Capacitor protection system and method based on eddy current self-driven direct current magnetic bias suppression device

Abstract

The invention discloses a capacitor protection system and method based on an eddy current self-driven direct current magnetic bias suppression device, and relates to the technical field of direct current magnetic bias governance, and the capacitor protection system comprises a controller, a blocking capacitor, a zinc oxide resistor and a first switch, the eddy current self-driven switch comprises a coil I, a coil II and a switch II, the coil I and the coil II are electrified to generate magnetic force to push the switch II to brake, the coil I and the switch II are connected in series to a branch where the blocking capacitor is located, and the coil I is connected in parallel with a voltmeter; a driving mechanism used for supplying power to the second coil is arranged in an independent circuit where the second coil is located. The controller is used for collecting signals of the voltmeter, controlling opening and closing of the first switch and controlling on-off of a circuit of the second coil. The direct current magnetic bias treatment device has the effect of protecting the blocking capacitor in the direct current magnetic bias treatment device.

Description

Technical Field

[0001] The present application relates to the field of DC bias control technology, and in particular to a capacitor protection system and method based on an eddy current self-driven DC bias suppression device. Background Art

[0002] DC bias refers to the process in which a unidirectional magnetic flux is generated in the transformer core when DC current passes through the transformer winding, causing the core to operate in the nonlinear region of the magnetization curve, triggering a series of abnormal phenomena. DC bias can have a significant impact on the operating performance of the transformer and the stability of the power grid.

[0003] Depending on the specific circumstances, DC bias can be addressed through methods such as capacitor blocking, resistor current limiting, and reverse current injection. The capacitor blocking method utilizes the DC blocking and AC passing properties of capacitors (blocking DC but passing AC). By connecting a capacitor in series with the transformer's neutral point, it blocks DC current while allowing AC current to flow. This method is suitable for higher-voltage substations and effectively suppresses DC bias.

[0004] An existing DC bias control device based on the capacitor isolation method includes a capacitor and a zinc oxide resistor connected in parallel. As the device continues to be used, when the current flowing through the branch where the capacitor is located is large, the capacitor is likely to be broken down. Once the DC blocking capacitor in the device is broken down and damaged, the capacitor's DC blocking and AC passing function will directly disappear, which significantly reduces the device's effect on controlling DC bias. Summary of the Invention

[0005] In order to protect the DC blocking capacitor of a DC bias control device, the present application provides a capacitor protection system and method based on an eddy current self-driven DC bias suppression device.

[0006] In the first aspect, the capacitor protection system based on the eddy current self-driven DC bias suppression device provided by the present application adopts the following technical solutions: A capacitor protection system based on an eddy current self-driven DC bias suppression device includes a controller and a DC blocking capacitor, a zinc oxide resistor, and a first switch connected in parallel. The branch where the DC blocking capacitor is located is equipped with an eddy current self-driven switch. The eddy current self-driven switch includes a first coil, a second coil, and a second switch. Energizing the first and second coils generates a magnetic force capable of pushing the second switch to open. The first coil and the second switch are connected in series to the branch where the DC blocking capacitor is located. A voltmeter is connected in parallel to the first coil. The independent circuit where the second coil is located is equipped with a drive mechanism for supplying power to the second coil. The controller is used to collect signals from the voltmeter, control the closing and opening of the switch 1, and control the circuit on and off of the coil 2.

[0007] Generally speaking, when a large AC current flows through the neutral point of a transformer, it can be conducted to the ground through a DC-blocking capacitor. However, if the current flowing through the DC-blocking capacitor is large, there is a possibility of the capacitor breaking down. With the above technical solution, when a large current flows through the branch containing the DC-blocking capacitor, the current flows through Coil 1 of the eddy current self-driven switch. Coil 1 generates a magnetic force that pushes Switch 2 of the eddy current self-driven switch to open, disconnecting the branch containing the DC-blocking capacitor. This protects the DC-blocking capacitor and reduces the possibility of its breakdown.

[0008] When it is difficult to drive switch 2 of the eddy current self-driven switch to open by relying on coil 1 alone, switch 1 is first controlled to close to transfer the current to ground and keep the neutral point grounded. Then, power is supplied to coil 2 through the driving mechanism, so that coil 2 generates magnetic force to push switch 2 to open, thereby cutting off the branch where the DC blocking capacitor is located, thereby protecting the DC blocking capacitor.

[0009] The capacitor protection system in this device can reduce the possibility of large AC current breaking down the DC blocking capacitor, and keep the neutral point of the transformer grounded before disconnecting the branch where the DC blocking capacitor is located, significantly improving the safety and stability of the DC bias device application.

[0010] In a preferred example, the present application can be further configured as follows: the driving mechanism includes an energy storage capacitor and a thyristor, and the coil 2, the energy storage capacitor and the thyristor are arranged in series.

[0011] Through the above technical solution, when it is difficult to drive switch 2 of the eddy current self-driven switch to open by relying solely on coil 1, the energy storage capacitor is controlled to discharge the circuit where it is located, so that coil 2 generates magnetic force, pushing switch 2 to open, thereby opening the branch where the DC blocking capacitor is located, and further protecting the DC blocking capacitor.

[0012] In a preferred example, the present application can be further configured as follows: the directions of the magnetic fluxes generated by energizing the coils 1 and 2 are consistent.

[0013] With the above technical solution, since the magnetic fluxes generated by coils 1 and 2 after being energized are in the same direction, the magnetic forces generated by coils 1 and 2 can be superimposed on each other, thereby accelerating the opening speed of switch 2 and further reducing the possibility of damage to the DC blocking capacitor.

[0014] In the second aspect, based on the above-mentioned capacitor protection system based on the eddy current self-driven DC bias suppression device, the present application also provides a capacitor protection method based on the eddy current self-driven DC bias suppression device, which adopts the following technical solution: A capacitor protection method based on an eddy current self-driven DC bias suppression device, the method comprising: Real-time monitoring of the measured voltage value of the voltmeter; If the measured voltage value 1 reaches the trip voltage threshold 1 of the eddy current self-driven switch, obtaining the trip result of the switch 2; If the switch 2 is not opened, the switch 1 is controlled to close; The energy storage capacitor is controlled to discharge the circuit where it is located, so that coil 2 is energized and switch 2 is opened.

[0015] With this technical solution, if the measured voltage reaches the trip voltage threshold of the eddy current self-driven switch, but Switch 2 is not actually tripped, Switch 1 is first controlled to close, diverting the current to ground and maintaining the neutral point grounded. The energy storage capacitor is then controlled to discharge Coil 2. When energized, Coil 2 generates a magnetic force that pushes Switch 2 to open, disconnecting the branch containing the DC blocking capacitor and effectively protecting it, thereby reducing the possibility of it being broken down by large fault currents.

[0016] In a preferred example, the present application may be further configured to, after transferring the fault current, further include: Stopping the energy storage capacitor from discharging the circuit to which it is connected; Control switch 1 is open.

[0017] Through the above technical solution, after the fault current is transferred, the energy storage capacitor stops discharging to the branch where it is located. At this time, the magnetic force of Coil 1 and Coil 2 disappears due to the loss of current, and Switch 2 of the eddy current self-driven switch automatically closes, restoring the function of the DC blocking capacitor in the circuit of "isolating DC and passing AC", and controlling Switch 1 to open, keeping the neutral point grounded through the branch where the DC blocking capacitor is located.

[0018] In a preferred example, the present application may be further configured to, after controlling the energy storage capacitor to discharge the circuit to which it is connected, further include: If the second switch is not opened, obtaining a second measured voltage value of the energy storage capacitor; Comparing the measured voltage value 2 with the opening voltage threshold 2 at which the coil 2 can drive the switch 2 to open; If the measured voltage value 2 reaches the trip voltage threshold 2, a maintenance alarm message for the line where the energy storage capacitor is located is generated; if the measured voltage value 2 does not reach the trip voltage threshold 2, a power alarm message for the energy storage capacitor is generated.

[0019] Through the above technical solution, if coil two fails to drive switch two of the eddy current self-driven switch to open, the measured voltage value two of the energy storage capacitor is obtained. If the measured voltage value two of the energy storage capacitor has reached the opening voltage threshold two (opening voltage threshold two, that is, the minimum voltage value of the energy storage capacitor at which coil two can drive switch two to open), it means that the voltage of the energy storage capacitor has met the basic requirement of driving switch two to open. However, if switch two still cannot be opened, it means that there is a fault in the circuit where the energy storage capacitor is located. At this time, a maintenance alarm message for the line where the energy storage capacitor is located is generated to alert the operator to repair the line where the energy storage capacitor is located.

[0020] If the measured voltage value 2 of the energy storage capacitor does not reach the trip voltage threshold 2, it means that the current voltage of the energy storage capacitor is insufficient to drive the switch 2 to open, and an energy storage capacitor power alarm message is generated to warn the operator to replenish the energy storage capacitor and increase the voltage of the energy storage capacitor so that the energy storage capacitor can be restored to a state sufficient to drive the switch 2 to open.

[0021] In a preferred example, the present application may be further configured to, after generating the power alarm information of the energy storage capacitor and charging the energy storage capacitor, further include: Calculate the estimated charging time based on the measured voltage value of the energy storage capacitor, the trip voltage threshold, and the charging speed; During the estimated charging time period, switch 1 is kept in the closed state; After the expected charging time period has passed, the control switch is opened.

[0022] Through the above technical solution, the charging speed of the energy storage capacitor can be preset or calculated based on actual voltage changes. In short, the charging speed of the energy storage capacitor can be specifically quantified. The voltage difference between the two is calculated by subtracting the measured voltage value from the trip voltage threshold value. This voltage difference is then divided by the charging speed of the energy storage capacitor to determine the expected charging time of the energy storage capacitor.

[0023] During the estimated charging time, since Switch 2 cannot be opened, Switch 1 must remain closed to continue diverting any fault current that may be generated during this time. After the estimated charging time, the voltage of the energy storage capacitor reaches the second trip voltage threshold. The energy storage capacitor discharges Coil 2, driving Switch 2 to open. At this point, there's no need to ground Switch 1 through the branch it resides on to control the opening of Switch 1.

[0024] In a preferred example, the present application may be further configured such that, after the energy storage capacitor is fully charged, the following steps are further included: Obtain the number of energy cycles of the energy storage capacitor; Comparing the number of electric energy cycles with an upper limit of cycles preset for the energy storage capacitor; If the number of power cycles reaches the upper limit, an alarm message for replacing the energy storage capacitor will be generated.

[0025] As the energy storage capacitor is continuously charged and discharged, its service life is also continuously shortened. Through the above technical solution, by recording the number of energy storage capacitor energy cycles and comparing the number of energy cycles with the number of cycles on the line, if the number of energy cycles has reached the number of cycles on the line, an energy storage capacitor replacement alarm message is generated, warning the operator to replace the energy storage capacitor in order to maintain the driving effect of coil two on switch two.

[0026] In summary, this application has the following beneficial technical effects: 1. When a large fault AC current is generated at the neutral point of the transformer, the fault current is grounded through another branch, and the branch where the DC blocking capacitor is located is automatically disconnected by the eddy current self-driven switch. This disconnects the branch where the DC blocking capacitor is located, effectively protecting the DC blocking capacitor while maintaining the neutral point grounding, thereby reducing the possibility of the DC blocking capacitor being broken down. 2. If the faulty AC current cannot drive the eddy current self-driven switch to open switch 2 through coil 1, the energy storage capacitor is controlled to discharge the circuit, so that coil 2 generates magnetic force to push switch 2 to open, disconnecting the branch where the DC blocking capacitor is located, further enhancing the protection effect of the DC blocking capacitor; 3. If coil 2 fails to drive switch 2 of the eddy current self-driven switch to open, the fault type of switch 2 failure to open is analyzed and alarm information of different fault types is issued to facilitate the operator to handle the equipment fault in a targeted manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a circuit diagram of the DC bias magnetic treatment device according to an embodiment of the present application.

[0028] Figure 2 This is a circuit diagram of the circuit where the energy storage capacitor is located in an embodiment of the present application.

[0029] Figure 3 It is a flow chart of the capacitor protection method implemented in this application; Figure 4 It is a flow chart of the capacitor protection method implemented in this application; Figure 5 This is a flow chart of generating maintenance alarm information and power alarm information in the capacitor protection method implemented in this application; Figure 6 It is a flow chart of the capacitor protection method implemented in this application; Figure 7 This is a flow chart of generating replacement alarm information for energy storage capacitors in the capacitor protection method implemented in this application.

[0030] Description of reference numerals: 1. DC blocking capacitor; 2. Zinc oxide resistor; 3. Switch 1; 41. Coil 1; 411. Voltmeter; 42. Coil 2; 43. Switch 2; 51. Energy storage capacitor; 52. Thyristor. DETAILED DESCRIPTION

[0031] The following is combined with Figure 1 -Attached Figure 7 This application is described in further detail.

[0032] The embodiments of the present application disclose a capacitor protection system based on an eddy current self-driven DC bias suppression device and a capacitor protection method based on an eddy current self-driven DC bias suppression device.

[0033] Refer to the attached Figure 1 and attached Figure 2 As shown, the capacitor protection system based on the eddy current self-driven DC bias suppression device includes a controller, a DC blocking capacitor 1, a zinc oxide resistor 2 and a switch 3, wherein the DC blocking capacitor 1, the zinc oxide resistor 2 and the switch 3 are arranged in parallel with each other, and the branch where the zinc oxide resistor 2 is located is connected in series with a fuse.

[0034] Refer to the attached Figure 1 and attached Figure 2 As shown, the branch circuit where DC-blocking capacitor 1 is located is equipped with an eddy current self-driven switch. This eddy current self-driven switch includes coil 1 41, coil 2 42, and switch 2 43. When coil 1 41 and coil 2 42 are energized, they generate a magnetic force that can push switch 2 43 to open. The magnetic flux generated by energizing coils 1 41 and 2 42 is in the same direction. Coil 1 41 and switch 2 43 are connected in series to the branch circuit where DC-blocking capacitor 1 is located. A voltmeter 411 is connected in parallel to coil 1 41. The independent circuit where coil 2 42 is located is equipped with a drive mechanism for supplying power to coil 2 42.

[0035] The controller is used to collect the signal of the voltmeter 411, control the closing and opening of the switch 1 3, and control the circuit on and off of the coil 2 42.

[0036] Refer to the attached Figure 1 and attached Figure 2 As shown, the driving mechanism includes an energy storage capacitor 51 and a thyristor 52 , and the coil 2 42 , the energy storage capacitor 51 and the thyristor 52 are connected in series.

[0037] During the normal operation of the DC bias magnetic treatment equipment, if a small fault AC is generated at the neutral point of the transformer, the fault AC can be introduced into the ground through the DC blocking capacitor 1, and the DC blocking capacitor 1 can also isolate the DC from damaging the internal equipment of the transformer.

[0038] If a large fault AC current is generated at the transformer's neutral point, blocking capacitor 1 could break down if the branch circuit containing it is not promptly disconnected. In this device, when the fault AC current passes through coil 1 41, it generates magnetic force, pushing switch 2 43 of the eddy current self-driven switch to open. During this process, the branch circuit containing blocking capacitor 1 is automatically disconnected without requiring a trigger command, effectively protecting blocking capacitor 1 and minimizing the possibility of a breakdown.

[0039] If the faulty AC power cannot drive the switch 2 43 of the eddy current self-driven switch to open, the switch 1 3 is first controlled to close to transfer the fault current and maintain the neutral point of the transformer grounded; then, the energy storage capacitor 51 is controlled to discharge the independent circuit in which it is located, so that the coil 2 42 generates magnetic force after being energized, pushing the switch 2 43 of the eddy current self-driven switch to open, cutting off the branch where the DC blocking capacitor 1 is located, and protecting the DC blocking capacitor 1.

[0040] Based on the above-mentioned capacitor protection system based on the eddy current self-driven DC bias device, the embodiment of the present application also discloses a capacitor protection method based on the eddy current self-driven DC bias suppression device, which adopts the following technical solution: Refer to the attached Figure 1 and attached Figure 2 As shown, a capacitor protection method based on an eddy current self-driven DC bias suppression device includes: S101 , monitor the measured voltage value 1 of the voltmeter 411 in real time.

[0041] In practice, since the voltage value at both ends of coil 1 41 is monitored by voltmeter 411, by real-time monitoring of the measured voltage value 1 of voltmeter 411, it can be known whether, in theory, coil 1 41 of the eddy current driven switch meets the minimum requirement to drive switch 2 43 to open.

[0042] S102 : If the measured voltage value 1 reaches the trip voltage threshold 1 of the eddy current self-driven switch, the trip result of the switch 2 43 is obtained.

[0043] In practice, the trip voltage threshold 1 can be understood as the minimum voltage across coil 1 41 when the magnetic force generated by coil 1 41 alone is sufficient to drive switch 2 43 to open. If the measured voltage value 1 reaches the trip voltage threshold 1, the trip result of switch 2 43 is obtained, which may include whether the trip is complete or incomplete.

[0044] S103: If the switch 2 43 is not opened, the switch 1 3 is controlled to be closed.

[0045] In practice, if the opening of switch 2 43 is not completed, switch 1 3 is controlled to be closed first, that is, the faulty AC power is transferred first to keep the neutral point of the transformer grounded.

[0046] S104 , controlling the energy storage capacitor 51 to discharge the circuit in which it is located, so that the coil 2 42 is energized and the switch 2 43 is opened.

[0047] During implementation, after the neutral point of the transformer is grounded through switch 1 3 , the energy storage capacitor 51 is controlled to discharge the independent circuit in which it is located. At this time, coil 2 42 is energized to generate magnetic force, which pushes switch 2 43 of the eddy current self-driven switch to open, disconnecting the branch where the DC blocking capacitor 1 is located, thereby protecting the DC blocking capacitor 1.

[0048] Refer to the attached Figure 4 As shown in Figure 1, after the fault current is transferred, the following processing steps are also included: S201 , stop the energy storage capacitor 51 from discharging the circuit to which it is connected.

[0049] In practice, after the fault current is transferred, the energy storage capacitor 51 stops discharging to the branch where it is located. At this time, the magnetic force of coil 1 41 and coil 2 42 disappears due to the loss of current, and switch 2 43 of the eddy current self-driven switch automatically closes, restoring the function of the DC blocking capacitor 1 in the circuit of "isolating DC and passing AC".

[0050] S201, control switch 3 to open.

[0051] In practice, by controlling the switch 1 3 to be open, the DC power generated thereafter cannot affect the internal components of the transformer through the branch where the switch 1 3 is located.

[0052] Refer to the attached Figure 5 As shown, in step S104, after controlling the energy storage capacitor 51 to discharge the circuit where it is located, the following processing steps may also be included: S301 : If the second switch 43 is not opened, obtain the second measured voltage value of the energy storage capacitor 51 .

[0053] In practice, if the switch 2 43 is not opened after being driven again by the coil 2 42 , the measured voltage value 2 of the energy storage capacitor 51 is obtained (ie, the lowest voltage across the energy storage capacitor 51 when the coil 2 42 drives the switch 2 43 to open).

[0054] S302 : Compare the measured voltage value 2 with the opening voltage threshold 2 at which the coil 2 42 can drive the switch 2 43 to open.

[0055] S303. If the second measured voltage value reaches the second trip voltage threshold, a maintenance alarm message for the line where the energy storage capacitor 51 is located is generated; if the second measured voltage value does not reach the second trip voltage threshold, a power alarm message for the energy storage capacitor 51 is generated.

[0056] During implementation, if the measured voltage value 2 reaches the trip voltage threshold 2, it means that the voltage of the energy storage capacitor 51 is able to meet the basic requirement of driving the switch 2 43 to trip, but the switch 2 43 still cannot trip, which means that there is a fault in the circuit where the energy storage capacitor 51 is located. At this time, a maintenance alarm message of the line where the energy storage capacitor 51 is located is generated to warn the operator to repair the line where the energy storage capacitor 51 is located.

[0057] If the measured voltage value 2 of the energy storage capacitor 51 does not reach the trip voltage threshold 2, it means that the current voltage of the energy storage capacitor 51 is insufficient to drive the switch 2 43 to trip, and then a power alarm message of the energy storage capacitor 51 is generated to warn the operator to replenish the energy of the energy storage capacitor 51 and increase the voltage of the energy storage capacitor 51 so that the energy storage capacitor 51 can be restored to a state sufficient to drive the switch 2 43 to trip.

[0058] Refer to the attached Figure 6 As shown, in step S303, after generating the power alarm information of the energy storage capacitor 51 and charging the energy storage capacitor 51, the following processing steps may also be included: S401 , calculating an estimated charging time based on the second measured voltage value of the energy storage capacitor 51 , the second trip voltage threshold, and the charging speed.

[0059] In practice, the charging speed of the energy storage capacitor 51 can be preset or calculated based on actual voltage changes. In short, the charging speed of the energy storage capacitor 51 can be specifically quantified.

[0060] The voltage difference between the two is obtained by subtracting the measured voltage value 2 from the trip voltage threshold 2. The estimated charging time of the energy storage capacitor 51 can be obtained by dividing the voltage difference by the charging speed of the energy storage capacitor 51.

[0061] S402: During the estimated charging time period, maintain the switch 3 in the closed state.

[0062] In practice, during the time period corresponding to the expected charging time, since the switch 2 43 cannot be opened at present, it is necessary to keep the switch 1 3 in the closed state to continuously transfer the fault current that may be generated during this time period.

[0063] S403: After the expected charging time period has passed, control the switch to open.

[0064] During implementation, after the expected charging time, the voltage of the energy storage capacitor 51 has reached the trip voltage threshold 2. At this time, after the energy storage capacitor 51 discharges the coil 2 42, it can push the switch 2 43 to trip. At this time, there is no need to ground through the branch where the switch 1 3 is located to control the switch 1 3 to trip, and at the same time, it also reduces the impact of DC power on the internal components of the transformer.

[0065] Refer to the attached Figure 7 As shown, after the energy storage capacitor 51 is charged, the following processing steps may also be included: S501 , obtaining the number of electric energy cycles of the energy storage capacitor 51 .

[0066] In practice, each charge and discharge of the energy storage capacitor 51 is recorded, and the number of charge and discharge times of the energy storage capacitor 51 is accumulated. In this way, the number of electric energy cycles of the energy storage capacitor 51 can be directly obtained after each charging of the energy storage capacitor 51 is completed.

[0067] S502 : Compare the number of electric energy cycles with the upper limit of cycles preset for the energy storage capacitor 51 .

[0068] S503: If the number of cycles of electric energy reaches the upper limit of the number of cycles, a replacement alarm message for the energy storage capacitor 51 is generated.

[0069] In practice, if the number of power cycles has reached the upper limit, a replacement alarm message for the energy storage capacitor 51 is generated to warn the operator to replace the energy storage capacitor 51 in order to maintain the driving effect of the coil 2 42 on the switch 2 43 .

[0070] If the number of electric energy cycles does not reach the upper limit of the cycle, it means that the energy storage capacitor 51 can still be used normally. When the line is normal, the coil 2 42 can generate magnetic force to push the switch 2 43 to open.

[0071] The embodiments of this specific implementation method are all preferred embodiments of the present application and are not intended to limit the scope of protection of the present application in turn. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A capacitor protection system based on an eddy current self-driven DC bias suppression device, characterized in that: The invention comprises a controller and a DC blocking capacitor (1), a zinc oxide resistor (2) and a switch (3) connected in parallel with each other. The branch where the DC blocking capacitor (1) is located is equipped with an eddy current self-driven switch. The eddy current self-driven switch comprises a coil (41), a coil (42) and a switch (43). When the coil (41) and the coil (42) are energized, a magnetic force is generated to push the switch (43) to open. The coil (41) and the switch (43) are connected in series to the branch where the DC blocking capacitor (1) is located. The coil (41) is connected in parallel with a voltmeter (411). A driving mechanism for supplying power to the coil (42) is provided in the independent circuit where the coil (42) is located. The controller is used to collect signals from a voltmeter (411), control the closing and opening of a switch (3), and control the on / off of a circuit of a coil (42).

2. The capacitor protection system based on the eddy current self-driven DC bias suppression device according to claim 1 is characterized in that: The driving mechanism comprises an energy storage capacitor (51) and a thyristor (52), and the second coil (42), the energy storage capacitor (51) and the thyristor (52) are connected in series.

3. The capacitor protection system based on the eddy current self-driven DC bias suppression device according to claim 2 is characterized in that: The directions of the magnetic fluxes generated by the coil 1 (41) and the coil 2 (42) when energized are consistent.

4. A capacitor protection method based on an eddy current self-driven DC bias suppression device, based on the capacitor protection system based on an eddy current self-driven DC bias suppression device according to claim 3, characterized in that: The method comprises: Real-time monitoring of the measured voltage value of the voltmeter (411); If the measured voltage value 1 reaches the opening voltage threshold 1 of the eddy current self-driven switch, the opening result of the switch 2 (43) is obtained; If the switch 2 (43) has not been opened, the switch 1 (3) is controlled to be closed; The energy storage capacitor (51) is controlled to discharge the circuit in which it is located, so that the coil 2 (42) is energized to push the switch 2 (43) to open.

5. The capacitor protection method based on the eddy current self-driven DC bias suppression device according to claim 3 is characterized in that: After transferring the fault current, it also includes: Stopping the energy storage capacitor (51) from discharging the circuit in which it is located; Control switch 1 (3) to open.

6. The capacitor protection method based on the eddy current self-driven DC bias suppression device according to claim 4 is characterized in that: After controlling the energy storage capacitor (51) to discharge the circuit where it is located, the method further includes: If the second switch (43) has not completed the opening, obtaining the second measured voltage value of the energy storage capacitor (51); Comparing the measured voltage value 2 with the opening voltage threshold 2 at which the coil 2 (42) can drive the switch 2 (43) to open; If the measured voltage value 2 reaches the trip voltage threshold 2, a maintenance alarm message of the line where the energy storage capacitor (51) is located is generated; if the measured voltage value 2 does not reach the trip voltage threshold 2, a power alarm message of the energy storage capacitor (51) is generated.

7. The capacitor protection method based on the eddy current self-driven DC bias suppression device according to claim 6 is characterized in that: After generating the electric quantity warning information of the energy storage capacitor (51) and charging the energy storage capacitor (51), the method further includes: Calculating an estimated charging time based on a measured voltage value 2 of the energy storage capacitor (51), a trip voltage threshold 2, and a charging speed; During the estimated charging time period, maintaining the switch 1 (3) in a closed state; After the expected charging time period has passed, the control switch 1 (3) is opened.

8. The capacitor protection method based on the eddy current self-driven DC bias suppression device according to claim 7 is characterized in that: After the energy storage capacitor (51) is charged, the following steps are also included: Obtaining the number of electric energy cycles of the energy storage capacitor (51); Comparing the number of electric energy cycles with an upper limit of the number of cycles preset by the energy storage capacitor (51); If the number of electric energy cycles reaches the upper limit of the number of cycles, a replacement warning message for the energy storage capacitor (51) is generated.

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