A self-driving eddy current DC bias magnetic treatment device and method with self-checking function
By utilizing the self-testing function of the eddy current self-driven DC bias control device, the problems of poor reliability and high operation and maintenance costs of traditional devices are solved. This enables real-time monitoring and prediction of the health status of devices, thereby improving system reliability and reducing operation and maintenance costs.
Patent Information
- Application Number
- CN202510907263.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-02
- Publication Date
- 2025-09-30
- Estimated Expiration
- 2045-07-02
AI Technical Summary
Traditional DC bias control equipment uses power electronic components as capacitor bypasses and the control system collects neutral point current signals as the action signals for bypass switches, which has problems such as poor reliability and high operation and maintenance costs.
An eddy current self-driven DC bias control device is adopted, which includes a DC blocking protection module, a current generator, a monitoring module, and a judgment module. The self-testing function is realized through eddy current self-driven switching components and high-energy zinc oxide components. The device monitors and judges the health status of each component in the DC blocking protection module and uses the current generator to simulate fault current for detection.
It improves the reliability of the device, reduces operation and maintenance costs, and enables real-time monitoring and prediction of the health status of the device through self-testing function, thereby reducing the risk of failure.
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Figure CN120414435B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of DC bias magnetic treatment, and in particular to an eddy current self-driven DC bias magnetic treatment device and method with a self-checking function. Background Art
[0002] When a DC transmission system operates in bipolar asymmetric or unipolar mode, a certain amount of DC current flows into the earth through the DC grounding electrode, creating unequal potentials on the earth's surface. This DC current can then enter the transformer windings through the neutral point, generating a DC current in the transformer windings. This shifts the transformer's magnetic flux density operating point and causes DC bias in the transformer. Existing capacitive DC bias control devices, which mostly use power electronic switches as bypass systems, present two major issues: 1) The power components themselves have strict operating conditions that are difficult to meet on-site, posing a risk of failure; 2) The control system is complex, and the electronic components themselves have stringent temperature requirements, resulting in a high risk of failure.
[0003] Traditional DC bias magnetic treatment equipment uses power electronic components as capacitor bypass and the control system collects neutral point current signals as the action signals of the bypass switch, resulting in poor reliability and high operation and maintenance costs. Summary of the Invention
[0004] The problem solved by the present invention is that traditional DC bias magnetic treatment equipment uses power electronic components as capacitor bypass and the control system collects neutral point current signals as action signals of bypass switches, which has the problems of poor reliability and high operation and maintenance costs.
[0005] In order to solve the above problems, the present invention provides an eddy current self-driven DC bias magnetic treatment device with a self-checking function, characterized in that the device comprises:
[0006] A DC isolation protection module, the DC isolation protection module comprising a DC isolation capacitor connected in series with the neutral point of the transformer, a high-energy zinc oxide component connected in parallel with the DC isolation capacitor, and an eddy current self-driven switch component; a maintenance isolation knife connected in series between the neutral point of the transformer and the ground wire; an input isolation knife connected in series between the DC isolation capacitor and the neutral point of the transformer; and the eddy current self-driven switch component comprising a self-driven coil connected in series between the input isolation knife and the DC isolation capacitor, and an eddy current self-driven switch connected in parallel with the high-energy zinc oxide component;
[0007] A current generator is used to release a simulated fault current to the DC isolation protection module when the DC isolation protection module is being repaired;
[0008] A monitoring module is used to monitor the status information of the DC isolation capacitor, high-energy zinc oxide, and eddy current self-driven switch in the DC isolation protection module;
[0009] The judgment module is used to judge the health status of each component in the DC isolation protection module according to the status information of the DC isolation capacitor, high-energy zinc oxide and eddy current self-driven switch in the DC isolation protection module during the maintenance process.
[0010] Preferably, the operation process of the DC isolation protection module is as follows:
[0011] During normal operation, the system is put into operation with the isolating knife closed and the isolating knife disconnected for maintenance. The eddy current self-driven 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 limit the voltage across the capacitor, thus protecting the DC blocking capacitor.
[0012] When the high-energy zinc oxide component parameter abnormality protection fails, the short-circuit current flows through the self-driving coil of the eddy current self-driven switch component, and the eddy current drives the eddy current disk of the eddy current self-driven switch to close the arc extinguishing chamber and bypass the capacitor bank. After the short-circuit current disappears, the eddy current self-driven switch returns to the open state.
[0013] Preferably, the process of using the current generator to repair the DC isolation protection module is as follows:
[0014] There is a locking connection between the maintenance isolating switch and the input isolating switch. When maintenance is required, the maintenance isolating switch is closed and the input isolating switch is disconnected. The current generator is connected in parallel to both ends of the DC blocking capacitor to simulate the release of the fault current through the current generator.
[0015] After the current is released through the current generator, the status information of the DC blocking capacitor, high-energy zinc oxide and eddy current self-driven switch are monitored respectively through the monitoring module; after the current release of the current generator is turned off, the opening action of the eddy current self-driven switch is monitored.
[0016] Preferably, the monitoring module includes:
[0017] The DC blocking capacitor health monitoring unit is used to evaluate the insulation aging status of the DC blocking capacitor by measuring the capacitance decay rate and dielectric loss angle of the DC blocking capacitor;
[0018] A high-energy zinc oxide diagnostic unit is used to monitor temperature changes of the high-energy zinc oxide and current changes passing through the high-energy zinc oxide;
[0019] The self-driven switch life prediction unit is used to monitor the closing and opening action time of the eddy current self-driven switch.
[0020] Preferably, 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, and the specific process is as follows:
[0021] 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, calculate the effective values of the current and voltage, and calculate the capacitance decay rate of the DC blocking capacitor by comparing historical data.
[0022] If the capacitance decay rate reaches the preset decay rate risk threshold, further testing is performed on the blocking capacitor: a high-frequency test signal is injected, the impedance spectrum of the blocking capacitor is measured, and the equivalent series resistance and capacitive reactance are calculated. The dielectric loss tangent is calculated based on the equivalent series resistance and capacitive reactance, and the insulation aging status of the blocking capacitor is determined based on the dielectric loss tangent.
[0023] If the calculated dielectric loss tangent value of the DC blocking capacitor is greater than the preset standard loss tangent value, the DC blocking capacitor needs to be repaired or replaced;
[0024] If the calculated dielectric loss tangent value of the blocking capacitor is less than or equal to the preset standard loss tangent value, it indicates that the blocking capacitor is in normal condition.
[0025] Preferably, the judgment module judges the health status of the high-energy zinc oxide in the DC isolation protection module according to the status information of the high-energy zinc oxide in the DC isolation protection module, and the specific process is as follows:
[0026] The high-energy zinc oxide diagnostic unit uses a current transformer to collect information about the current variation through the high-energy zinc oxide and generates a current-time variation curve. It also uses a temperature sensor to collect information about the temperature variation of the high-energy zinc oxide and generates a temperature-time variation curve.
[0027] Obtain the standard curve of high-energy zinc oxide current-temperature variation based on historical data, integrate the current-time variation curve and the temperature-time variation curve to generate the actual current-temperature variation curve;
[0028] The standard temperature at which high-energy zinc oxide reaches a preset current standard value is obtained through the current-temperature change standard curve, and the actual temperature at which high-energy zinc oxide reaches a preset current standard value is obtained through the current-temperature change actual curve;
[0029] The deterioration of high-energy zinc oxide can be judged by comparing the actual temperature with the standard temperature:
[0030] If the actual temperature is less than or equal to the standard temperature, it means that the state of high-energy zinc oxide is normal;
[0031] 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 will issue an alarm to repair or replace the high-energy zinc oxide.
[0032] Preferably, the judgment module judges the health status of the eddy current self-driven switch in the DC isolation protection module according to the status information of the eddy current self-driven switch in the DC isolation protection module, and the specific process is as follows:
[0033] The self-driven switch life prediction unit collects the closing action time and opening action time of the eddy current self-driven switch, and judges the health status of the eddy current self-driven 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:
[0034] 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 eddy current self-driven switch is in normal state;
[0035] 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.
[0036] Preferably, the monitoring module further includes:
[0037] 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:
[0038] ,
[0039] 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;
[0040] Compare the calculated device health index with the preset health index threshold:
[0041] 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;
[0042] 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.
[0043] 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.
[0044] 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:
[0045] 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.
[0046] 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;
[0047] 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.
[0048] Beneficial effects: The present invention provides an eddy current self-driven DC bias magnetic treatment device and method with a self-checking function. By providing a DC isolation protection module, the present invention solves the problem that conventional DC bias magnetic treatment equipment uses power electronic components as capacitor bypass and the control system collects the neutral point current signal as the action signal of the bypass switch, which results in poor reliability and high operation and maintenance costs.
[0049] At the same time, a current generator is set up. When the health test of the DC isolation protection module is required, the current generator is connected in parallel at both ends of the series circuit of the self-driving coil and the DC isolation capacitor, and a simulated fault current is released to the DC isolation protection module through the current generator for detection. At the same time, the health status of each component in the DC isolation protection module is monitored through the monitoring module, and the monitoring data is analyzed through the judgment module to obtain the health status value of each component. BRIEF DESCRIPTION OF THE DRAWINGS
[0050] Figure 1 This is a block diagram of the eddy current self-driven DC bias magnetic treatment device with a self-checking function of the present invention;
[0051] Figure 2 This is the circuit diagram of the DC isolation protection module of the present invention;
[0052] Figure 3 This is a circuit diagram of the DC isolation protection module of the present invention when it is put into use;
[0053] Figure 4 This is a circuit diagram for repairing the DC isolation protection module of the present invention;
[0054] Figure 5 This is a flow chart of the eddy current self-driven DC bias magnetic treatment method with a self-checking function of the present invention. DETAILED DESCRIPTION
[0055] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.
[0056] like Figure 1-2 As shown, an embodiment of the present invention provides an eddy current self-driven DC bias magnetic treatment device with a self-checking function, the device comprising:
[0057] A DC isolation protection module, the DC isolation protection module comprising a DC isolation capacitor connected in series with the neutral point of the transformer, a high-energy zinc oxide component connected in parallel with the DC isolation capacitor, and an eddy current self-driven switch component; a maintenance isolation knife connected in series between the neutral point of the transformer and the ground wire; an input isolation knife connected in series between the DC isolation capacitor and the neutral point of the transformer; and the eddy current self-driven switch component comprising a self-driven coil connected in series between the input isolation knife and the DC isolation capacitor, and an eddy current self-driven switch connected in parallel with the high-energy zinc oxide component;
[0058] The high-energy zinc oxide component includes high-energy zinc oxide. When a single-phase grounding asymmetric short circuit occurs in the transformer, the inrush current flows through the DC blocking capacitor C, causing the voltage on the DC blocking capacitor C to rise rapidly, triggering the high-energy zinc oxide to conduct, thereby limiting the voltage across the DC blocking capacitor C and protecting the DC blocking capacitor C.
[0059] High-energy zinc oxide components also include fuses, which function to protect against current flow. A fuse, consisting of a melt and a tube, is connected in series in a circuit as a metal conductor. When the current exceeds a certain value, the fuse generates heat, melting the melt and thus disconnecting the current for protection. When a circuit malfunction or anomaly occurs, the current continues to rise. When the current exceeds the specified value, the heat generated by the fuse melts the melt, disconnecting the circuit and protecting the DC-blocking capacitors in the circuit.
[0060] The device also includes: a current generator, which is used to release a simulated fault current for the DC isolation protection module when the DC isolation protection module is being repaired; the current generator mentioned in this embodiment can be a conventional large current generator, and examples of models include: SLQ-82 series, DDG series, HYSL-1000A, STDL-200S, NYD-G960, etc.; this type of current generator is suitable for load testing of electrical equipment, temperature rise testing, etc.
[0061] A monitoring module is used to monitor the status information of the DC isolation capacitor, high-energy zinc oxide, and eddy current self-driven switch in the DC isolation protection module;
[0062] The judgment module is used to judge the health status of each component in the DC isolation protection module according to the status information of the DC isolation capacitor, high-energy zinc oxide and eddy current self-driven switch in the DC isolation protection module during the maintenance process.
[0063] See also Figure 3 ,Furthermore, the operation process of the DC isolation protection module is as follows:
[0064] During normal operation, the system is put into operation with the isolating knife closed and the isolating knife disconnected for maintenance. The eddy current self-driven 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 limit the voltage across the capacitor, thus protecting the DC blocking capacitor.
[0065] When the high-energy zinc oxide component parameter abnormality protection fails, the short-circuit current flows through the self-driving coil of the eddy current self-driven switch component, and the eddy current drives the eddy current disk of the eddy current self-driven switch to close the arc extinguishing chamber and bypass the capacitor bank. After the short-circuit current disappears, the eddy current self-driven switch returns to the open state.
[0066] See also Figure 4 , further, the process of using the current generator to repair the DC isolation protection module is as follows:
[0067] There is a locking connection between the maintenance isolating switch and the input isolating switch. When maintenance is required, the maintenance isolating switch is closed and the input isolating switch is disconnected. The current generator is connected in parallel to both ends of the DC blocking capacitor to simulate the release of the fault current through the current generator.
[0068] After the current is released through the current generator, the status information of the DC blocking capacitor, high-energy zinc oxide and eddy current self-driven switch are monitored respectively through the monitoring module; after the current release of the current generator is turned off, the opening action of the eddy current self-driven switch is monitored.
[0069] Furthermore, the monitoring module includes:
[0070] The DC blocking capacitor health monitoring unit is used to evaluate the insulation aging status of the DC blocking capacitor by measuring the capacitance decay rate and dielectric loss angle of the DC blocking capacitor;
[0071] A high-energy zinc oxide diagnostic unit is used to monitor temperature changes of the high-energy zinc oxide and current changes passing through the high-energy zinc oxide;
[0072] Self-driven switch life prediction unit, used to monitor the closing and opening action time of eddy current self-driven switches
[0073] 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, extracts the fundamental component through fast Fourier transform, calculates the effective value of the current and voltage, corrects the capacitance value based on the power factor angle, and calculates the capacitance attenuation rate of the DC blocking capacitor by comparing historical data. The specific formula is as follows:
[0074] ,
[0075] in, is the capacitor current fundamental effective value, is the fundamental effective value of the capacitor voltage, is the power factor, reflecting the phase difference between current and voltage. The system power frequency is obtained by monitoring the phase difference between the fundamental current and voltage of the capacitor in real time and combining it with the capacitance calculation formula to deduce the capacitance attenuation rate. .
[0076] If the capacitance attenuation rate reaches the preset attenuation rate risk threshold, the blocking capacitor is further tested: inject a high-frequency test signal, measure the impedance spectrum of the blocking capacitor, calculate the equivalent series resistance and capacitive reactance, and calculate the dielectric loss tangent through the equivalent series resistance and capacitive reactance. To judge the insulation aging status of the DC blocking capacitor, the specific formula is as follows:
[0077] ,
[0078] in, is the equivalent series resistance; For capacitive reactance.
[0079] The smaller the dielectric loss tangent value, the higher the efficiency of the DC blocking capacitor and the less energy loss; the larger the dielectric loss tangent value, the more serious the aging of the DC blocking capacitor.
[0080] Furthermore, a temperature sensor is used for real-time correction, formula:
[0081] ,
[0082] in, is the material temperature coefficient, is the reference temperature (usually 25°C), is the detected temperature of the DC blocking capacitor.
[0083] Furthermore, 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:
[0084] 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, calculate the effective values of the current and voltage, and calculate the capacitance decay rate of the DC blocking capacitor by comparing historical data.
[0085] If the capacitance decay rate reaches the preset decay rate risk threshold, further testing is performed on the blocking capacitor: a high-frequency test signal is injected, the impedance spectrum of the blocking capacitor is measured, and the equivalent series resistance and capacitive reactance are calculated. The dielectric loss tangent is calculated based on the equivalent series resistance and capacitive reactance, and the insulation aging status of the blocking capacitor is determined based on the dielectric loss tangent.
[0086] If the calculated dielectric loss tangent value of the DC blocking capacitor is greater than the preset standard loss tangent value, the DC blocking capacitor needs to be repaired or replaced;
[0087] If the calculated dielectric loss tangent value of the blocking capacitor is less than or equal to the preset standard loss tangent value, it indicates that the blocking capacitor is in normal condition.
[0088] The high-energy zinc oxide diagnostic unit uses a current transformer to collect information about the current variation through the high-energy zinc oxide and generates a current-over-time curve. It also uses a temperature sensor to collect information about the temperature variation of the high-energy zinc oxide and generates a temperature-over-time curve.
[0089] Obtain the standard curve of high-energy zinc oxide current-temperature variation based on historical data, integrate the current-time variation curve and the temperature-time variation curve to generate the actual current-temperature variation curve;
[0090] The standard temperature at which high-energy zinc oxide reaches a preset current standard value is obtained through the current-temperature change standard curve, and the actual temperature at which high-energy zinc oxide reaches a preset current standard value is obtained through the current-temperature change actual curve;
[0091] Furthermore, the judgment module compares the actual temperature with the standard temperature to judge the deterioration of high-energy zinc oxide:
[0092] If the actual temperature is less than or equal to the standard temperature, it means that the state of high-energy zinc oxide is normal;
[0093] 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 will issue an alarm to repair or replace the high-energy zinc oxide.
[0094] Furthermore, the self-driven switch life prediction unit collects the closing action time and opening action time of the eddy current self-driven switch respectively, and judges the health status of the eddy current self-driven 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.
[0095] Furthermore, the judgment module is used to make judgments:
[0096] 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 eddy current self-driven switch is in normal state;
[0097] 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.
[0098] Of course, optionally, the monitoring module also includes:
[0099] 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:
[0100] ,
[0101] 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;
[0102] Furthermore, the judgment module compares the calculated device health index with the preset health index threshold:
[0103] 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;
[0104] 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.
[0105] Optionally, the device further includes a control module configured to generate a control signal and issue a corresponding alarm based on the determination information from the determination module. If the determination module determines that the blocking capacitor is abnormal and needs to be replaced, the control module receives the determination information generated by the determination module and controls an alarm to issue an alarm indicating that the blocking capacitor needs to be replaced, thereby reminding personnel to replace the blocking capacitor.
[0106] See also Figure 5 Another embodiment of the present invention provides a method for controlling eddy current self-driven DC bias magnetic treatment with a self-checking function, using the eddy current self-driven DC bias magnetic treatment device with a self-checking function, the method comprising:
[0107] 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.
[0108] 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;
[0109] Perform on-site calculations and analysis based on the information obtained by the monitoring module to evaluate and analyze the health of DC blocking capacitors, high-energy zinc oxide components, and eddy current self-driven switches;
[0110] The control module generates a control signal based on the judgment information of the judgment module and issues corresponding alarm information.
[0111] During specific implementation, the method first connects the DC blocking protection module to the neutral point of the transformer. During normal operation of the system, the blocking knife is closed, the blocking knife is disconnected during maintenance, the eddy current self-driven 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, thereby protecting the DC blocking capacitor.
[0112] When the high-energy zinc oxide module parameter abnormality protection fails, the short-circuit current flows through the self-driving 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 and bypass the capacitor bank. After the short-circuit current disappears, the eddy current self-driven switch returns to the open state;
[0113] The high-energy zinc oxide module also includes a fuse, which is used to protect the current. The fuse consists of a melt and a 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 the melt, thereby disconnecting the current and achieving a protective effect. When a circuit fault or abnormality occurs, the current continues to rise. When the current exceeds the specified value, the heat generated by the fuse itself melts the melt, disconnecting the circuit and protecting the DC blocking capacitor in the circuit.
[0114] When the DC isolation protection module needs to be repaired, after the maintenance isolation knife is closed, the isolation knife is disconnected and the current generator is connected in parallel to both ends of the DC isolation capacitor to simulate the release of fault current through the current generator;
[0115] After the current is released through the current generator, the status information of the DC blocking capacitor, high-energy zinc oxide and eddy current self-driven switch are monitored respectively through the monitoring module; after the current release of the current generator is turned off, the opening action of the eddy current self-driven switch is monitored;
[0116] The monitoring module monitors the status information of the DC blocking capacitor, high-energy zinc oxide component and eddy current self-driven switch respectively, and the judgment module judges the health status of each component respectively, and finally the control module implements the alarm action.
[0117] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.
Claims
1. An eddy current self-driven DC bias magnetic treatment device with self-checking function, characterized in that: The device comprises: A DC isolation protection module, the DC isolation protection module comprising a DC isolation capacitor connected in series with the neutral point of the transformer, a high-energy zinc oxide component connected in parallel with the DC isolation capacitor, and an eddy current self-driven switch component; a maintenance isolation knife connected in series between the neutral point of the transformer and the ground wire; an input isolation knife connected in series between the DC isolation capacitor and the neutral point of the transformer; and the eddy current self-driven switch component comprising a self-driven coil connected in series between the input isolation knife 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 is used to release a simulated fault current to the DC isolation protection module when the DC isolation protection module is being repaired; A monitoring module is used to monitor the status information of the DC isolation capacitor, high-energy zinc oxide, and eddy current self-driven switch in the DC isolation protection module; A judgment module is used to judge the health status of each component in the DC isolation protection module according to the status information of the DC isolation capacitor, high-energy zinc oxide and eddy current self-driven switch in the DC isolation protection module during the maintenance process; The monitoring module includes: The DC blocking capacitor health monitoring unit is used to evaluate the insulation aging status 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 diagnostic unit is used to monitor temperature changes of the high-energy zinc oxide and current changes passing through the high-energy zinc oxide; Self-driven switch life prediction unit, used to monitor the closing and opening action time of the eddy current self-driven switch; 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 a current transformer and a voltage transformer to collect the current and voltage signals of the DC blocking capacitor, calculate the effective values of the current and voltage, and calculate the capacitance attenuation rate of the DC blocking capacitor. The specific formula is as follows: ， in, is the capacitor current fundamental effective value, is the fundamental effective value of the capacitor voltage, is the power factor, reflecting the phase difference between current and voltage. The system power frequency; by real-time monitoring of the phase difference between the fundamental current and voltage of the capacitor, combined with the capacitor The calculation formula derives the capacitance value attenuation rate; If the capacitance decay rate reaches the preset decay rate risk threshold, further testing is performed on the blocking capacitor: a high-frequency test signal is injected, the impedance spectrum of the blocking capacitor is measured, and the equivalent series resistance and capacitive reactance are calculated. The dielectric loss tangent is calculated based on the equivalent series resistance and capacitive reactance. The dielectric loss tangent is then used to determine the insulation aging status of the blocking capacitor. The specific formula is as follows: ， in, is the equivalent series resistance; is the capacitive reactance; If the calculated dielectric loss tangent value of the DC blocking capacitor is greater than the preset standard loss tangent value, the DC blocking capacitor needs to be repaired or replaced; If the calculated dielectric loss tangent value of the blocking capacitor is less than or equal to the preset standard loss tangent value, it means that the blocking capacitor is in normal condition; The judgment module judges the health status of the high-energy zinc oxide in the DC isolation protection module according to the status information of the high-energy zinc oxide in the DC isolation protection module. The specific process is as follows: The high-energy zinc oxide diagnostic unit uses a current transformer to collect information about the current variation through the high-energy zinc oxide and generates a current-time variation curve. It also uses a temperature sensor to collect information about the temperature variation of the high-energy zinc oxide and generates a temperature-time variation curve. Obtain the standard curve of high-energy zinc oxide current-temperature variation based on historical data, integrate the current-time variation curve and the temperature-time variation curve to generate the actual current-temperature variation curve; The standard temperature at which high-energy zinc oxide reaches a preset current standard value is obtained through the current-temperature change standard curve, and the actual temperature at which high-energy zinc oxide reaches a preset current standard value is obtained through the current-temperature change actual curve; The deterioration of high-energy zinc oxide can be judged 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 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 will issue an alarm to repair or replace the high-energy zinc oxide; The judgment module judges the health status of the eddy current self-driven switch in the DC isolation protection module according to the status information of the eddy current self-driven switch in the DC isolation protection module. The specific process is as follows: The self-driven switch life prediction unit collects the closing action time and opening action time of the eddy current self-driven switch, and judges the health status of the eddy current self-driven 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 eddy current self-driven switch is in normal state; 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; The monitoring module also 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.
2. The eddy current self-driven DC bias magnetic treatment device with self-checking function according to claim 1 is characterized in that: The operation process of the DC isolation protection module is as follows: During normal operation, the system is put into operation with the isolating knife closed and the isolating knife disconnected for maintenance. The eddy current self-driven 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 limit the voltage across the capacitor, thus protecting the DC blocking capacitor. When the high-energy zinc oxide component parameter abnormality protection fails, the short-circuit current flows through the self-driving coil of the eddy current self-driven switch component, and the eddy current drives the eddy current disk of the eddy current self-driven switch to close the arc extinguishing chamber and bypass the capacitor bank. After the short-circuit current disappears, the eddy current self-driven switch returns to the open state.
3. The eddy current self-driven DC bias magnetic treatment device with self-checking function according to claim 1 is characterized in that: The process of using the current generator to repair 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, the maintenance isolating switch is closed and the input isolating switch is disconnected. The current generator is connected in parallel to both ends of the DC blocking capacitor to simulate the release of the fault current through the current generator. After the current is released through the current generator, the status information of the DC blocking capacitor, high-energy zinc oxide and eddy current self-driven switch are monitored respectively through the monitoring module; after the current release of the current generator is turned off, the opening action of the eddy current self-driven switch is monitored.
4. The eddy current self-driven DC bias magnetic treatment device with self-checking function according to claim 1 is 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.
5. A method for treating eddy current self-driven DC bias magnetic field with a self-checking function, using the eddy current self-driven DC bias magnetic field treatment device with a self-checking function according to any one of claims 1 to 4, 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.