A switching arc pressure measuring device and a measuring method

Abstract

The application discloses a kind of switch arc voltage measuring device and measuring method, measuring device includes measurement capacitor unit, signal acquisition unit and data processing unit;Measurement capacitor unit includes high-voltage arm measurement capacitor and low-voltage arm measurement capacitor;Signal acquisition unit is connected with low-voltage arm measurement capacitor, and it is configured to corresponding acquisition and pre-processing of the voltage signal input to low-voltage arm measurement capacitor;Data processing unit and signal acquisition unit are connected, and it is configured to determine the arc voltage of the break of the switch contact end to be measured according to the voltage signal data after pre-processing, and in combination with the voltage division ratio relationship of high-voltage arm measurement capacitor and low-voltage arm measurement capacitor.The switch arc voltage measuring device and measuring method provided by the application can realize real-time measurement of switch arc voltage by using capacitor voltage division principle, and will not affect the normal work and insulation performance of switch device.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of voltage measurement of switching electrical equipment, and particularly relates to a switching arc voltage measurement device and a measurement method. BACKGROUND

[0002] In recent years, flexible HVDC transmission technology has been widely applied, and UHVDC transmission system has attracted attention due to its excellent performance in renewable energy integration, power system expansion, and improvement of power grid stability. As the backbone equipment in the DC power system, the DC power switch device, especially the medium and high voltage DC circuit breaker, is responsible for completing the operation mode switching and line fault clearing of the DC power transmission system, which is of great significance to the safe, economic and flexible operation of the DC power system. In the field of rail transit, the DC circuit breaker is an indispensable key protection device for the rail traction DC power supply system. With the large-scale construction of rail transit, the rail traction DC power supply system is applied more and more widely, and the demand for medium and high voltage DC circuit breakers with good breaking capacity is also increasing.

[0003] Arc voltage is an important parameter that can reflect the arc extinguishing performance of medium and high voltage DC circuit breakers to a large extent. At the same time, arc voltage can also accurately reflect the action state of the moving and static contacts of the circuit breaker during the opening process, which is beneficial to the design and development of many artificial zero-crossing type high voltage and large capacity DC circuit breakers. Therefore, many researchers and engineering designers have been interested in its measurement for many years.

[0004] However, in current practical engineering applications, due to the high system voltage level of the DC circuit breaker, for example, the system voltage of the medium and high voltage DC circuit breaker is at least in the kilovolt level, and the highest can reach tens of kilovolts. Since the circuit breaker and other power switch devices will form a gap between the moving and static contacts when they are operated, the corresponding system voltage is applied to the gap. Therefore, the voltage measurement at the gap between the moving and static contacts cannot use ordinary low voltage measurement methods. However, if high voltage level measurement instruments and equipment such as high voltage probes are used, considering the large range and high graduation value of the high voltage probe, it is difficult to ensure the accuracy of the results and there is a large error in the measurement of the arc voltage between the gap formed during the opening process of the circuit breaker and other power switch devices.

[0005] The voltage divider is a commonly used measurement instrument in the field of voltage measurement, mainly including resistance divider, capacitance divider and resistance-capacitance divider. Among them, the resistance divider is not suitable for being connected in parallel to the contacts of the circuit breaker and other switch devices due to its conduction characteristics. Compared with the resistance divider, the capacitance divider has complete breaking characteristics under DC conditions and has the advantage of no phase angle error.

[0006] In view of safety and reliability, a long distance is often present between the acquisition unit (or oscilloscope) and the voltage divider in the traditional capacitive voltage division measurement scheme, and thus a coaxial cable is needed for connection. The coaxial cable is bulky and conducts alternating current, that is, the current direction is reversed several times per second, and the coaxial cable has a certain wave impedance. The presence of the wave impedance causes the wave to be folded and reflected in the propagation process, thereby causing interference to the measurement result.

[0007] Patent application No. CN110297121A discloses a capacitive voltage divider low-voltage measurement circuit and a measurement method, aiming to solve the technical problems that the capacitive voltage divider low-voltage test circuit in the prior art may have large errors in the division ratio and amplitude. The technical solution proposes a complex topology design and a tedious parameter adjustment method, finally reduces the influence of the wave impedance of the coaxial cable on the voltage measurement, and reduces the measurement error of the voltage amplitude.

[0008] Patent application No. CN108333421A discloses a high-voltage cable overvoltage test device and a method thereof, which comprises a standard capacitor, a voltage recording module for recording voltage waveforms, a CPU for processing voltage waveforms and calculating data, and a control module. One end of the standard capacitor is connected to the shielding layer of the high-voltage cable, and the other end is grounded. The high-voltage end of the standard capacitor is connected to the voltage recording module. The voltage recording module is connected to the CPU. The CPU is connected to the control module. The invention is based on the capacitive voltage divider formed by the self-capacitance of the cable and the additional division capacitance in series. However, this technical solution can only be applied to cables with single-ended grounding shielding layers or similar applications that can provide self-capacitance. The installation of the measurement device requires to damage the physical structure of the cable product. The measurement and adjustment method is complicated and the process is complex.

[0009] The disclosure of the above background art is only used to assist in understanding the inventive concept and technical solutions of the present application, and does not necessarily belong to the prior art of the present patent application, nor does it necessarily provide technical teaching. In the absence of explicit evidence that the above-mentioned content has been disclosed before the filing date of the present patent application, the above-mentioned background art should not be used to evaluate the novelty and inventiveness of the present application. SUMMARY

[0010] In order to overcome the deficiencies in the prior art, the present application provides a switch arc voltage measurement device and a measurement method, and the specific technical solutions are as follows:

[0011] On the one hand, a switch arc voltage measurement device is provided, which is used for measuring the arc voltage of the fracture of the switch contact to be measured, and comprises a measurement capacitance unit, a signal acquisition unit and a data processing unit.

[0012] The measurement capacitor unit comprises a high-voltage arm measurement capacitor C1 and a low-voltage arm measurement capacitor C2, one end of the high-voltage arm measurement capacitor C1 is connected with a lead-out line of a high-voltage side of a break of a switch contact to be measured, the other end of the high-voltage arm measurement capacitor C1 and one end of the low-voltage arm measurement capacitor C2 are connected, and the other end of the low-voltage arm measurement capacitor C2 is connected with a lead-out line of a low-voltage side of the break of the switch contact to be measured;

[0013] The signal acquisition unit is connected with the low-voltage arm measurement capacitor C2 and is configured to acquire and pre-process a voltage signal input by the low-voltage arm measurement capacitor C2;

[0014] The data processing unit is connected with the signal acquisition unit and is configured to determine an arc voltage between the two ends of the break of the switch contact to be measured according to the pre-processed arc voltage signal data and in combination with a voltage division ratio relationship of the high-voltage arm measurement capacitor C1 and the low-voltage arm measurement capacitor C2.

[0015] Further, the measurement device further comprises an overvoltage protection unit, the signal acquisition unit is connected with the low-voltage arm measurement capacitor C2 through the overvoltage protection unit, the overvoltage protection unit is connected in parallel between the two ends of the low-voltage arm measurement capacitor C2 and is composed of a surge protection device with a voltage clamping function; an action threshold of the overvoltage protection unit needs to be higher than the arc voltage, and a clamping voltage of the overvoltage protection unit should not be higher than a bearing limit of the signal acquisition unit and the data processing unit.

[0016] Further, the measurement device further comprises a first resistor, a first inductor, a second resistor and a second inductor, the lead-out line of the high-voltage side of the break of the switch contact to be measured, the first resistor, the first inductor and the high-voltage arm measurement capacitor C1 are connected in sequence, the lead-out line of the low-voltage side of the break of the switch contact to be measured, the second resistor, the second inductor and the low-voltage arm measurement capacitor C2 are connected in sequence, and the low-voltage side of the break of the switch contact to be measured is grounded.

[0017] Further, the switch to be measured is a direct-current circuit breaker, the signal acquisition unit comprises a sampling module, a filtering module and an amplifying module connected in sequence, the sampling module is used for sampling processing of a voltage signal input by the low-voltage arm measurement capacitor C2, the filtering module is used for filtering processing of the acquired voltage signal, and the amplifying module is used for appropriate amplification of the voltage signal after the filtering processing.

[0018] On the other hand, a switch arc voltage measurement method is provided, comprising the following steps:

[0019] The measurement device is connected between the two ends of the switch contact to be measured;

[0020] The voltage signal data between the two ends of the low-voltage arm measurement capacitor C2 acquired and pre-processed by the signal acquisition unit;

[0021] The data processing unit calculates the arc voltage between the two ends of the switch under test according to the voltage division ratio relationship between the high-voltage arm measured capacitance C1 and the low-voltage arm measured capacitance C2, and the voltage signal data collected and preprocessed by the signal collection unit.

[0022] Further, the signal collection unit is connected to the measurement capacitance unit through an overvoltage protection unit, and when the overvoltage protection unit detects that the voltage between the two ends of the low-voltage arm measured capacitance C2 exceeds a preset threshold, the connection between the signal collection unit and the measurement capacitance unit is disconnected.

[0023] Further, the time of existence of the arc between the start of the opening of the switch under test and the complete opening is obtained through the real-time recorded arc voltage data, and if the time of existence of the single arc is greater than a first preset value, it is judged that the opening action of the switch under test is delayed, and the maintenance personnel need to be notified to maintain the switch under test.

[0024] Further, the size of the arc voltage between the start of the opening of the switch under test and the complete opening is obtained through the real-time recorded arc voltage data, and if the time when the arc voltage is less than a second preset value is greater than a third preset value, it is judged that the switch under test has a risk of burning out, and the maintenance personnel need to be notified to maintain the switch under test.

[0025] Further, if the switch under test is displayed in a closed state, and the arc voltage is monitored to exist, it is judged that the switch under test has not completed the closing, and the maintenance personnel need to be notified to maintain the switch under test; during the maintenance process, if the maintenance personnel find that the switch under test has actually completed the closing, the measurement device needs to be maintained.

[0026] Compared with the prior art, the present application has the following advantages: by adopting the capacitance voltage division principle, real-time measurement of the switch arc voltage can be realized, and by using the characteristics of the capacitance that it blocks direct current and passes alternating current, for the direct current system voltage, the measurement capacitance unit will show complete opening characteristics, so as to not affect the normal work and insulation performance of the switch device. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a frame schematic diagram of a switch arc voltage measurement device provided by an embodiment of the present application;

[0028] Figure 2 is a measurement capacitance unit access circuit schematic diagram in a switch arc voltage measurement device provided by an embodiment of the present application;

[0029] Figure 3 is a flowchart of a switch arc voltage measurement method provided by an embodiment of the present application. DETAILED DESCRIPTION

[0030] In order to better understand the technical scheme of the present application, the technical scheme in the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of the present application.

[0031] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or a chronological sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion.

[0032] In one embodiment of the present application, a switching arc voltage measuring device is provided for measuring the arc voltage of a to-be-measured switch contact fracture, which comprises a measurement capacitor unit, a signal acquisition unit and a data processing unit; see Figure 1 The measurement capacitor unit comprises a high-voltage arm measurement capacitor C1 and a low-voltage arm measurement capacitor C2. One end of the high-voltage arm measurement capacitor C1 is connected to the lead-out line of the high-voltage side of the to-be-measured switch contact fracture, the other end of the high-voltage arm measurement capacitor C1 and one end of the low-voltage arm measurement capacitor C2 are connected, and the other end of the low-voltage arm measurement capacitor C2 is connected to the lead-out line of the low-voltage side of the to-be-measured switch contact fracture.

[0033] The signal acquisition unit is connected to the low-voltage arm measurement capacitor C2 and is configured to acquire and preprocess the voltage signal input by the low-voltage arm measurement capacitor C2, so as to meet the requirements of subsequent data further processing.

[0034] The data processing unit is connected to the signal acquisition unit and is configured to determine the arc voltage between the two ends of the to-be-measured switch contact fracture according to the preprocessed arc voltage signal data and in combination with the voltage division ratio relationship of the high-voltage arm measurement capacitor C1 and the low-voltage arm measurement capacitor C2.

[0035] Specifically, the to-be-tested switch is a direct current circuit breaker, and the high-voltage arm measurement capacitor C1 and the low-voltage arm measurement capacitor C2 are non-calibrated capacitors, which have the characteristics of stable capacitance value and high voltage resistance. In addition to the different capacitance values, the other specification parameters are consistent. The signal acquisition unit comprises a sampling module, a filtering module and an amplification module connected in sequence, the sampling module is used for sampling and processing the voltage signal input by the low-voltage arm measurement capacitor C2, the filtering module is used for filtering the collected voltage signal, and the amplification module is used for appropriately amplifying the voltage signal after filtering, so as to facilitate further processing of subsequent data. The data processing unit comprises a microprocessor and an upper computer

[0036] In order to provide safety and power supply for the back-end measurement circuit, the measurement device further comprises an overvoltage protection unit and a power supply unit, the signal acquisition unit is connected with the low-voltage arm measurement capacitor C2 through the overvoltage protection unit, the overvoltage protection unit can be a pressure-sensitive resistor (MOV), a transient voltage suppression diode (TVS), a gas discharge tube (GDT) or a combination of multiple devices in series and parallel; the overvoltage protection unit is connected in parallel across the low-voltage arm measurement capacitor C2 and is composed of a surge protection device with voltage clamping function; the action threshold of the overvoltage protection unit needs to be higher than the arc voltage, and the clamping voltage thereof should not be higher than the bearing limit of the signal acquisition unit and the data processing unit. The power supply unit comprises a commercial power supply, a switching power supply or a battery pack, which supplies power to the signal acquisition unit and the data processing unit.

[0037] In order to protect the capacitor measurement unit, referring to Figure 2 , the measurement device further comprises a first resistor, a first inductor, a second resistor and a second inductor, the to-be-tested switch contact fracture high-voltage side lead-out line, the first resistor, the first inductor and the high-voltage arm measurement capacitor C1 are connected in sequence, the to-be-tested switch contact fracture low-voltage side lead-out line, the second resistor, the second inductor and the low-voltage arm measurement capacitor C2 are connected in sequence, and the to-be-tested switch contact fracture low-voltage side is grounded.

[0038] The switch arc voltage measuring device provided by the embodiment has the following advantages: non-invasive, without destroying the structure of the existing device; the self-made capacitor is a non-standard product, with small parasitic parameters, small size and structure, high voltage resistance and good frequency response characteristics; integrated design, short voltage signal transmission distance, without the need of coaxial cable, and ordinary copper core line; overvoltage suppression and protection of the rear-end measuring circuit through the protection unit; data transmission to the host computer, without being limited to an oscilloscope.

[0039] The switch arc voltage measuring device provided by the embodiment has the following advantages: non-invasive, without destroying the structure of the existing device; the self-made capacitor is a non-standard product, with small parasitic parameters, small size and structure, high voltage resistance and good frequency response characteristics; integrated design, short voltage signal transmission distance, without the need of coaxial cable, and ordinary copper core line; overvoltage suppression and protection of the rear-end measuring circuit through the protection unit; data transmission to the host computer, without being limited to an oscilloscope.

[0040] In one embodiment of the present application, a switch arc voltage measuring method is provided, comprising the following steps:

[0041] The measuring device is connected to the ends of the switch contacts to be measured; the voltage signal data at the ends of the low-voltage arm measuring capacitor C2 is collected and preprocessed by the signal acquisition unit; the data processing unit calculates the arc voltage at the ends of the switch to be measured according to the voltage division ratio relationship between the high-voltage arm measuring capacitor C1 and the low-voltage arm measuring capacitor C2, in combination with the voltage signal data collected and preprocessed by the signal acquisition unit. The signal acquisition unit is connected to the measuring capacitor unit through the overvoltage protection unit, and the overvoltage protection unit disconnects the connection between the signal acquisition unit and the measuring capacitor unit when the voltage at the ends of the low-voltage arm measuring capacitor C2 exceeds the preset threshold.

[0042] Specifically, referring to Figure 3The measurement device is connected to the dynamic and static contact of the switch device, and it is assumed that the voltage of the breakage is U at this time; when the switch device is closed, the voltage U is 0 under the premise of ignoring the on-state voltage drop; when the switch device starts to open, the arc is generated between the dynamic and static contact of the switch device, and the voltage U of the breakage is equal to the arc voltage; with the increasing distance between the dynamic and static contact, the arc length is stretched, and the arc voltage will gradually rise, and remains unchanged after entering the stable arc stage. In this process, the measurement capacitor unit will bear the transient arc voltage with high frequency amplitude variation, and according to the voltage division ratio relationship between the high-voltage arm measurement capacitor C1 and the low-voltage arm measurement capacitor C2, the dynamically changing arc voltage signal is proportionally introduced and sent to the signal acquisition unit in the rear end. The signal acquisition unit is directly connected with the low-voltage arm measurement capacitor C2, and the voltage division signal of the arc voltage borne by the low-voltage arm measurement capacitor C2 is collected and pretreated correspondingly, so that the voltage division signal meets the requirements of subsequent data further processing; the data processing unit is directly connected with the signal acquisition unit, and is used for receiving the voltage data of the low-voltage arm measurement capacitor C2, and determining the arc voltage between the breakage of the switch device to be measured according to the voltage division ratio relationship between the high-voltage arm measurement capacitor C1 and the low-voltage arm measurement capacitor C2.

[0043] When the switch device is completely opened and the arc is extinguished, the voltage between the breakage of the switch device is equal to the system voltage, at this time, the measurement capacitor unit will directly bear the high voltage of the system, and the overvoltage protection unit will act quickly. Because the capacitor has the characteristics of direct current isolation and alternating current transmission, for the direct current system voltage, the measurement capacitor unit will show complete breakage characteristics, so as not to affect the normal work of the switch device; and the overvoltage protection unit acts quickly under the action of the system high voltage, and clamps the voltage between the low-voltage arm measurement capacitor C2 within the limit of the rear-end measurement circuit, so as to protect the rear-end measurement circuit from being damaged by the system high voltage.

[0044] According to the arc voltage data processed by the data processing unit, the safety monitoring of the switch to be measured can be carried out, which specifically includes:

[0045] Through the real-time recorded arc voltage data, the time of the arc existing between the start of opening and the complete opening of the switch to be measured is obtained, if the time of single arc existing is greater than the first preset value, it is judged that the opening action of the switch to be measured is delayed, and the maintenance personnel needs to be notified to maintain the switch to be measured. For example, if the time of single arc existing is greater than 0.5s, it indicates that the separation mechanism of the switch contact appears failure, so that the switch cannot be quickly disconnected, and should be maintained. Through multiple opening tests, the stability of the opening speed of the circuit breaker is tested.

[0046] By the real-time recorded arc voltage data, the size of the arc voltage between the start of the opening of the switch under test to the complete opening is obtained, if the time when the arc voltage is less than the second preset value is greater than the third preset value, it is judged that the switch under test has the risk of burning out, and the maintenance personnel need to be notified to maintain the switch under test. For example, the time when the single arc voltage is less than 20V is greater than 0.25s, which indicates that the contact of the switch has the risk of being burned out, because the smaller the arc voltage is, the greater the current at the contact is, and the temperature at the contact rises rapidly, and if the time is too long, the switch under test is easily damaged.

[0047] If the switch under test shows in the closing state, and the arc voltage is monitored to appear, it is judged that the switch under test has not completed closing, and the maintenance personnel need to be notified to maintain the switch under test; during the maintenance process, if the maintenance personnel find that the switch under test has actually completed closing, the measuring device needs to be maintained. For example, the external system has shown that the switch device has been closed, but the arc voltage can still be monitored, which indicates that the switch has not actually completely closed, or the measuring device has failed, and both need to be maintained and checked.

[0048] The switch arc voltage measurement method provided in the embodiment can realize real-time measurement of the switch arc voltage by adopting the capacitor voltage division principle, and by using the characteristics of the capacitor that it is direct current blocking and alternating current passing, the measuring capacitor unit will show complete breaking characteristics for the direct current system voltage, so that the normal work and insulation performance of the switch device are not affected.

[0049] The switch arc voltage measurement device and measurement method provided in the application overcome the defects and deficiencies of the existing measurement devices or measurement schemes, can accurately measure the arc voltage between the breaking points of the switch during the breaking process, avoid the interference problem of the coaxial cable transmission measurement signal, can withstand the system voltage between the breaking points of the switch after the switch completes the breaking, maintain good insulation performance, and do not affect the normal work and insulation performance of the switch device.

[0050] The above only describes the preferred embodiments of the application, and does not limit the patent scope, any equivalent structure or equivalent flow transformation made by using the content of the specification and drawings, direct or indirect application in other related technical fields, are also included in the patent protection scope of the application.

Claims

1. A switched arc pressure measurement device, characterized by, It is used for measuring arc voltage of the switch contact fracture to be measured, and comprises a measurement capacitance unit, a signal acquisition unit and a data processing unit; The measurement capacitance unit comprises a high-voltage arm measurement capacitance C1 and a low-voltage arm measurement capacitance C2, one end of the high-voltage arm measurement capacitance C1 is connected with an outgoing line of a high-voltage side of the switch contact fracture to be measured, the other end of the high-voltage arm measurement capacitance C1 and one end of the low-voltage arm measurement capacitance C2 are connected, the other end of the low-voltage arm measurement capacitance C2 is connected with an outgoing line of a low-voltage side of the switch contact fracture to be measured, and the high-voltage arm measurement capacitance C1 and the low-voltage arm measurement capacitance C2 are consistent in other specification parameters except for different capacitance values; The signal acquisition unit is connected with the low-voltage arm measurement capacitance C2 and is configured to collect and pre-process voltage signals input by the low-voltage arm measurement capacitance C2; The data processing unit is connected with the signal acquisition unit and is configured to determine arc voltage between two ends of the switch contact fracture to be measured according to pre-processed arc voltage signal data and in combination with a voltage division ratio relationship of the high-voltage arm measurement capacitance C1 and the low-voltage arm measurement capacitance C2; The signal acquisition unit is connected with the low-voltage arm measurement capacitance C2 through an overvoltage protection unit, the overvoltage protection unit is connected in parallel between two ends of the low-voltage arm measurement capacitance C2 and is composed of a surge protection device with a voltage clamping function, an action threshold value of the overvoltage protection unit needs to be higher than the arc voltage, and a clamping voltage of the overvoltage protection unit should not be higher than a bearing limit of the signal acquisition unit and the data processing unit; The first resistance, the first inductance, the second resistance and the second inductance are further included, the outgoing line of the high-voltage side of the switch contact fracture to be measured, the first resistance, the first inductance and the high-voltage arm measurement capacitance C1 are sequentially connected, the outgoing line of the low-voltage side of the switch contact fracture to be measured, the second resistance, the second inductance and the low-voltage arm measurement capacitance C2 are sequentially connected, and the low-voltage side of the switch contact fracture to be measured is grounded; A method for measuring switch arc voltage by using the switch arc voltage measurement device comprises the following steps: obtaining a time of existence of an arc between starting opening and complete opening of the switch to be measured through real-time recorded arc voltage data, judging that there is a delay in the opening action of the switch to be measured if the time of existence of the single arc is greater than a first preset value, and notifying maintenance personnel to maintain the switch to be measured; Obtaining a size of arc voltage between starting opening and complete opening of the switch to be measured through real-time recorded arc voltage data, judging that there is a risk of burning out of the switch to be measured if the arc voltage is less than a second preset value for a time greater than a third preset value, and notifying maintenance personnel to maintain the switch to be measured.

2. The switched-arc pressure measurement device of claim 1, wherein, The switch to be measured is a direct-current circuit breaker, the signal acquisition unit comprises a sampling module, a filtering module and an amplifying module which are sequentially electrically connected, the sampling module is used for sampling processing voltage signals input by the low-voltage arm measurement capacitance C2, the filtering module is used for filtering processing of the collected voltage signals, and the amplifying module is used for appropriate amplification of the voltage signals after filtering processing.

3. A method of measuring switch arc voltage, characterized by, The method comprises the following steps: The switch arc voltage measurement device according to any one of claims 1 is connected to both ends of the switch contact to be measured; The signal acquisition unit acquires and pre-processes the voltage signal data across the low-voltage arm measurement capacitor C2; The data processing unit calculates the arc voltage across the switch contact to be measured according to the voltage signal data acquired and pre-processed by the signal acquisition unit, in combination with the voltage division ratio relationship between the high-voltage arm measurement capacitor C1 and the low-voltage arm measurement capacitor C2.

4. The switched-arc voltage measurement method of claim 3, wherein, The signal acquisition unit is connected to the measurement capacitor unit through an overvoltage protection unit, which disconnects the connection between the signal acquisition unit and the measurement capacitor unit when it detects that the voltage across the low-voltage arm measurement capacitor C2 exceeds a preset threshold.

5. The switched-arc voltage measurement method of claim 3, wherein, The time of the existence of the arc between the start of the opening of the switch to be measured and the complete opening is obtained through the real-time recorded arc voltage data, and if the time of the existence of the single arc is greater than a first preset value, it is determined that the opening action of the switch to be measured is delayed, and the maintenance personnel need to be notified to maintain the switch to be measured.

6. The switched-arc voltage measurement method of claim 3, wherein, The size of the arc voltage between the start of the opening of the switch to be measured and the complete opening is obtained through the real-time recorded arc voltage data, and if the time when the arc voltage is less than a second preset value is greater than a third preset value, it is determined that the switch to be measured has a risk of burning out, and the maintenance personnel need to be notified to maintain the switch to be measured.

7. The switched-arc voltage measurement method of claim 3, wherein, If the switch to be measured is in the closed state and the arc voltage is monitored, it is determined that the switch to be measured has not completed the closing, and the maintenance personnel need to be notified to maintain the switch to be measured.

8. The switched-arc voltage measurement method of claim 7, wherein, If the maintenance personnel find that the switch to be measured has actually completed the closing during the maintenance process, the measurement device needs to be maintained.

Images