed data acquisition module 3 electrically connected to the multi-channel non-contact voltage sensing module 1 in a one-to-one correspondence. The multi-channel high-speed data acquisition module 3 is electrically connected to the synchronous trigger module 2, respectively, so that the synchronous trigger unit sends a multi-channel external trigger signal.

[0038] Through the implementation of the above-mentioned non-contact overvoltage measurement system embodiment, the synchronous trigger unit can meet the external trigger test requirements, ensure that the high-speed data acquisition unit is triggered to capture the bus voltage analog signal during the opening and closing action, and improve the data acquisition efficiency. The synchronous trigger unit is used to perform electrical-to-optical processing on the trigger level signal available on site, and send out multiple external trigger signals with adjustable delay to drive the multi-channel high-speed data acquisition module 3 to collect the bus voltage analog signal obtained by the corresponding non-contact voltage sensing module 1, so that the non-contact overvoltage measurement system can measure multiple measured points at the same time, thereby meeting the simultaneous measurement of different measured points to improve the measurement efficiency of overvoltage measurement.

[0039] The present invention is further illustrated by taking specific measured points as examples: Implementation method (1), for measurement at the circuit breaker busbar: The assembly flange 15 is assembled along the window on the housing of the circuit breaker device, and the high-speed data acquisition module 3 is encapsulated as a whole in the shielding housing 31, and assembled with the low-voltage electrode plate 13 through the screw holes, so that the non-contact overvoltage measurement system is installed at the busbar of the circuit breaker; After the non-contact overvoltage measurement system, the stray capacitance between the sensing electrode 11 and the high-voltage busbar of the circuit breaker is the high-voltage arm of the non-contact voltage sensing module 1, and the PCB capacitor plate is the low-voltage arm of the non-contact voltage sensing module 1. The two form a capacitive voltage divider to convert the high-voltage busbar voltage signal into an analog signal within the amplitude range that the high-speed data acquisition module 3 can receive; The high-speed data acquisition module 3 performs local signal capture and data processing; The data acquisition card 32 in the high-speed data acquisition module 3 receives the trigger signal sent by the synchronous trigger module 2 through the trigger photoelectric unit 34, so as to obtain the bus voltage signal at a specific moment; The high-speed data acquisition card 32 collects the bus voltage analog signal obtained by the non-contact voltage sensing module 1 through the impedance conversion unit 35. The impedance conversion unit 35 realizes that the voltage analog signal measurement frequency band covers the power frequency to 10MHz; The high-speed data acquisition card 32 exchanges data with the host computer 4 through the communication photoelectric unit 33; Before the non-contact voltage measurement system is put into use, the scale factor is calibrated according to the original monitoring signal of the on-site power frequency signal. Implementation method (2), for measurement at PT: The assembly flange 15 is assembled along the window on the equipment housing at the PT, and the high-speed data acquisition module 3 is encapsulated as a whole in the shielding housing 31, and assembled with the low-voltage electrode plate 13 through the screw holes, so that the non-contact overvoltage measurement system is installed at the circuit breaker busbar; After the non-contact overvoltage measurement system, the stray capacitance between the sensing electrode 11 and the high-voltage busbar of the circuit breaker is the high-voltage arm of the non-contact voltage sensing module 1, and the PCB capacitor plate is the low-voltage arm of the non-contact voltage sensing module 1. The two form a capacitive voltage divider to convert the high-voltage busbar voltage signal into an analog signal within the amplitude range that the high-speed data acquisition module 3 can receive; The high-speed data acquisition module 3 performs local signal capture and data processing; The data acquisition card 32 in the high-speed data acquisition module 3 receives the trigger signal sent by the synchronous trigger module 2 through the trigger photoelectric unit 34, so as to obtain the bus voltage signal at a specific moment; The high-speed data acquisition card 32 collects the bus voltage analog signal obtained by the non-contact voltage sensing module 1 through the impedance conversion unit 35. The impedance conversion unit 35 realizes that the voltage analog signal measurement frequency band covers the power frequency to 10MHz; The high-speed data acquisition card 32 exchanges data with the host computer 4 through the communication photoelectric unit 33; Before the non-contact voltage measurement system is put into use, the scale factor is calibrated according to the original monitoring signal of the on-site power frequency signal.

[0040] Implementation method (2), for measurement of pulse power device: The assembly flange 15 is assembled along the window on the pulse power device housing, and the high-speed data acquisition module 3 is encapsulated as a whole in the shielding housing 31, and assembled with the low-voltage electrode plate 13 through the screw holes, so that the non-contact overvoltage measurement system is installed at the circuit breaker busbar; After the non-contact overvoltage measurement system, the stray capacitance between the sensing electrode 11 and the high-voltage busbar of the circuit breaker is the high-voltage arm of the non-contact voltage sensing module 1, and the PCB capacitor plate is the low-voltage arm of the non-contact voltage sensing module 1. The two form a capacitive voltage divider to convert the high-voltage busbar voltage signal into an analog signal within the amplitude range that the high-speed data acquisition module 3 can receive; The high-speed data acquisition module 3 performs local signal capture and data processing; The data acquisition card 32 in the high-speed data acquisition module 3 receives the trigger signal sent by the synchronous trigger module 2 through the trigger photoelectric unit 34, so as to obtain the bus voltage signal at a specific moment; The high-speed data acquisition card 32 collects the bus voltage analog signal obtained by the non-contact voltage sensing module 1 through the impedance conversion unit 35. The impedance conversion unit 35 realizes that the voltage analog signal measurement frequency band covers the power frequency to 10MHz; The high-speed data acquisition card 32 exchanges data with the host computer 4 through the communication photoelectric unit 33; Before the non-contact voltage measurement system is put into use, the scale factor is calibrated according to the original monitoring signal of the on-site power frequency signal.

[0041] The present invention also discloses a scale factor calibration method, which uses the above-mentioned non-contact overvoltage measurement system. The scale factor calibration method includes: S1. When the non-contact overvoltage measurement system is in steady-state operation, the bus voltage information in the original voltage monitoring system and the analog signal obtained by the non-contact overvoltage measurement system are read simultaneously, and the average value of the preset number of readings is taken; S2, adjusting the non-contact overvoltage measurement system to different working voltage conditions, repeating step S1 to obtain data under at least five different working voltages, and drawing a fitting straight line, and determining that the slope of the fitting straight line is the scale factor of the non-contact overvoltage measurement system under the power frequency voltage measurement condition; S3, determining the scale factor of the non-contact overvoltage measurement system according to the scale factor obtained in step S2, and when changing the measuring point, repeating steps S1 to S2 to recalibrate the scale factor of the non-contact overvoltage measurement system.

[0042] Through the implementation of the above-mentioned scale factor calibration method embodiment, since the impedance transformation unit 35 of the non-contact overvoltage measurement system realizes the measurement of broadband analog signals, the scale factors of low-frequency signals and high-frequency signals are consistent, which meets the application scenario of industrial frequency superposition impact. Therefore, the scale factor of the non-contact overvoltage measurement system is calibrated using the industrial frequency voltage signal of the measured point, which effectively solves the technical route The difficult problem that the scale factor is difficult to calibrate due to the change of the stray capacitance value caused by the change of the measured point.

[0043] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. For those skilled in the art, the technical solutions described in the above embodiments can be modified, or some of the technical features therein can be replaced by equivalents; and all these modifications and replacements should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A non-contact overvoltage measurement system, characterized in that: The non-contact overvoltage measurement system comprises: The non-contact voltage sensing module is connected to the device housing at the measured point and is used to obtain the bus voltage analog signal by forming a voltage divider through stray capacitance; The synchronous trigger module is used to convert the trigger level signal available on site into light through electrical processing and send out an external trigger signal with adjustable delay; A high-speed data acquisition module, electrically connected to the synchronous trigger module and the non-contact voltage sensing module, respectively, for receiving an external trigger signal sent in response to the synchronous trigger module, and acquiring the bus voltage analog signal obtained by the non-contact voltage sensing module through impedance transformation; The host computer is connected to the high-speed data acquisition module for receiving the bus voltage analog signal uploaded by the high-speed data acquisition module and performing processing and analysis.

2. The non-contact overvoltage measurement system according to claim 1, characterized in that: The non-contact voltage sensing module includes a sensing electrode, a PCB capacitor plate and a low-voltage electrode plate, wherein the sensing electrode is used to sense and obtain the bus voltage analog signal of the measured point, and the stray capacitance between the sensing electrode and the high-voltage bus at the measured point constitutes a high-voltage arm; The low-voltage electrode plate, the PCB capacitor plate and the sensing electrode are electrically connected in sequence, and the PCB capacitor plate is located between the low-voltage electrode plate and the sensing electrode to form a low-voltage arm, and the low-voltage electrode plate is electrically connected to the high-speed data acquisition module.

3. The non-contact overvoltage measurement system according to claim 2, characterized in that: The non-contact voltage sensing module further includes a switching electrode, and the sensing electrode is electrically connected to the PCB capacitor plate through the switching electrode.

4. The non-contact overvoltage measurement system according to claim 3, characterized in that: The non-contact voltage sensing module also includes an assembly flange, on which is provided an assembly end that matches with the window on the housing of the measured point device, and the sensing electrode is arranged on the assembly end, and the assembly flange is provided with a connecting end opposite to the assembly end, the low-voltage electrode plate is arranged on the connecting end, and the high-speed data acquisition module is arranged on the low-voltage electrode plate, and the switching electrode and the PCB capacitor plate are both arranged in the assembly flange.

5. The non-contact overvoltage measurement system according to claim 4, characterized in that: An integrated channel penetrating the assembly end and the connection end is provided in the middle of the assembly flange, a matching insulating support is provided at the assembly end in the integrated channel, the low-voltage electrode plate is mounted on the end surface of the connection end, and a supporting portion is integrally provided on the low-voltage electrode plate, the supporting portion is matched and arranged in the integrated channel, and the inner end surface of the supporting portion is in close contact with the inner end surface of the insulating support; A first positioning groove is provided on the inner end surface of the insulating support, and the switching electrode and the PCB capacitor plate are both arranged in the first positioning groove. A second positioning groove is provided on the outer end surface of the insulating support, and the sensing electrode is embedded in the second positioning groove.

6. The non-contact overvoltage measurement system according to claim 5, characterized in that: The insulating support is also provided with a guide channel connecting the first positioning groove and the second positioning groove. The switching electrode includes a first electrode portion and a second electrode portion which are integrally formed in a "T" shape. The first electrode portion is cooperatively arranged in the first positioning groove, the second electrode portion is cooperatively arranged in the guide channel, and an embedding groove is provided on the bottom end surface of the second electrode portion. The sensing electrode includes a third electrode portion and a fourth electrode portion which are integrally formed in a "T" shape. The third electrode portion is cooperatively arranged in the second positioning groove, and the fourth electrode portion is cooperatively embedded in the embedding groove along the guide channel.

7. The non-contact overvoltage measurement system according to claim 1, characterized in that: The high-speed data acquisition module includes a shielding shell, and a data acquisition card, a communication photoelectric unit, a trigger photoelectric unit and an impedance conversion unit arranged in the shielding shell. The data acquisition card is electrically connected to the communication photoelectric unit, the trigger photoelectric unit and the impedance conversion unit respectively. The trigger photoelectric unit is electrically connected to the synchronous trigger module for receiving an external trigger signal sent by the synchronous trigger module. The impedance conversion unit is electrically connected to the non-contact voltage sensing module for collecting the bus voltage analog signal obtained by the non-contact voltage sensing module. The communication photoelectric unit is connected to the host computer for data exchange.

8. The non-contact overvoltage measurement system according to claim 7, characterized in that: The high-speed data acquisition module also includes a power supply unit and a DC-DC conversion unit. The power supply unit is electrically connected to the data acquisition card through the DC-DC conversion unit.

9. The non-contact overvoltage measurement system according to claim 1, characterized in that: The non-contact overvoltage measurement system includes a plurality of non-contact voltage sensing modules and a high-speed data acquisition module electrically connected to the plurality of non-contact voltage sensing modules in a one-to-one correspondence. The plurality of high-speed data acquisition modules are electrically connected to the synchronous trigger module respectively so that the synchronous trigger unit sends out a plurality of external trigger signals.

10. A scale factor calibration method, characterized in that: Using the non-contact overvoltage measurement system according to any one of claims 1 to 9, the scale factor calibration method comprises: S1. When the non-contact overvoltage measurement system is in steady-state operation, the bus voltage information in the original voltage monitoring system and the analog signal obtained by the non-contact overvoltage measurement system are read simultaneously, and the average value of the preset number of readings is taken; S2, adjusting the non-contact overvoltage measurement system to different working voltage conditions, repeating step S1 to obtain data under at least five different working voltages, and drawing a fitting straight line, and determining that the slope of the fitting straight line is the scale factor of the non-contact overvoltage measurement system under power frequency voltage measurement conditions; S3. Determine the scale factor of the non-contact overvoltage measurement system according to the scale factor obtained in step S2, and when the measuring point is changed, repeat steps S1 to S2 to recalibrate the scale factor of the non-contact overvoltage measurement system.

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