Fault isolation method and device, power transmission system, storage medium and program product

Abstract

The invention discloses a fault isolation method and device, a power transmission system, a storage medium and a program product, and relates to the technical field of flexible direct current power transmission. When the first preset change rate is greater than a first preset change rate and is greater than a second preset change rate, a target circuit breaker on the target power transmission line is controlled to execute a commutation operation and an opening operation, and the first preset change rate is greater than the second preset change rate; and if the target fault identification result of the target traveling wave feature on the target power transmission line is that a fault exists, controlling the target circuit breaker to execute secondary commutation operation so as to isolate the fault on the target power transmission line. Fault isolation is carried out by combining the characteristics of rapid action and high sensitivity of current change rate protection and the characteristic of strong interference resistance of traveling wave protection, and the problem of how to realize reliable isolation of faults in the multi-terminal flexible direct-current power transmission system is solved.

Description

Technical Field

[0001] The present application relates to the field of flexible direct current transmission technology, and in particular to a fault isolation method, equipment, transmission system, storage medium and program product. Background Art

[0002] In a multi-terminal flexible direct current transmission system, since VSC-HVDC (Voltage Source Converter-High Voltage Direct Current, a high-voltage direct current transmission technology based on voltage source converter) has the characteristics of weak inertia and low impedance, when a fault occurs in the multi-terminal flexible direct current transmission system, the fault current will spread rapidly and seriously overcurrent will occur within a few milliseconds, threatening the safe and stable operation of the power grid. Therefore, how to achieve reliable isolation of faults in a multi-terminal flexible direct current transmission system needs to be solved urgently. Summary of the invention

[0003] The main purpose of this application is to provide a fault isolation method, device, power transmission system, storage medium and program product, aiming to solve the technical problem of how to achieve reliable isolation of faults in a multi-terminal flexible direct current transmission system.

[0004] To achieve the above objectives, the present application proposes a fault isolation method, which includes:

[0005] When it is detected that the target current change rate on the target transmission line in the multi-terminal flexible direct current transmission system is less than the first preset change rate and greater than the second preset change rate, the target circuit breaker on the target transmission line is controlled to perform a commutation operation and a tripping operation, wherein the first preset change rate is greater than the second preset change rate;

[0006] If the target fault identification result of the target traveling wave characteristic on the target transmission line is that a fault exists, the target circuit breaker is controlled to perform a secondary commutation operation to isolate the fault on the target transmission line.

[0007] In one embodiment, the multi-terminal flexible direct current transmission system is a multi-terminal symmetrical monopole direct current system;

[0008] When it is detected that the target current change rate on the target transmission line in the multi-terminal flexible direct current transmission system is less than the first preset change rate and greater than the second preset change rate, before the step of controlling the target circuit breaker on the target transmission line to perform a commutation operation and a tripping operation, the fault isolation method further includes:

[0009] Obtaining a first equivalent inductance and a second equivalent inductance of at least one equivalent transmission line on any equivalent fault circuit of a multi-terminal symmetrical monopole DC system, wherein the first equivalent inductance is the equivalent inductance of the equivalent transmission line when each converter on any equivalent fault circuit works alone when a first fault point on the fault transmission line in any equivalent fault circuit fails, and the second equivalent inductance is the equivalent inductance of the equivalent transmission line when each converter works alone when a second fault point on the fault transmission line fails, and the first fault point is closer to the selected circuit breaker on the fault transmission line than the second fault point;

[0010] Determining a first preset change rate according to a loop voltage of any equivalent fault loop and at least one second equivalent inductance;

[0011] A second preset change rate is determined according to the loop voltage and at least one first equivalent inductance.

[0012] In one embodiment, when it is detected that the target current change rate on the target transmission line in the multi-terminal flexible direct current transmission system is less than the first preset change rate and greater than the second preset change rate, after the step of controlling the target circuit breaker on the target transmission line to perform a commutation operation and a tripping operation, the fault isolation method further includes:

[0013] If the target fault identification result is that there is no fault, the target circuit breaker is controlled to perform a reset operation.

[0014] In one embodiment, when it is detected that the target current change rate on the target transmission line in the multi-terminal flexible direct current transmission system is less than the first preset change rate and greater than the second preset change rate, before the step of controlling the target circuit breaker on the target transmission line to perform a commutation operation and a tripping operation, the fault isolation method includes:

[0015] Collect the current change rate and traveling wave characteristics on each transmission line in the multi-terminal flexible DC transmission system;

[0016] Each current change rate is compared with a first preset change rate and a second preset change rate.

[0017] In one embodiment, after the step of collecting the current change rate and the traveling wave characteristics on each transmission line in the multi-terminal flexible direct current transmission system, the fault isolation method further includes:

[0018] For each transmission line, fault identification is performed based on the characteristics of the traveling wave to obtain the fault identification result;

[0019] If any fault identification result is that a fault exists, the circuit breaker on any corresponding transmission line is controlled to perform commutation operation and opening operation to isolate the fault on any transmission line.

[0020] In one embodiment, the target traveling wave characteristics include traveling wave characteristics of a transmission current and / or traveling wave characteristics of a transmission voltage on the target transmission line.

[0021] In addition, to achieve the above objectives, the present application also proposes a fault isolation device, which includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the fault isolation method as described above.

[0022] In addition, to achieve the above objectives, the present application also proposes a power transmission system, the power transmission system comprising:

[0023] Such as the fault isolation device mentioned above.

[0024] In addition, to achieve the above-mentioned purpose, the present application also proposes a storage medium, which is a computer-readable storage medium. A computer program is stored on the storage medium. When the computer program is executed by a processor, the steps of the fault isolation method as described above are implemented.

[0025] In addition, to achieve the above-mentioned purpose, the present application also provides a computer program product, which includes a computer program. When the computer program is executed by a processor, the steps of the fault isolation method as described above are implemented.

[0026] One or more technical solutions proposed in this application have at least the following technical effects:

[0027] The present application provides a fault isolation method, device, power transmission system, storage medium and program product. When a fault occurs in a multi-terminal flexible direct current transmission system, the target circuit breaker on the target transmission line is controlled to perform a primary commutation operation and a tripping operation according to the target current change rate on the target transmission line of the fault, and the target circuit breaker is controlled to perform a secondary commutation operation according to the target fault identification result of the target traveling wave characteristic on the target transmission line. Thus, after the circuit breaker is pre-started according to the current change rate on the transmission line, the circuit breaker is controlled to complete the shutdown action according to the traveling wave characteristic on the transmission line, and the fault isolation is performed by combining the characteristics of rapid action and high sensitivity of the current change rate protection and the characteristics of strong anti-interference of the traveling wave protection, so as to achieve the purpose of rapid and reliable fault isolation and solve the problem of how to achieve reliable fault isolation in a multi-terminal flexible direct current transmission system. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related technologies, the drawings required for use in the embodiments or the related technical descriptions are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 This is an exemplary partial circuit schematic diagram of the power transmission system of the present application;

[0031] Figure 2 This is a flow chart of the first embodiment of the fault isolation method of the present application;

[0032] Figure 3 for Figure 2 Schematic diagram of equivalent circuit;

[0033] Figure 4 for Figure 3 An exemplary equivalent circuit schematic diagram of;

[0034] Figure 5 for Figure 3 Another exemplary equivalent circuit schematic diagram of ;

[0035] Figure 6 A schematic diagram of the device structure of the hardware operating environment involved in the fault isolation method in the embodiment of the present application.

[0036] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0037] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application and are not used to limit the present application.

[0038] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0039] The main solution of the embodiment of the present application is: when it is detected that the target current change rate on the target transmission line in the multi-terminal flexible direct current transmission system is less than the first preset change rate and greater than the second preset change rate, the target circuit breaker on the target transmission line is controlled to perform a primary commutation operation and a tripping operation, wherein the first preset change rate is greater than the second preset change rate; if the target fault identification result of the target traveling wave characteristic on the target transmission line is that a fault exists, the target circuit breaker is controlled to perform a secondary commutation operation to isolate the fault on the target transmission line.

[0040] Therefore, the present application provides a solution. When a fault occurs in a multi-terminal flexible direct current transmission system, the target circuit breaker on the target transmission line is controlled to perform a primary commutation operation and a tripping operation according to the target current change rate on the target transmission line of the fault, and the target circuit breaker is controlled to perform a secondary commutation operation according to the target fault identification result of the target traveling wave characteristic on the target transmission line. Thus, after the circuit breaker is pre-started according to the current change rate on the transmission line, the circuit breaker is controlled to complete the shutdown action according to the traveling wave characteristic on the transmission line, and the characteristics of the current change rate protection that is fast and highly sensitive and the characteristics of the traveling wave protection that is strong in anti-interference are combined to isolate the fault, thereby achieving the purpose of quickly and reliably isolating the fault, and solving the problem of how to achieve reliable isolation of faults in a multi-terminal flexible direct current transmission system.

[0041] First, an embodiment of the present application provides a power transmission system, which may include:

[0042] Such as the fault isolation device below.

[0043] It should be noted that the transmission system is a multi-terminal flexible direct current transmission system, which may include multiple transmission lines, each of which is equipped with two circuit breakers. When a transmission fault occurs on the target transmission line, the fault isolation device can control the target circuit breaker on the target transmission line to perform a shutoff action according to the fault isolation method below, thereby isolating the transmission fault from the fault isolation device.

[0044] In one example, if Figure 1 As shown, the power transmission system is a four-terminal symmetrical monopole power transmission system, and the power transmission system may include converters MMC1 to MMC4, Lineij is the power transmission line between converter i and converter j, and DCCBij is the circuit breaker between converter i and converter j. In the four-terminal symmetrical monopole power transmission system, if a power transmission fault occurs on the transmission lines Line12 and Line21 between converter MMC1 and converter MMC2, the circuit breakers DCCB12 and / or DCCB21 may be controlled to perform a shutdown action to isolate converters MMC1 and MMC4, and during the power transmission fault, converters MMC2 and MMC3 implement the power transmission function.

[0045] Based on this, the present application embodiment provides a fault isolation method, referring to Figure 2 , Figure 2 This is a flow chart of the first embodiment of the fault isolation method of the present application.

[0046] In this embodiment, the fault isolation method may include steps S100 to S200:

[0047] Step S100, when it is detected that the target current change rate on the target transmission line in the multi-terminal flexible direct current transmission system is less than the first preset change rate and greater than the second preset change rate, the target circuit breaker on the target transmission line is controlled to perform a commutation operation and a tripping operation.

[0048] Wherein, the first preset change rate is greater than the second preset change rate.

[0049] It should be noted that the first preset change rate is the maximum current change rate on the target transmission line when the protection range of the target DC circuit breaker on the target transmission line fails, and the second preset change rate is the minimum current change rate on the target transmission line when the protection range of the target DC circuit breaker on the target transmission line fails. The first preset change rate and the second preset change rate can be determined by analyzing or simulating the topological structure of the multi-terminal flexible DC transmission system, or can be determined based on engineering experience.

[0050] When the target current change rate on the target transmission line is within the range between the first preset change rate and the second preset change rate, it indicates that a fault occurs on the target transmission line. At this time, the target circuit breaker on the target transmission line can be controlled to perform a shutoff operation to isolate the fault. The target current change rate can be the current change rate of the current flowing through the target circuit breaker.

[0051] Step S200: If the target fault identification result of the target traveling wave characteristic on the target transmission line is that a fault exists, the target circuit breaker is controlled to perform a secondary commutation operation to isolate the fault on the target transmission line.

[0052] It should be noted that the current change rate on the transmission line is easily affected by the system interference signal. When the target current change rate on the target transmission line is within the range between the first preset change rate and the second preset change rate, in order to avoid the influence of the system interference signal, the target circuit breaker is not directly controlled to be completely shut down, but the target circuit breaker is first controlled to perform a commutation operation and a tripping operation to perform pre-start; when it is judged that the abnormal situation of the target current change rate is caused by a non-system interference signal according to the target traveling wave characteristics on the target transmission line, the target circuit breaker is controlled to perform a secondary commutation operation to completely shut down the target circuit breaker and isolate the fault on the target transmission line. Among them, the system interference signal can be an interference signal caused by factors such as power system oscillation, transition resistance, distributed capacitance current and current transformer saturation.

[0053] In a feasible implementation manner, the target traveling wave characteristics include traveling wave characteristics of a transmission current and / or traveling wave characteristics of a transmission voltage on a target transmission line.

[0054] It is understandable that, based on the traveling wave characteristics of the transmission current and / or the traveling wave characteristics of the transmission voltage on the transmission line, the transient changes of the transmission current and / or the transmission voltage can be accurately detected to determine whether a fault occurs in the transmission line.

[0055] In this embodiment, before step S100, the fault isolation method may further include: collecting current change rates and traveling wave characteristics on each transmission line in the multi-terminal flexible direct current transmission system; and comparing each current change rate with a first preset change rate and a second preset change rate.

[0056] It should be noted that during the operation of the multi-terminal flexible DC transmission system, the current change rate and traveling wave characteristics on each transmission line can be collected in real time to perform fault detection.

[0057] It can be understood that the current change rate can be the current change rate of the transmission current flowing through the circuit breaker on the transmission line. The traveling wave characteristics can be the traveling wave characteristics of the transmission current flowing through the circuit breaker and / or the traveling wave characteristics of the transmission voltage across the circuit breaker. At this time, the target circuit breaker can be a circuit breaker whose current change rate on the target transmission line is within the range between the first preset change rate and the second preset change rate.

[0058] In a feasible implementation manner, after step S100, the fault isolation method may further include: if the target fault identification result is that there is no fault, controlling the target circuit breaker to perform a reset operation.

[0059] It can be understood that if the target fault identification result is that there is no fault, it means that the abnormality of the target current change rate may be caused by system interference. At this time, the multi-terminal flexible DC transmission system has not failed, the target circuit breaker is controlled to reset, and no fault isolation operation is performed.

[0060] This embodiment provides a fault isolation method. When a fault occurs in a multi-terminal flexible direct current transmission system, the target circuit breaker on the target transmission line is controlled to perform a primary commutation operation and a tripping operation according to the target current change rate on the target transmission line of the fault, and the target circuit breaker is controlled to perform a secondary commutation operation according to the target fault identification result of the target traveling wave characteristic on the target transmission line. Thus, after the circuit breaker is pre-started according to the current change rate on the transmission line, the circuit breaker is controlled to complete the shutdown action according to the traveling wave characteristic on the transmission line. The fault isolation is performed by combining the characteristics of rapid action and high sensitivity of the current change rate protection and the characteristics of strong anti-interference of the traveling wave protection, achieving the purpose of rapid and reliable fault isolation, and solving the problem of how to achieve reliable fault isolation in a multi-terminal flexible direct current transmission system.

[0061] In a feasible implementation, the multi-terminal flexible direct current transmission system is a multi-terminal symmetrical monopole direct current system;

[0062] Before step S100, the fault isolation method may further include: obtaining a first equivalent inductance and a second equivalent inductance of at least one equivalent transmission line on any equivalent fault circuit of the multi-terminal symmetrical monopole DC system, wherein the first equivalent inductance is the equivalent inductance of the equivalent transmission line when each converter on any equivalent fault circuit works alone when a first fault point on the fault transmission line in any equivalent fault circuit fails, and the second equivalent inductance is the equivalent inductance of the equivalent transmission line when each converter works alone when a second fault point on the fault transmission line fails, and the first fault point is closer to the selected circuit breaker on the fault transmission line than the second fault point; determining a first preset change rate according to the loop voltage of any equivalent fault circuit and at least one second equivalent inductance; determining a second preset change rate according to the loop voltage and at least one first equivalent inductance.

[0063] It should be noted that the equivalent fault circuit may be an equivalent circuit of the multi-terminal symmetrical unipolar DC system after isolating the faulty transmission line when a transmission fault occurs in the multi-terminal symmetrical unipolar DC system. Therefore, before the fault isolation is performed in this embodiment, each equivalent fault circuit of the multi-terminal symmetrical unipolar DC system may be analyzed to determine the current change rate range on the faulty transmission line corresponding to each equivalent fault circuit.

[0064] In actual use, since it is possible to determine whether a transmission fault occurs on a transmission line by collecting the current change rate of the transmission current flowing through the circuit breaker on each transmission line, there are two fault points corresponding to the circuit breakers on a transmission line.

[0065] It is understandable that when determining an equivalent fault circuit, a circuit breaker can be determined as a selected circuit breaker on any transmission line, and any transmission line can be used as a faulty transmission line to obtain any equivalent fault circuit. Among them, an equivalent fault circuit can include one or more equivalent transmission lines and one or more converters. When a fault occurs at any fault point of the faulty transmission line and a converter works alone, a first equivalent inductance or a second equivalent inductance can be determined for each equivalent transmission line in the equivalent fault circuit.

[0066] In one example, if Figure 1 As shown in the figure, when the transmission line between MMC1 and MMC2 fails, the equivalent circuit of the four-terminal symmetrical single-pole DC system is as follows: Figure 3 When MMC2 works alone, Figure 3 The equivalent circuit can be equivalent to Figure 4 In the equivalent fault circuit shown in FIG. 1 , when a power transmission fault occurs at the fault point F1, that is, when the current change rate of DCCB12 is within the range of the first preset change rate and the second preset change rate, the first equivalent inductance includes L1 eq21 、L1eq22 and L1 eq23 When a power transmission fault occurs at the fault point F2, the second equivalent inductance includes L2 eq21 、L2 eq22 and L2 eq23 .in,

[0067] L1 eq21 =L 12 +L 21 +L d2

[0068] L1 eq22 =L 23 +L 32 +L MMC3 +L d3

[0069] L1 eq23 =L MMC2 +L d2

[0070] L2 eq21 =L d2

[0071] L2 eq22 =L 23 +L 32 +L MMC3 +L d3

[0072] L2 eq23 =L MMC2 +L d2

[0073] LN eqik is the equivalent inductance of the equivalent transmission line k under the action of the i-th converter when the N-th fault point fails, L ij is the equivalent inductance of the transmission line between converter i and converter j, L di is the current limiting inductance of converter i, L MMCi is the equivalent inductance of converter i.

[0074] When MMC3 works alone, Figure 3 The equivalent circuit can be equivalent to Figure 5 The equivalent fault circuit shown in the figure shows that when a power transmission fault occurs at the fault point F1, the first equivalent inductance includes L1 eq31 、L1 eq32 and L1 eq33 When a power transmission fault occurs at the fault point F2, the second equivalent inductance includes L2 eq31 、L2 eq32 and L2 eq33 .in,

[0075] L1 eq31 =L 12 +L 21 +L d2

[0076] L1 eq32 =L d2 +L MMC2

[0077] L1 eq33 =L 32 +L 23 +2L d3 +L d2 +L MMC4

[0078] L2 eq31 =L d2

[0079] L2 eq32 =L d2 +L MMC2

[0080] L2 eq33 =L 32 +L 23 +2L d3 +L d2 +L MMC4

[0081] At this time, the current change rate flowing through DCCB21 is the superposition of the current change rates when MMC2 and MMC3 act separately, where:

[0082]

[0083] set max is the first preset change rate, set min is the second preset change rate, Uc0 is the circuit voltage of any equivalent fault circuit, specifically, the rated voltage of any equivalent fault circuit.

[0084] It can be understood that in a multi-terminal symmetrical unipolar DC system, after the selected circuit breaker is determined based on the fault topology of the multi-terminal symmetrical unipolar DC system, the current change rate range on each transmission line when a transmission line fails can be determined according to the current change rate under different fault points.

[0085] Therefore, this embodiment provides a fault isolation method, which determines the current change rate range on the transmission line when each transmission line fails based on the fault topology structure of the multi-terminal symmetrical monopole DC system. Compared with simulating the multi-terminal flexible DC transmission system to determine the current change rate range, or determining the current change rate range based on engineering experience, the obtained current change rate range is not affected by artificially set parameters, the obtained current change rate range is more accurate, and the calculation efficiency of the current change rate range is improved.

[0086] In a feasible implementation manner, after the step of "collecting the current change rate and traveling wave characteristics on each transmission line in the multi-terminal flexible direct current transmission system", the fault isolation method may also include: for each transmission line, fault identification is performed according to the traveling wave characteristics to obtain a fault identification result; if any fault identification result is that a fault exists, the circuit breaker on any corresponding transmission line is controlled to perform commutation operation and opening operation to isolate the fault on any transmission line.

[0087] It should be noted that the fault isolation equipment can collect the current change rate and traveling wave characteristics of each transmission line at the same time, identify the fault according to the current change rate and traveling wave characteristics respectively, and obtain the fault identification result of each transmission line according to the traveling wave characteristics. When a fault occurs in a multi-terminal flexible DC transmission system, if the current change rate protection is not activated and the circuit breaker does not perform pre-action, if the fault identification result shows that there is no fault, the circuit breaker is controlled to shut down according to the fault identification result to achieve fault isolation. At this time, the faults of the multi-terminal flexible DC transmission system may include single-pole short circuit or open circuit faults, high-resistance faults, etc.

[0088] Therefore, this embodiment provides a fault isolation method, which can achieve fault isolation through traveling wave protection when the current change rate protection is not activated, making the fault isolation method more reliable.

[0089] The present application provides a fault isolation device, which includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the fault isolation method in the above-mentioned embodiment one.

[0090] Reference below Figure 6, which shows a schematic diagram of the structure of a fault isolation device suitable for implementing the embodiment of the present application. The fault isolation device in the embodiment of the present application may include but is not limited to mobile terminals such as controllers, laptops, PDAs (Personal Digital Assistants), PADs (Portable Application Descriptions: tablet computers), etc., and fixed terminals such as desktop computers, etc. Figure 6 The fault isolation device shown is merely an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0091] like Figure 6 As shown, the fault isolation device may include a processing device 1001 (e.g., a central processing unit, a graphics processor, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM: Read Only Memory) 1002 or a program loaded from a storage device 1003 to a random access memory (RAM: Random Access Memory) 1004. In RAM1004, various programs and data required for the operation of the fault isolation device are also stored. The processing device 1001, ROM1002, and RAM1004 are connected to each other through a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Generally, the following systems can be connected to the I / O interface 1006: an input device 1007 including, for example, a touch screen, a touch pad, a keyboard, a mouse, an image sensor, a microphone, etc.; an output device 1008 including, for example, a liquid crystal display (LCD: Liquid Crystal Display), a speaker, etc.; a storage device 1003 including, for example, a magnetic tape, a hard disk, etc.; and a communication device 1009. The communication device 1009 can allow the fault isolation device to communicate with other devices wirelessly or by wire to exchange data. Although the figure shows a fault isolation device with various systems, it should be understood that it is not required to implement or have all the systems shown. More or fewer systems can be implemented or have alternatively.

[0092] In particular, according to the embodiments disclosed in the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiments disclosed in the present application include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through a communication device, or installed from a storage device 1003, or installed from a ROM 1002. When the computer program is executed by the processing device 1001, the above-mentioned functions defined in the method of the embodiment disclosed in the present application are executed.

[0093] The fault isolation device provided by the present application adopts the fault isolation method in the above embodiment, which can solve the technical problem of how to achieve reliable isolation of faults in a multi-terminal flexible direct current transmission system. Compared with the related art, the beneficial effects of the fault isolation device provided by the present application are the same as the beneficial effects of the fault isolation method provided by the above embodiment, and the other technical features in the fault isolation device are the same as the features disclosed in the method of the previous embodiment, which will not be repeated here.

[0094] It should be understood that the various parts disclosed in this application can be implemented by hardware, software, firmware or a combination thereof. In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0095] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0096] The present application provides a computer-readable storage medium having computer-readable program instructions (ie, computer programs) stored thereon, and the computer-readable program instructions are used to execute the fault isolation method in the above-mentioned embodiment.

[0097] The computer-readable storage medium provided in the present application may be, for example, a USB flash drive, but is not limited to electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, systems or devices, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, system or device. The program code contained on the computer-readable storage medium may be transmitted using any appropriate medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination of the above.

[0098] The computer-readable storage medium may be included in the fault isolation device; or may exist independently without being assembled into the fault isolation device.

[0099] The above-mentioned computer-readable storage medium carries one or more programs. When the above-mentioned one or more programs are executed by the fault isolation device, the fault isolation device: when it is detected that the target current change rate on the target transmission line in the multi-terminal flexible direct current transmission system is less than the first preset change rate and greater than the second preset change rate, the target circuit breaker on the target transmission line is controlled to perform a primary commutation operation and a tripping operation, wherein the first preset change rate is greater than the second preset change rate; if the target fault identification result of the target traveling wave characteristic on the target transmission line is that a fault exists, the target circuit breaker is controlled to perform a secondary commutation operation to isolate the fault on the target transmission line.

[0100] Computer program code for performing the operations of the present application may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0101] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0102] The modules involved in the embodiments described in this application may be implemented by software or hardware, wherein the name of the module does not constitute a limitation on the unit itself in some cases.

[0103] The readable storage medium provided in this application is a computer-readable storage medium, which stores computer-readable program instructions (i.e., computer programs) for executing the above-mentioned fault isolation method, and can solve the technical problem of how to achieve reliable isolation of faults in a multi-terminal flexible direct current transmission system. Compared with the related art, the beneficial effects of the computer-readable storage medium provided in this application are the same as the beneficial effects of the fault isolation method provided in the above-mentioned embodiment, and will not be repeated here.

[0104] The present application also provides a computer program product, including a computer program, which implements the steps of the fault isolation method as described above when executed by a processor.

[0105] The computer program product provided in this application can solve the technical problem of how to achieve reliable isolation of faults in a multi-terminal flexible direct current transmission system. Compared with the related art, the beneficial effects of the computer program product provided in this application are the same as the beneficial effects of the fault isolation method provided in the above embodiment, which will not be elaborated here.

[0106] The above descriptions are only some embodiments of the present application, and are not intended to limit the patent scope of the present application. All equivalent structural changes made using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect applications in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A fault isolation method, characterized in that: The fault isolation method comprises: When it is detected that the target current change rate on the target transmission line in the multi-terminal flexible direct current transmission system is less than a first preset change rate and greater than a second preset change rate, controlling the target circuit breaker on the target transmission line to perform a commutation operation and a tripping operation, wherein the first preset change rate is greater than the second preset change rate; If the target fault identification result of the target traveling wave characteristic on the target transmission line is that a fault exists, the target circuit breaker is controlled to perform a secondary commutation operation to isolate the fault on the target transmission line.

2. The fault isolation method according to claim 1, characterized in that: The multi-terminal flexible direct current transmission system is a multi-terminal symmetrical monopole direct current system; Before the step of controlling a target circuit breaker on the target transmission line to perform a commutation operation and a tripping operation when it is detected that the target current change rate on the target transmission line in the multi-terminal flexible direct current transmission system is less than a first preset change rate and greater than a second preset change rate, the fault isolation method further comprises: Obtaining a first equivalent inductance and a second equivalent inductance of at least one equivalent transmission line on any equivalent fault circuit of the multi-terminal symmetrical monopole DC system, wherein the first equivalent inductance is the equivalent inductance of the equivalent transmission line when each converter on any equivalent fault circuit works alone when a first fault point on the faulty transmission line in the equivalent fault circuit fails, and the second equivalent inductance is the equivalent inductance of the equivalent transmission line when each converter works alone when a second fault point on the faulty transmission line fails, and the first fault point is closer to the selected circuit breaker on the faulty transmission line than the second fault point; Determining the first preset change rate according to the loop voltage of any one of the equivalent fault loops and at least one of the second equivalent inductances; The second preset change rate is determined according to the loop voltage and at least one of the first equivalent inductances.

3. The fault isolation method according to claim 1, characterized in that: After the step of controlling a target circuit breaker on the target transmission line to perform a commutation operation and a tripping operation when it is detected that the target current change rate on the target transmission line in the multi-terminal flexible direct current transmission system is less than the first preset change rate and greater than the second preset change rate, the fault isolation method further comprises: If the target fault identification result is that there is no fault, the target circuit breaker is controlled to perform a reset operation.

4. The fault isolation method according to claim 1, characterized in that: Before the step of controlling a target circuit breaker on the target transmission line to perform a commutation operation and a tripping operation when it is detected that the target current change rate on the target transmission line in the multi-terminal flexible direct current transmission system is less than a first preset change rate and greater than a second preset change rate, the fault isolation method comprises: Collecting the current change rate and traveling wave characteristics on each transmission line in the multi-terminal flexible direct current transmission system; Each of the current change rates is compared with the first preset change rate and the second preset change rate.

5. The fault isolation method according to claim 4, characterized in that: After the step of collecting the current change rate and traveling wave characteristics on each transmission line in the multi-terminal flexible direct current transmission system, the fault isolation method further includes: For each of the transmission lines, fault identification is performed according to the traveling wave characteristics to obtain a fault identification result; If any fault identification result is that a fault exists, the circuit breaker on any corresponding transmission line is controlled to perform commutation operation and opening operation to isolate the fault on any transmission line.

6. The fault isolation method according to claim 1, characterized in that: The target traveling wave characteristics include traveling wave characteristics of the transmission current and / or traveling wave characteristics of the transmission voltage on the target transmission line.

7. A fault isolation device, characterized in that: The fault isolation device comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program implements the steps of the fault isolation method according to any one of claims 1 to 6 when executed by the processor.

8. A power transmission system, characterized in that: The power transmission system comprises: The fault isolation device as claimed in claim 7.

9. A storage medium, characterized in that: The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, the steps of the fault isolation method according to any one of claims 1 to 6 are implemented.

10. A computer program product, characterized in that The computer program product comprises a computer program, and when the computer program is executed by a processor, the steps of the fault isolation method according to any one of claims 1 to 6 are implemented.

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