Eddy current self-driving type direct current magnetic bias treatment device with self-checking function and eddy current self-driving type direct current magnetic bias treatment method

Abstract

The invention provides an eddy current self-driven direct current magnetic bias treatment device and method with a self-checking function, and relates to the technical field of direct current magnetic bias treatment. The device comprises a direct current blocking protection module, the direct current blocking protection module comprises a direct current blocking capacitor connected with a neutral point of a transformer in series and a bypass protection unit connected with the direct current blocking capacitor in parallel, and the bypass protection unit comprises high-energy zinc oxide and an eddy current self-driving switch assembly; the current generator is used for releasing simulated fault current for the direct current blocking protection module when the direct current blocking protection module is overhauled; the monitoring module is used for monitoring state information of the blocking protection module; the judgment module is used for judging the health state of each device in the direct current blocking protection module according to the state information of a direct current blocking capacitor, high-energy zinc oxide and an eddy current self-driven switch in the direct current blocking protection module in the maintenance process; and the control module is used for sending out corresponding alarm information according to the judgment information of the judgment module. The problems of complex control and low reliability in a traditional scheme are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of DC bias mitigation, and more particularly, to an eddy current self-driven DC bias mitigation device and method with a self-checking function. Background Art

[0002] When the DC transmission system operates in bipolar asymmetry or monopole mode, a certain amount of DC current flows into the ground through the DC grounding electrode, and at the same time, unequal potentials are formed on the ground surface. At this time, the DC current may enter the transformer winding through the transformer neutral point, forming a DC current in the transformer winding, and the operating point of the transformer magnetic density shifts, causing DC bias in the transformer. Most of the existing capacitor-type DC bias mitigation devices use power electronic switches as the bypass system, and there are the following two main problems: 1) The operation of the power electronic device itself has high requirements for the working conditions, which are difficult to meet on-site and there are potential failure hazards; 2) The control system is complex, and the electronic component itself has strict requirements for the ambient temperature, and there is a risk of high failure rate.

[0003] The traditional DC bias mitigation equipment uses power electronic components as the capacitor bypass and the control system collects the neutral point current signal as the action signal of the bypass switch, which has the problems of poor reliability and high operation and maintenance costs. Summary of the Invention

[0004] The problem solved by the present invention is that the traditional DC bias mitigation equipment uses power electronic components as the capacitor bypass and the control system collects the neutral point current signal as the action signal of the bypass switch, which has the problems of poor reliability and high operation and maintenance costs.

[0005] To solve the above problems, on the one hand, the present invention provides an eddy current self-driven DC bias mitigation device with a self-checking function, characterized in that the device includes: A DC isolation and protection module, which includes a DC isolation capacitor connected in series with the transformer neutral point, a high-energy zinc oxide component connected in parallel with the DC isolation capacitor, and an eddy current self-driven switch component. There is a maintenance disconnect switch connected in series between the transformer neutral point and the ground wire, and an input disconnect switch is connected in series between the DC isolation capacitor and the transformer neutral point. The eddy current self-driven switch component includes a self-driven coil connected in series between the input disconnect switch and the DC isolation capacitor and an eddy current self-driven switch connected in parallel with the high-energy zinc oxide component; A current generator, which is used to release an analog fault current to the DC isolation and protection module when the DC isolation and protection module is under maintenance; A monitoring module, which is used to monitor the state information of the DC isolation capacitor, high-energy zinc oxide, and eddy current self-driven switch in the DC isolation and protection module; A judgment module, which is used to judge the health status of each device in the DC isolation and protection module according to the state information of the DC isolation capacitor, high-energy zinc oxide, and eddy current self-driven switch in the DC isolation and protection module during the maintenance process.

[0006] Preferably, the operation process of the DC isolation protection module is as follows: When the system is operating normally, the isolating switch is closed, the maintenance isolating switch is open, the eddy current self-driving switch is in the off state, and the DC isolation capacitor is in the DC isolation operation state. When a short circuit occurs in the system, the voltage on the DC isolation capacitor rises rapidly, triggering the high-energy zinc oxide to conduct and limiting the voltage across the capacitor, thereby protecting the DC isolation capacitor; When the protection fails due to abnormal parameters of the high-energy zinc oxide component, the short-circuit current flows through the self-driving coil of the eddy current self-driving switch component, and the eddy current disk of the eddy current self-driving switch is driven by the eddy current to close the arc extinguishing chamber, bypassing the capacitor bank. After the short-circuit current disappears, the eddy current self-driving switch returns to the off working condition.

[0007] Preferably, the process of using the current generator to maintain the DC isolation protection module is as follows: There is a locking connection between the maintenance isolating switch and the input isolating switch. When maintenance is required, after the maintenance isolating switch is closed, the input isolating switch is opened, and the current generator is connected in parallel across the DC isolation capacitor to simulate the release of the fault current through the current generator; After releasing the current through the current generator, the monitoring module monitors the status information of the DC isolation capacitor, the high-energy zinc oxide, and the eddy current self-driving switch respectively; after turning off the current release of the current generator, the opening action of the eddy current self-driving switch is monitored.

[0008] Preferably, the monitoring module includes: A DC isolation capacitor health monitoring unit for evaluating the insulation aging state of the DC isolation capacitor by measuring the capacitance decay rate and the dielectric loss angle of the DC isolation capacitor; A high-energy zinc oxide diagnosis unit for monitoring the temperature change information of the high-energy zinc oxide and the change information of the current magnitude passing through the high-energy zinc oxide; A self-driving switch life prediction unit for monitoring the closing and opening action times of the eddy current self-driving switch.

[0009] Preferably, the judgment module judges the health state of the DC isolation capacitor in the DC isolation protection module according to the status information of the DC isolation capacitor in the DC isolation protection module. The specific process is as follows: The DC isolation capacitor health monitoring unit uses current transformers and voltage transformers to collect the current and voltage signals of the DC isolation capacitor respectively, calculates the effective values of the current and voltage respectively, and calculates the capacitance decay rate of the DC isolation capacitor by comparing with historical data; If the capacitance decay rate reaches the preset decay rate risk threshold, further tests are performed on the DC-blocking capacitor: injecting a high-frequency test signal, measuring the impedance spectrum of the DC-blocking capacitor, calculating the equivalent series resistance and capacitive reactance, calculating the tangent of the dielectric loss angle through the equivalent series resistance and capacitive reactance, and judging the insulation aging state of the DC-blocking capacitor through the tangent of the dielectric loss angle: If the calculated tangent value of the dielectric loss angle of the DC-blocking capacitor is greater than the preset standard tangent value of the loss angle, the DC-blocking capacitor needs to be repaired or replaced; If the calculated tangent value of the dielectric loss of the DC-blocking capacitor is less than or equal to the preset standard tangent value of the loss, it indicates that the state of the DC-blocking capacitor is normal.

[0010] Preferably, the judgment module judges the health state of the high-energy zinc oxide in the DC-blocking protection module according to the state information of the high-energy zinc oxide in the DC-blocking protection module. The specific process is as follows: The high-energy zinc oxide diagnosis unit uses a current transformer to collect the change information of the current passing through the high-energy zinc oxide, generates a current-time change curve, and uses a temperature sensor to collect the temperature-time change information of the high-energy zinc oxide and generates a temperature-time change curve; Obtain the high-energy zinc oxide current-temperature change standard curve according to historical data, integrate the current-time change curve and the temperature-time change curve, and generate the current-temperature change actual curve; Obtain the standard temperature at which the high-energy zinc oxide reaches the preset current standard value through the current-temperature change standard curve, and obtain the actual temperature at which the high-energy zinc oxide reaches the preset current standard value through the current-temperature change actual curve; Judge the deterioration of the high-energy zinc oxide by comparing the actual temperature with the standard temperature: If the actual temperature is less than or equal to the standard temperature, it indicates that the state of the high-energy zinc oxide is normal; If the actual temperature is greater than the standard temperature, it indicates that the fission of the high-energy zinc oxide is serious, and the controller issues an alarm for repairing or replacing the high-energy zinc oxide.

[0011] Preferably, the judgment module judges the health state of the eddy current self-driving switch in the DC-blocking protection module according to the state information of the eddy current self-driving switch in the DC-blocking protection module. The specific process is as follows: The self-driving switch life prediction unit respectively collects the closing action time and opening action time of the eddy current self-driving switch, and judges the health state of the eddy current self-driving switch by comparing the closing action time with the preset standard closing action time and the opening action time with the preset standard opening action time: If the closing action time is less than or equal to the standard closing action time and the opening action time is less than or equal to the standard opening action time, it indicates that the state of the eddy current self-driving switch is normal; If the closing action time is longer than the standard closing action time or the opening action time is longer than the standard opening action time, the eddy current self-driven switch needs to be repaired or replaced.

[0012] Preferably, the monitoring module further includes: The comprehensive health assessment unit is used to construct the equipment health index based on the capacitance decay rate of the DC blocking capacitor, the temperature rise curve of the high-energy zinc oxide, and the eddy current self-driven switch action time series: , in, 、 、 is the weight coefficient, ; is the measured capacitance value, is the initial capacitance value, is the peak temperature of zinc oxide, is the standard temperature rise threshold, is the actual action time of the switch, is the standard action time; Compare the calculated device health index with the preset health index threshold: If the device health index is greater than the preset health index threshold, it means that the DC isolation protection module is in normal health; If the device health index is lower than the preset health index threshold, the system automatically pushes a maintenance work order and starts switching the backup DC isolation branch.

[0013] Preferably, the device further comprises a control module, which is used to generate a control signal and issue corresponding alarm information according to the judgment information of the judgment module.

[0014] Another aspect of the present invention is a method for controlling eddy current self-driven DC bias magnetic treatment with a self-checking function, which uses the above-mentioned eddy current self-driven DC bias magnetic treatment device with a self-checking function, and is characterized in that the method comprises: The DC bias of the transformer is controlled by the DC isolation protection module. When the DC isolation protection module needs to be repaired, the maintenance isolation knife is closed and then disconnected. A current generator is installed at both ends of the DC isolation capacitor to release a simulated fault current for the DC isolation protection module for detection. The monitoring module monitors the status information of the DC isolation capacitor, high-energy zinc oxide and eddy current self-driven switch in the DC isolation protection module; Based on the amount of information obtained by the monitoring module, on-site calculation and analysis are performed to evaluate and analyze the health status of DC blocking capacitors, high-energy zinc oxide components and eddy current self-driven switches.

[0015] Beneficial effects: For an eddy current self-driven DC bias mitigation device and method with a self-check function according to the present invention, the problem that traditional DC bias mitigation equipment uses power electronic components as capacitor bypasses and the control system collects neutral point current signals as the action signals of bypass switches is solved by the provided DC isolation protection module, which has problems of poor reliability and high operation and maintenance costs. Meanwhile, a current generator is provided. When it is necessary to perform a health test on the DC isolation protection module, the current generator is connected in parallel across the series circuit of the self-driven coil and the DC isolation capacitor, and the current generator releases simulated fault current for the DC isolation protection module for detection. At the same time, the health status of each device in the DC isolation protection module is monitored by a monitoring module, and the monitoring data is analyzed by a judgment module to obtain the health status values of each device. Description of the Drawings

[0016] Figure 1 It is a block diagram of an eddy current self-driven DC bias mitigation device with a self-check function according to the present invention; Figure 2 It is a circuit diagram of the DC isolation protection module according to the present invention; Figure 3 It is a schematic circuit diagram when the DC isolation protection module is put into use according to the present invention; Figure 4 It is a schematic circuit diagram when the DC isolation protection module is under maintenance according to the present invention; Figure 5 It is a flowchart of an eddy current self-driven DC bias mitigation method with a self-check function according to the present invention. Detailed Embodiments

[0017] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention is provided in conjunction with the accompanying drawings.

[0018] As Figure 1-2 shown, an embodiment of the present invention provides an eddy current self-driven DC bias mitigation device with a self-check function, and the device includes: A DC isolation protection module, the DC isolation protection module includes a DC isolation capacitor connected in series with the transformer neutral point, a high-energy zinc oxide component connected in parallel with the DC isolation capacitor, and an eddy current self-driven switch component. A maintenance disconnect switch is connected in series between the transformer neutral point and the ground wire, and an input disconnect switch is connected in series between the DC isolation capacitor and the transformer neutral point. The eddy current self-driven switch component includes a self-driven coil connected in series between the input disconnect switch and the DC isolation capacitor and an eddy current self-driven switch connected in parallel with the high-energy zinc oxide component; The high-energy zinc oxide component includes high-energy zinc oxide. When a single-phase grounding asymmetrical short circuit occurs in the transformer, the impact current flows through the DC isolation capacitor C, causing the voltage across the DC isolation capacitor C to rise rapidly, triggering the high-energy zinc oxide to conduct, so as to limit the voltage across the DC isolation capacitor C and play a role in protecting the DC isolation capacitor C.

[0019] The high-energy zinc oxide component further includes a fuse, and the function of the fuse is to protect the current. The fuse consists of a fuse element and a fuse tube, and is connected in series as a metal conductor in the circuit. When the current exceeds a certain value, the fuse will generate heat to melt its fuse element, thereby disconnecting the current and achieving the protection effect; when a fault or abnormality occurs in the circuit, along with the continuous increase of the current, when the current exceeds the specified value, the heat generated by the fuse itself melts the fuse element, so as to disconnect the circuit and protect the DC-blocking capacitor in the circuit.

[0020] The device further includes: a current generator, which is used to release an analog fault current for the DC-blocking protection module during the maintenance of the DC-blocking protection module; the current generator mentioned in this embodiment can be a conventional high-current generator, and the model examples are: SLQ-82 series, DDG series, HYSL-1000A, STDL-200S, NYD-G960, etc.; this type of current generator is applicable to electrical equipment load testing, temperature rise test, etc.

[0021] A monitoring module, which is used to monitor the status information of the DC-blocking capacitor, high-energy zinc oxide, and eddy current self-driving switch in the DC-blocking protection module; A judgment module, which is used to judge the health status of each device in the DC-blocking protection module according to the status information of the DC-blocking capacitor, high-energy zinc oxide, and eddy current self-driving switch in the DC-blocking protection module during the maintenance process.

[0022] Please refer to Figure 3 , further, the operation process of the DC-blocking protection module is as follows: When the system is operating normally, the isolating switch is closed and the maintenance isolating switch is open. The eddy current self-driving switch is in the off state, and the DC-blocking capacitor is in the DC-blocking operation state. When a short circuit occurs in the system, the voltage on the DC-blocking capacitor rises rapidly, triggering the high-energy zinc oxide to conduct and restricting the voltage across the capacitor, playing a role in protecting the DC-blocking capacitor; When the protection fails due to abnormal parameters of the high-energy zinc oxide component, the short-circuit current flows through the self-driving coil of the eddy current self-driving switch component, and the eddy current disk of the eddy current self-driving switch is driven by the eddy current to close the arc extinguishing chamber, bypassing the capacitor bank. After the short-circuit current disappears, the eddy current self-driving switch resumes the off working condition.

[0023] Please refer to Figure 4 , further, the process of using the current generator to maintain the DC-blocking protection module is as follows: There is a locking connection between the maintenance isolating switch and the input isolating switch. When maintenance is required, after the maintenance isolating switch is closed, the input isolating switch is disconnected, and the current generator is connected in parallel across the DC-blocking capacitor to simulate and release a fault current through the current generator; After releasing current through the current generator, the monitoring module monitors the status information of the DC-blocking capacitor, the high-energy zinc oxide, and the eddy current self-driving switch respectively; after turning off the current release of the current generator, the opening action of the eddy current self-driving switch is monitored.

[0024] Furthermore, the monitoring module includes: A DC-blocking capacitor health monitoring unit, which is used to evaluate the insulation aging state of the DC-blocking capacitor by measuring the capacitance decay rate and the dielectric loss angle of the DC-blocking capacitor; A high-energy zinc oxide diagnosis unit, which is used to monitor the temperature change information of the high-energy zinc oxide and the change information of the current magnitude passing through the high-energy zinc oxide; A self-driving switch life prediction unit, which is used to monitor the closing and opening action times of the eddy current self-driving switch Among them, the DC-blocking capacitor health monitoring unit uses a current transformer and a voltage transformer to collect the current and voltage signals of the DC-blocking capacitor respectively, extracts the fundamental wave component through fast Fourier transform, calculates the effective values of the current and voltage respectively, corrects the capacitance value based on the power factor angle, and calculates the capacitance decay rate of the DC-blocking capacitor through historical data comparison. The specific formula is as follows: , Among them, is the effective value of the fundamental wave of the capacitor current, is the effective value of the fundamental wave of the capacitor voltage, is the power factor, reflecting the phase difference between the current and the voltage, is the system power frequency; by real-time monitoring of the phase difference between the fundamental wave current and voltage of the capacitor, the capacitance decay rate is deduced by combining the capacitance calculation formula .

[0025] If the capacitance decay rate reaches the preset decay rate risk threshold, further tests are carried out on the DC-blocking capacitor: injecting a high-frequency test signal, measuring the impedance spectrum of the DC-blocking capacitor, calculating the equivalent series resistance and capacitive reactance, calculating the tangent of the dielectric loss angle through the equivalent series resistance and capacitive reactance, and judging the insulation aging state of the DC-blocking capacitor through the tangent of the dielectric loss angle. The specific formula is as follows: Among them, , Among them, is the equivalent series resistance; is the capacitive reactance.

[0026] The smaller the tangent value of the dielectric loss angle, the higher the efficiency of the DC-blocking capacitor and the less the energy loss; the larger the tangent value of the dielectric loss angle, the more serious the aging of the DC-blocking capacitor.

[0027] Furthermore, real-time correction is adopted using a temperature sensor. The formula: , Wherein, is the temperature coefficient of the material, is the reference temperature (usually 25°C), is the detected temperature of the DC-blocking capacitor.

[0028] Furthermore, the judgment module judges the health state of the DC-blocking capacitor in the DC-blocking protection module according to the state information of the DC-blocking capacitor in the DC-blocking protection module. The specific process is as follows: The DC-blocking capacitor health monitoring unit uses a current transformer and a voltage transformer to collect the current and voltage signals of the DC-blocking capacitor respectively, calculates the effective values of the current and voltage respectively, and calculates the capacitance decay rate of the DC-blocking capacitor by comparing with historical data; If the capacitance decay rate reaches the preset decay rate risk threshold, further tests are carried out on the DC-blocking capacitor: injecting a high-frequency test signal, measuring the impedance spectrum of the DC-blocking capacitor, calculating the equivalent series resistance and capacitive reactance, calculating the tangent of the dielectric loss angle through the equivalent series resistance and capacitive reactance, and judging the insulation aging state of the DC-blocking capacitor through the tangent of the dielectric loss angle: If the calculated tangent value of the dielectric loss angle of the DC-blocking capacitor is greater than the preset standard tangent value of the loss angle, the DC-blocking capacitor needs to be repaired or replaced; If the calculated tangent value of the dielectric loss of the DC-blocking capacitor is less than or equal to the preset standard tangent value of the loss, it means that the state of the DC-blocking capacitor is normal.

[0029] The high-energy zinc oxide diagnosis unit uses a current transformer to collect the information on the change in the magnitude of the current passing through the high-energy zinc oxide, generates a current-time change curve, uses a temperature sensor to collect the information on the change in the temperature of the high-energy zinc oxide over time, and generates a temperature-time change curve; Obtain the standard curve of the current-temperature change of the high-energy zinc oxide according to historical data, integrate the current-time change curve and the temperature-time change curve, and generate the actual current-temperature change curve; Obtain the standard temperature at which the high-energy zinc oxide reaches the preset current standard value through the standard curve of the current-temperature change, and obtain the actual temperature at which the high-energy zinc oxide reaches the preset current standard value through the actual curve of the current-temperature change; Furthermore, the judgment module judges the deterioration of the high-energy zinc oxide by comparing the actual temperature with the standard temperature: If the actual temperature is less than or equal to the standard temperature, it means that the state of the high-energy zinc oxide is normal; If the actual temperature is greater than the standard temperature, it means that the fission of the high-energy zinc oxide is serious, and the controller issues an alarm for the repair or replacement of the high-energy zinc oxide.

[0030] Further, the self-driving switch life prediction unit respectively collects the closing action time and opening action time of the eddy current self-driving switch, and judges the health state of the eddy current self-driving switch by comparing the closing action time with the preset standard closing action time and the opening action time with the preset standard opening action time. Furthermore, it is judged by the judgment module: If the closing action time is less than or equal to the standard closing action time and the opening action time is less than or equal to the standard opening action time, it means that the state of the eddy current self-driving switch is normal; If the closing action time is greater than the standard closing action time or the opening action time is greater than the standard opening action time, the eddy current self-driving switch needs to be repaired or replaced.

[0031] Of course, optionally, the monitoring module further includes: A comprehensive health assessment unit, which is used to construct an equipment health index according to the capacitance decay rate of the DC-blocking capacitor, the high-energy zinc oxide temperature rise curve and the eddy current self-driving switch action time series: , wherein, , , are weight coefficients, ; is the measured capacitance value, is the initial capacitance value, is the zinc oxide peak temperature, is the standard temperature rise threshold, is the actual action time of the switch, is the standard action time; Furthermore, the calculated equipment health index is compared with the preset health index threshold by the judgment module: If the equipment health index is greater than the preset health index threshold, it means that the health state of the DC-blocking protection module is normal; If the equipment health index is less than the preset health index threshold, the system automatically pushes a maintenance work order and initiates the switching of the standby DC-blocking branch.

[0032] Of course, optionally, the device further includes a control module, which is used to generate a control signal and send out corresponding alarm information according to the judgment information of the judgment module. For example, if the judgment module judges that the DC-blocking capacitor is abnormal and needs to be replaced, the control module receives the judgment information generated by the judgment module, and the control module controls the alarm to emit an alarm sound for replacing the DC-blocking capacitor to remind the staff to replace the DC-blocking capacitor.

[0033] Please refer to Figure 5 ​​​​​​, Another embodiment of the present invention provides a method for governing DC bias with self-check function using the eddy current self-driven DC bias governing device with self-check function, and the method includes: Governing the DC bias of the transformer through the DC isolation protection module. When it is necessary to repair the DC isolation protection module, after the repair disconnecting switch is closed, the input disconnecting switch is disconnected. By installing a current generator at both ends of the DC isolation capacitor, an analog fault current is released for the DC isolation protection module for detection; Monitoring the status information of the DC isolation capacitor, high-energy zinc oxide, and eddy current self-driven switch in the DC isolation protection module through the monitoring module; Performing on-site calculation and analysis based on the information obtained by the monitoring module, and evaluating and analyzing the health status of the DC isolation capacitor, high-energy zinc oxide component, and eddy current self-driven switch; Generating a control signal and sending out corresponding alarm information through the control module according to the judgment information of the judgment module.

[0034] When this method is specifically implemented, first connect the DC isolation protection module to the neutral point of the transformer. When the system is operating normally, the input disconnecting switch is closed, the repair disconnecting switch is open, the eddy current self-driven switch is in the off state, and the DC isolation capacitor is in the DC isolation operation state. When a short circuit occurs in the system, the voltage on the DC isolation capacitor rises rapidly, triggering the high-energy zinc oxide to conduct and limiting the voltage across the capacitor, playing a role in protecting the DC isolation capacitor; When the protection fails due to abnormal parameters of the high-energy zinc oxide module, the short-circuit current flows through the self-driven coil of the eddy current self-driven switch assembly, and the eddy current drives the eddy current disk of the eddy current self-driven switch to close the arc extinguishing chamber, bypassing the capacitor bank. After the short-circuit current disappears, the eddy current self-driven switch returns to the off operating condition; The high-energy zinc oxide module also includes a fuse, and the function of the fuse is to protect the current. The fuse consists of a fuse element and a fuse tube, and is connected in series in the circuit as a metal conductor. When the current exceeds a certain value, the fuse generates heat to melt its fuse element, thereby disconnecting the current to achieve the protection effect; when a fault or abnormality occurs in the circuit, along with the continuous increase of the current, when the current exceeds the specified value, the heat generated by the fuse itself melts the fuse element to disconnect the circuit and protect the DC isolation capacitor in the circuit; When it is necessary to repair the DC isolation protection module, after the repair disconnecting switch is closed, the input disconnecting switch is disconnected, and the current generator is connected in parallel to both ends of the DC isolation capacitor to simulate and release a fault current through the current generator; After releasing the current through the current generator, monitor the status information of the DC isolation capacitor, high-energy zinc oxide, and eddy current self-driven switch respectively through the monitoring module; after closing the current release of the current generator, monitor the opening action of the eddy current self-driven switch; The monitoring module monitors the status information of the DC-blocking capacitor, the high-energy zinc oxide component, and the eddy current self-driving switch respectively, and the judgment module judges the health status of each device respectively. Finally, the control module implements the alarm action.

[0035] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will all fall within the protection scope of the present invention.

Claims

1. A self - checking eddy - current self - driven DC bias mitigation device, characterized in that, The device includes: A DC-blocking protection module, which includes a DC-blocking capacitor connected in series with the neutral point of the transformer, a high-energy zinc oxide component connected in parallel with the DC-blocking capacitor, and an eddy current self-driving switch component. There is a maintenance disconnect switch connected in series between the neutral point of the transformer and the ground wire, and a closing disconnect switch is connected in series between the DC-blocking capacitor and the neutral point of the transformer. The eddy current self-driving switch component includes a self-driving coil connected in series between the closing disconnect switch and the DC-blocking capacitor and an eddy current self-driving switch connected in parallel with the high-energy zinc oxide component; A current generator, which is used to release an analog fault current to the DC-blocking protection module when the DC-blocking protection module is under maintenance; A monitoring module, which is used to monitor the status information of the DC-blocking capacitor, high-energy zinc oxide, and eddy current self-driving switch in the DC-blocking protection module; A judgment module, which is used to judge the health status of each device in the DC-blocking protection module according to the status information of the DC-blocking capacitor, high-energy zinc oxide, and eddy current self-driving switch in the DC-blocking protection module during the maintenance process.

2. The eddy current self-driven DC bias control device with self-checking function according to claim 1, characterized in that, The operation process of the DC-blocking protection module is as follows: When the system is operating normally, the closing disconnect switch is closed, the maintenance disconnect switch is open, the eddy current self-driving switch is in the open state, and the DC-blocking capacitor is in the DC-blocking operation state. When a short circuit occurs in the system, the voltage on the DC-blocking capacitor rises rapidly, triggering the high-energy zinc oxide to conduct and limiting the voltage across the capacitor, playing a role in protecting the DC-blocking capacitor; When the protection fails due to abnormal parameters of the high-energy zinc oxide component, the short-circuit current flows through the self-driving coil of the eddy current self-driving switch component, and the eddy current drives the eddy current disk of the eddy current self-driving switch to close the arc extinguishing chamber, bypassing the capacitor bank. After the short-circuit current disappears, the eddy current self-driving switch returns to the open operating condition.

3. The eddy current self-driven DC bias mitigation device with a self-check function according to claim 1, characterized in that, The process of using the current generator to maintain the DC-blocking protection module is as follows: There is a locking connection between the maintenance disconnect switch and the closing disconnect switch. When maintenance is required, after the maintenance disconnect switch is closed, the closing disconnect switch is opened, and the current generator is connected in parallel across the DC-blocking capacitor to simulate and release a fault current through the current generator; After releasing the current through the current generator, the monitoring module monitors the status information of the DC-blocking capacitor, high-energy zinc oxide, and eddy current self-driving switch respectively; after closing the current release of the current generator, the opening action of the eddy current self-driving switch is monitored.

4. The eddy current self-driven DC bias mitigation device with a self-check function according to claim 3, characterized in that, The monitoring module includes: A DC-blocking capacitor health monitoring unit, which is used to evaluate the insulation aging state of the DC-blocking capacitor by measuring the capacitance decay rate and dielectric loss angle of the DC-blocking capacitor; A high-energy zinc oxide diagnosis unit, which is used to monitor the temperature change information of the high-energy zinc oxide and the change information of the current magnitude passing through the high-energy zinc oxide; A self-driving switch life prediction unit, which is used to monitor the closing and opening action times of the eddy current self-driving switch.

5. The eddy current self-driven DC bias mitigation device with self-check function according to claim 4, characterized in that, The judgment module judges the health status of the DC-blocking capacitor in the DC-blocking protection module according to the status information of the DC-blocking capacitor in the DC-blocking protection module. The specific process is as follows: The DC-blocking capacitor health monitoring unit uses current transformers and voltage transformers to collect the current and voltage signals of the DC-blocking capacitor respectively, calculates the effective values of the current and voltage respectively, and calculates the capacitance decay rate of the DC-blocking capacitor by comparing with historical data; If the capacitance decay rate reaches the preset decay rate risk threshold, further tests are performed on the DC-blocking capacitor: inject a high-frequency test signal, measure the impedance spectrum of the DC-blocking capacitor, calculate the equivalent series resistance and capacitive reactance, calculate the tangent of the dielectric loss angle through the equivalent series resistance and capacitive reactance, and judge the insulation aging state of the DC-blocking capacitor through the tangent of the dielectric loss angle: If the calculated tangent value of the dielectric loss angle of the DC-blocking capacitor is greater than the preset standard tangent value of the loss angle, the DC-blocking capacitor needs to be repaired or replaced; If the calculated tangent value of the dielectric loss of the DC-blocking capacitor is less than or equal to the preset standard tangent value of the loss, it means that the state of the DC-blocking capacitor is normal.

6. The eddy current self-driven DC bias control device with a self-check function according to claim 4, characterized in that, The judgment module judges the health state of the high-energy zinc oxide in the DC-blocking protection module according to the state information of the high-energy zinc oxide in the DC-blocking protection module. The specific process is as follows: The high-energy zinc oxide diagnosis unit uses a current transformer to collect the change information of the current passing through the high-energy zinc oxide, generates a current-time change curve, collects the temperature-time change information of the high-energy zinc oxide through a temperature sensor, and generates a temperature-time change curve; Obtain the standard curve of the current-temperature change of the high-energy zinc oxide according to historical data, integrate the current-time change curve and the temperature-time change curve, and generate the actual curve of the current-temperature change; Obtain the standard temperature at which the high-energy zinc oxide reaches the preset current standard value through the standard curve of the current-temperature change, and obtain the actual temperature at which the high-energy zinc oxide reaches the preset current standard value through the actual curve of the current-temperature change; Judge the deterioration of the high-energy zinc oxide by comparing the actual temperature with the standard temperature: If the actual temperature is less than or equal to the standard temperature, it means that the state of the high-energy zinc oxide is normal; If the actual temperature is greater than the standard temperature, it means that the fission of the high-energy zinc oxide is serious, and the controller issues an alarm for repairing or replacing the high-energy zinc oxide.

7. The eddy current self-driven DC bias mitigation device with self-check function according to claim 4, characterized in that, The judgment module judges the health state of the eddy current self-driving switch in the DC-blocking protection module according to the state information of the eddy current self-driving switch in the DC-blocking protection module. The specific process is as follows: The self-driving switch life prediction unit respectively collects the closing action time and opening action time of the eddy current self-driving switch, and judges the health state of the eddy current self-driving switch by comparing the closing action time with the preset standard closing action time and the opening action time with the preset standard opening action time: If the closing action time is less than or equal to the standard closing action time and the opening action time is less than or equal to the standard opening action time, it means that the state of the eddy current self-driving switch is normal; If the closing action time is greater than the standard closing action time or the opening action time is greater than the standard opening action time, the eddy current self-driving switch needs to be repaired or replaced.

8. The eddy current self-driven DC bias mitigation device with a self-check function according to claim 4, characterized in that, The monitoring module further includes: A comprehensive health assessment unit for constructing an equipment health index according to the capacitance decay rate of the DC-blocking capacitor, the temperature rise curve of the high-energy zinc oxide and the action time series of the eddy current self-driving switch; ， Among them, , , are weight coefficients, ; is the measured capacitance value, is the initial capacitance value, is the peak temperature of zinc oxide, is the standard temperature rise threshold, is the actual operation time of the switch, is the standard operation time; Compare the calculated equipment health index with the preset health index threshold: If the equipment health index is greater than the preset health index threshold, it means that the health state of the DC-blocking protection module is normal; If the device health index is lower than the preset health index threshold, the system automatically pushes a maintenance work order and starts switching the backup DC isolation branch.

9. The eddy current self-driven DC bias mitigation device with self-check function according to claim 1, characterized in that, The device further comprises a control module, which is used to generate a control signal and issue corresponding alarm information according to the judgment information of the judgment module.

10. A method for governing DC bias by eddy current self-driving type with self-checking function, which uses the eddy current self-driving type DC bias governing device with self-checking function described in any one of the above claims 1-9, and is characterized in that, The method comprises: The DC bias of the transformer is controlled by the DC isolation protection module. When the DC isolation protection module needs to be repaired, the maintenance isolation knife is closed and then disconnected. A current generator is installed at both ends of the DC isolation capacitor to release a simulated fault current for the DC isolation protection module for detection. The monitoring module is used to obtain status information of the DC isolation capacitor, high-energy zinc oxide component, and eddy current self-driven switch in the DC isolation protection module; Based on the status information obtained by the monitoring module, on-site calculation and analysis are performed to evaluate and analyze the health status of DC blocking capacitors, high-energy zinc oxide components and eddy current self-driven switches.

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