Zero-loss deep current limiting device matched with automatic reclosing and control method thereof

Abstract

The application provides a zero-loss deep current limiting device matched with automatic reclosing and a control method thereof, comprising a current limiting reactor, a fast circuit breaker and a split-phase controller, the current limiting reactor and the fast circuit breaker are connected in parallel first and then connected with the split-phase controller respectively. The application realizes fast switching of the current limiting reactor by controlling the zero-loss deep current limiting device matched with automatic reclosing. The device is zero-loss and has no voltage drop in normal operation, and realizes deep current limiting quickly when a short-circuit fault occurs. When a near-zone fault occurs during parallel operation of the 10kV bus, the device can cooperate with the automatic reclosing of the 10kV feeder circuit breaker to normally cut off the short-circuit current and isolate the fault. The application solves the problem that the short-circuit current increases year by year with the development of the power grid and exceeds the breaking capacity of the circuit breaker, and realizes the cooperation of the zero-loss deep current limiting device with the automatic reclosing, so that the zero-loss deep current limiting can be realized continuously.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of power grid protection, and particularly relates to a zero-loss deep current limiting device capable of cooperating with automatic reclosing and a control method thereof. BACKGROUND

[0002] With the expansion of the power grid scale and the increasingly close connection between power grids, the short-circuit current of each voltage level bus of the power grid is increasing year by year, among which the short-circuit current of the 10kV bus generally approaches or exceeds the breaking capacity of the circuit breaker, and the circuit breaker cannot normally cut off the short-circuit current. When reclosing occurs on a permanent fault or multiple transient faults, the working conditions of the circuit breaker are further deteriorated, thereby bringing a series of problems of power grid, equipment and personal safety, which are increasingly prominent and cause serious economic and social impacts. The short-circuit current exceeding the standard has become a key problem affecting the future development of the power grid.

[0003] At present, the methods for limiting the short-circuit current of the 10kV bus mainly include: selecting a high-impedance transformer, installing a fixed current limiting reactor on the 10kV side of a low-impedance transformer, and converting the 10kV bus to parallel operation. However, the methods of using a high-impedance transformer and installing a fixed current limiting reactor on the 10kV side of a traditional low-impedance transformer have large power loss and bus voltage drop, low current limiting depth, poor cooperation with automatic reclosing, and the circuit breaker needs to cut off a large short-circuit current for multiple times in a short time, which has a large risk of equipment and life. The method of converting the 10kV bus to parallel operation changes the network topology of the system and reduces the power supply reliability. SUMMARY

[0004] Therefore, the present application aims to solve the above technical problems existing in the current methods for limiting the short-circuit current of the 10kV bus.

[0005] In order to solve the above technical problems, the present application provides the following technical solutions:

[0006] In a first aspect, the present application provides a zero-loss deep current limiting device capable of cooperating with automatic reclosing, comprising: a current limiting reactor, a fast circuit breaker and a split-phase controller, the current limiting reactor and the fast circuit breaker are connected in parallel first and then connected with the split-phase controller respectively.

[0007] The current limiting reactor is used to limit the short-circuit current and reduce the short-circuit current to below the limit breaking current of the 10kV feeder circuit breaker, so as to ensure that the 10kV feeder circuit breaker can normally trip and isolate the fault in the near area.

[0008] The fast circuit breaker is used to realize the switching of the current limiting reactor by itself, and the current limiting reactor is put into the circuit when the fast circuit breaker is tripped, and the current limiting reactor is taken out of the circuit when the fast circuit breaker is closed.

[0009] The phase separation controller is used for cooperating the current limiting reactor with the automatic reclosing when the line is in fault, controlling the fast circuit breaker to open when the line is in fault, so that the current limiting reactor is put into the circuit, waiting for the protection action delay, then controlling the fast circuit breaker to close, so that the current limiting reactor is taken out of the circuit, waiting for the automatic reclosing action after the current limiting reactor is taken out of the circuit, and waiting for the next fault occurrence after the reclosing delay.

[0010] Further, it further comprises a return current transformer and an action current transformer.

[0011] The return current transformer is installed in the current limiting reactor branch, and is used for collecting the 10kV normal working current.

[0012] The action current transformer is installed in the fast circuit breaker branch, and is used for collecting the 10kV fault short-circuit current.

[0013] Further, it further comprises a capacitor bank.

[0014] The capacitor bank is composed of a plurality of capacitor banks, and is used for providing power supply for the fast circuit breaker opening and closing, and each capacitor bank which completes charging can supply power for the fast circuit breaker opening and closing once.

[0015] Further, when the line is in fault, the fast circuit breaker is controlled to open, so that the current limiting reactor is put into the circuit, and after waiting for the protection action delay, the fast circuit breaker is controlled to close, so that the current limiting reactor is taken out of the circuit, and specifically:

[0016] It is judged whether the current value of the action current transformer is greater than or equal to the current limiting input setting value, if yes, the capacitor bank which completes charging in the capacitor bank is discharged, so that the current limiting reactor is put into the circuit;

[0017] After waiting for the protection action delay, it is judged whether the current value of the return current transformer is less than the current limiting exit setting value, if yes, the capacitor bank is discharged again, so that the current limiting reactor is taken out of the circuit.

[0018] Further, when the line is in permanent fault, the current limiting reactor is cooperated with the automatic reclosing, and specifically includes:

[0019] The first capacitor bank which completes charging is discharged, the current limiting reactor is put into operation, the fault line is tripped, the first capacitor bank is discharged again, the current limiting reactor is taken out of operation, the fault line is reclosed, the permanent fault is reclosed, the second capacitor bank which completes charging is discharged, the current limiting reactor is put into operation, and the fault line is accelerated to trip, and the second capacitor bank is discharged again, so that the current limiting reactor is taken out of operation.

[0020] Further, when the line is in multiple transient faults, the current limiting reactor is cooperated with the automatic reclosing, and specifically includes:

[0021] When transient fault occurs in each line, the charged capacitor group discharges, the current limiting reactor is put into operation, the fault line is tripped, the charged capacitor group discharges again, the current limiting reactor is withdrawn from operation, the fault line is reclosed, the switch energy storage and reclosing charging are carried out, and preparation is made for the next fault.

[0022] In the second aspect, the application provides a zero-loss deep current limiting device control method matched with automatic reclosing, applied to the zero-loss deep current limiting device matched with automatic reclosing in the first aspect, and comprising the following steps:

[0023] S201: detecting the charging condition of the capacitor group, if at least one group of the capacitor group has completed charging, executing step 203, otherwise executing step 202;

[0024] S202: waiting for the capacitor group to complete charging;

[0025] S203: detecting the on-off state of the current limiting reactor, if the current limiting reactor is in the off state, executing step 204, if the current limiting reactor is in the on state, executing step 207;

[0026] S204: detecting whether the current value of the operating current transformer is normal, if greater than or equal to the current limiting on-set value, executing step 205, otherwise returning to step 203;

[0027] S205: controlling the discharged capacitor group of the capacitor group that has completed charging to discharge, driving the quick circuit breaker to trip, and putting the current limiting reactor into operation;

[0028] S206: waiting for the relay protection device to act to isolate the fault, and returning to step 201 after the protection action delay;

[0029] S207: detecting whether the current value of the return current transformer is restored, if less than the current limiting off-set value, executing step 208, otherwise returning to step 203;

[0030] S208: controlling the discharged capacitor group of the capacitor group that has completed charging to discharge, driving the quick circuit breaker to close, and withdrawing the current limiting reactor from operation;

[0031] S209: after the current limiting reactor is withdrawn from operation, waiting for the automatic reclosing to act, and returning to step 201 after the reclosing delay.

[0032] In summary, the application provides a zero-loss deep current limiting device compatible with automatic reclosing and a control method thereof, comprising a current limiting reactor, a fast circuit breaker and a phase separation controller, the current limiting reactor and the fast circuit breaker are connected in parallel first and then connected with the phase separation controller respectively; the phase separation controller cooperates the current limiting reactor with the automatic reclosing when a fault occurs in the line, controls the fast circuit breaker to open when a fault occurs in the line, so that the current limiting reactor is put into the circuit, controls the fast circuit breaker to close after a protection action delay, so that the current limiting reactor is taken out of the circuit, waits for the automatic reclosing action after being taken out, and waits for the next fault occurrence after a reclosing delay. The application realizes the fast putting and taking of the current limiting reactor by controlling the zero-loss deep current limiting device to cooperate with the automatic reclosing. The device is zero-loss and has no voltage drop in normal operation, and realizes deep current limiting quickly when a short-circuit fault occurs, so that the 10kV busbar parallel operation can be ensured, the automatic reclosing 10kV feeder circuit breaker can normally cut off the short-circuit current when a near-zone fault occurs, and the fault can be isolated. The problem that the short-circuit current increases year by year with the development of the power grid and exceeds the breaking capacity of the circuit breaker is solved, the zero-loss deep current limiting device is cooperated with the automatic reclosing, and the zero-loss deep current limiting can be realized continuously. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only constitute some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0034] Figure 1 A structural block diagram of a zero-loss deep current limiting device compatible with automatic reclosing is provided for the embodiments of the application.

[0035] Figure 2 A flowchart of a control method of a zero-loss deep current limiting device compatible with automatic reclosing is provided for the embodiments of the application.

[0036] Figure 3 A timing diagram of a zero-loss deep current limiting device compatible with reclosing when a permanent fault occurs is provided for the embodiments of the application.

[0037] Figure 4 A timing diagram of a zero-loss deep current limiting device compatible with reclosing when multiple transient faults occur is provided for the embodiments of the application. DETAILED DESCRIPTION

[0038] In order to make the objectives, characteristics and advantages of the present application more obvious and easy to understand, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the following described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0039] With the expansion of the power grid scale and the increasingly close connection between power grids, the short-circuit current of each voltage level bus of the power grid is increasing year by year, among which the short-circuit current of the 10kV bus generally approaches or exceeds the breaking capacity of the circuit breaker, and the circuit breaker cannot normally cut off the short-circuit current. When reclosing occurs on a permanent fault or multiple transient faults, the working conditions of the circuit breaker are further deteriorated, thereby bringing a series of problems of power grid, equipment and personal safety, which are increasingly prominent, causing serious economic and social impact. The short-circuit current exceeding the standard has become a key problem affecting the future development of the power grid.

[0040] At present, the methods for limiting the short-circuit current of the 10kV bus mainly include: selecting high-impedance transformers, installing fixed current-limiting reactors on the 10kV side of low-impedance transformers, and converting the 10kV bus to parallel operation, etc.

[0041] Selecting high-impedance transformers can increase the short-circuit impedance of the system, thereby reducing the short-circuit current of the system, but the procurement cost of high-impedance transformers is high, and the structural characteristics of high-impedance transformers inevitably result in more leakage flux and winding interlinking, thereby increasing the stray loss and power loss. Therefore, limited by the power loss and procurement cost, the current limiting of high-impedance transformers often cannot achieve deep current limiting, the short-circuit current is still large, and the 10kV bus still needs to be converted to split-column operation, sacrificing the reliability of power supply. When the high-impedance transformer is combined with the traditional automatic reclosing mode and reclosed on a permanent fault or multiple transient faults, the circuit breaker needs to cut off the large short-circuit current multiple times in a short time, and the working conditions of the circuit breaker are continuously deteriorated, resulting in the decrease of the breaking capacity of the circuit breaker, which may not be able to normally cut off the short-circuit current.

[0042] Installing fixed current-limiting reactors on the 10kV side of the traditional low-impedance transformer can effectively reduce the short-circuit current of the 10kV bus, and this method is simple and widely applicable, but the direct current resistance of the fixed current-limiting reactor will inevitably lead to the decrease of the 10kV bus voltage, and large power loss will also occur during long-term operation. In addition, the fixed current-limiting reactor also cannot achieve deep current limiting, and the 10kV bus needs to be converted to split-column operation, sacrificing the reliability of power supply, and when combined with reclosing, it also has the problem of being unable to cut off the large short-circuit current multiple times.

[0043] 10kV busbar is converted into separate column operation, the topology of the network is changed, the short-circuit impedance of the network is improved, and the short-circuit current is reduced, but the electrical connectivity of the system is changed, which is not conducive to stable operation of the system and reduces the reliability.

[0044] Based on this, the application provides a zero-loss deep current limiting device matched with automatic reclosing and a control method thereof.

[0045] The following will introduce an embodiment of the zero-loss deep current limiting device matched with automatic reclosing in detail.

[0046] Please refer to Figure 1 The embodiment provides a zero-loss deep current limiting device matched with automatic reclosing, which comprises a current limiting reactor, a fast circuit breaker and a phase separation controller.

[0047] In the embodiment, the current limiting reactor is used to limit the short-circuit current, and the short-circuit current is reduced to below the limit breaking current of the 10kV feeder circuit breaker, so that the 10kV feeder circuit breaker can normally trip and isolate the fault when a near-zone fault occurs.

[0048] In the embodiment, the fast circuit breaker is used to realize the switching of the current limiting reactor, the current limiting reactor is put into the circuit when the fast circuit breaker is tripped, and the current limiting reactor is taken out of the circuit when the fast circuit breaker is closed.

[0049] In the embodiment, the phase separation controller is used to cooperate the current limiting reactor with the automatic reclosing when a fault occurs in the line, the fast circuit breaker is controlled to be tripped when the line is faulty, so that the current limiting reactor is put into the circuit, the fast circuit breaker is controlled to be closed after a protection action delay, so that the current limiting reactor is taken out of the circuit, and the automatic reclosing is waited for after the current limiting reactor is taken out of the circuit, and the next fault is waited for after the automatic reclosing delay.

[0050] In order to facilitate the phase separation controller to obtain the fault and normal condition of the line, so as to control the current limiting reactor to cooperate with the automatic reclosing, a return current transformer and an action current transformer can be installed in the current limiting reactor branch and the fast circuit breaker branch respectively. The return current transformer is used to collect the 10kV normal working current, and the action current transformer is used to collect the 10kV fault short-circuit current.

[0051] In an embodiment, the phase separation controller controls the opening and closing of the fast circuit breaker through a capacitor bank. The capacitor bank is composed of a plurality of capacitor groups, and is used to provide power supply for the opening and closing of the fast circuit breaker. Each capacitor group that completes charging can provide the opening and closing of the fast circuit breaker once. Considering practicability and economy, three capacitor groups, i.e., a first group of capacitors, a second group of capacitors and a third group of capacitors, are arranged in the capacitor bank.

[0052] Based on the design of current transformer and capacitor bank, the line fault phase controller controls the switching logic of the current limiting reactor as follows:

[0053] Judge whether the current value of the action current transformer is greater than or equal to the current limiting input set value, if yes, discharge the charged capacitor bank in the capacitor bank to make the current limiting reactor input circuit;

[0054] After waiting for the protection action delay, judge whether the current value of the return current transformer is less than the current limiting exit set value, if yes, discharge the capacitor bank again to make the current limiting reactor exit the circuit.

[0055] When the line fails, the current limiting reactor cooperates with the reclosing timing as follows:

[0056] Please refer to Figure 3 , Figure 3 is the 10kV zero-loss deep current limiting device cooperating with the reclosing timing when permanent fault occurs. Specifically, if the 10kV line fails, the first group of capacitor banks (such as group I capacitor) is discharged, the current limiting reactor is put into operation, the fault line is tripped, and the first group of capacitor banks (group I capacitor) is discharged again, the current limiting reactor is taken out of operation; the fault line recloses, recloses on permanent fault, the second group of capacitor banks (such as group II capacitor) is discharged, the current limiting reactor is put into operation, the fault line is accelerated tripping, and the second group of capacitor banks (group II capacitor) is discharged again, the current limiting reactor is taken out of operation.

[0057] Please refer to Figure 4 , Figure 4 is the 10kV zero-loss deep current limiting device cooperating with the reclosing timing when multiple transient faults occur. Specifically, when the 10kV line fails for the first time, a group of capacitor banks (such as group I capacitor) is discharged, the current limiting reactor is put into operation, the fault line is tripped, and the group of capacitor banks (group I capacitor) is discharged again, the current limiting reactor is taken out of operation; the fault line recloses, performs switch energy storage and reclosing charging to prepare for the next fault; the 10kV line fails for the second time, a group of capacitor banks (such as group II capacitor) is discharged, the current limiting reactor is put into operation, the fault line is tripped, and the group of capacitor banks (group II capacitor) is discharged again, the current limiting reactor is taken out of operation; the fault line recloses, performs switch energy storage and reclosing charging to prepare for the next fault; the 10kV line fails for the third time, a group of capacitor banks (such as group III capacitor) is discharged, the current limiting reactor is put into operation, the fault line is tripped, and the group of capacitor banks (group III capacitor) is discharged again, the current limiting reactor is taken out of operation; the fault line recloses, performs switch energy storage and reclosing charging to prepare for the next fault.

[0058] The embodiment provides a zero-loss deep current limiting device matched with automatic reclosing, which comprises a current limiting reactor, a fast circuit breaker and a split-phase controller, the current limiting reactor and the fast circuit breaker are connected with the split-phase controller in parallel and then connected with the split-phase controller respectively; the split-phase controller matches the current limiting reactor with the automatic reclosing when a line fault occurs, controls the fast circuit breaker to be tripped when the line fault occurs, so that the current limiting reactor is put into the circuit, controls the fast circuit breaker to be closed after a protection action delay, so that the current limiting reactor is taken out of the circuit, waits for an automatic reclosing action after being taken out of the circuit, and waits for the occurrence of the next fault after a reclosing delay. The device collects 10kV bus short-circuit current, drives the fast circuit breaker to be opened and closed by using a capacitor as an energy storage power supply, controls the current limiting reactor to be put in and taken out by the split-phase controller, and realizes the matching with the 10kV zero-loss deep current limiting device and the reclosing.

[0059] The above is a detailed introduction to the embodiment of the zero-loss deep current limiting device matched with automatic reclosing, and the embodiment of the control method of the zero-loss deep current limiting device matched with automatic reclosing will be introduced in detail below.

[0060] Please refer to Figure 2 The embodiment provides a control method of the zero-loss deep current limiting device matched with automatic reclosing, which is applied to the zero-loss deep current limiting device matched with automatic reclosing and comprises the following steps.

[0061] Step 201, detecting capacitor group charging condition, if at least one of the three capacitor groups has completed charging, executing step 203, otherwise executing step 202 to wait for capacitor group charging;

[0062] Step 202, providing waiting capacitor group charging;

[0063] Step 203, detecting current limiting reactor put-in and take-out state, if the fast circuit breaker is in the closed position, the current limiting reactor is in the take-out state, executing step 204, if the fast circuit breaker is in the tripped position, the current limiting reactor is in the put-in state, executing step 207;

[0064] Step 204, detecting whether the fast circuit breaker current, namely the action current transformer current I1, is normal, if I1 is greater than or equal to the current limiting put-in setting value IK1, judging that a short-circuit fault occurs and executing step 205, otherwise judging that no short-circuit is sent and returning to step 203;

[0065] Step 205, controlling the nth capacitor group to be discharged, driving the fast circuit breaker to be tripped, and putting in the current limiting reactor;

[0066] Step 206, waiting for a relay protection device action to isolate a fault after the current limiting reactor is put in, and returning to step 201 after a protection action delay;

[0067] Step 207, detecting whether the current of the current limiting reactor, i.e. the current I2 of the return current transformer, is restored, if I2 is less than or equal to the current limiting input setting value IK2, it is judged that the short-circuit fault is removed, step 208 is executed, otherwise it is judged that the short-circuit fault is not removed, and step 203 is returned;

[0068] Step 208, discharging the nth capacitor bank, driving the fast circuit breaker to close, and exiting the current limiting reactor;

[0069] Step 209, after exiting the current limiting reactor, waiting for the automatic reclosing operation, and returning to step 201 after the reclosing delay.

[0070] The embodiment provides a zero-loss deep current limiting device control method which can cooperate with automatic reclosing, and the zero-loss deep current limiting device is controlled to realize fast switching of the current limiting reactor in cooperation with automatic reclosing. When in normal operation, the device is zero-loss and has no voltage drop, when a short-circuit fault occurs, deep current limiting is realized quickly, when a near-zone permanent fault or multiple transient faults occur in 10kV bus parallel operation, the automatic reclosing 10kV feeder circuit breaker can cut off the short-circuit current and isolate the fault. The problem that the short-circuit current increases year by year with the development of the power grid and exceeds the breaking capacity of the circuit breaker is solved, the zero-loss deep current limiting device cooperates with the automatic reclosing, and the zero-loss deep current limiting can be realized continuously.

[0071] The above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A zero-loss deep current limiting device that can be used in conjunction with automatic reclosing, characterized in that, include: The system includes a current-limiting reactor, a fast circuit breaker, and a phase-splitting controller. The current-limiting reactor and the fast circuit breaker are first connected in parallel and then connected to the phase-splitting controller respectively. The current-limiting reactor is used to limit the short-circuit current and reduce the short-circuit current to below the limit breaking current of the 10kV feeder circuit breaker, so as to ensure that the 10kV feeder circuit breaker can normally trip and isolate the fault in the near-zone fault. The fast circuit breaker is used to enable or disable the current-limiting reactor by its own opening and closing. When the fast circuit breaker opens, the current-limiting reactor is engaged in the circuit, and when the fast circuit breaker closes, the current-limiting reactor is disengaged from the circuit. The phase-separation controller is used to coordinate the current-limiting reactor with the automatic reclosing when a line fault occurs. When a line fault occurs, the controller controls the fast circuit breaker to open so that the current-limiting reactor is put into the circuit. After waiting for the protection action delay, the controller controls the fast circuit breaker to close so that the current-limiting reactor is taken out of the circuit. After being taken out, the controller waits for the automatic reclosing action. After the reclosing delay, the controller waits for the next fault to occur. It also includes: return current transformers and operating current transformers; The return current transformer is installed in the current-limiting reactor branch and is used to collect the 10kV normal operating current. The operating current transformer is installed in the branch of the fast circuit breaker and is used to collect 10kV fault short-circuit current. Also includes: capacitor banks; The capacitor bank consists of several sets of capacitor banks, which are used to provide power for the opening and closing of the fast circuit breaker. Each set of capacitor banks that has been fully charged can power the fast circuit breaker to open and close once. When a line fault occurs, the fast circuit breaker is controlled to trip, allowing the current-limiting reactor to enter the circuit. After a protection operation delay, the fast circuit breaker is controlled to close, allowing the current-limiting reactor to exit the circuit. Specifically: Determine whether the current value of the operating current transformer is greater than or equal to the current limiting activation setting. If so, discharge the capacitor bank that has completed charging in the capacitor bank so that the current limiting reactor can be activated in the circuit. After the protection action delay, determine whether the current value of the return current transformer is less than the current limiting exit setting. If so, discharge the capacitor bank again to allow the current limiting reactor to exit the circuit. In the event of a permanent line fault, the current-limiting reactor will be coordinated with the automatic reclosing circuit breaker, specifically including: When the first set of capacitors, having completed charging, discharges, the current-limiting reactor is put into operation, the faulty line trips, and then the first set of capacitors discharges again, the current-limiting reactor is taken out of operation; when the faulty line reclosing is activated, it recloses to a permanent fault, when the second set of capacitors, having completed charging, discharges, the current-limiting reactor is put into operation, the faulty line trips faster, and then the second set of capacitors discharges again, the current-limiting reactor is taken out of operation.

2. The zero-loss deep current limiting device that can be used in conjunction with automatic reclosing according to claim 1, characterized in that, When multiple transient faults occur on the line, the current-limiting reactor is coordinated with the automatic reclosing device, specifically including: When a momentary fault occurs on the line, the charged capacitor bank discharges, the current-limiting reactor is put into operation, the faulty line trips, the charged capacitor bank discharges again, and the current-limiting reactor is taken out of operation; the faulty line reclosing operation is performed to store switch energy and reclose charging in preparation for the next fault.

3. A control method for a zero-loss deep current limiting device that can be used in conjunction with automatic reclosing, characterized in that, The zero-loss deep current limiting device applicable to the automatic reclosing circuit as described in claim 1 includes the following steps: S201: Detect the charging status of the capacitor bank. If at least one capacitor bank has been fully charged, proceed to step 203; otherwise, proceed to step 202. S202: Wait for the capacitor bank to finish charging; S203: Detect the on / off state of the current-limiting reactor. If the current-limiting reactor is in the off state, execute step 204. If the current-limiting reactor is in the on state, execute step 207. S204: Check whether the current value of the operating current transformer is normal. If it is greater than or equal to the current limiting setting value, proceed to step 205; otherwise, return to step 203. S205: Control the capacitor bank that has completed charging to discharge, drive the fast circuit breaker to open, and connect the current-limiting reactor; S206: Wait for the relay protection device to operate and isolate the fault, and return to step 201 after the protection operation delay; S207: Detect whether the current value of the returned current transformer has recovered. If it is less than the current limiting exit set value, then execute step 208; otherwise, return to step 203. S208: Control the capacitor bank that has completed charging to discharge, drive the fast circuit breaker to close, and deactivate the current-limiting reactor; S209: After exiting the current-limiting reactor, wait for the automatic reclosing action. After the reclosing delay, return to step 201.

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