AC fault protection method, device, electronic equipment and storage medium

Abstract

The present application discloses an AC fault protection method, device, electronic device and storage medium in an AC / DC power distribution system. The method includes: when a fault is detected on the AC distribution network side of a converter in the AC / DC power distribution system, the converter is locked to cut off the short-circuit current channel supplying the fault point; the AC distribution network in the AC / DC power distribution system is isolated from the fault, and the fault location is determined according to the result of the fault isolation action on the AC distribution network; the converter is controlled according to the fault location using a matching control method. The scope of power outage caused by the fault is reduced and the reliability of power supply of the AC / DC power distribution system is improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of fault protection of AC / DC power distribution systems, and more particularly to an AC fault protection method, device, electronic device, and storage medium in an AC / DC power distribution system. Background Art

[0002] The AC / DC hybrid distribution system is a distribution network that includes both AC and DC distribution links. In current research and demonstration applications, it is mainly based on the existing AC distribution network by adding DC-type new energy sources, loads, and energy storage access; or by conducting flexible interconnection between multiple AC terminals through DC links; or by building a local multi-terminal DC distribution network and AC grid interconnection to form an AC / DC hybrid distribution network. With the increase in the types and scale of distribution network loads and the development of distributed new energy and energy storage, traditional AC distribution networks are increasingly unable to meet users' demands for power supply efficiency, power supply reliability, and flexible control capabilities of distribution systems. Therefore, the power supply reliability of AC / DC hybrid systems is a technical problem that needs to be urgently solved by technicians in this field. Summary of the invention

[0003] The embodiments of the present invention provide an AC fault protection method, device, electronic device and storage medium, which can reduce the scope of power outage caused by the fault and improve the reliability of power supply of the AC / DC power distribution system.

[0004] In a first aspect, an embodiment of the present invention provides an AC fault protection method in an AC / DC power distribution system, comprising:

[0005] When a fault is detected on the AC distribution network side of a converter in an AC / DC power distribution system, the converter is locked to cut off a short-circuit current channel supplying the fault point;

[0006] Isolate the fault of the AC distribution network in the AC / DC power distribution system, and determine the fault location based on the result of the AC distribution network fault isolation operation;

[0007] The converter is controlled by adopting a matching control method according to the fault location.

[0008] In a second aspect, an embodiment of the present invention further provides an AC fault protection device in an AC / DC power distribution system, comprising:

[0009] A fault detection module is used to detect a fault on the AC distribution network side of a converter in an AC / DC power distribution system, and lock the converter to cut off a short-circuit current channel supplying the fault point;

[0010] A fault location determination module is used to isolate the fault of the AC distribution network in the AC / DC power distribution system, and determine the fault location according to the result of the action of isolating the fault of the AC distribution network;

[0011] The control processing module is used to control the converter by adopting a matching control method according to the fault location.

[0012] In a third aspect, an embodiment of the present invention further provides an electronic device, including:

[0013] one or more processors;

[0014] A storage device for storing one or more programs;

[0015] The one or more programs are executed by the one or more processors, so that the one or more processors implement the AC fault protection method in the AC / DC power distribution system provided in any embodiment of the present invention.

[0016] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, an AC fault protection method in an AC / DC power distribution system as provided in any embodiment of the present invention is implemented. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a flow chart of an AC fault protection method in an AC / DC power distribution system provided in an embodiment of the present invention;

[0018] Figure 2A is a flow chart of another AC fault protection method in an AC / DC power distribution system provided in an embodiment of the present invention;

[0019] Figure 2B is a distributed feeder automation protection schematic diagram provided in an embodiment of the present invention;

[0020] Figure 2C It is a flow chart of a protection coordination action of an AC / DC power distribution system provided by an embodiment of the present invention;

[0021] Figure 2D is a flow chart of another protection coordination action of an AC / DC power distribution system provided by an embodiment of the present invention;

[0022] Figure 2E It is a flow chart of another protection coordination action of an AC / DC power distribution system provided by an embodiment of the present invention;

[0023] Figure 3 is a structural schematic diagram of an AC fault protection device in an AC / DC power distribution system provided in an embodiment of the present invention;

[0024] Figure 4 It is a structural schematic diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0025] The present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only the parts related to the present application, rather than all structures, are shown in the accompanying drawings.

[0026] It should be mentioned before discussing the exemplary embodiments in more detail that some exemplary embodiments are described as processes or methods depicted as flow charts. Although the flow charts describe the steps as sequential processes, many of the steps therein can be implemented in parallel, concurrently or simultaneously. In addition, the order of the steps can be rearranged. The process can be terminated when its operation is completed, but can also have additional steps not included in the accompanying drawings. The process can correspond to a method, function, procedure, subroutine, subprogram, etc.

[0027] In the AC / DC hybrid distribution system, both the AC distribution network and the DC distribution network have their own relay protection systems. The relay protection in the AC distribution network is the same as that in the traditional AC distribution network, while the relay protection in the DC distribution network is configured according to the working principle of the power electronic equipment in the system and the division of the protection area. Since the AC distribution network is interconnected with the DC distribution network through the converter, and the converter belongs to the protection range of the DC distribution network, the DC distribution protection generally also includes the protection of the AC side of the converter. Usually, after detecting the AC side fault of the converter, the converter at that end is locked and the AC outlet circuit breaker of the converter is tripped, cutting off the connection between the DC distribution network and the AC distribution network at that end, and ensuring the normal operation of other parts of the DC distribution network. Since the converter is the boundary of the protection area of ​​the DC distribution network, its relay protection does not make a fine distinction between the location of the AC side fault, that is, no matter where the fault point appears in the AC system, including inside the AC distribution network and at the AC side outlet bus of the converter, as long as the converter detects the AC fault, the converter at that end will be locked. The relay protection of the AC distribution network and the DC distribution network are configured separately, and no coordinated protection is formed. Once a fault occurs in the AC system, even if the fault is located in a certain section of the distribution line in the AC distribution network, the selective protection of this section of the line will still cause the converter to lock, expand the scope of the power outage caused by the fault, and reduce the power supply reliability of the AC / DC hybrid system. Therefore, the present application provides an AC fault protection method in an AC / DC distribution system.

[0028] Figure 11 is a flow chart of an AC fault protection method provided in an embodiment of the present invention. The method can be applied to the case of protecting AC faults in an AC / DC power distribution system. The method can be executed by an AC fault protection device in an AC / DC power distribution system. The device can be implemented by software and / or hardware and can be integrated into an electronic device. Figure 1 As shown, the AC fault protection method in the AC / DC power distribution system in this embodiment includes the following steps:

[0029] S110: When a fault is detected on the AC distribution network side of a converter in the AC / DC power distribution system, the converter is locked to cut off a short-circuit current channel supplying the fault point.

[0030] The AC / DC power distribution system may refer to a power distribution network that includes both AC and DC power distribution links.

[0031] A converter can refer to a device that converts AC to DC and is composed of a single or multiple converter bridges. For example, in an AC / DC power distribution system, a converter connects the AC distribution network with the DC distribution network to achieve the conversion of AC to DC. Converters can be divided into two categories: rectifiers and inverters. Rectifiers convert AC to DC, while inverters convert DC to AC.

[0032] Locking can mean cutting off the connection with other equipment. For example, if a relay protection device is included in the converter, when a fault occurs on the AC side, the converter at that end will be locked and the converter AC outlet circuit breaker will be tripped, so that the current on the AC side is 0, cutting off the connection between the DC distribution network and the AC distribution network at that end, and ensuring the normal operation of other parts of the DC distribution network.

[0033] S120: Isolate the fault of the AC distribution network in the AC / DC power distribution system, and determine the fault location according to the result of isolating the fault of the AC distribution network.

[0034] Among them, fault isolation can refer to disconnecting the faulty distribution line from other lines when a fault occurs in the AC / DC distribution network. For example, in an AC distribution network, the fault isolation of the AC distribution network itself is completed by the distributed feeder automation device of the AC distribution network. When a power switch fails, the power switch is disconnected from other lines to ensure the normal operation of other lines.

[0035] The fault location may refer to the location where the fault occurs in the AC distribution network. The fault location may be determined based on the fault isolation action in the AC distribution network. For example, if the flexible DC outlet switch in the AC distribution network is tripped, the fault is located on the busbar on the AC outlet side of the converter or the feeder line connected to the busbar.

[0036] S130: Control the converter by adopting a matching control method according to the fault location.

[0037] The controlling the converter by adopting a matching control method according to the fault location includes: automatically selecting to unlock the converter to restore power supply or to permanently lock the converter by adopting a matching control method according to the fault location.

[0038] Adopting a matching control method may mean controlling the converter in different ways according to the fault location. For example, in an AC distribution network, if the fault is located at the busbar on the AC outlet side of the converter or the feeder line connected to the busbar, the converter remains in a locked state and enters a permanent lockout.

[0039] The embodiment of the present invention provides an AC fault protection method, which locks the converter to cut off the short-circuit current channel supplying the fault point when a fault is detected on the AC distribution network side of the converter in the AC / DC power distribution system; isolates the AC distribution network in the AC / DC power distribution system, and determines the fault location according to the result of the fault isolation of the AC distribution network; and controls the converter in a matching control mode according to the fault location. The method of coordinating the AC and DC network relay protection and cooperating to complete the AC fault processing is that the converter that detects the fault faster is locked first, the AC distribution network selectively protects through distributed feeder automation, and the converter selectively switches the operation mode according to the result of the AC distribution network action and automatically unlocks the new operation mode. The AC fault protection method provided by the embodiment of the present invention realizes rapid protection coordination and fault processing between AC and DC, and reduces the scope of power outages caused by faults and improves the power supply reliability of AC and DC power distribution systems.

[0040] Figure 2A 1 is a flow chart of another AC fault protection method in an AC / DC power distribution system provided in an embodiment of the present invention. The embodiment of the present invention further optimizes the above embodiment on the basis of the above embodiment, and the embodiment of the present invention can be combined with various optional solutions in one or more of the above embodiments. Figure 2A As shown, the AC fault protection method in the AC / DC power distribution system provided in the embodiment of the present invention may include the following steps:

[0041] S210: When a fault is detected on the AC distribution network side of a converter in the AC / DC power distribution system, the converter is locked to cut off a short-circuit current channel supplying the fault point.

[0042] S220. The distributed feeder automation device of the AC distribution network completes fault isolation of the AC distribution network itself.

[0043] Among them, the fault isolation of the AC distribution network itself is completed by the distributed feeder automation device of the AC distribution network, and the distributed feeder automation device includes: power switch, flexible DC outlet switch, trunk switch, branch switch, intelligent terminal, busbar, distribution branch line and distribution trunk line, etc.

[0044] like Figure 2B The figure shows the principle diagram of distributed feeder automation protection. In the figure, bus 1 is the substation distribution bus, and the conventional power supply of the AC / DC distribution system is provided by bus 1; bus 2 is the AC export side bus of the flexible DC converter equipment; bus 3 and bus 4 are the distribution buses of the ring network distribution cabinet. A smart terminal unit (STU) is configured at each of the above busbars, and the smart terminal units realize peer-to-peer information sharing through a peer-to-peer communication network. Circuit breaker S1 connects the substation bus and the feeder line, which is called the power switch; circuit breaker S2 connects the flexible DC converter AC bus and the feeder line, which is called the flexible DC export switch; circuit breaker S 31 、Circuit breaker S 34 、Circuit breaker S 43 And circuit breaker S 42 The circuit breaker S3 and the circuit breaker S4 connect the distribution bus of the ring network distribution cabinet and the distribution branch line, and only one side of them can obtain power, which is called the branch line switch.

[0045] The action logic of various switchgear when a fault occurs in the main circuit of the system is as follows:

[0046] When overcurrent occurs in one and only one of the power switch and all its neighboring switches, the fault occurs in the circuit near the power switch and the power switch is tripped; conversely, if overcurrent does not occur in the power switch and all its neighboring switches, or if overcurrent occurs in two or more switches, the fault does not occur in the circuit near the power switch and the power switch does not operate.

[0047] When overcurrent occurs in only one of all switches adjacent to the main switch, the fault occurs in the line or bus near the main switch, and the main switch is tripped; conversely, if overcurrent does not occur in all switches adjacent to several line switches, or if overcurrent occurs in two or more switches, the fault does not occur in the line or bus near the main switch, and the main switch does not operate.

[0048] When overcurrent occurs in only one of all switches adjacent to the branch switch, the fault occurs in the line or bus near the branch switch, and the branch switch is tripped; conversely, if overcurrent does not occur in all switches adjacent to the branch switch, or overcurrent occurs in two or more switches, the fault does not occur in the line or bus near the branch switch, and the branch switch does not operate.

[0049] When overcurrent occurs in one and only one of all switches adjacent to the flexible DC export switch, the fault occurs in the line or bus near the flexible DC export switch, and the flexible DC export switch is tripped; conversely, if overcurrent does not occur in all switches adjacent to the flexible DC export switch, or overcurrent occurs in two or more switches, the fault does not occur in the line or bus near the flexible DC export switch, and the flexible DC export switch does not operate.

[0050] When a fault occurs in the AC distribution network, the distributed feeder automation device of the AC distribution network completes the fault isolation of the AC distribution network itself, which facilitates the determination of the fault location.

[0051] S230: Determine the fault location according to the result of isolating the fault on the AC distribution network.

[0052] Among them, the identification mechanism for determining the fault location according to the action result of fault isolation of the AC distribution network is as follows:

[0053] If the flexible DC export switch is opened, the fault is located at the busbar on the AC export side of the converter or the feeder line connected to the busbar;

[0054] If the flexible DC export switch is not opened and the bus voltage on the AC export side of the converter is restored, the fault is located in at least one distribution branch line of the AC distribution network;

[0055] If the flexible DC export switch is not opened and the bus voltage on the AC export side of the converter is not restored, the fault is located in at least one distribution trunk line of the AC distribution network.

[0056] In the coordination process of AC and DC networks, the converter determines the fault location based on the results of the fault isolation operation, and determines whether the fault is located on the converter AC bus, AC distribution branch line or AC distribution trunk line.

[0057] S240: Use a matching control method according to the fault location to automatically select whether to unlock the converter to restore power supply or permanently lock it.

[0058] After the system determines the location of the fault, the control processing method of the converter at that end is as follows according to the different fault locations:

[0059] If the fault is located at the busbar on the AC outlet side of the converter or the feeder line connected to the busbar, the converter will remain in the locked state and enter permanent lockout;

[0060] If the fault is located in at least one distribution branch of the AC distribution network, the fault has been cleared, the AC distribution network resumes its working state before the fault, and the converter restarts according to the mode before the fault occurs;

[0061] If the fault is located in at least one distribution trunk of the AC distribution network, the fault has been cleared, and the feeder line between the power bus of the AC distribution network distribution station to the fault point has resumed power supply, while the feeder line between the AC distribution network fault point and the AC side bus of the converter is disconnected due to the loss of connection with the power supply of the distribution station. At this time, the distribution network is required to provide emergency AC voltage support to quickly restore power supply to the power outage area without faults, and the converter switches to the constant AC side voltage mode (VF mode) and restarts.

[0062] In an optional solution of this embodiment, when the flexible DC outlet switch is opened, the specific process of the protection coordination action of the AC / DC power distribution system is as follows: Figure 2C As shown, the following steps may be included:

[0063] A1: The system is in normal operation mode;

[0064] A2: Determine whether a fault occurs on the AC side;

[0065] A3: If a fault occurs, the converter detects the fault and locks out; if no fault occurs, the system is in normal operation mode;

[0066] A4: The distributed feeder automation device of the AC distribution network completes the fault isolation of the AC distribution network itself;

[0067] A5: Determine whether the flexible DC outlet switch is open;

[0068] A6: If the switch is open, the converter is set to discharge mode; if the switch is not open, other modes are used accordingly;

[0069] A7: The inverter discharge is completed;

[0070] A8: The inverter is permanently locked.

[0071] In this embodiment, the converter contains capacitors inside. When the converter is working normally, current always exists. Short-term lockout of the converter will not cause discharge, but long-term lockout of the converter will cause discharge to ensure that there is no electricity at the fault location, thereby reducing the scope of power outage caused by the fault.

[0072] In an optional solution of this embodiment, when the flexible DC export switch is not opened and the bus voltage on the AC export side of the converter is restored, the specific process of the protection coordination action of the AC / DC power distribution system is as follows: Figure 2D As shown, the following steps may be included:

[0073] B1: The system is in normal operation mode;

[0074] B2: Determine whether a fault occurs on the AC side;

[0075] B3: If a fault occurs, the converter detects the fault and locks out; if no fault occurs, the system is in normal operation mode;

[0076] B4: The distributed feeder automation device of the AC distribution network completes the fault isolation of the AC distribution network itself;

[0077] B5: Determine whether the flexible DC outlet switch is open;

[0078] B6: If the switch is not open, determine whether the AC output bus of the converter is de-energized; if the switch is open, then other modes are used accordingly;

[0079] B7: If the AC export bus of the converter loses power, other corresponding modes will be adopted; if the AC export bus of the converter does not lose power, the converter will restart according to the mode before the fault occurs.

[0080] In an optional solution of this embodiment, when the flexible DC export switch is not opened and the bus voltage on the AC export side of the converter is not restored, the specific process of the protection coordination action of the AC / DC power distribution system is as follows: Figure 2E As shown, the following steps may be included:

[0081] C1: The system is in normal operation mode;

[0082] C2: Determine whether a fault occurs on the AC side;

[0083] C3: If a fault occurs, the converter detects the fault and locks out; if no fault occurs, the system is in normal operation mode;

[0084] C4: The distributed feeder automation device of the AC distribution network completes the fault isolation of the AC distribution network itself;

[0085] C5: Determine whether the flexible DC outlet switch is open;

[0086] C6: If the switch is not open, determine whether the AC output bus of the converter is de-energized; if the switch is open, then other modes are used accordingly;

[0087] C7: If the AC export bus of the converter loses power, the converter switches to the constant AC side voltage mode (VF mode) and restarts; if the AC export bus of the converter does not lose power, other modes are used accordingly;

[0088] By adopting the protection coordination method for AC side faults in the AC / DC hybrid power distribution system provided by the embodiment of the present invention, the AC / DC hybrid power distribution system can coordinate the relay protection function of the converter at the end of the AC distribution network where the fault point is located and the DC distribution network to which it is connected when an AC fault occurs, and the distributed feeder automation device of the AC distribution network completes the fault isolation of the AC distribution network itself; determines the fault location based on the action result of fault isolation of the AC distribution network; and automatically selects to unlock and restore power supply or permanently lock the converter based on the fault location by using a matching control method. Reduce the scope of power outages caused by faults and improve the power supply reliability of the AC / DC distribution system.

[0089] Figure 3 1 is a schematic diagram of the structure of an AC fault protection device in an AC / DC power distribution system provided in an embodiment of the present invention. The device can be applied to the case of protecting AC faults in an AC / DC power distribution system. The device can be implemented by software and / or hardware and integrated in an electronic device. The device is used to implement the AC fault protection method in the AC / DC power distribution system provided in the above embodiment. Figure 3 As shown, the AC fault protection device in the AC / DC power distribution system provided in this embodiment includes: a fault detection module 310, a fault location determination module 320 and a control processing module 330, wherein:

[0090] The fault detection module 310 is used to detect that a fault occurs on the AC distribution network side of the converter in the AC / DC power distribution system, and lock the converter to cut off the short-circuit current channel supplying the fault point;

[0091] A fault location determination module 320 is used to isolate the fault of the AC distribution network in the AC / DC power distribution system, and determine the fault location according to the result of the action of isolating the fault of the AC distribution network;

[0092] The control processing module 330 is used to control the converter by adopting a matching control method according to the fault location.

[0093] Based on the above embodiment, optionally, the fault location determination module 320 includes:

[0094] The AC distribution network's own fault isolation is completed by the distributed feeder automation device of the AC distribution network;

[0095] Among them, the distributed feeder automation device includes: power switch, flexible DC outlet switch, trunk switch, branch switch, intelligent terminal, busbar, distribution branch line and distribution trunk line, etc.

[0096] On the basis of the above embodiment, optionally, the AC distribution network fault isolation completed by the distributed feeder automation device of the AC distribution network includes:

[0097] When overcurrent occurs in only one of the power switch and all the switches adjacent to it, the fault occurs in the circuit near the power switch, and the power switch is tripped;

[0098] When overcurrent occurs in only one of all switches adjacent to the main switch, the fault occurs in the line or busbar near the main switch, and the main switch is tripped;

[0099] When overcurrent occurs in only one of all switches adjacent to the branch switch, the fault occurs in the line or busbar near the branch switch, and the branch switch is tripped;

[0100] When overcurrent occurs in only one of all switches adjacent to the flexible DC export switch, the fault occurs in the line or busbar near the flexible DC export switch, and the flexible DC export switch is tripped.

[0101] Based on the above embodiment, optionally, determining the fault location according to the fault isolation action result of the AC distribution network includes:

[0102] If the flexible DC export switch is opened, the fault is located at the busbar on the AC export side of the converter or the feeder line connected to the busbar;

[0103] If the flexible DC export switch is not opened and the bus voltage on the AC export side of the converter is restored, the fault is located in at least one distribution branch line of the AC distribution network;

[0104] If the flexible DC export switch is not opened and the bus voltage on the AC export side of the converter is not restored, the fault is located in at least one distribution trunk line of the AC distribution network.

[0105] On the basis of the above embodiment, optionally, the controlling the converter by adopting a matching control method according to the fault location includes:

[0106] The matching control method is adopted according to the fault location to automatically select whether to unlock the converter to restore power supply or permanently lock it.

[0107] Based on the above embodiment, optionally, the method of automatically selecting unlocking and restoring power supply or permanently locking the converter according to the fault location by using a matching control method includes:

[0108] If the fault is located at the busbar on the AC outlet side of the converter or the feeder line connected to the busbar, the converter will remain in the locked state and enter permanent lockout;

[0109] If the fault is located in at least one distribution branch of the AC distribution network, the fault has been cleared, the AC distribution network resumes its working state before the fault, and the converter restarts according to the mode before the fault occurs;

[0110] If the fault is located in at least one distribution trunk line of the AC distribution network, the feeder line between the fault point of the AC distribution network and the AC side bus of the converter is de-energized, and the converter switches to a constant AC side voltage mode and restarts.

[0111] The AC fault protection device in the AC / DC power distribution system provided in the embodiment of the present invention can execute the AC fault protection method in the AC / DC power distribution system provided in any embodiment of the present invention mentioned above, and has the corresponding functions and beneficial effects of executing the AC fault protection method in the AC / DC power distribution system. For detailed processes, please refer to the relevant operations of the AC fault protection method in the AC / DC power distribution system in the aforementioned embodiments.

[0112] Figure 4 Schematic diagram of the structure of an electronic device provided in an embodiment of the present application. An embodiment of the present application provides an electronic device, in which an AC fault protection device in an AC / DC power distribution system provided in an embodiment of the present application can be integrated. Figure 4 As shown, this embodiment provides an electronic device 400, which includes: one or more processors 420; a storage device 410, which is used to store one or more programs. When the one or more programs are executed by the one or more processors 420, the one or more processors 420 implement the AC fault protection method in the AC / DC power distribution system provided in the embodiment of the present application. The method includes:

[0113] When a fault is detected on the AC distribution network side of a converter in an AC / DC power distribution system, the converter is locked to cut off a short-circuit current channel supplying the fault point;

[0114] Isolate the fault of the AC distribution network in the AC / DC power distribution system, and determine the fault location based on the result of the AC distribution network fault isolation operation;

[0115] The converter is controlled by adopting a matching control method according to the fault location.

[0116] Of course, those skilled in the art can understand that the processor 420 also implements the technical solution of the AC fault protection method in the AC / DC power distribution system provided in any embodiment of the present application.

[0117] Figure 4 The electronic device 400 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.

[0118] like Figure 4 As shown, the electronic device 400 includes a processor 420, a storage device 410, an input device 430, and an output device 440; the number of the processor 420 in the electronic device can be one or more. Figure 4A processor 420 is taken as an example; the processor 420, the storage device 410, the input device 430 and the output device 440 in the electronic device can be connected via a bus or other means. Figure 4 The connection via bus 450 is taken as an example.

[0119] The storage device 410 is a computer-readable storage medium that can be used to store software programs, computer executable programs, and module units, such as program instructions corresponding to the AC fault protection method in the AC / DC power distribution system in the embodiment of the present application.

[0120] The storage device 410 may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system and at least one application required for a function; the data storage area may store data created according to the use of the terminal, etc. In addition, the storage device 410 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage device. In some instances, the storage device 410 may further include a memory remotely arranged relative to the processor 420, and these remote memories may be connected via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0121] The input device 430 may be used to receive input numbers, character information or voice information, and generate key signal input related to user settings and function control of the electronic device. The output device 440 may include electronic devices such as a display screen and a speaker.

[0122] The electronic device provided in the embodiment of the present application can achieve the technical effect of reducing the scope of power outages caused by faults and improving the reliability of power supply of AC and DC power distribution systems.

[0123] In an embodiment of the present invention, a computer readable medium is provided, on which a computer program is stored. When the program is executed by a processor, the program is used to execute an AC fault protection method in an AC / DC power distribution system. The method includes:

[0124] When a fault is detected on the AC distribution network side of a converter in an AC / DC power distribution system, the converter is locked to cut off a short-circuit current channel supplying the fault point;

[0125] Isolate the fault of the AC distribution network in the AC / DC power distribution system, and determine the fault location based on the result of the AC distribution network fault isolation operation;

[0126] The converter is controlled by adopting a matching control method according to the fault location.

[0127] Optionally, when the program is executed by a processor, it can also be used to execute the AC fault protection method in an AC / DC power distribution system provided in any embodiment of the present invention.

[0128] The computer storage medium of the embodiment of the present invention may adopt any combination of one or more computer-readable media. The computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples (non-exhaustive list) of computer-readable storage media include: 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), a flash memory, an optical fiber, a portable CD-ROM, an optical storage device, a magnetic storage device, or any suitable combination of the above. The computer-readable storage medium may be any tangible medium containing or storing a program, which may be used by or in combination with an instruction execution system, device or device.

[0129] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, which carry computer-readable program code. Such propagated data signals may take a variety of forms, including but not limited to: electromagnetic signals, optical signals, or any suitable combination of the above. Computer-readable signal media may also be any computer-readable medium other than a computer-readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0130] The program code contained on the computer-readable medium may be transmitted using any appropriate medium, including but not limited to: wireless, wire, optical cable, radio frequency (RF), etc., or any suitable combination of the above.

[0131] Computer program code for performing the operations of the present invention 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).

[0132] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for AC fault protection in an AC / DC power distribution system, characterized in that: The method comprises: When a fault is detected on the AC distribution network side of a converter in an AC / DC power distribution system, the converter is locked to cut off a short-circuit current channel supplying the fault point; Isolate the fault of the AC distribution network in the AC / DC power distribution system, and determine the fault location based on the result of the AC distribution network fault isolation operation; Controlling the converter by adopting a matching control method according to the fault location; Wherein, the fault isolation of the AC distribution network in the AC / DC power distribution system includes: The AC distribution network's own fault isolation is completed by the distributed feeder automation device of the AC distribution network; The distributed feeder automation device includes: a power switch, a flexible DC outlet switch, a trunk switch, a branch switch, an intelligent terminal, a busbar, a distribution branch line and a distribution trunk line; The busbars include the substation distribution busbar, the flexible DC converter AC outlet side busbar and the ring network distribution cabinet distribution busbar; an intelligent terminal is configured at each busbar; the first circuit breaker connects the substation distribution busbar and the feeder line, which is called the power switch; the second circuit breaker connects the flexible DC converter AC outlet side busbar and the feeder line, which is called the flexible DC outlet switch; the third circuit breaker, the fourth circuit breaker, the fifth circuit breaker and the sixth circuit breaker connect the distribution trunk line and the ring network distribution cabinet distribution busbar, both sides of which can obtain power, which are called trunk switches; the seventh circuit breaker and the eighth circuit breaker connect the ring network distribution cabinet distribution busbar and the distribution branch line, only one side of which can obtain power, which are called branch switches; Wherein, determining the fault location according to the result of the action of isolating the fault on the AC distribution network includes: If the flexible DC export switch is opened, the fault is located at the busbar on the AC export side of the converter or the feeder line connected to the busbar; If the flexible DC export switch is not opened and the bus voltage on the AC export side of the converter is restored, the fault is located in at least one distribution branch line of the AC distribution network; If the flexible DC export switch is not opened and the bus voltage on the AC export side of the converter is not restored, the fault is located in at least one distribution trunk line of the AC distribution network; Wherein, the controlling the converter by adopting a matching control method according to the fault location comprises: If the fault is located at the busbar on the AC outlet side of the converter or the feeder line connected to the busbar, the converter will remain in the locked state and enter permanent lockout; If the fault is located in at least one distribution branch of the AC distribution network, the fault has been cleared, the AC distribution network resumes its working state before the fault, and the converter restarts according to the mode before the fault occurs; If the fault is located in at least one distribution trunk line of the AC distribution network, the feeder line between the fault point of the AC distribution network and the AC side bus of the converter is de-energized, and the converter switches to a constant AC side voltage mode and restarts.

2. The method according to claim 1, characterized in that The AC distribution network's own fault isolation is completed by the distributed feeder automation device of the AC distribution network, including: When overcurrent occurs in only one of the power switch and all the switches adjacent to it, the fault occurs in the circuit near the power switch, and the power switch is tripped; When overcurrent occurs in only one of all switches adjacent to the main switch, the fault occurs in the line or busbar near the main switch, and the main switch is tripped; When overcurrent occurs in only one of all switches adjacent to the branch switch, the fault occurs in the line or busbar near the branch switch, and the branch switch is tripped; When overcurrent occurs in only one of all switches adjacent to the flexible DC export switch, the fault occurs in the line or busbar near the flexible DC export switch, and the flexible DC export switch is tripped.

3. An AC fault protection device in an AC / DC power distribution system, characterized in that: The device comprises: A fault detection module is used to detect a fault on the AC distribution network side of a converter in an AC / DC power distribution system, and lock the converter to cut off a short-circuit current channel supplying the fault point; A fault location determination module is used to isolate the fault of the AC distribution network in the AC / DC power distribution system, and determine the fault location according to the result of the action of isolating the fault of the AC distribution network; A control processing module, used to control the converter by adopting a matching control method according to the fault location; The fault location determination module is specifically used to complete the fault isolation of the AC distribution network itself by the distributed feeder automation device of the AC distribution network; The distributed feeder automation device includes: a power switch, a flexible DC outlet switch, a trunk switch, a branch switch, an intelligent terminal, a busbar, a distribution branch line and a distribution trunk line; The busbars include the substation distribution busbar, the flexible DC converter AC outlet side busbar and the ring network distribution cabinet distribution busbar; an intelligent terminal is configured at each busbar; the first circuit breaker connects the substation distribution busbar and the feeder line, which is called the power switch; the second circuit breaker connects the flexible DC converter AC outlet side busbar and the feeder line, which is called the flexible DC outlet switch; the third circuit breaker, the fourth circuit breaker, the fifth circuit breaker and the sixth circuit breaker connect the distribution trunk line and the ring network distribution cabinet distribution busbar, both sides of which can obtain power, which are called trunk switches; the seventh circuit breaker and the eighth circuit breaker connect the ring network distribution cabinet distribution busbar and the distribution branch line, only one side of which can obtain power, which are called branch switches; The fault location determination module is also used for, if the flexible DC outlet switch is opened, the fault is located at the busbar on the AC outlet side of the converter or the feeder line connected to the busbar; If the flexible DC export switch is not opened and the bus voltage on the AC export side of the converter is restored, the fault is located in at least one distribution branch line of the AC distribution network; If the flexible DC export switch is not opened and the bus voltage on the AC export side of the converter is not restored, the fault is located in at least one distribution trunk line of the AC distribution network; The control processing module is specifically used to keep the converter in a locked state and enter a permanent lock state if the fault is located at the busbar on the AC outlet side of the converter or the feeder line connected to the busbar; If the fault is located in at least one distribution branch of the AC distribution network, the fault has been cleared, the AC distribution network resumes its working state before the fault, and the converter restarts according to the mode before the fault occurs; If the fault is located in at least one distribution trunk line of the AC distribution network, the feeder line between the fault point of the AC distribution network and the AC side bus of the converter is de-energized, and the converter switches to a constant AC side voltage mode and restarts.

4. An electronic device, characterized in that: include: one or more processing devices; A storage device for storing one or more programs; When the one or more programs are executed by the one or more processing devices, the one or more processing devices implement the AC fault protection method in the AC / DC power distribution system according to any one of claims 1-2.

5. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by the processing device, the AC fault protection method in the AC / DC power distribution system described in any one of claims 1-2 is implemented.

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