Online monitoring method and device for vacuum degree of vacuum bubble arc extinguish chamber of high-voltage switch circuit breaker

Abstract

The invention discloses a high-voltage switch circuit breaker vacuum bubble arc extinguish chamber vacuum degree on-line monitoring method and device. The method comprises the steps of measuring a main loop current value of a high-voltage switch circuit breaker at the moment of opening and closing through a current transformer; performing spectrum analysis on the main loop current at the moment of opening and closing through fast Fourier transform to obtain an opening and closing arc spectrum value; according to the current on-off current value, calculating the residual electrical life of the contact; and calculating the vacuum degree of the arc extinguish chamber of the vacuum bubble of the high-voltage switch circuit breaker according to the current value of the main loop at the moment of opening and closing, the frequency spectrum value of the opening and closing arc at the moment of opening and closing and the current service life of the contact. And the vacuum degree condition of the high-voltage switch circuit breaker is comprehensively judged by combining the measured current value of the loop when the high-voltage switch circuit breaker is switched on and switched off, the residual electric life of the contact and the arc-extinguishing discharge frequency spectrum at the switching-on and switching-off moment, so that the problem that misjudgment exists when the vacuum degree is judged only by depending on the arc-extinguishing discharge frequency spectrum is solved, and the practical value is higher.

Description

Technical Field

[0001] The present invention belongs to the technical field of safety monitoring of high-voltage switch circuit breakers, and more specifically, relates to a method and device for online monitoring the vacuum degree of a vacuum bubble arc extinguishing chamber of a high-voltage switch circuit breaker. Background Art

[0002] The high-voltage switch circuit breaker will produce an arcing effect under the influence of the circuit current when it is opened and closed with load. If the arcing is too large, the opening and closing contacts will be burned, causing premature damage to the opening and closing contacts of the high-voltage switch circuit breaker. In order to effectively extinguish the arc generated at the moment of opening and closing the high-voltage switch circuit breaker with load, a vacuum bubble is usually used to extinguish the arc in a vacuum arc extinguishing chamber, which is now widely used. The vacuum bubble of the high-voltage switch circuit breaker is affected by the processing technology and long-term use, which will cause its vacuum degree to decrease. The reduction of the vacuum degree of the vacuum bubble of the high-voltage switch circuit breaker will also reduce the arc extinguishing performance of the vacuum bubble.

[0003] The existing technologies for vacuum degree detection of vacuum bubbles in high-voltage switch circuit breakers are: The patent with application number CN201610205545.5 discloses a microwave vacuum warning device for high-voltage switch circuit breakers. Total reflection occurs on the metal shielding cover. Among the media through which the microwave signal passes, except for the relative dielectric constant of the gas in the vacuum interrupter, the dielectric constants of the other media remain unchanged. The relative dielectric constant of the gas in the vacuum interrupter is measured by the transmission method, and the change of the relative dielectric constant of the gas in the vacuum interrupter is quantified by the reflection coefficient of the microwave signal, so as to measure the change of the vacuum degree in the high-voltage switch circuit breaker. However, the shielding cover needs to be installed, which is susceptible to the pressure equalization conditions required by the installation space and the electric field distribution, and it is difficult to meet the on-site test conditions.

[0004] The patent with application number CN202210323277.2 discloses an online vacuum degree monitoring method and device for high-voltage high-voltage switch circuit breakers. The monitoring method captures the electromagnetic wave signal of the high-voltage high-voltage switch circuit breaker by an antenna arranged outside the vacuum interrupter, and obtains the first data point through the data acquisition system; the first data point is filtered to obtain the second data point, and the second data point is decomposed by wavelet packet to construct the first eigenvector of the second data point; the first eigenvector is input into the PCA-BP neural network optimization model, and the PCA-BP neural network optimization model uses the principal component analysis method to reduce the feature dimension and screen the first eigenvector to obtain the second eigenvector, and then monitors the vacuum degree of the high-voltage high-voltage switch circuit breaker according to the second eigenvector and outputs the vacuum degree monitoring result. However, this method needs to go through the neural network optimization model, the calculation amount is large, and the high-frequency electromagnetic signal coupled by the antenna is easily affected by environmental noise.

[0005] The patent with application number CN202311718727.9 discloses a high-frequency signal acquisition circuit and method for vacuum arc extinguishing of high-voltage switch breaker with adaptive follow-up amplification, which belongs to the field of signal processing. It includes a capacitive voltage divider sensor, a second-order RC passive high-pass filter circuit, an adaptive follow-up signal conditioning circuit based on spectrum feedback method, a high-speed analog-to-digital conversion circuit and a microprocessor circuit, a switch-on and switch-off command input circuit, a power supply circuit, a display circuit, and a communication circuit; the spectrum of the instantaneous high-frequency voltage signal of the high-voltage switch breaker during the switch-on and switch-off process is collected by a capacitive voltage divider sensor installed on the busbar, and the frequency corresponding to the spectrum of the collected high-frequency signal is obtained by fast Fourier transform, and the amplification factor of the AC high-frequency signal is determined according to the corresponding relationship between the frequency and the amplification factor; according to the size of the spectrum, the vacuum degree of the arc extinguishing chamber of the high-voltage switch breaker is indirectly reflected. However, this method uses a single voltage signal to reflect the spectrum of the current signal, but the spectrum of the breaking current of the vacuum bubble arc extinguishing chamber is related to the vacuum degree and the size of the on-off current, and the vacuum degree cannot be fully reflected by simply collecting the current spectrum. Summary of the invention

[0006] In order to solve the deficiencies in the prior art, the present invention provides an online monitoring method for the vacuum degree of a vacuum bubble arc extinguishing chamber of a high-voltage switch circuit breaker based on a current and current spectrum analysis method. The method measures the circuit current of the high-voltage switch circuit breaker at the moment of opening and closing by a current transformer. According to Kirchhoff's law, the current at each point on the same branch is consistent. The arcing current inside the vacuum arc extinguishing chamber is obtained based on the measured circuit current at the moment of opening and closing. Then, the current discharge spectrum at the moment of opening and closing is obtained by performing FFT transformation on the collected current signal. At the same time, the current value of the circuit when the high-voltage switch circuit breaker is opened and closed and the contact life are combined as the basis to comprehensively judge the vacuum degree of the high-voltage switch circuit breaker.

[0007] The present invention adopts the following technical solution.

[0008] The first aspect of the present invention provides a method for online monitoring of vacuum degree of a vacuum bubble interrupter of a high-voltage switch circuit breaker, comprising the following steps: Measure the main circuit current value of the high-voltage switch circuit breaker at the moment of opening and closing through the current transformer; Through fast Fourier transform, the spectrum of the main circuit current at the moment of opening and closing is analyzed to obtain the spectrum value of the opening and closing arc. Calculate the remaining electrical life of the contact according to the breaking current value; The vacuum degree of the vacuum bubble interrupter of the high-voltage switch circuit breaker is calculated based on the main circuit current value at the moment of opening and closing, the arc spectrum value at the moment of opening and closing, and the current contact life.

[0009] Preferably, during the fast Fourier transform, a window function is used to transform the collected current data into a frequency domain. The window function used is defined in the time domain as: , in, is the number of the current sampling point. is the number of sample points; Perform FFT transformation on it and obtain the modulus of the discrete window function and Phase for: , in, is the angular frequency, .

[0010] Preferably, the remaining electrical life of the contact is calculated in the following manner: Obtain the initial relative life of high-voltage switch circuit breakers before commissioning ; Rated breaking current And the number of interruptions allowed under the rated breaking current ; Calculate the relative wear of the contacts during each breaking process after commissioning ; Calculate the remaining relative life of the contact after this breaking : , in, For the Relative wear of contacts after the first breaking, is the current breaking times of the high voltage circuit breaker, is the initial value of relative electrical life, a new high voltage circuit breaker .

[0011] Preferably, the relative wear of the contacts during each breaking process is It is calculated as follows: Collect the main circuit current value at each disconnection and the rated breaking current value For comparison, when When , the electrical wear of the contacts is: , when When , the electrical wear of the contacts is: , in, It is the rated breaking current of the circuit breaker.

[0012] Preferably, the calculation of the relative vacuum degree of the vacuum bubble interrupter of the high-voltage switch circuit breakerh , specifically: according to the main circuit current value at the moment of opening and closing I Calculate the current proportionality factor K : , in, is the rated breaking current of the circuit breaker; Vacuum degree of vacuum interrupter h The calculation formula is: , in, X is the arc spectrum value at the moment of opening and closing, L is the current contact life, ɑ is the proportionality factor, which depends on the rated current of the circuit breaker , take a coefficient between 0 and 1, rated current The smaller it is, the closer the value is to 1.

[0013] The second aspect of the present invention provides an online monitoring device for the vacuum degree of a vacuum bubble interrupter of a high-voltage switch circuit breaker, using the monitoring method described in the first aspect of the present invention, comprising a current transformer module, a high-speed A / D sampling circuit, a power supply module, a storage module, a switch-off command input module, a switch-on command input module, a microprocessor module, a communication module, and a display module: The current transformer module is composed of a three-phase current transformer and a resistor in parallel, and the output ends of the three-phase current transformers are respectively connected to the input ends of three high-speed A / D sampling circuits; The output end of the high-speed A / D sampling circuit is connected to the I / O port of the input end of the microprocessor module; the output ends of the opening command input module and the closing command input module are connected to the I / O port of the input end of the microprocessor module; the input end of the communication module is connected to the communication port of the output end of the microprocessor module; the input end of the display module is connected to the I / O port of the input end of the microprocessor module; the output end of the power module is connected to the power interface corresponding to the microprocessor module; the input end of the storage module is connected to the I / O port of the output end of the microprocessor module; The output ends of the opening command input module and the closing command input module transmit signals to the microprocessor module during opening and closing. The microprocessor module begins to obtain the effective value of the current, the remaining electrical life of the contacts, and the vacuum condition. The process is as follows: the current transformer module collects the bus current and converts it into voltage so that the high-speed A / D can sample the current; the high-speed A / D sampling circuit samples the current, and the sampled current signal is sent to the microprocessor circuit for calculation and fast Fourier transform, that is, spectrum analysis is performed to obtain the remaining electrical life and vacuum condition of the contacts, which are displayed on the display circuit and transmitted to the remote end through the communication module.

[0014] Preferably, the current transformer uses a current transformer with a transformation ratio of 2000:1, 5A / 2.5mA, the current at the output end of the current transformer is 0-2.5mA, and a 1kΩ resistor is connected in parallel to the output end of the current transformer to convert the current into a 0-2.5V voltage signal.

[0015] Preferably, when measuring a large current of any magnitude, another large current transformer with a transformation ratio of 100A / 5A, 500A / 5A, 1000A / 5A, 2000A / 5A or 5000A / 5A is connected to the input end of the current transformer according to the magnitude of the measured current.

[0016] Preferably, the high-speed A / D sampling circuit adopts a 10-bit successive approximation type High-speed analog-to-digital converter, the opening and closing time of the high-voltage switch circuit breaker is 5-10ms. A 1MHz sampling frequency is selected, and 5000-10000 points can be collected in 5-10mS. The window function is used to select 4096 points near the maximum value for FFT transformation. The collection of 4096 points can collect the frequency spectrum characteristics of the high-voltage switch circuit breaker loop current signal during the opening and closing process.

[0017] Preferably, the opening command input module and the closing command input module are respectively connected by passive switch signals.

[0018] The beneficial effects of the present invention are as follows: 1) by directly obtaining the main circuit current signal of the high-voltage switch circuit breaker at the moment of load opening and closing by means of a current transformer, the current signal can be directly collected without filtering and amplification, making the measurement circuit simpler; by performing FFT transformation on the collected signal, the arc extinguishing discharge spectrum at the moment of opening and closing is obtained, and by comparing it with the opening and closing spectrum during commissioning or maintenance, the degree of vacuum degree degradation can be judged; 2) In order to more accurately realize the online monitoring of the vacuum degree of the vacuum bubble arc extinguishing chamber of the high-voltage switch circuit breaker, considering the influence of the opening and closing current and the electrical life of the contacts on the arc extinguishing discharge spectrum at the moment of opening and closing, it is proposed to combine the measured current value of the circuit when the high-voltage switch circuit breaker is opened and closed, the calculated electrical life of the contacts and the arc extinguishing discharge spectrum at the moment of opening and closing to comprehensively judge the vacuum degree of the high-voltage switch circuit breaker. This overcomes the problem of misjudgment when judging the vacuum degree of the high-voltage switch circuit breaker solely by relying on the arc extinguishing discharge spectrum at the moment of opening and closing, and is more practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the principle structure diagram of the vacuum degree online monitoring device of the vacuum bubble arc extinguishing chamber of the high-voltage switch circuit breaker; Figure 2 The present invention is a flow chart of the method for online monitoring of vacuum degree of vacuum bubble arc extinguishing chamber of high voltage switch circuit breaker. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only embodiments of a part of the present invention, rather than all embodiments. Based on the spirit of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0021] like Figure 2 As shown, Embodiment 1 of the present invention provides a method for online monitoring of vacuum degree of a vacuum bubble interrupter of a high-voltage switch circuit breaker, comprising the following steps: Measure the main circuit current value of the high-voltage switch circuit breaker at the moment of opening and closing through the current transformer; Through fast Fourier transform, the spectrum of the main circuit current at the moment of opening and closing is analyzed to obtain the spectrum value of the opening and closing arc. Calculate the remaining electrical life of the contact according to the breaking current value; The vacuum degree of the vacuum bubble interrupter of the high-voltage switch circuit breaker is calculated based on the main circuit current value at the moment of opening and closing, the arc spectrum value at the moment of opening and closing, and the current contact life.

[0022] Preferably, during the fast Fourier transform, a window function is used to convert the collected data into a frequency domain to reduce spectrum leakage. Specifically, the frequency domain of the current data of this embodiment is 4096; The window function used is defined in the time domain as: , in, is the number of the sample point, is the number of sample points; Performing FFT transformation on it, we can get , in, , is the continuous spectrum of the rectangular window, and the formula is: , The spectrum expression of the discrete window function is obtained: , in,

[0023] The modulus of the discrete window function is obtained as , the phase is .

[0024] Preferably, the remaining electrical life of the contact is calculated as follows: Assume that the electrical wear of a new high-voltage switch circuit breaker under rated breaking current is M , the allowed number of interruptions is N M , the total amount of wear allowed for the high-voltage switch breaker is considered as a fixed threshold , the total allowable wear and relative electrical life are both considered 100%; then the relative wear during a single interruption for ; Assume a total of I Type of breaking current; i The breaking current is , the allowed breaking times are , the relative electrical wear is , ; Then we can deduce: , in, To break the current The amount of electrical wear during a single interruption; Calculate the remaining relative life of the contact after this breaking : , in, For the Relative wear of contacts after the first breaking, is the current breaking times of the high voltage circuit breaker, is the initial value of relative electrical life, a new high voltage circuit breaker .

[0025] Preferably, the relative wear of the contacts during each breaking process is It is calculated as follows: Collect the main circuit current value at each disconnection and the rated breaking current value For comparison, when When , the electrical wear of the contacts is: , when When , the electrical wear of the contacts is: , in, is the rated breaking current of the circuit breaker, It is i Breaking current The number of disconnections below.

[0026] Preferably, the calculation of the relative vacuum degree of the vacuum bubble interrupter of the high-voltage switch circuit breaker h , specifically: according to the main circuit current value at the moment of opening and closing I Calculate the current proportionality factor K : , in, is the rated breaking current of the circuit breaker; Vacuum degree of vacuum interrupter h The calculation formula is: , in, X is the arc spectrum value at the moment of opening and closing, L is the current contact life, ɑ is the proportionality factor, which depends on the rated current of the circuit breaker , take a coefficient between 0 and 1, rated current The smaller it is, the closer the value is to 1.

[0027] It should be noted that the arc spectrum value at the moment of opening and closing X , contact life L , current proportionality factor K All values ​​are between 0 and 1.

[0028] like Figure 1 As described, Embodiment 2 of the present invention proposes an online monitoring device for vacuum degree of vacuum bubble interrupter of high-voltage switch circuit breaker, using the monitoring method described in the first aspect of the present invention, including a current transformer module, a high-speed A / D sampling circuit, a power supply module, a storage module, a switch-off command input module, a switch-on command input module, a microprocessor module, a communication module, and a display module; The current transformer module is composed of a three-phase current transformer and a resistor in parallel, and the output ends of the three-phase current transformers are respectively connected to the input ends of three high-speed A / D sampling circuits; The output end of the high-speed A / D sampling circuit is connected to the I / O port of the input end of the microprocessor module; the output ends of the opening command input module and the closing command input module are connected to the I / O port of the input end of the microprocessor module; the input end of the communication module is connected to the communication port of the output end of the microprocessor module; the input end of the display module is connected to the I / O port of the input end of the microprocessor module; the output end of the power module is connected to the power interface corresponding to the microprocessor module; the input end of the storage module is connected to the I / O port of the output end of the microprocessor module; The output ends of the opening command input module and the closing command input module transmit signals to the microprocessor module during opening and closing. The microprocessor module begins to obtain the effective value of the current, the remaining electrical life of the contacts, and the vacuum condition. The process is as follows: the current transformer module collects the bus current and converts it into voltage so that the high-speed A / D can sample the current; the high-speed A / D sampling circuit samples the current, and the sampled current signal is sent to the microprocessor circuit for calculation and fast Fourier transform, that is, spectrum analysis is performed to obtain the remaining electrical life and vacuum condition of the contacts, which are displayed on the display circuit and transmitted to the remote end through the communication module.

[0029] Preferably, the current transformer uses a current transformer with a transformation ratio of 2000:1, 5A / 2.5mA, the current at the output end of the current transformer is 0-2.5mA, and a 1kΩ resistor is connected in parallel to the output end of the current transformer to convert the current into a 0-2.5V voltage signal.

[0030] Preferably, when measuring a large current of any magnitude, another large current transformer with a transformation ratio of 100A / 5A, 500A / 5A, 1000A / 5A, 2000A / 5A or 5000A / 5A is connected to the input end of the current transformer according to the magnitude of the measured current.

[0031] Preferably, the high-speed A / D sampling circuit adopts a 10-bit successive approximation type High-speed analog-to-digital converter, the opening and closing time of the high-voltage switch circuit breaker is 5-10ms. A 1MHz sampling frequency is selected, and 5000-10000 points can be collected in 5-10mS. The window function is used to select 4096 points near the maximum value for FFT transformation. The collection of 4096 points can collect the frequency spectrum characteristics of the high-voltage switch circuit breaker loop current signal during the opening and closing process.

[0032] Preferably, the opening command input module and the closing command input module are respectively connected by passive switch signals.

[0033] The beneficial effects of the present invention are as follows: 1) by directly obtaining the main circuit current signal of the high-voltage switch circuit breaker at the moment of load opening and closing by means of a current transformer, the current signal can be directly collected without filtering and amplification, making the measurement circuit simpler; by performing FFT transformation on the collected signal, the arc extinguishing discharge spectrum at the moment of opening and closing is obtained, and by comparing it with the opening and closing spectrum during commissioning or maintenance, the degree of vacuum degree degradation can be judged; 2) In order to more accurately realize the online monitoring of the vacuum degree of the vacuum bubble arc extinguishing chamber of the high-voltage switch circuit breaker, considering the influence of the opening and closing current and the electrical life of the contacts on the arc extinguishing discharge spectrum at the moment of opening and closing, it is proposed to combine the measured current value of the circuit when the high-voltage switch circuit breaker is opened and closed, the calculated electrical life of the contacts and the arc extinguishing discharge spectrum at the moment of opening and closing to comprehensively judge the vacuum degree of the high-voltage switch circuit breaker. This overcomes the problem of misjudgment when judging the vacuum degree of the high-voltage switch circuit breaker solely by relying on the arc extinguishing discharge spectrum at the moment of opening and closing, and is more practical.

[0034] The present disclosure may be a system, a method and / or a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present disclosure.

[0035] A computer-readable storage medium may be a tangible device that can hold and store instructions used by an instruction execution device. A computer-readable storage medium may be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the above. More specific examples (a non-exhaustive list) of computer-readable storage media include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punch card or a raised structure in a groove on which instructions are stored, and any suitable combination of the above. The computer-readable storage medium used herein is not to be interpreted as a transient signal itself, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., a light pulse through a fiber optic cable), or an electrical signal transmitted through a wire.

[0036] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing device, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical fiber transmissions, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in the computer-readable storage medium in each computing / processing device.

[0037] The computer program instructions for performing the operations of the present disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages, such as Smalltalk, C++, etc., and conventional procedural programming languages, such as "C" language or similar programming languages. The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer, partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., using an Internet service provider to connect through the Internet). In some embodiments, by using the state information of the computer-readable program instructions to personalize an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), the electronic circuit may execute the computer-readable program instructions, thereby implementing various aspects of the present disclosure.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for online monitoring of vacuum degree of vacuum bubble interrupter of high voltage switch circuit breaker, characterized in that: The following steps are involved: Measure the main circuit current value of the high-voltage switch circuit breaker at the moment of opening and closing through the current transformer; Through fast Fourier transform, the spectrum of the main circuit current at the moment of opening and closing is analyzed to obtain the spectrum value of the opening and closing arc. Calculate the remaining electrical life of the contact according to the breaking current value; The vacuum degree of the vacuum bubble interrupter of the high-voltage switch circuit breaker is calculated based on the main circuit current value at the moment of opening and closing, the arc spectrum value at the moment of opening and closing, and the current contact life.

2. The method for online monitoring of vacuum degree of vacuum bubble interrupter of high voltage switch circuit breaker according to claim 1, characterized in that: During the fast Fourier transform, the window function is used to transform the collected current data into the frequency domain. The window function used is defined in the time domain as: ， in, is the number of the current sampling point. is the number of sample points; Perform FFT transformation on it and obtain the modulus of the discrete window function and Phase for: ， in, is the angular frequency, .

3. The method for online monitoring of vacuum degree of vacuum bubble interrupter of high voltage switch circuit breaker according to claim 2, characterized in that: Calculate the remaining electrical life of the contacts as follows: Obtain the initial relative life of high-voltage switch circuit breakers before commissioning , Rated breaking current And the number of interruptions allowed under the rated breaking current ; Calculate the relative wear of the contacts during each breaking process after commissioning ; Calculate the remaining relative life of the contact after this breaking : ， in, For the Relative wear of contacts after the first breaking, is the current breaking times of the high voltage circuit breaker, is the initial value of relative electrical life, a new high voltage circuit breaker .

4. The method for online monitoring of vacuum degree of vacuum bubble interrupter of high voltage switch circuit breaker according to claim 3, characterized in that: Relative contact wear during each breaking process It is calculated as follows: Collect the main circuit current value at each disconnection and the rated breaking current value For comparison, when When , the electrical wear of the contacts is: ， when When , the electrical wear of the contacts is: ， in, is the rated breaking current of the circuit breaker. Substituting the two equations into the relative electrical life formula of the high-voltage switch circuit breaker can obtain the remaining relative electrical life of the high-voltage switch circuit breaker.

5. A method for online monitoring of vacuum degree of vacuum bubble interrupter of high voltage switch circuit breaker according to claim 1 or 4, characterized in that: Calculating the relative vacuum degree of the vacuum bubble interrupter of the high-voltage switch circuit breaker h Specifically: according to the main circuit current value at the moment of opening and closing I Calculate the current proportionality factor K : ， in, is the rated breaking current of the circuit breaker; Vacuum degree of vacuum interrupter h The calculation formula is: ， in, X is the arc spectrum value at the moment of opening and closing, L is the current contact life, ɑ is the proportionality factor, which depends on the rated current of the circuit breaker , take a coefficient between 0 and 1, rated current The smaller it is, the closer the value is to 1.

6. An online monitoring device for vacuum degree of vacuum bubble interrupter of high voltage switch circuit breaker, using the monitoring method according to any one of claims 1 to 5, comprising: Current transformer module, high-speed A / D sampling circuit, power module, storage module, opening command input module, closing command input module, microprocessor module, communication module, display module; characterized in that: The current transformer module is composed of a three-phase current transformer and a resistor in parallel, and the output ends of the three-phase current transformers are respectively connected to the input ends of three high-speed A / D sampling circuits; The output end of the high-speed A / D sampling circuit is connected to the I / O port of the input end of the microprocessor module; the output ends of the opening command input module and the closing command input module are connected to the I / O port of the input end of the microprocessor module; the input end of the communication module is connected to the communication port of the output end of the microprocessor module; the input end of the display module is connected to the I / O port of the input end of the microprocessor module; the output end of the power module is connected to the power interface corresponding to the microprocessor module; the input end of the storage module is connected to the I / O port of the output end of the microprocessor module; The output ends of the opening command input module and the closing command input module transmit signals to the microprocessor module during opening and closing. The microprocessor module begins to obtain the effective value of the current, the remaining electrical life of the contacts, and the vacuum condition. The process is as follows: the current transformer module collects the bus current and converts it into voltage so that the high-speed A / D can sample the current; the high-speed A / D sampling circuit samples the current, and the sampled current signal is sent to the microprocessor circuit for calculation and fast Fourier transform, that is, spectrum analysis is performed to obtain the remaining electrical life and vacuum condition of the contacts, which are displayed on the display circuit and transmitted to the remote end through the communication module.

7. The device for online monitoring vacuum degree of vacuum bubble interrupter of high voltage switch circuit breaker according to claim 6, characterized in that: The current transformer uses a current transformer with a transformation ratio of 2000:1, 5A / 2.5mA. The current at the output end of the current transformer is 0-2.5mA. A 1kΩ resistor is connected in parallel to the output end of the current transformer to convert the current into a 0-2.5V voltage signal.

8. The device for online monitoring vacuum degree of vacuum bubble interrupter of high voltage switch circuit breaker according to claim 7, characterized in that: When measuring a large current of any magnitude, another large current transformer with a transformation ratio of 100A / 5A, 500A / 5A, 1000A / 5A, 2000A / 5A or 5000A / 5A is connected to the input end of the current transformer according to the magnitude of the measured current.

9. The device for online monitoring vacuum degree of vacuum bubble interrupter of high voltage switch circuit breaker according to claim 6, characterized in that: High-speed A / D sampling circuit adopts 10-bit successive approximation type High-speed analog-to-digital converter, the opening and closing time of the high-voltage switch circuit breaker is 5-10ms. A 1MHz sampling frequency is selected, and 5000-10000 points can be collected in 5-10mS. The window function is used to select 4096 points near the maximum value for FFT transformation. The collection of 4096 points can collect the frequency spectrum characteristics of the high-voltage switch circuit breaker loop current signal during the opening and closing process.

10. The device for online monitoring vacuum degree of vacuum bubble interrupter of high voltage switch circuit breaker according to claim 6, characterized in that: The opening command input module and the closing command input module are respectively connected using passive switch signals.

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