Method, medium and system for preventing serious system failure caused by damage to closing resistor

Abstract

This invention discloses a method, medium, and system for preventing serious system failures caused by damage to the closing resistor. The method includes: rotating the AC filter circuit breaker of the converter station by 180° during installation, so that the closing resistor of the AC filter circuit breaker is moved from the busbar side of the circuit breaker to the capacitor side of the circuit breaker; monitoring the operating condition of the AC filter circuit breaker in real time; and executing the action corresponding to the protection output criterion if the operating condition of the AC filter circuit breaker meets the protection output criterion. This invention can effectively solve serious system failures caused by closing resistor problems, and can isolate the fault in the early stages of the fault through differential protection or failure protection of the AC filter, making it highly practical in engineering practice.

Description

Technical Field

[0001] This invention relates to the field of circuit breaker protection and control technology, and in particular to a method, medium, and system for preventing serious system failures caused by damage to the closing resistor. Background Technology

[0002] In power systems, the opening and closing of circuit breakers can generate operational overvoltages. Therefore, closing resistors must be installed on circuit breakers. These resistors are deactivated before the main contacts close and activated after the closing command is given. They are then short-circuited and deactivated when the main contacts close to prevent operational overvoltages. Taking the AC filter area of ​​a DC converter station as an example, the circuit breaker is equipped with a closing resistor on the bus side. In actual operation, due to manufacturing and on-site installation processes, the damping effect of the closing resistor on inrush current weakens over time, potentially even causing a short circuit in the main circuit through the closing resistor. Due to the circuit breaker's structural design, the closing resistor is located in the dead zone of the failure protection. Even when the circuit breaker contacts are open, the fault cannot be isolated. The fault can only be isolated by bus differential protection after the fault current increases to the kiloampere level and reaches the differential protection setting, which can easily cause irreversible damage to the equipment. Summary of the Invention

[0003] This invention provides a method, medium, and system for preventing serious system failures caused by damage to the closing resistor, in order to solve the problem of serious system failures caused by damage to the closing resistor of the AC filter circuit breaker in the prior art converter station.

[0004] Firstly, a method is provided to prevent serious system failures caused by damage to the closing resistor, including:

[0005] Rotate the AC filter circuit breaker of the converter station by 180° during installation, so that the closing resistance of the AC filter circuit breaker is moved from the bus side of the circuit breaker break to the capacitor side of the circuit breaker break.

[0006] The operating conditions of the group's AC filter circuit breaker are monitored in real time. If the operating conditions of the group's AC filter circuit breaker meet the protection output criteria, the action corresponding to the protection output criteria is executed.

[0007] In a second aspect, a computer-readable storage medium is provided, wherein computer program instructions are stored on the computer-readable storage medium; when the computer program instructions are executed by a processor, they implement the method for preventing serious system failure caused by damage to the closing resistor as described in the first aspect embodiment above.

[0008] Thirdly, a system is provided to prevent serious system failures caused by damage to the closing resistor, comprising: a computer-readable storage medium as described in the second aspect embodiment above.

[0009] Thus, the embodiments of the present invention can effectively solve the serious system failure caused by the closing resistor problem. The fault can be isolated in the early stage of the fault through the differential protection or failure protection of the group AC filter, which has strong practicality in engineering practice. Attached Figure Description

[0010] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a flowchart of a method for preventing serious system failure caused by damage to the closing resistor according to an embodiment of the present invention;

[0012] Figure 2 This is a typical installation diagram of a group AC filter circuit breaker in the prior art;

[0013] Figure 3 This is a typical installation diagram of the group AC filter circuit breaker according to an embodiment of the present invention;

[0014] Figure 4 This is a protection configuration diagram of the circuit breaker according to an embodiment of the present invention;

[0015] Figure 5 This is a logical schematic diagram of the failure protection criterion in an embodiment of the present invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] This invention discloses a method for preventing serious system failures caused by damage to the closing resistor. For example... Figure 1 As shown, the method includes the following steps:

[0018] Step S1: Rotate the AC filter circuit breaker of the converter station by 180° during installation, so that the closing resistor of the AC filter circuit breaker is moved from the bus side of the circuit breaker to the capacitor side of the circuit breaker.

[0019] The two ends of the AC filter circuit breaker are connected to the circuit breaker busbar and the circuit breaker capacitor, respectively. For example... Figure 2 and 3As shown, the group AC filter circuit breaker includes: arc-extinguishing chamber 1, arc-extinguishing chamber 2, closing resistor 3, closing resistor auxiliary break 4, circuit breaker break bus-side current transformer CT 5, and circuit breaker break capacitor-side current transformer CT 6. Both the circuit breaker break bus-side current transformer CT 5 and the circuit breaker break capacitor-side current transformer CT 6 have at least one winding. It should be understood that a large group AC filter includes multiple group AC filters.

[0020] Figure 2 This describes a typical installation method for existing group AC filter circuit breakers. From Figure 2 It can be seen that in the existing installation method, the closing resistor 3 of the group AC filter circuit breaker is closer to the circuit breaker busbar side than the arc-extinguishing chamber 1 and arc-extinguishing chamber 2, and the arc-extinguishing chamber 1 and arc-extinguishing chamber 2 are closer to the circuit breaker capacitor side than the closing resistor 3.

[0021] Based on the above structure, from Figure 4 The protection configuration diagram of the circuit breaker shown in the specific embodiment can be used to obtain the AC filter group bus differential protection formula ΔI=I 12LH -I 26LH When the starting current ΔI>I set (I set When the preset current threshold is reached, the protection device will activate. There are 26 windings, denoted as 1LH to 26LH. Therefore, the protection range of the small group filter differential protection is between windings 12 and 13 to windings 25 and 26 of the current transformer in the small group AC filter, and the protection range of the large group filter differential protection is between windings 1, 2, 9, 10, 15, and 16 of the current transformer. The closing resistor 3 is located between the 14th winding and the break points of arc-extinguishing chambers 1 and 2 of the circuit breaker, falling within the differential protection range of both the small and large group filters. However, if a ground discharge accident occurs in the small group AC filter circuit breaker through the closing resistor 3, even if the break points of arc-extinguishing chambers 1 and 2 of the small group AC filter circuit breaker are opened, the fault is still not isolated. Therefore, the closing resistor 3 is located in the dead zone of the small group differential protection and within the range of the large group differential protection. Thus, after a fault occurs in the closing resistor 3, fault isolation cannot be achieved through the small group differential protection.

[0022] For the reasons mentioned above, such as Figure 3As shown, in this embodiment of the invention, the AC filter circuit breaker of the group is rotated 180° and then the corresponding leads are installed. After rotation, a new protection range for the filter components is obtained, and the location of the closing resistor 3 is transferred from the dead zone of the group differential protection to the protection zone. Therefore, if an abnormal ground discharge accident occurs at the closing resistor 3, the fault point can be completely isolated by the operation of the group differential protection using the breaks in arc-extinguishing chambers 1 and 2, preventing a large-scale tripping event caused by the inability of the group to isolate the fault.

[0023] Step S2: Monitor the operating conditions of the group's AC filter circuit breaker in real time. If the operating conditions of the group's AC filter circuit breaker meet the protection output criteria, execute the action corresponding to the protection output criteria.

[0024] Regarding this step, the embodiments of the present invention can be divided into two methods depending on different situations, as follows:

[0025] First execution method:

[0026] The system monitors the operating conditions of the group AC filter circuit breaker in real time. If the operating conditions of the group AC filter circuit breaker meet the group filter differential protection criteria, the group filter differential protection device will trip the group AC filter circuit breaker.

[0027] The differential protection criterion for the group filter is as described above, namely, the starting current ΔI > I. set .

[0028] The second execution method:

[0029] The operating conditions of the AC filter circuit breaker in the group are monitored in real time. When the protection action of the converter station causes the AC filter circuit breaker in the group to trip, if the operating conditions of the AC filter circuit breaker in the group meet the failure protection criteria, the failure protection device will trip all circuit breakers connected to the bus.

[0030] It should be understood that the tripping of the group AC filter circuit breaker due to the group filter differential protection criterion under the aforementioned first execution mode also falls under the category of the group AC filter circuit breaker tripping caused by a protection action output from the converter station. Therefore, after the first execution mode, if the failure protection criterion is met, the second execution mode will continue.

[0031] Furthermore, the tripping of the group AC filter circuit breaker due to a protection action at the converter station is not limited to the case where the operating conditions of the group AC filter circuit breaker meet the group filter differential protection criteria. It may also be caused by other protection actions, such as the tripping of the group AC filter circuit breaker due to the differential protection of the large group filter.

[0032] It should also be understood that the tripping of the group AC filter circuit breaker caused by non-protection actions will not lead to the execution of the second execution mode. For example, if the tripping of the group AC filter circuit breaker is caused by a secondary circuit fault, even if the failure protection criterion is met, the second execution mode will not be triggered.

[0033] Specifically, such as Figure 5 As shown, the failure protection criteria include: failure protection start current is greater than the preset current threshold, failure pressure plate is activated, group failure control word is activated, group failure start input is normal, and group input is normal.

[0034] like Figure 4 In one specific embodiment shown, the configuration diagram of the large and small AC filter protections is configured according to a typical design scheme. The current at the large protection measuring point is I of the incoming circuit breaker. 1LH , I 2LH , I 9LH , I 10LH and the I of the filter 15LH , I 16LH The current of the group is collected and used as a criterion for differential and failure detection. The currents at the protection measurement points of the group AC filter are I... 12LH , I 13LH , I 25LH , I 26LH According to the collected measurement points, when a ground fault occurs in the closing resistor of the circuit breaker, both the large and small differential protection groups are within the protection range. However, since the small group's operation cannot clear the fault, and if the protection fails, the criterion only uses the current I collected from the winding measurement points of the small group circuit breaker windings 15LH and 16LH. 15LH , I 16LH Although the differential current still exists after the group's AC filter circuit breaker is disconnected, due to I 15LH , I 16LH Located on the capacitor side, no current flows after the circuit breaker is opened, and the failure protection cannot be properly initiated after the small group circuit breaker trips. Only the large group differential protection can trip the large group busbar. The fault current is large when the small group AC filter circuit breaker trips. Therefore, regarding the failure protection initiation current, this embodiment of the invention proposes the following optimized failure protection criterion. Specifically, the formula for the failure protection initiation current in this embodiment of the invention is:

[0035]

[0036] Where I represents the failure protection starting current, N, where N represents the number of samples in one power frequency cycle, I M,n I represents the current I collected during the nth sampling period of a power frequency cycle, flowing through the first winding of the current transformer on the capacitor side of the circuit breaker of the AC filter circuit breaker.R,n This represents the current in the second winding of the current transformer on the bus side of the circuit breaker of the AC filter circuit breaker, collected for the nth time within one power frequency cycle.

[0037] In cases where the current transformer winding on the capacitor side of the circuit breaker of the AC filter circuit breaker group has multiple windings, the first winding is one of the windings of the current transformer on the capacitor side of the circuit breaker closer to the busbar side of the circuit breaker. For example... Figure 4 As shown, windings 15LH to 17LH are the windings of the current transformer on the capacitor side of the circuit breaker break. The windings of the current transformer on the capacitor side of the circuit breaker break that are closer to the busbar side of the circuit breaker break are windings 15LH or 16LH. One of these two windings can be selected as the first winding.

[0038] Where the current transformer winding on the busbar side of the AC filter circuit breaker has multiple windings, the second winding is one of the windings of the current transformer on the busbar side of the circuit breaker closer to the capacitor side of the circuit breaker. More preferably, the second winding is one of the windings of the current transformer on the busbar side of the circuit breaker closest to the capacitor side of the circuit breaker. Figure 4 As shown, windings 12LH to 14LH are the windings of the current transformer on the busbar side of the circuit breaker. The winding of the current transformer on the busbar side of the circuit breaker closest to the capacitor side of the circuit breaker is winding 14LH, which can be selected as the second winding.

[0039] More preferably, to improve the reliability of the protection, two identical protection logics, A and B, are typically loaded. For the two identical protection logics, to improve reliability, each can use the current flowing through a different first winding for calculation. For example, protection logic A uses winding L15H as the first winding; protection logic B uses winding L16H as the first winding.

[0040] The failure protection criterion introduces the current flowing through the winding of the current transformer on the bus side of the circuit breaker break as an auxiliary criterion. When there is current on either the current transformer on the bus side of the circuit breaker break or the current transformer on the capacitor side of the circuit breaker break, the current starting condition can be met.

[0041] When the criteria are met, all circuit breakers connected to the busbar are tripped, and preferably the failure protection device will activate after a preset delay time T. It should be understood that the tripped circuit breakers include the group AC filter circuit breaker.

[0042] The above methods can effectively solve the problem of serious system failure caused by ground discharge due to closing resistor fault.

[0043] This invention also discloses a computer-readable storage medium storing computer program instructions; when the computer program instructions are executed by a processor, they implement the method described in the above embodiments for preventing serious system failures caused by damage to the closing resistor.

[0044] This invention also discloses a system for preventing serious system failures caused by damage to the closing resistor, comprising: a computer-readable storage medium as described in the above embodiments.

[0045] In summary, this invention addresses a design flaw discovered during the operation of AC filters in high-voltage DC systems. Specifically, it addresses the inability to quickly isolate faults when a short circuit to ground occurs in the closing resistor of a group AC filter circuit breaker. While ensuring equipment safety, this invention modifies the installation location of the closing resistor and rationally sets the failure protection criteria, thereby including the closing resistor within the protection range of the group AC filter. This allows for accurate identification of the initial stage of minor discharge caused by component degradation, preventing the escalation of accidents due to abnormal closing resistors. It effectively reduces the fault range or lowers the circuit breaker current during fault tripping, ensuring safe and stable equipment operation. This provides a scientific solution to the problem of abnormal closing resistors in AC filter circuit breakers in high-voltage / ultra-high-voltage DC systems and has strong practical applicability in engineering practice.

[0046] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preventing serious system failures caused by damage to the closing resistor, characterized in that, include: Rotate the AC filter circuit breaker of the converter station by 180° during installation, so that the closing resistance of the AC filter circuit breaker is moved from the bus side of the circuit breaker break to the capacitor side of the circuit breaker break. The operating conditions of the group AC filter circuit breaker are monitored in real time. If the operating conditions of the group AC filter circuit breaker meet the protection output criteria, the action corresponding to the protection output criteria is executed. The steps for executing the action corresponding to the protection exit criterion include: The operating conditions of the group AC filter circuit breaker are monitored in real time. If the operating conditions of the group AC filter circuit breaker meet the group filter differential protection criteria, the group filter differential protection device will trip the group AC filter circuit breaker. The group filter differential protection criteria are the starting current. , Indicates the preset current threshold; The operating conditions of the group AC filter circuit breaker are monitored in real time. When the protection action of the converter station causes the group AC filter circuit breaker to trip, if the operating conditions of the group AC filter circuit breaker meet the failure protection criteria, the failure protection device will trip all circuit breakers connected to the bus. The failure protection criterion includes: the failure protection start current is greater than a preset current threshold. The following are abnormalities: malfunctioning pressure plate input, malfunctioning control word input, malfunctioning start input, and no abnormality in group input; The formula for the failure protection starting current is: ； in, I Indicates the failure protection starting current; , , n =1, 2, ..., N , N This represents the number of samples per power frequency cycle. Represents the first [number]th ... n The current collected in this second sampling is the current flowing through the first winding of the current transformer on the capacitor side of the circuit breaker of the AC filter circuit breaker of the group. Represents the first [number]th ... n The current collected in this second sample is the current flowing through the second winding of the current transformer on the busbar side of the AC filter circuit breaker of the group.

2. The method for preventing serious system failure caused by damage to the closing resistor according to claim 1, characterized in that: If the current transformer winding of the circuit breaker capacitor side of the AC filter circuit breaker has multiple windings, then the first winding is one of the windings of the current transformer winding of the circuit breaker capacitor side that is closer to the busbar side of the circuit breaker.

3. The method for preventing serious system failure caused by damage to the closing resistor according to claim 1, characterized in that: If the current transformer winding on the busbar side of the AC filter circuit breaker has multiple windings, then the second winding is one of the windings of the current transformer on the busbar side of the circuit breaker that is closer to the capacitor side of the circuit breaker.

4. The method for preventing serious system failure caused by damage to the closing resistor according to claim 3, characterized in that: The second winding is one of the windings of the current transformer on the circuit breaker busbar side closest to the circuit breaker capacitor side.

5. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer program instructions; when the computer program instructions are executed by a processor, they implement the method as described in any one of claims 1 to 4 for preventing serious system failures caused by damage to the closing resistor.

6. A system for preventing serious system failures caused by damage to the closing resistor, characterized in that, include: The computer-readable storage medium as described in claim 5.

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