Fault isolation method and device, computer equipment and readable storage medium

Abstract

The invention discloses a fault isolation method and device, computer equipment and a readable storage medium, and belongs to the technical field of direct current power transmission system protection. The fault isolation method comprises the following steps: acquiring a protection action signal sent by a direct current filter protection device, a high-voltage side disconnecting link division command sent by the direct current filter protection device, head end current of a direct current filter and a disconnecting link position of a high-voltage side disconnecting link; in response to the fact that a preset judgment condition is met, judging that the high-voltage side knife switch has a failure fault; and in response to a failure fault of the high-voltage side knife switch, sending a locking command to lock the fault pole, and tripping off an alternating-current wire inlet switch of the fault pole. Therefore, after the direct current filter protection device sends out a high-voltage side disconnecting link division command, even if the high-voltage side disconnecting link fails, the failure can be detected, and the measure of locking the fault pole is continuously taken to ensure the isolation of the fault point, prevent the stable operation of a power grid from being influenced by the continuous existence and even expansion of the fault, and improve the safety of a power system.

Description

Technical Field

[0001] This application belongs to the technical field of DC transmission system protection, and particularly relates to a fault isolation method, device, computer device, and readable storage medium. Background Art

[0002] As the main device for suppressing DC-side harmonics in a DC transmission system, the stable operation of a DC filter is an important factor in ensuring the safe and reliable operation of DC transmission. When a fault occurs within the DC filter, it is necessary to isolate the fault as soon as possible to prevent power transmission interruption or equipment damage.

[0003] Currently, the DC filter is connected to the DC side of the DC transmission system through a high-voltage side disconnect switch and is equipped with a DC filter protection device. When a fault occurs within the DC filter, the DC filter protection device issues a protection action signal. If the effective value of the current at the head end of the DC filter is lower than the arc-breaking capacity of the high-voltage side disconnect switch at this time, the DC filter protection device simultaneously issues a command to disconnect the high-voltage side disconnect switch to isolate the fault point by disconnecting the high-voltage side disconnect switch.

[0004] However, once the high-voltage side disconnect switch fails to operate, the DC transmission system will continuously inject fault current into the fault point, thereby affecting the safe and stable operation of the power system or causing equipment damage. Summary of the Invention

[0005] Object of the Invention: This application provides a fault isolation method for achieving fault isolation when a high-voltage side disconnect switch of a DC filter in a DC transmission system fails; another object of this application is to provide a fault isolation device; another object of this application is to provide a computer device for implementing the above control method; another object of the present invention is to provide a storage medium for storing a computer program for implementing the above control method.

[0006] Technical Solution: A fault isolation method of this application is used to achieve fault isolation when a high-voltage side disconnect switch of a DC filter in a DC transmission system fails. The DC transmission system includes at least one group of DC filters. The DC filter is connected to the DC side of the DC transmission system through the high-voltage side disconnect switch, and the DC filter is protected by a DC filter protection device. The fault isolation method is characterized in that it includes:

[0007] Obtain the protection action signal issued by the DC filter protection device, the command to disconnect the high-voltage side disconnect switch issued by the DC filter protection device, the current at the head end of the DC filter, and the position of the disconnect switch of the high-voltage side disconnect switch;

[0008] In response to meeting a preset judgment condition, it is determined that the high-voltage side disconnect switch has the failure fault;

[0009] In response to the occurrence of the malfunction of the high-voltage side disconnect switch, a blocking command is issued to block the faulty pole and trip the AC incoming switch of the faulty pole;

[0010] Wherein, the preset judgment condition is determined based on the protection action signal, the command for disconnecting the high-voltage side disconnect switch, the head-end current, and the position of the disconnect switch.

[0011] In some embodiments, the preset judgment condition includes:

[0012] After obtaining the command for disconnecting the high-voltage side disconnect switch, the protection action signal is not restored within the first time setting value;

[0013] Or, after obtaining the command for disconnecting the high-voltage side disconnect switch, the effective value of the head-end current is always greater than the preset current value within the second time setting value;

[0014] Or, after obtaining the command for disconnecting the high-voltage side disconnect switch, the position of the disconnect switch is always in the closed position within the third time setting value;

[0015] Or, between the fourth time setting value and the fifth time setting value after obtaining the command for disconnecting the high-voltage side disconnect switch, the DC filter protection device issues the protection action signal or the command for disconnecting the high-voltage side disconnect switch again;

[0016] Or, between the sixth time setting value and the seventh time setting value after obtaining the command for disconnecting the high-voltage side disconnect switch, the effective value of the head-end current is always greater than the preset current value;

[0017] Or, between the eighth time setting value and the ninth time setting value after obtaining the command for disconnecting the high-voltage side disconnect switch, the position of the disconnect switch is always in the closed position.

[0018] In some embodiments, any one of the first time setting value, the second time setting value, the third time setting value, the fourth time setting value, the sixth time setting value, and the eighth time setting value is greater than the longest opening time of the high-voltage side disconnect switch;

[0019] The fifth time setting value is greater than the fourth time setting value, the seventh time setting value is greater than the sixth time setting value, and the ninth time setting value is greater than the eighth time setting value.

[0020] In some embodiments, any one of the third time setting value and the eighth time setting value is greater than the longest opening time of the high-voltage side disconnect switch;

[0021] The durations of the first time setting value, the second time setting value, the fourth time setting value, and the sixth time setting value are greater than the longest time for the high-voltage side disconnect switch to complete arc interruption in response to the opening command;

[0022] The fifth time setting value is greater than the fourth time setting value, the seventh time setting value is greater than the sixth time setting value, and the ninth time setting value is greater than the eighth time setting value.

[0023] In some embodiments, the preset current value is greater than the effective value of the sampling error of the current transformer at the head end of the DC filter, and the preset current value is less than or equal to the effective value of the head end current under the current operating condition of the DC power transmission system.

[0024] In some embodiments, the preset current value is adjusted based on the operating condition of the DC power transmission system.

[0025] Correspondingly, the present application further provides a fault isolation device for achieving fault isolation when a failure occurs in the high-voltage side disconnector of the DC filter in the DC power transmission system. The DC power transmission system includes at least one group of DC filters, the DC filters are connected to the DC side of the DC power transmission system through the high-voltage side disconnector, and the DC filters are protected by a DC filter protection device. The fault isolation device includes:

[0026] An acquisition unit configured to acquire a protection action signal sent by the DC filter protection device, a command to disconnect the high-voltage side disconnector sent by the DC filter protection device, the head end current of the DC filter, and the disconnector position of the high-voltage side disconnector;

[0027] A judgment unit configured to judge that the high-voltage side disconnector has the failure fault in response to meeting a preset judgment condition;

[0028] A processing unit configured to issue a blocking command to block the faulty pole and trip the AC incoming switch of the faulty pole in response to the high-voltage side disconnector having the failure fault;

[0029] Wherein, the preset judgment condition is determined based on the protection action signal, the command to disconnect the high-voltage side disconnector, the head end current, and the disconnector position.

[0030] In some embodiments, the judgment unit is further configured to include the following preset judgment conditions:

[0031] After acquiring the command to disconnect the high-voltage side disconnector, the protection action signal does not return within a first time setting value;

[0032] Or, after acquiring the command to disconnect the high-voltage side disconnector, the effective value of the head end current is always greater than the preset current value within a second time setting value;

[0033] Alternatively, after obtaining the command for the HV side disconnector, the position of the disconnector remains in the closed position within the third time setting value;

[0034] Alternatively, after obtaining the command for the HV side disconnector, between the fourth time setting value and the fifth time setting value, the DC filter issues the protection action signal or the command for the HV side disconnector again;

[0035] Alternatively, after obtaining the command for the HV side disconnector, between the sixth time setting value and the seventh time setting value, the effective value of the head-end current is always greater than the preset current value;

[0036] Alternatively, after obtaining the command for the HV side disconnector, between the eighth time setting value and the ninth time setting value, the position of the disconnector remains in the closed position.

[0037] Correspondingly, the present application further provides a computer device, including a memory and a processor, where the memory stores a computer program, and is characterized in that when the processor executes the computer program, the steps of the fault isolation method described in any one of the above are implemented.

[0038] Correspondingly, the present application further provides a computer-readable storage medium, storing a computer program, and is characterized in that when the computer program is executed by a processor, the steps of the fault isolation method described in any one of the above are implemented.

[0039] Beneficial effects: Compared with the prior art, a fault isolation method of the present application includes: obtaining a protection action signal issued by a DC filter protection device, a command for the HV side disconnector issued by the DC filter protection device, the head-end current of the DC filter, and the position of the HV side disconnector; in response to meeting a preset judgment condition, it is determined that a malfunction occurs in the HV side disconnector; in response to a malfunction occurring in the HV side disconnector, a blocking command is issued to block the faulty pole and trip the AC incoming switch of the faulty pole; where the preset judgment condition is determined based on the protection action signal, the command for the HV side disconnector, the head-end current, and the position of the disconnector. In this way, after the DC filter protection device issues a command for the HV side disconnector, even if a malfunction occurs in the HV side disconnector, this fault can be detected, and measures to block the faulty pole are continued to ensure isolation of the fault point, preventing the fault from continuing to exist or even expanding and affecting the stable operation of the power grid, and improving the security of the power system.

[0040] It can be understood that a fault isolation device of the present application has all the technical features and beneficial effects of the above fault isolation method, and will not be elaborated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The following will make the technical solutions and other beneficial effects of the present application obvious by describing the specific embodiments of the present application in detail in conjunction with the drawings.

[0042] Figure 1 Schematic diagram of the DC filter topology structure of the present application;

[0043] Figure 2 Schematic flow diagram of a fault isolation method of the present application;

[0044] Figure 3 Schematic diagram of the structure of a fault isolation device of the present application. Detailed implementation manners

[0045] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part 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 skilled in the art without creative efforts belong to the scope of protection of the present application.

[0046] In the description of the present application, it should be noted that unless otherwise clearly defined and limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, and can be the connection inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations. In the description of the present application, "a plurality of" means two or more, unless otherwise clearly specifically limited. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more features.

[0047] The following disclosure provides many different implementation manners or examples for implementing different structures of the present application. To simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present application.

[0048] Please refer to Figure 1 , Figure 1Schematically shows the topology diagram of the DC filter of the present application; when the DC transmission system is operating normally, the DC filter is connected to the DC side of the DC transmission system through the high-voltage side disconnecting switch. When the protection device of the DC filter does not issue a protection action signal and / or a command to open the high-voltage side disconnecting switch, the position of the disconnecting switch of the high-voltage side disconnecting switch is in the closed position and harmonic current flows through the head CT (Current Transformer), generating a head current.

[0049] In an embodiment of the present application, a fault isolation method is provided. Please refer to Figure 2 , Figure 2 Schematically shows the flow diagram of a fault isolation method of the present application; a fault isolation method provided in an embodiment of the present application is used to achieve fault isolation when a malfunction occurs in the high-voltage side disconnecting switch of the DC filter in the DC transmission system. The DC transmission system includes at least one group of DC filters. The DC filter is connected to the DC side of the DC transmission system through the high-voltage side disconnecting switch. The DC filter is protected by a DC filter protection device. The fault isolation method includes:

[0050] Step 101, obtain the protection action signal issued by the DC filter protection device, the command to open the high-voltage side disconnecting switch issued by the DC filter protection device, the head current of the DC filter, and the position of the high-voltage side disconnecting switch; wherein, the command to open the high-voltage side disconnecting switch refers to the command to open the high-voltage side disconnecting switch.

[0051] Step 102, in response to meeting a preset judgment condition, determine that a malfunction has occurred in the high-voltage side disconnecting switch; wherein, the preset judgment condition is determined based on the protection action signal, the command to open the high-voltage side disconnecting switch, the head current, and the position of the disconnecting switch. Specifically, the preset judgment conditions include: after obtaining the command to open the high-voltage side disconnecting switch, the protection action signal has not been restored within the first time setting value; or, after obtaining the command to open the high-voltage side disconnecting switch, the effective value of the head current is always greater than the preset current value within the second time setting value; or, after obtaining the command to open the high-voltage side disconnecting switch, the position of the disconnecting switch is always in the closed position within the third time setting value; or, after obtaining the command to open the high-voltage side disconnecting switch, between the fourth time setting value and the fifth time setting value, the DC filter protection device issues a protection action signal or a command to open the high-voltage side disconnecting switch again; or, after obtaining the command to open the high-voltage side disconnecting switch, between the sixth time setting value and the seventh time setting value, the effective value of the head current is always greater than the preset current value; or, after obtaining the command to open the high-voltage side disconnecting switch, between the eighth time setting value and the ninth time setting value, the position of the disconnecting switch is always in the closed position.

[0052] It should be noted that the time constants in the above judgment conditions satisfy the following conditions: any one of the first time constant, the second time constant, the third time constant, the fourth time constant, the sixth time constant, and the eighth time constant is greater than the longest opening time of the high-voltage side disconnector; the fifth time constant is greater than the fourth time constant, the seventh time constant is greater than the sixth time constant, and the ninth time constant is greater than the eighth time constant.

[0053] Alternatively, the time constants in the judgment condition satisfy the following conditions: any one of the third time constant and the eighth time constant is greater than the longest opening time of the high-voltage side disconnector;

[0054] The durations of the first time constant, the second time constant, the fourth time constant, and the sixth time constant are greater than the longest time for the high-voltage side disconnector to complete arc interruption in response to the opening command.

[0055] The fifth time constant is greater than the fourth time constant, the seventh time constant is greater than the sixth time constant, and the ninth time constant is greater than the eighth time constant.

[0056] The current constant in the judgment condition satisfies the following conditions: the preset current value is greater than the effective value of the sampling error of the current transformer at the head end of the DC filter, and the preset current value is less than or equal to the effective value of the head end current under the current operating condition of the DC transmission system.

[0057] In some embodiments, the preset current value is adjusted based on the operating condition of the DC transmission system.

[0058] Step 103, in response to the failure of the high-voltage side disconnector, a blocking command is issued to block the faulty pole and trip the AC incoming switch of the faulty pole.

[0059] In this way, after the DC filter protection device issues a command to open the high-voltage side disconnector, even if the high-voltage side disconnector fails, this kind of failure can be detected, and the measure of blocking the faulty pole is continued to ensure the isolation of the fault point, prevent the continuous existence or expansion of the fault from affecting the stable operation of the power grid, and improve the safety of the power system.

[0060] Correspondingly, the embodiment of the present application further provides a fault isolation device. Please refer to Figure 3 , Figure 3Schematically shows a structural schematic diagram of a fault isolation device of the present application. A fault isolation device provided by the present application is used to achieve fault isolation when a failure occurs in the high-voltage side disconnect switch of a DC filter in a DC power transmission system. The DC power transmission system includes at least one group of DC filters. The DC filters are connected to the DC side of the DC power transmission system through the high-voltage side disconnect switch. The DC filters are protected by a DC filter protection device. The fault isolation device includes an acquisition unit, a judgment unit, and a processing unit. Among them, the acquisition unit is configured to obtain a protection action signal sent by the DC filter protection device, a command to disconnect the high-voltage side disconnect switch sent by the DC filter protection device, the current at the head end of the DC filter, and the position of the disconnect switch of the high-voltage side disconnect switch; the judgment unit is configured to judge that a failure has occurred in the high-voltage side disconnect switch in response to meeting a preset judgment condition; the processing unit is configured to issue a blocking command in response to a failure occurring in the high-voltage side disconnect switch to block the faulty pole and trip the AC incoming switch of the faulty pole; among them, the preset judgment condition is determined based on the protection action signal, the command to disconnect the high-voltage side disconnect switch, the head end current, and the position of the disconnect switch.

[0061] In some embodiments, the judgment unit is further configured to include the following preset judgment conditions:

[0062] After obtaining the command to disconnect the high-voltage side disconnect switch, the protection action signal has not been restored within the first time setting value;

[0063] Or, after obtaining the command to disconnect the high-voltage side disconnect switch, the effective value of the head end current is always greater than the preset current value within the second time setting value;

[0064] Or, after obtaining the command to disconnect the high-voltage side disconnect switch, the position of the disconnect switch is always in the closed position within the third time setting value;

[0065] Or, between the fourth time setting value and the fifth time setting value after obtaining the command to disconnect the high-voltage side disconnect switch, the DC filter protection device issues a protection action signal or a command to disconnect the high-voltage side disconnect switch again;

[0066] Or, between the sixth time setting value and the seventh time setting value after obtaining the command to disconnect the high-voltage side disconnect switch, the effective value of the head end current is always greater than the preset current value;

[0067] Or, between the eighth time setting value and the ninth time setting value after obtaining the command to disconnect the high-voltage side disconnect switch, the position of the disconnect switch is always in the closed position.

[0068] Correspondingly, an embodiment of the present application further provides a computer device, including a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, the steps of the fault isolation method in any one of the above embodiments are implemented.

[0069] Correspondingly, an embodiment of the present application further provides a computer-readable storage medium storing a computer program, which when executed by a processor implements the steps of the fault isolation method in any one of the above embodiments.

[0070] The following Figure 1 further describes the fault isolation method provided by the present application. As Figure 1 shown, assume that the effective value of the current at the head end of the DC filter under the current working condition is 5A.

[0071] Assume that a fault occurs in the DC filter area. The DC filter protection device issues a protection action signal and a command to disconnect the high-voltage side switchblade. Then, the high-voltage side switchblade should disconnect the head-end current within the longest time (e.g., less than 30s) for it to respond to the opening command to complete arc interruption. The protection action signal is reset and will not act again after resetting. And the high-voltage side switchblade becomes in the open position within the designed longest opening time (e.g., less than 40s) to complete the fault isolation operation.

[0072] Specifically, the following judgment conditions are used to judge whether the high-voltage side switchblade has a malfunction. After obtaining the command to disconnect the high-voltage side switchblade, if the protection action signal does not return within the first time setting value (e.g., 40s), it is determined that the high-voltage side switchblade has a malfunction; or after obtaining the command to disconnect the high-voltage side switchblade, if the head-end current is not disconnected within the second time setting value (e.g., 40s) and its effective value (e.g., 100A) is always greater than the preset current value (e.g., 4A), it is determined that the high-voltage side switchblade has a malfunction; or after obtaining the command to disconnect the high-voltage side switchblade, if the position of the high-voltage side switchblade does not become in the open position within the third time setting value (e.g., 40s) and is always in the closed position, it is determined that the high-voltage side switchblade has a malfunction; or after obtaining the command to disconnect the high-voltage side switchblade, if the DC filter protection device issues a protection action signal or a command to disconnect the high-voltage side switchblade again between the fourth time setting value (e.g., 40s) and the fifth time setting value (e.g., 100s), it is determined that the high-voltage side switchblade has a malfunction; or after obtaining the command to disconnect the high-voltage side switchblade, if the effective value of the head-end current (e.g., 100A) is always greater than the preset current value (e.g., 4A) between the sixth time setting value (e.g., 40s) and the seventh time setting value (e.g., 41s), it is determined that the high-voltage side switchblade has a malfunction; or after obtaining the command to disconnect the high-voltage side switchblade, if the switchblade position of the high-voltage side switchblade is always in the closed position between the eighth time setting value (e.g., 40s) and the ninth time setting value (e.g., 41s), it is determined that the high-voltage side switchblade has a malfunction.

[0073] After confirming that the high-voltage side switchblade has a malfunction, a blocking command is issued to block the faulty pole and trip the AC incoming line switch of the faulty pole to prevent the long-term existence of the fault from endangering the safe and stable operation of the entire power system or damaging equipment.

[0074] In addition, to improve the isolation speed after a failure of the high-voltage side disconnector, the embodiment of the present application can also determine whether the high-voltage side disconnector has a failure according to the following steps: after obtaining the command to open the high-voltage side disconnector, if the protection action signal does not return within the first time setting value (e.g., 30 s), it is determined that the high-voltage side disconnector has a failure; or after obtaining the command to open the high-voltage side disconnector, if the head-end current is not disconnected within the second time setting value (e.g., 30 s), and the effective value of the head-end current (e.g., 100 A) is always greater than the preset current value (e.g., 4 A), it is determined that the high-voltage side disconnector has a failure; or after obtaining the command to open the high-voltage side disconnector, if the DC filter protection device issues a protection action signal or a command to open the high-voltage side disconnector again between the fourth time setting value (e.g., 30 s) and the fifth time setting value (e.g., 100 s), it is determined that the high-voltage side disconnector has a failure; or after obtaining the command to open the high-voltage side disconnector, if the effective value of the head-end current (e.g., 100 A) is always greater than the preset current value (e.g., 4 A) between the sixth time setting value (e.g., 30 s) and the seventh time setting value (e.g., 31 s), it is determined that the high-voltage side disconnector has a failure. In this way, the failure judgment time is shortened by 10 s, and a faster fault isolation speed can be obtained.

[0075] The above has introduced in detail a fault isolation method, device, computer device, and readable storage medium provided by the embodiments of the present application. Specific examples are used in the present application to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the technical solution and its core idea of the present application; those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A fault isolation method for achieving fault isolation when a high-voltage side disconnector of a DC filter fails in a DC transmission system. The DC transmission system includes at least one group of DC filters. The DC filters are connected to the DC side of the DC transmission system through the high-voltage side disconnector, and the DC filters are protected by a DC filter protection device. It is characterized in that, The fault isolation method includes: Obtaining a protection action signal sent by the DC filter protection device, a command for disconnecting the high-voltage side disconnector sent by the DC filter protection device, the current at the head end of the DC filter, and the position of the high-voltage side disconnector; In response to meeting a preset judgment condition, it is determined that the high-voltage side disconnector has a malfunction; In response to the high-voltage side disconnector having a malfunction, a blocking command is issued to block the faulty pole and trip the AC incoming switch of the faulty pole; Wherein, the preset judgment condition is determined based on the protection action signal, the command for disconnecting the high-voltage side disconnector, the head-end current, and the position of the disconnector.

2. The fault isolation method according to claim 1, wherein The preset judgment condition includes: After obtaining the command for disconnecting the high-voltage side disconnector, the protection action signal has not been restored within the first time setting value; Or, after obtaining the command for disconnecting the high-voltage side disconnector, the effective value of the head-end current is always greater than a preset current value within the second time setting value; Or, after obtaining the command for disconnecting the high-voltage side disconnector, the position of the disconnector is always in the closed position within the third time setting value; Or, after obtaining the command for disconnecting the high-voltage side disconnector, between the fourth time setting value and the fifth time setting value, the DC filter protection device sends the protection action signal or the command for disconnecting the high-voltage side disconnector again; Or, after obtaining the command for disconnecting the high-voltage side disconnector, between the sixth time setting value and the seventh time setting value, the effective value of the head-end current is always greater than the preset current value; Or, after obtaining the command for disconnecting the high-voltage side disconnector, between the eighth time setting value and the ninth time setting value, the position of the disconnector is always in the closed position.

3. The fault isolation method according to claim 2, wherein Any one of the first time setting value, the second time setting value, the third time setting value, the fourth time setting value, the sixth time setting value, and the eighth time setting value is greater than the longest opening time of the high-voltage side disconnector; The fifth time setting value is greater than the fourth time setting value, the seventh time setting value is greater than the sixth time setting value, and the ninth time setting value is greater than the eighth time setting value.

4. The fault isolation method according to claim 2, wherein Any one of the third time setting value and the eighth time setting value is greater than the longest opening time of the high-voltage side disconnector; The durations of the first time setting value, the second time setting value, the fourth time setting value, and the sixth time setting value are greater than the longest time for the high-voltage side disconnector to complete arc interruption in response to the opening command; The fifth time setting value is greater than the fourth time setting value, the seventh time setting value is greater than the sixth time setting value, and the ninth time setting value is greater than the eighth time setting value.

5. The fault isolation method according to claim 2, characterized in that, The preset current value is greater than the effective value of the sampling error of the head-end current transformer of the DC filter and is less than or equal to the effective value of the head-end current under the current operating condition of the DC power transmission system.

6. The fault isolation method according to claim 5, characterized in that, The preset current value is adjusted based on the operating condition of the DC power transmission system.

7. A fault isolation device is used to achieve fault isolation when a failure occurs in the high-voltage side disconnecting switch of a DC filter in a DC transmission system. The DC transmission system includes at least one group of DC filters. The DC filters are connected to the DC side of the DC transmission system through the high-voltage side disconnecting switch. The DC filters are protected by a DC filter protection device. It is characterized in that The fault isolation device includes: A collection unit, which is configured to obtain a protection action signal sent by the DC filter protection device, a command to disconnect the high-voltage side disconnector sent by the DC filter protection device, the current at the head end of the DC filter, and the position of the high-voltage side disconnector. A judgment unit, which is configured to judge that the high-voltage side disconnector has a malfunction if a preset judgment condition is met. A processing unit, which is configured to issue a blocking command to block the faulty pole and trip the AC incoming switch of the faulty pole in response to the malfunction of the high-voltage side disconnector. Wherein, the preset judgment condition is determined based on the protection action signal, the command to disconnect the high-voltage side disconnector, the head end current, and the disconnector position.

8. The fault isolation device according to claim 7, characterized in that, The judgment unit is further configured to include the following preset judgment conditions: After obtaining the command to disconnect the high-voltage side disconnector, the protection action signal has not been restored within the first time setting value. Or, after obtaining the command to disconnect the high-voltage side disconnector, the effective value of the head end current is always greater than a preset current value within the second time setting value. Or, after obtaining the command to disconnect the high-voltage side disconnector, the disconnector position is always in the closed position within the third time setting value. Or, after obtaining the command to disconnect the high-voltage side disconnector, between the fourth time setting value and the fifth time setting value, the DC filter protection device sends the protection action signal or the command to disconnect the high-voltage side disconnector again. Or, after obtaining the command to disconnect the high-voltage side disconnector, between the sixth time setting value and the seventh time setting value, the effective value of the head end current is always greater than the preset current value. Or, after obtaining the command to disconnect the high-voltage side disconnector, between the eighth time setting value and the ninth time setting value, the disconnector position is always in the closed position.

9. A computer device, comprising a memory and a processor, the memory storing a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the fault isolation method according to any one of claims 1 to 6.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the fault isolation method according to any one of claims 1 to 6.

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