Circuit protection method and device, electronic equipment and readable storage medium

Abstract

The embodiment of the invention provides a circuit protection method and device, electronic equipment and a readable storage medium, and the method comprises the steps: obtaining historical load data and a current parameter of at least one protection terminal; determining a threshold value according to the historical load data; determining a protection judgment parameter corresponding to the protection terminal according to the threshold value and the current parameter; transmitting at least one protection judgment parameter between adjacent protection terminals; determining a difference value of protection judgment parameters between the first protection terminal and the second protection terminal; determining a fault section position corresponding to the protection terminal according to the difference value; controlling a protection terminal at a power supply side in two ends of the fault section to execute a three-phase tripping action of the circuit breaker; controlling the circuit breaker completing the three-phase tripping action to perform reclosing action; and determining a reclosing result of the reclosing action. According to the scheme of the invention, no power failure is caused in an instantaneous fault, and accurate and rapid on-site double-end isolation of a permanent fault is realized.

Description

Technical Field

[0001] This invention relates to the field of power system relay protection technology, and more specifically, to a circuit protection method, apparatus, electronic device, and readable storage medium. Background Technology

[0002] Currently, among the existing fault protection methods for distribution lines considering distributed power supply integration, traditional overcurrent protection achieves localized protection based on single-ended electrical quantities, while traditional differential protection achieves fault isolation through real-time exchange of current values ​​via communication. However, the sheer number of distribution lines connected to distributed power sources results in excessive data transmission, leading to slow isolation speeds for transient faults in these lines. Such transient faults can cause power outages at the load, resulting in insufficient power supply reliability. Furthermore, traditional differential protection transmits current, requiring high synchronization and involving large data transmission volumes. Summary of the Invention

[0003] The purpose of this invention is to provide a circuit protection method, device, electronic device, and readable storage medium that can solve the problems of insufficient selectivity, sensitivity, and reliability of traditional overcurrent protection and drive differential protection in power distribution lines with distributed power supply access, and achieve uninterrupted power supply for transient faults and rapid and accurate isolation of permanent faults from both ends.

[0004] In view of this, an embodiment of the first aspect of the present invention provides a circuit protection method.

[0005] A second aspect of the present invention provides a circuit protection device.

[0006] An embodiment of the third aspect of the present invention provides an electronic device.

[0007] An embodiment of the fourth aspect of the present invention provides a readable storage medium.

[0008] To achieve the above objectives, an embodiment of the first aspect of the present invention provides a circuit protection method, the method comprising: acquiring historical load data and current parameters of at least one protection terminal; determining a threshold value based on the historical load data; determining protection judgment parameters corresponding to the protection terminal based on the threshold value and the current parameters, each protection judgment parameter being assigned a time stamp; transmitting at least one protection judgment parameter between adjacent protection terminals, wherein each protection terminal receives a protection judgment parameter corresponding to another protection terminal and transmits it to a second protection terminal via a first protection terminal; determining the difference between the protection judgment parameters between the first protection terminal and the second protection terminal; determining the location of the fault section corresponding to the protection terminal based on the difference; and controlling the power supply side located at both ends of the fault section. The protection terminal executes the three-phase tripping action of the circuit breaker; controls the circuit breaker that has completed the three-phase tripping action to perform a reclosing action; determines the reclosing result of the reclosing action, the reclosing result including a first result and a second result; when the reclosing result is the first result, it determines that the protection terminal on the load side of the fault section is in a protection off state; when the reclosing result is the second result, it determines that the protection terminal on the load side of the fault section is in a protection execution state; wherein, the difference includes a first difference, a second difference, and a third difference; when the difference is the first difference, it determines that the protection terminal is located at both ends of the non-fault section; when the difference is the second difference, it determines that the protection terminal is located on the power supply side at both ends of the fault section; when the difference is the third difference, it determines that the protection terminal is located on the load side at both ends of the fault section.

[0009] According to the circuit protection method provided by this invention, when a transient short-circuit fault occurs in a power distribution line, protection judgment parameters are determined by the current parameters of the protection terminal, and the fault section is determined according to the protection judgment parameters. The protection terminals located at both ends of the fault section are then controlled to perform corresponding protection isolation actions. Distributed power sources are small-scale power generation equipment or systems located on the user side or near the load. By distributing distributed power sources across various nodes of the power distribution network, distributed power supplies are provided to the power generation equipment. The protection terminals, distributed across different sections of the power distribution network, enable timely protection measures to be taken when a fault occurs in the power distribution network, providing transient isolation of the circuit fault, thereby reducing circuit fault losses and improving fault isolation efficiency.

[0010] Specifically, by sampling and calculating each protection terminal in the line, the threshold value and current parameters corresponding to each protection terminal are determined. The current parameters include the effective values ​​of the three-phase current, and the threshold value is the larger of the maximum load current and the maximum output current. Then, based on the threshold value and current parameters, the protection judgment parameters corresponding to the protection terminal are determined, thereby determining whether the protection terminal is located upstream or downstream of the fault point. When the protection terminal is located upstream of the fault point, the current flows from the power source through the protection terminal to the fault point, causing the effective value amplitude of the protection terminal to be greater than the threshold value. When the protection terminal is located downstream of the fault point, when a fault occurs, the current flowing in the downstream section of the line decreases, and the effective value amplitude of the protection terminal will be less than the threshold value. The protection judgment parameters are determined by the threshold value and current parameters, thus determining whether the protection terminal is located upstream or downstream of the fault point. After determining the protection terminal section, the difference in protection judgment parameters between two adjacent protection terminals determines whether the protection terminal is located on the power supply side or the load side of the fault section. This triggers a trip operation on the power supply side circuit breaker, followed by reclosing. After the reclosing operation, the result is used to determine whether the protection terminals on the load side at both ends of the fault section have initiated protection actions. The reclosing action drives the protection terminals to protect the load side of the fault section, thus achieving uninterrupted power supply during transient faults in distributed power supply lines and precise, rapid, local, dual-end isolation of permanent faults.

[0011] Furthermore, once the specific location of the protection terminal in the fault section is determined, the system will control the protection terminal located on the power supply side at both ends of the fault section to perform three-phase tripping of the circuit breaker, that is, to disconnect the phase current. In this way, the current supply of the fault section is separated from that of the normal section. After the tripping operation is completed, the system will control the corresponding circuit breaker to reclose, so that the transient fault in the line can be quickly isolated and the power supply can be quickly restored after isolation.

[0012] After the protection terminals on the power supply side at both ends of the faulty section execute three-phase tripping of the circuit breaker and control the corresponding circuit breaker to perform reclosing operations, the reclosing result is judged. If the reclosing operation is completed and the instantaneous fault in the faulty section is eliminated, and the line returns to normal operation, it is judged as the first result, i.e., the distribution line has experienced an instantaneous fault. If the reclosing operation is completed but the instantaneous fault in the faulty section is not eliminated, and the line has not resumed power supply, it is judged as the second result, i.e., the distribution line has experienced a permanent fault. After determining the reclosing result as the first result, the protection terminal on the load side of the faulty section switches to the protection off state, stops protection operation, and resumes normal monitoring, i.e., the instantaneous fault has disappeared and no further isolation operation is required. After determining the reclosing result as the second result, the protection terminal on the load side of the faulty section switches to the protection execution state, working with the power supply side circuit breaker to achieve double-end isolation, preventing the fault point from continuing to carry power or affecting other non-faulty sections.

[0013] In the above technical solution, determining the reclosing result of the reclosing action includes: acquiring the current information of the first protection terminal and the second protection terminal, the current information including first current information and second current information; if the values ​​corresponding to the first current information and the second current information both change, determining the reclosing result as the first result; if the values ​​corresponding to the first current information or the second current information do not change, determining the reclosing result as the second result.

[0014] In this scheme, the reclosing result is determined based on changes in current information at both ends. The success of reclosing is judged by the current information (three-phase current RMS value or zero-sequence current) collected by the power supply side protection terminal (first protection terminal) and the load side protection terminal (second protection terminal) of the fault section. Specifically, when both the values ​​corresponding to the first current information from the first protection terminal and the values ​​corresponding to the second current information from the second protection terminal change significantly, it is determined that power supply to the line in the fault section has been restored. Furthermore, when both the values ​​corresponding to the first and second current information change, and the current characteristics are determined to conform to the normal operating mode based on the current information, the transient fault is determined to be eliminated, i.e., the reclosing result is the first result, and the reclosing is successful. If the values ​​corresponding to the first or second current information do not change, i.e., the current value of at least one protection terminal does not change as expected, it indicates that the fault point in the fault section still exists, and the fault in the fault section is determined to be a permanent fault; the line in the fault section cannot be restored to normal operation.

[0015] In any of the above technical solutions, optionally, the threshold value is determined based on historical load data, including: determining the maximum load current and the maximum output current based on historical load data; when the maximum load current is greater than the maximum output current, the threshold value is determined to be the maximum load current; otherwise, the threshold value is determined to be the maximum output current.

[0016] In this scheme, the maximum load current and maximum output current of the distribution network lines are determined using historical load data from the distribution network system. The maximum load current is determined by all loads downstream of the line where the protection terminal is located, and refers to the highest current value the distribution network line needs to carry under maximum load conditions. The maximum output current is determined by the installed capacity of distributed generation, and refers to the maximum current capacity the distribution network can provide under ideal operating conditions. The maximum output current is calculated based on the grid's design capacity and the specifications of the distribution lines. By determining the larger of the maximum load current and maximum output current in the distribution network lines, a threshold value for the distribution network lines is determined. In other words, by selecting a larger threshold value, current flow from the load end to the centralized power source end is avoided when the load is low and the distributed generation output is high, preventing overcurrent protection misjudgments and reducing unnecessary tripping.

[0017] In any of the above technical solutions, optionally, the protection judgment parameter corresponding to the protection terminal is determined based on the threshold value and the current parameter, including: determining the effective value amplitude corresponding to the effective value of the three-phase current of at least one protection terminal; determining the current imbalance coefficient and setting value of each protection terminal based on the current parameter; when the current imbalance coefficient is less than or equal to the setting value, determining the protection judgment parameter corresponding to the protection terminal as the first parameter; when the current imbalance coefficient is greater than the setting value and the effective value amplitude is greater than the threshold value, determining the protection judgment parameter corresponding to the protection terminal as the second parameter; when the current imbalance coefficient is greater than the setting value and the effective value amplitude is less than or equal to the threshold value, determining the protection judgment parameter corresponding to the protection terminal as the third parameter; wherein the second parameter is a fixed positive value, and the third parameter is a fixed negative value with the same absolute value as the second parameter but opposite sign.

[0018] In this scheme, since the grounding method of the distributed power source is the same as that of the distribution network side, both being neutral point non-effective grounding, under normal operating conditions, the distribution lines still only have positive sequence current, and the current imbalance coefficient is almost zero. Under fault operation conditions, zero sequence current or negative sequence current will appear in the lines, and the current imbalance coefficient will be large. Therefore, the current imbalance coefficient of the protection terminal is used as the protection start criterion. When the line is operating normally, the protection judgment parameter is the first parameter, which is zero; when the current imbalance coefficient is greater than the setting value, it is determined that a fault has occurred in the system. The setting value is determined by sampling the imbalance coefficient of each protection terminal, measuring the range of the imbalance coefficient under normal conditions, and then adding a safety margin to avoid false triggering under normal fluctuation conditions. When the current imbalance coefficient is greater than the setting value, it is further determined whether the protection terminal is located in the upstream or downstream section of the fault point. When the effective value amplitude of the three-phase current of the protection terminal is greater than the threshold value, it is determined that the protection terminal is located in the upstream section of the fault point; when the effective value amplitude of the three-phase current of the protection terminal is less than the threshold value, it is determined that the protection terminal is located in the downstream section of the fault point. When the protection terminal is located upstream of the fault point, the protection judgment parameter is determined as the second parameter and set to a fixed positive value, such as 1 or 2; when the protection terminal is located downstream of the fault point, the protection judgment parameter is determined as the third parameter and set to a fixed negative value with the same absolute value as the second parameter but opposite sign, such as -1 or -2.

[0019] In any of the above technical solutions, optionally, determining the difference between the protection judgment parameters between the first protection terminal and the second protection terminal includes: obtaining at least one protection judgment parameter transmitted from the first protection terminal to the second protection terminal; obtaining a timestamp corresponding to the protection judgment parameter; and determining the difference between the at least one protection judgment parameter of the first protection terminal and the protection judgment parameter of the second protection terminal based on the timestamp.

[0020] In this scheme, when the power distribution line is operating normally, at least one protection judgment parameter will be transmitted from the protection terminal of the upstream section to the protection terminal of the downstream section, or vice versa. During this process, multiple protection judgment parameters will cause excessive transmission volume and reduced data synchronization accuracy. By attaching a time stamp to each protection judgment parameter, the protection terminal transmits the parameter once for each sampling calculation and judgment during the transmission of the protection judgment parameter to the adjacent terminal in the communication channel. Furthermore, when the second protection terminal receives the protection judgment parameter from the first protection terminal, it compares the protection judgment parameter with the closest sampling time based on the time stamp, thereby reducing the amount of data processing and improving the data synchronization accuracy.

[0021] In any of the above technical solutions, optionally, determining the location of the fault section corresponding to the protection terminal based on the difference includes: when the protection judgment parameters of the first protection terminal and the protection judgment parameters of the second protection terminal are the same, determining the difference as a first difference; when the protection judgment parameter of the first protection terminal is a second parameter and the protection judgment parameter of the second protection terminal is a third parameter, determining the difference as a second difference; when the protection judgment parameter of the first protection terminal is a third parameter and the protection judgment parameter of the second protection terminal is a second parameter, determining the difference as a third difference.

[0022] In this scheme, because the current suddenly increases within the fault section, the difference between the protection judgment parameters of the local terminal and the remote terminal also increases significantly. By judging the difference between the protection judgment parameters of the local terminal and the remote terminal, it is determined whether the protection terminal is located on the power supply side or the load side on both sides of the fault section. Specifically, when the local protection judgment parameter and the remote protection judgment parameter are equal, that is, the difference between the protection judgment parameters is zero, it is determined that the current of the local terminal and the remote terminal are the same, and both are located in the regions at both ends of the non-fault section; when the local protection judgment parameter is the second parameter and the remote protection judgment parameter is the third parameter, that is, the local terminal is located in the section upstream of the fault point and the remote terminal is located in the section downstream of the fault point, it means that the protection terminal is located on the power supply side of the fault section, and the corresponding difference is the second difference; when the local protection judgment parameter is the third parameter and the remote protection judgment parameter is the second parameter, that is, the local terminal is located in the section downstream of the fault point and the remote terminal is located in the section upstream of the fault point, it means that the protection terminal is located on the load side of the fault section, and the corresponding difference is the third difference. By determining the difference in protection judgment parameters for each pair of adjacent terminals, sections with significant differences are identified. Furthermore, the protection judgment parameters of the terminals are used to determine whether the power supply side or load side is located in the faulty section, thereby identifying the section where the transient fault occurred.

[0023] An embodiment of the second aspect of the present invention provides a circuit protection device, comprising: an acquisition module for acquiring historical load data and current parameters of at least one protection terminal; a determination module for determining a threshold value based on the historical load data; a fault judgment module for determining protection judgment parameters corresponding to the protection terminal based on the threshold value and the current parameters, wherein each protection judgment parameter is associated with a time stamp; a transmission module for transmitting at least one protection judgment parameter between adjacent protection terminals, wherein each protection terminal receives protection judgment parameters corresponding to another protection terminal and transmits them to a second protection terminal via a first protection terminal; a segment determination module for determining the difference between the protection judgment parameters between the first protection terminal and the second protection terminal, and determining the location of the fault segment corresponding to the protection terminal based on the difference; and a control module. The protection module controls the protection terminal on the power supply side at both ends of the fault section to perform a three-phase trip of the circuit breaker; controls the circuit breaker that has completed the three-phase trip to perform a reclosing operation; the protection module determines the reclosing result of the reclosing operation, the reclosing result including a first result and a second result; when the reclosing result is the first result, it determines that the protection terminal on the load side of the fault section is in a protection off state; when the reclosing result is the second result, it determines that the protection terminal on the load side of the fault section is in a protection execution state; wherein, the difference includes a first difference, a second difference, and a third difference; when the difference is the first difference, it determines that the protection terminal is located at both ends of the non-fault section; when the difference is the second difference, it determines that the protection terminal is located on the power supply side at both ends of the fault section; when the difference is the third difference, it determines that the protection terminal is located on the load side at both ends of the fault section.

[0024] In any of the above technical solutions, optionally, the protection module is further configured to: acquire current information of the first protection terminal and the second protection terminal, the current information including first current information and second current information; determine the reclosing result as the first result when both the value corresponding to the first current information and the value corresponding to the second current information have changed; and determine the reclosing result as the second result when neither the value corresponding to the first current information nor the value corresponding to the second current information has changed.

[0025] The circuit protection device provided by this invention utilizes the judgment parameters generated by each protection terminal to achieve real-time monitoring and direction differentiation of current changes, ensuring accurate detection and location of faults even under bidirectional current conditions. When a transient fault occurs in a distribution line connected to a distributed power source, the fault location is detected promptly and the fault section is isolated. By comparing the magnitude of the effective value amplitude and threshold value of the three-phase current of each protection terminal, it is determined whether each protection terminal is located upstream or downstream of the fault point. Furthermore, the relative positional relationship between each protection terminal and the fault point is compared using a difference judgment method for further screening. If a pair of adjacent protection terminals is found, and one detects a current exceeding the threshold value while the other does not, then these two protection terminals can be determined to be located at opposite ends of the fault point, and the section between them is the fault section. The system then controls these two protection terminals to issue commands to instruct circuit breakers and other devices to trip, and reclosing is performed after the tripping operation is completed. After the reclosing operation is completed, the protection terminal on the load side at both ends of the fault section is determined based on the reclosing result. The reclosing operation drives the protection terminal to protect the load side of the fault section, thereby achieving uninterrupted power supply in the event of transient faults in the distribution line connected to the distributed power source, and precise and rapid local double-end isolation of permanent faults.

[0026] An embodiment of the third aspect of this application provides an electronic device, including a processor, a memory, and a program or instructions stored in the memory and executable on the processor, wherein the program or instructions, when executed by the processor, implement the steps of the circuit protection method as described in the first aspect.

[0027] An embodiment of the fourth aspect of this application provides a readable storage medium on which a program or instructions are stored, which, when executed by a processor, implement the steps of the circuit protection method as described in the first aspect.

[0028] Additional aspects and advantages of the technical solutions of the present invention will become apparent in the following description or may be learned by practice of the invention. Attached Figure Description

[0029] Figure 1 A schematic flowchart of a circuit protection method according to an embodiment of this application is shown;

[0030] Figure 2 A partial flowchart of a circuit protection method according to an embodiment of this application is shown;

[0031] Figure 3 A partial flowchart of a circuit protection method according to an embodiment of this application is shown;

[0032] Figure 4 A partial flowchart of a circuit protection method according to an embodiment of this application is shown;

[0033] Figure 5 A partial flowchart of a circuit protection method according to an embodiment of this application is shown;

[0034] Figure 6 A partial flowchart of a circuit protection method according to an embodiment of this application is shown;

[0035] Figure 7 A schematic block diagram of a circuit protection device according to an embodiment of this application is shown;

[0036] Figure 8 A schematic block diagram of an electronic device according to an embodiment of this application is shown;

[0037] Figure 9 A schematic diagram of a power distribution network according to an embodiment of this application is shown.

[0038] in, Figures 7 to 9 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0039] 900: Circuit protection device; 902: Acquisition module; 904: Determination module; 906: Fault judgment module; 908: Transmission module; 910: Section determination module; 912: Control module; 914: Protection module; 1000: Electronic equipment; 1109: Memory; 1110: Processor; 2000: Distribution network; 2002: Protection terminal; 2004: Load; 3000: Centralized power supply; DG: Distributed power supply; L: Distribution line; L1: Main line; F: Transient fault. Detailed Implementation

[0040] To better understand the above-described objectives, features, and advantages of the embodiments of the present invention, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0041] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, embodiments of the invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below.

[0042] The following is in conjunction with the appendix Figures 1 to 9 The circuit protection method, apparatus, electronic device, and readable storage medium provided in this application will be described in detail through specific embodiments and application scenarios.

[0043] This embodiment provides a circuit protection method, such as Figure 1 As shown, it includes:

[0044] Step S102: Obtain historical load data and current parameters of at least one protection terminal;

[0045] Step S104: Determine the threshold value based on historical load data;

[0046] Step S106: Determine the protection judgment parameters corresponding to the protection terminal based on the threshold value and current parameters;

[0047] Step S108: Transmit at least one protection judgment parameter between adjacent protection terminals, and each protection terminal receives the protection judgment parameter corresponding to another protection terminal and transmits it to the second protection terminal through the first protection terminal;

[0048] Step S110: Determine the difference in protection judgment parameters between the first protection terminal and the second protection terminal;

[0049] Step S112: Determine the location of the fault section corresponding to the protection terminal based on the difference;

[0050] Step S114: Control the protection terminal on the power supply side located at both ends of the fault section to perform the three-phase tripping action of the circuit breaker;

[0051] Step S116: Control the circuit breaker that has completed the three-phase tripping action to perform a reclosing action;

[0052] Step S118: Determine the reclosing result of the reclosing operation;

[0053] Step S120: When the reclosing result is the first result, determine that the protection terminal on the load side of the fault section is in the protection off state; when the reclosing result is the second result, determine that the protection terminal on the load side of the fault section is in the protection execution state.

[0054] The difference includes a first difference, a second difference, and a third difference. When the difference is the first difference, the protection terminal is determined to be located at both ends of the non-faulty section. When the difference is the second difference, the protection terminal is determined to be located on the power supply side at both ends of the faulty section. When the difference is the third difference, the protection terminal is determined to be located on the load side at both ends of the faulty section.

[0055] According to the circuit protection method provided by this invention, when a transient short-circuit fault occurs in a power distribution line, protection judgment parameters are determined by the current parameters of the protection terminal, and the fault section is determined according to the protection judgment parameters. The protection terminals located at both ends of the fault section are then controlled to perform corresponding protection isolation actions. Distributed power sources are small-scale power generation equipment or systems located on the user side or near the load. By distributing distributed power sources to various nodes of the power distribution network, distributed power supplies are provided to the power generation equipment. The protection terminals, distributed in different sections of the power distribution network, enable timely protection measures to be taken when a fault occurs in the power distribution network, providing transient isolation of the circuit fault, thereby reducing circuit fault losses and improving fault isolation efficiency. By executing the three-phase tripping action of the circuit breaker on the power supply side of the fault section and performing a reclosing operation, when the circuit fault is determined to be permanent, the protection terminal on the load side of the fault section is controlled to trigger protection actions, achieving rapid and accurate double-end isolation of permanent faults and improving the power supply reliability of the power distribution line connected to the distributed power source.

[0056] Specifically, by sampling and calculating each protection terminal in the line, the threshold value and current parameters corresponding to each protection terminal are determined. The current parameters include the effective values ​​of the three-phase current, and the threshold value is the larger of the maximum load current and the maximum output current. Then, based on the threshold value and current parameters, the protection judgment parameters corresponding to the protection terminal are determined, thereby determining whether the protection terminal is located upstream or downstream of the fault point. When the protection terminal is located upstream of the fault point, the current flows from the power source through the protection terminal to the fault point, causing the effective value amplitude of the protection terminal to be greater than the threshold value. When the protection terminal is located downstream of the fault point, when a fault occurs, the current flowing in the downstream section of the line decreases, and the effective value amplitude of the protection terminal will be less than the threshold value. The protection judgment parameters are determined by the threshold value and current parameters, thus determining whether the protection terminal is located upstream or downstream of the fault point. After determining the section of the protection terminal, the difference in protection judgment parameters between two adjacent protection terminals determines whether the protection terminal is located on the power supply side or the load side of the fault section. This triggers a tripping operation on the power supply side circuit breaker, followed by reclosing. After the reclosing operation, the result is used to determine whether the protection terminal on the load side of the fault section should initiate protection. The reclosing operation drives the protection terminal to protect the load side of the fault section; that is, only the power supply side of the fault section initiates reclosing, while the load side does not. In the event of a transient fault, the load side of the fault section does not trigger protection; in the event of a permanent fault, the load side triggers protection. This ensures uninterrupted power supply during transient faults in distributed power supply lines and precise, rapid, local, two-way isolation of permanent faults.

[0057] Furthermore, by combining historical load and distributed power source processing methods to determine protection judgment parameters, the misjudgment of traditional fixed threshold values ​​in bidirectional current transmission is avoided, thereby improving the protection reliability of the circuit protection.

[0058] Furthermore, each protection judgment parameter is equipped with a corresponding time stamp.

[0059] Each protection terminal receives protection judgment parameters corresponding to another protection terminal and transmits them to the second protection terminal through the first protection terminal. That is, the protection terminal only needs to receive protection judgment parameters transmitted by the protection terminal on one side. By limiting the transmission of protection judgment parameters on one side, the amount of data transmission is reduced and the fault isolation efficiency is improved.

[0060] Specifically, the protection judgment parameters generated by each protection terminal reflect the current status of its corresponding monitoring area. By analyzing the protection judgment parameters of each protection terminal, the system can determine which terminals have detected currents exceeding the threshold value. Furthermore, by judging whether the currents of adjacent protection terminals exceed the threshold value, the fault section can be further analyzed. Specifically, when one current in a pair of adjacent protection terminals exceeds the threshold value while the other does not, the section between the protection terminals can be determined as the fault section. By analyzing whether it is located on the power supply side or the load side, a command is issued to the circuit breaker to trip, thereby achieving effective isolation of transient faults.

[0061] Once the exact location of the protection terminal in the fault section is determined, the system will control the protection terminal located on the power supply side at both ends of the fault section to perform a three-phase trip of the circuit breaker, that is, to disconnect the phase current. In this way, the current supply of the fault section is separated from that of the normal section. After the tripping operation is completed, the system will control the corresponding circuit breaker to reclose, so that the transient fault in the line can be quickly isolated and the power supply can be quickly restored after isolation.

[0062] Specifically, by operating the protection terminal located on the power supply side of the fault section to perform the three-stage tripping action of the circuit breaker, the fault current is immediately cut off, the upstream power supply to the fault section is interrupted, the damage of the short-circuit current to the load equipment is limited, and the further spread of the fault current is prevented. After completing the tripping action on the power supply side, the tripped circuit breaker is controlled to automatically attempt reclosing. If the reclosing is successful, the power supply is restored to verify the transient fault and avoid unnecessary power outages.

[0063] Understandably, by prioritizing tripping on the power supply side to quickly suppress fault current while keeping the load side in an untripped state, it is easier for subsequent protection terminals to perform protection actions, protecting lines, transformers, or other load equipment from the thermal effects and mechanical stress damage of short-circuit currents, improving the power supply reliability of distribution lines connected to distributed power sources, and reducing power outage losses caused by non-permanent faults.

[0064] Furthermore, after the reclosing operation was completed, the circuit did not regain power, confirming that the faulty section was a permanent fault.

[0065] Optionally, multiple protection terminals in the faulty section can send fault markers with timestamps. The timestamps are used to sort the multiple protection terminals in the faulty section. The protection terminal that sends the timestamp earliest performs the three-phase tripping action of the circuit breaker. At least one subsequent protection terminal determines whether to trip in coordination based on the time difference. When the time difference is too large, the corresponding protection terminal does not perform the three-phase tripping action of the circuit breaker.

[0066] Furthermore, the protection terminals located at both ends of the faulty section on the power supply side execute three-phase tripping of the circuit breakers. After tripping, the corresponding circuit breakers are controlled to perform reclosing operations. The reclosing result is then evaluated. If the reclosing operation completes and the momentary fault in the faulty section is eliminated, and the line returns to normal operation, this is considered the first result, indicating a momentary fault in the distribution line. If the reclosing operation completes but the momentary fault in the faulty section is not eliminated, and the line does not resume power supply, this is considered the second result, indicating a permanent fault in the distribution line. After determining the reclosing result as the first result, the protection terminal on the load side of the faulty section switches to protection off state, stops protection operation, and resumes normal monitoring, indicating that the momentary fault has disappeared and no further isolation operation is needed. If the reclosing result is then determined to be the second result, the protection terminal on the load side of the faulty section switches to protection execution state, working in conjunction with the power supply side circuit breaker to achieve double-end isolation, preventing the fault point from continuing to operate or affecting other non-faulty sections.

[0067] Understandably, by clarifying the fault nature of the faulty section of the distribution line through the reclosing result, a rapid judgment can be made on transient and permanent faults, achieving uninterrupted power supply for transient faults and accurate and rapid local double-end isolation for permanent faults. The protection terminal at the load end will only trigger protection action in the event of reclosing failure, avoiding false tripping caused by communication delays or transient disturbances. The power consumption at the load end will not be affected by the fault, thus improving the reliability and stability of the power supply of the distribution line.

[0068] Furthermore, the reclosing is a multi-stage reclosing system with a set reclosing interval time. When the first reclosing fails, it waits for the reclosing interval time to perform at least one reclosing action, reducing the risk of misjudging permanent faults and improving the recovery probability of transient faults.

[0069] Furthermore, by predicting the nature of the fault using historical data or real-time current waveforms, if the predicted fault section is a high-probability transient fault, rapid reclosing is prepared in advance; if the predicted fault is permanent, the protection terminal is put into an advance state. By predicting the nature of the fault, fault handling time is further shortened and fault detection efficiency is improved.

[0070] Furthermore, when the local protection judgment parameter and the remote protection judgment parameter are equal, that is, the difference between the protection judgment parameters is zero, it is determined that the current of the local terminal and the remote terminal are the same, and both are located at the two ends of the non-fault section. When the local protection judgment parameter is the second parameter and the remote protection judgment parameter is the third parameter, that is, the local terminal is located in the upstream section of the fault point and the remote terminal is located in the downstream section of the fault point, it indicates that the protection terminal is located on the power supply side of the fault section, and the corresponding difference is the second difference. When the local protection judgment parameter is the third parameter and the remote protection judgment parameter is the second parameter, that is, the local terminal is located in the downstream section of the fault point and the remote terminal is located in the upstream section of the fault point, it indicates that the protection terminal is located on the load side of the fault section, and the corresponding difference is the third difference.

[0071] In some embodiments, optionally, such as Figure 2 As shown, step S118: Determine the reclosing result of the reclosing operation, including:

[0072] Step S1180: Obtain the current information of the first protection terminal and the second protection terminal, the current information including the first current information and the second current information;

[0073] Step S1182: If both the value corresponding to the first current information and the value corresponding to the second current information change, determine the reclosing result as the first result.

[0074] Step S1184: If the value corresponding to the first current information or the value corresponding to the second current information has not changed, determine the reclosing result as the second result.

[0075] In this embodiment, the reclosing result is determined based on changes in the dual-terminal current information. The success of the reclosing is judged by the current information (three-phase current RMS value or zero-sequence current) collected by the power supply side protection terminal (first protection terminal) and the current information collected by the load side protection terminal (second protection terminal) of the fault section. Specifically, when both the values ​​corresponding to the first current information from the first protection terminal and the values ​​corresponding to the second current information from the second protection terminal change significantly, it is determined that power supply to the line in the fault section has been restored. Furthermore, when both the values ​​corresponding to the first and second current information change, and the current characteristics are determined to conform to the normal operating mode based on the current information, the transient fault is determined to be eliminated, i.e., the reclosing result is the first result, and the reclosing is successful. If the values ​​corresponding to the first or second current information do not change, i.e., the current value of at least one protection terminal does not change as expected, it indicates that the fault point in the fault section still exists, and the fault in the fault section is determined to be a permanent fault; the line in the fault section cannot be restored to normal operation.

[0076] Understandably, by using dual-terminal current collaborative verification, we can avoid misjudgment of faults caused by single-sided protection terminal current detection and improve the robustness of detecting power distribution line faults.

[0077] Furthermore, if the value corresponding to the first current information or the value corresponding to the second current information does not change, the protection terminal of the load-side terminal is immediately triggered to trip, shortening the fault disconnection time and improving the fault detection efficiency of the distribution line connected to the distributed power source.

[0078] In some embodiments, optionally, such as Figure 3 As shown, step S104: Determine the threshold value based on historical load data, including:

[0079] Step S1042: Determine the maximum load current and maximum output current based on historical load data;

[0080] Step S1044: When the maximum load current is greater than the maximum output current, the threshold value is determined to be the maximum load current; otherwise, the threshold value is determined to be the maximum output current.

[0081] In this embodiment, the maximum load current and maximum output current of the distribution network line are determined using historical load data from the distribution network system. The maximum load current is determined by all loads downstream of the line where the protection terminal is located, and refers to the highest current value the distribution network line needs to carry under maximum load conditions. The maximum output current is determined by the installed capacity of the distributed generation, and refers to the maximum current capacity the distribution network can provide under ideal operating conditions. The maximum output current is calculated based on the grid's design capacity and the specifications of the distribution line. By determining the larger of the maximum load current and maximum output current in the distribution network line, a threshold value for the distribution network line is determined. In other words, by selecting a larger threshold value, current flow from the load end to the centralized power source end is avoided when the load is low and the distributed generation output is high, preventing overcurrent protection misjudgment and reducing unnecessary tripping.

[0082] Understandably, by monitoring load changes during the historical operation of the line, its maximum load current is determined, which is the peak current when all downstream loads are operating simultaneously. The maximum output current of the distributed generation is calculated using historical operating records or installed capacity, i.e., the output current of the distributed generation at full load. By determining the larger of the maximum output current and the maximum load current as the threshold value, the protection criterion always covers the maximum current that the line may experience, whether caused by load demand or power generation output. Dynamically setting the threshold value balances load demand and power generation output, avoiding the limitations of traditional fixed threshold values ​​in bidirectional current transmission scenarios and enhancing the accuracy of fault detection.

[0083] Furthermore, historical load data is updated using a sliding time window, for example, a rolling 30-day update. By using a sliding time window update method, expired data is removed, and only recent valid data is retained, thus improving the robustness of fault detection.

[0084] Furthermore, historical fault data in the historical load data is identified, and the fault probability of current segments between multiple protection terminals is determined based on the historical fault data. The threshold value is dynamically adjusted based on the original threshold value and the fault probability, thereby quantifying the risk level of protection actions and achieving a balance between fault detection reliability and economy.

[0085] In some embodiments, optionally, such as Figure 4 As shown, step S106: Determine the protection judgment parameters corresponding to the protection terminal based on the threshold value and current parameters, including:

[0086] Step S1062: Determine the effective value amplitude corresponding to the effective value of the three-phase current of at least one protection terminal;

[0087] Step S1064: Determine the current imbalance coefficient and setting value for each protection terminal based on the current parameters;

[0088] Step S1066: When the current imbalance coefficient is less than or equal to the setting value, determine the protection judgment parameter corresponding to the protection terminal as the first parameter;

[0089] Step S1068: When the current imbalance coefficient is greater than the setting value and the effective value amplitude is greater than the threshold value, determine the protection judgment parameter corresponding to the protection terminal as the second parameter;

[0090] Step S1070: When the current imbalance coefficient is greater than the setting value and the effective value amplitude is less than or equal to the threshold value, the protection judgment parameter corresponding to the protection terminal is determined to be the third parameter.

[0091] In this embodiment, since the grounding method of the distributed power source is the same as that of the distribution network side, both being neutral point non-effective grounding methods, under normal operating conditions, the distribution line still only has positive sequence current, and the current imbalance coefficient is almost zero. Under fault operation conditions, zero sequence current or negative sequence current will appear in the line, and the current imbalance coefficient will be large. Therefore, the current imbalance coefficient of the protection terminal is used as the protection start criterion. When the line is operating normally, the protection judgment parameter is the first parameter, which is zero; when the current imbalance coefficient is greater than the setting value, it is determined that a fault has occurred in the system. The setting value is determined by sampling the imbalance coefficient of each protection terminal, measuring the range of the imbalance coefficient under normal conditions, and then adding a safety margin to avoid false triggering under normal fluctuation conditions. When the current imbalance coefficient is greater than the setting value, it is further determined whether the protection terminal is located in the upstream or downstream section of the fault point. When the effective value amplitude of the three-phase current of the protection terminal is greater than the threshold value, it is determined that the protection terminal is located in the upstream section of the fault point; when the effective value amplitude of the three-phase current of the protection terminal is less than the threshold value, it is determined that the protection terminal is located in the downstream section of the fault point. When the protection terminal is located upstream of the fault point, the protection judgment parameter is determined as the second parameter and set to a fixed positive value, such as 1 or 2; when the protection terminal is located downstream of the fault point, the protection judgment parameter is determined as the third parameter and set to a fixed negative value with the same absolute value as the second parameter but opposite sign, such as -1 or -2.

[0092] For example, the current imbalance coefficient is used to quantify the degree of imbalance in the three-phase current, such as the ratio of negative-sequence current to positive-sequence current. The setting value is a preset current imbalance threshold used to determine whether the protection operation condition has been met.

[0093] Understandably, by using the current imbalance coefficient and the effective value amplitude as dual criteria, combined with the threshold value, high-precision differentiation of fault types can be achieved, effectively distinguishing short-circuit faults from normal operating condition fluctuations, reducing the probability of false triggering during fault detection, and improving the accuracy of fault detection in distribution lines connected to distributed power sources.

[0094] Optionally, the setting value can be dynamically adjusted according to changes in the distribution line topology where the distributed power source is connected. When the distributed power source is online, the setting value is automatically reduced to increase sensitivity to power output imbalance; when a motor group or other load is connected to the load side, the setting value is automatically increased to reduce the impact of unbalanced current during load startup.

[0095] In some embodiments, optionally, such as Figure 5 As shown, step S110: Determining the difference in protection judgment parameters between the first protection terminal and the second protection terminal includes:

[0096] Step S1102: Obtain at least one protection judgment parameter transmitted from the first protection terminal to the second protection terminal;

[0097] Step S1104: Obtain the time stamp corresponding to the protection judgment parameter;

[0098] Step S1106: Determine the difference between at least one protection judgment parameter of the first protection terminal and the protection judgment parameter of the second protection terminal based on the time stamp.

[0099] In this embodiment, when the power distribution line is operating normally, at least one protection judgment parameter will be transmitted from the protection terminal of the upstream section to the protection terminal of the downstream section, or vice versa. During this process, multiple protection judgment parameters will cause excessive transmission volume and reduced data synchronization accuracy. By attaching a time stamp to each protection judgment parameter, the protection terminal transmits the protection judgment parameter to the adjacent terminal every time it is sampled, calculated, and judged. When the second protection terminal receives the protection judgment parameter from the first protection terminal, it compares the protection judgment parameter with the closest sampling time based on the time stamp, thereby reducing the amount of data processing and improving the data synchronization accuracy.

[0100] The first protection terminal is the peer protection terminal, and the second protection terminal is the local protection terminal. For each terminal, the difference between the local protection judgment parameter and the peer protection judgment parameter is calculated to determine the consistency direction judgment standard and improve processing efficiency.

[0101] For example, the first protection terminal is a power supply side terminal, and the second protection terminal is a load side terminal.

[0102] Furthermore, the first protection terminal transmits its protection judgment parameters to the second protection terminal via a communication channel. Each protection judgment parameter corresponds to a precise timestamp, recording the time point of parameter generation. The parameters at both ends are aligned based on the timestamps. If the times are not completely synchronized, interpolation or nearest neighbor matching is used to associate the protection judgment parameters within the time window. Aligning the protection judgment parameters at both ends through timestamps eliminates errors caused by communication delays or sampling asynchrony, ensuring that the difference calculation is based on the operating conditions at the same time, and avoiding misjudgments due to too many branch line sections.

[0103] Furthermore, the difference result can directly reflect the direction of the fault. When the difference result is positive, it is determined that the fault is located between the two protection terminals; when the difference result is zero or negative, it is determined that the fault is located outside the two protection terminals.

[0104] Optionally, the differences between protection judgment parameters corresponding to multiple protection terminals are determined based on time stamps, a difference matrix is ​​constructed, and the fault section is located based on the feature values ​​of the difference matrix or an identification algorithm. By constructing a difference matrix, the fault location problem in ring network distribution lines connected to distributed power sources is solved, improving the reliability of fault judgment.

[0105] In some embodiments, optionally, such as Figure 6 As shown, step S112: Determine the location of the fault section corresponding to the protection terminal based on the difference, including:

[0106] Step S1122: When the protection judgment parameters of the first protection terminal and the protection judgment parameters of the second protection terminal are the same, the difference is determined to be the first difference.

[0107] Step S1124: When the protection judgment parameter of the first protection terminal is the second parameter and the protection judgment parameter of the second protection terminal is the third parameter, determine the difference as the second difference;

[0108] Step S1126: When the protection judgment parameter of the first protection terminal is the third parameter and the protection judgment parameter of the second protection terminal is the second parameter, the difference is determined to be the third difference.

[0109] In this embodiment, because the current suddenly increases within the fault section, the difference between the protection judgment parameters of the local terminal and the remote terminal also increases significantly. By judging the difference between the protection judgment parameters of the local terminal and the remote terminal, it is determined whether the protection terminal is located on the power supply side or the load side on both sides of the fault section. Specifically, when the local protection judgment parameter and the remote protection judgment parameter are equal, that is, the difference between the protection judgment parameters is zero, it is determined that the current of the local terminal and the remote terminal are the same, and both are located in the regions at both ends of the non-fault section; when the local protection judgment parameter is the second parameter and the remote protection judgment parameter is the third parameter, that is, the local terminal is located in the upstream section of the fault point and the remote terminal is located in the downstream section of the fault point, it indicates that the protection terminal is located on the power supply side of the fault section, and the corresponding difference is the second difference; when the local protection judgment parameter is the third parameter and the remote protection judgment parameter is the second parameter, that is, the local terminal is located in the downstream section of the fault point and the remote terminal is located in the upstream section of the fault point, it indicates that the protection terminal is located on the load side of the fault section, and the corresponding difference is the third difference. By determining the difference in protection judgment parameters for each pair of adjacent terminals, sections with significant differences are identified. Furthermore, the protection judgment parameters of the terminals are used to determine whether the power supply side or load side is located in the faulty section, thereby identifying the section where the transient fault occurred.

[0110] Understandably, determining the fault section through three types of difference eliminates the need for complex time-series or frequency-domain analysis, reduces computational resource requirements, clearly distinguishes the location of the fault section, determines whether the fault is on the power supply side or the load side, enables selective tripping, minimizes the power outage range, and, combined with reclosing strategies and protection terminal protection strategies, achieves uninterrupted power supply and rapid identification of transient faults, thereby improving the power supply reliability of distribution lines with distributed power sources.

[0111] In one specific embodiment, optionally, such as Figure 9 As shown, the distribution network 2000 includes distributed generation (DG), centralized power supply (3000), distribution lines L, protection terminals 2002, and loads 2004. During normal operation, current flows from the distributed generation (DG) or centralized power supply (3000) to the loads 2004. In the distribution network 2000, the distribution network 2000 is connected to the main line L1 and operates in conjunction with the centralized power supply (3000). The centralized power supply (3000) supplies power to the entire distribution network, providing a large and stable power supply guarantee. The distributed generation (DG) is connected to each distribution line L, reducing the load pressure on the centralized power supply (3000).

[0112] Specifically, when a transient fault F occurs in power distribution line L, the circuit protection method is as follows:

[0113] The first step is sampling and calculation. That is, each protection terminal device i samples the three-phase current value and performs Discrete Fourier Transform calculation to obtain the effective value of the three-phase current. Three-sequence current value , , and current imbalance coefficient The three-phase current values ​​can be calculated using the complex number method based on the three-phase current values. 'i' represents the serial number of each protection terminal device, 'A' represents the first phase of the three-phase current, 'B' represents the second phase, and 'C' represents the third phase. This represents the current phase.

[0114] The second step involves each protection terminal 2002 comparing the protection criteria to determine the fault direction. According to industry standards, the grounding method of the distributed generation (DG) should be consistent with the grounding method on the 2000 side of the distribution network; therefore, both are neutral point non-effective grounding methods. Under normal operating conditions, the distribution line L still contains almost only positive sequence current, and the current imbalance coefficient is almost zero. Under fault conditions, zero-sequence and negative-sequence currents will appear in the line, and the current imbalance coefficient will be larger. Therefore, the current imbalance coefficient is used as the protection activation criterion. Under normal operating conditions, the protection judgment result is "0".

[0115] If the current imbalance coefficient is greater than the set value, a fault is determined to have occurred in the system. The effective value amplitude of the phase current is then considered. With threshold value A comparison is made to determine the fault direction. If the effective value of any phase current is greater than the threshold value, the protection terminal 2002 is considered to be located upstream of the fault point, and the protection judgment result is "1"; otherwise, the protection terminal 2002 is considered to be located downstream of the fault point, and the protection judgment result is "-1". Considering the access of distributed generation (DG), if the installed capacity is large enough, it may change the magnitude and direction of the current flowing through the protection terminal 2002 under normal operation. Therefore, the threshold value... The selection of the threshold value for overcurrent protection differs from that of traditional overcurrent protection, which uses a multiple of the rated current. Instead, it should be the maximum load current. and maximum output current The larger value in, i.e. .

[0116] The maximum load current is determined by all loads downstream of the line where the protection terminal is located, and the maximum output current is determined by the installed capacity of the distributed generation (DG). In summary, the conditions under which each protection terminal's 2002 protection judgment yields different results are as follows:

[0117] When the current imbalance coefficient is less than or equal to the setting value, the judgment result Result = "0";

[0118] Expressed as a formula:

[0119] ;

[0120] in, , , These are the three-sequence current values. This is the current imbalance coefficient. This is the setpoint value.

[0121] When the current imbalance coefficient is greater than the setting value and the effective value amplitude of the phase current is greater than the threshold value, the judgment result Result = "1";

[0122] Expressed as a formula:

[0123] ;

[0124] ;

[0125] in, , , These are the three-sequence current values. This is the current imbalance coefficient. This is the set value. This represents the effective value amplitude of the three-phase current. This is the threshold value.

[0126] When the current imbalance coefficient is greater than the setting value and the effective value amplitude of the phase current is less than or equal to the threshold value, the judgment result Result="-1";

[0127] Expressed as a formula:

[0128] ;

[0129] ;

[0130] in, , , These are the three-sequence current values. This is the current imbalance coefficient. This is the set value. This represents the effective value amplitude of the three-phase current. This is the threshold value.

[0131] The third step is to transmit the results. After each protection terminal 2002 is tagged with a time stamp, the judgment result is transmitted to the adjacent terminal through the communication channel. Each time a sample is sampled, a calculation and judgment are performed, the result is transmitted once.

[0132] The fourth step is to determine the location of the protection terminal 2002 based on the differential principle. After receiving the protection judgment result sent by the adjacent terminal j, this protection terminal device i compares it with the protection judgment result of the sampling time with the closest timestamp between the local and remote terminals. Based on the differential principle, the results of the two ends are subtracted, with the local result appearing first and the received result from the adjacent terminal appearing second. All possible judgment results are as follows, with a total of four cases:

[0133] (1) Local protection judgment result The received peer protection judgment result The difference between the two is 2, indicating that the protection terminal 2002 is located on the power supply side at both ends of the fault section.

[0134] (2) Local protection judgment result The received peer protection judgment result The difference between the two is -2, indicating that the protection terminal 2002 is located on the load side at both ends of the fault section.

[0135] (3) Local protection judgment result The received peer protection judgment result The difference between the two is 0, indicating that the protection terminal 2002 is not located at either end of the fault section, but only in the upstream section of the fault point.

[0136] (4) Local protection judgment result The received peer protection judgment result The difference between the two is 0, indicating that the protection terminal 2002 is not located at either end of the fault section, but only in the downstream section of the fault point.

[0137] In summary, the differences in protection judgment results between the faulty section and the non-faulty section are as follows:

[0138] At both ends of the fault section:

[0139] (1) Power supply side of the fault section: - = 2;

[0140] (2) Load side of the fault section: - = -2;

[0141] At both ends of the non-faulty section:

[0142] (1) Upstream of the fault point: - = 0, local protection judgment result The received peer protection judgment result ;

[0143] (2) Downstream of the fault point: - = 0, local protection judgment result The received peer protection judgment result .

[0144] The fifth step involves the protection terminal 2002 located at both ends of the fault section on the power supply side controlling the three-phase trip of the circuit breaker. Based on the calculation results from the previous step using the differential principle, the location of the protection terminal can be determined by using the difference between the local protection judgment result and the received remote protection judgment result. This allows for the determination of the next protection action for terminals at different locations. Specifically, the protection terminal 2002 located at both ends of the fault section controls the three-phase trip of the circuit breaker; the protection terminal 2002 located on the load side at both ends of the fault section remains in the protection initiation state, awaiting the action signal; and the protection terminal 2002 not located at either end of the fault section exits protection mode.

[0145] Protective actions include:

[0146] (1) Difference in protection judgment results corresponding to protection terminal 2002 - When > 1, protection terminal 2002 performs protection action, controlling the three-phase trip of the circuit breaker;

[0147] (2) Difference in protection judgment results corresponding to protection terminal 2002 - When the value is less than -1, the protection terminal 2002 remains in the protection enabled state and waits for the action signal.

[0148] (3) Difference in protection judgment results corresponding to protection terminal 2002 - When = 0, protection is off.

[0149] The sixth step is to reclose the tripped circuit breaker.

[0150] Step 7: Based on the reclosing result, determine whether the protection terminals on the load side at both ends of the faulty section should operate. If reclosing is successful, it indicates a transient fault or other disturbance, and the line has returned to normal operation; the protection terminals on the load side at both ends of the faulty section will deactivate. If reclosing fails, it indicates a permanent fault; the protection terminals on the load side at both ends of the faulty section will trigger protection operation.

[0151] This achieves precise and rapid local two-end isolation of short-circuit faults.

[0152] like Figure 7 As shown in the figure, this application embodiment also provides a circuit protection device 900, which includes: an acquisition module 902 for acquiring historical load data and current parameters of at least one protection terminal; a determination module 904 for determining a threshold value based on the historical load data; a fault judgment module 906 for determining protection judgment parameters corresponding to the protection terminal based on the threshold value and the current parameters, wherein each protection judgment parameter is associated with a time stamp; a transmission module 908 for transmitting at least one protection judgment parameter between adjacent protection terminals, wherein each protection terminal receives protection judgment parameters corresponding to another protection terminal and transmits them to a second protection terminal through a first protection terminal; and a section determination module 910 for determining the difference between the protection judgment parameters between the first protection terminal and the second protection terminal, and determining the location of the fault section corresponding to the protection terminal based on the difference. The control module 912 is used to control the protection terminal on the power supply side located at both ends of the fault section to perform the three-phase tripping action of the circuit breaker; and to control the circuit breaker that has completed the three-phase tripping action to perform the reclosing action; the protection module 914 is used to determine the reclosing result of the reclosing action, the reclosing result including a first result and a second result; when the reclosing result is the first result, it is determined that the protection terminal on the load side in the fault section is in the protection off state; when the reclosing result is the second result, it is determined that the protection terminal on the load side in the fault section is in the protection execution state; wherein, the difference includes a first difference, a second difference and a third difference; when the difference is the first difference, it is determined that the protection terminal is located at both ends of the non-fault section; when the difference is the second difference, it is determined that the protection terminal is located on the power supply side at both ends of the fault section; when the difference is the third difference, it is determined that the protection terminal is located on the load side at both ends of the fault section.

[0153] In some embodiments, optionally, the protection module 914 is further configured to: acquire current information of the first protection terminal and the second protection terminal, the current information including first current information and second current information; determine the reclosing result as the first result when both the value corresponding to the first current information and the value corresponding to the second current information have changed; and determine the reclosing result as the second result when neither the value corresponding to the first current information nor the value corresponding to the second current information has changed.

[0154] The circuit protection device 900 provided in this embodiment utilizes the judgment parameters generated by each protection terminal to achieve real-time monitoring and direction differentiation of current changes, ensuring accurate detection and location of faults even under bidirectional current conditions. When a transient fault occurs in a distribution line connected to a distributed power source, the fault location is detected promptly and the fault section is isolated. By comparing the magnitude of the effective value amplitude and threshold value of the three-phase current of each protection terminal, it is determined whether each protection terminal is located upstream or downstream of the fault point. Furthermore, the relative positional relationship between each protection terminal and the fault point is compared using a difference judgment method for further screening. If a pair of adjacent protection terminals is found, and one detects a current exceeding the threshold value while the other does not, then these two protection terminals can be determined to be located at opposite ends of the fault point, and the section between them is the fault section. The system then controls these two protection terminals to issue commands to instruct circuit breakers and other devices to perform tripping operations, and reclosing is performed after the tripping operation is completed. After the reclosing operation is completed, the protection terminal on the load side at both ends of the fault section is determined based on the reclosing result. The reclosing operation drives the protection terminal to protect the load side of the fault section, thereby achieving uninterrupted power supply in the event of transient faults in the distribution line connected to the distributed power source, and precise and rapid local double-end isolation of permanent faults.

[0155] like Figure 8 As shown, this application embodiment also provides an electronic device 1000, including a processor 1110, a memory 1109, and a program or instructions stored in the memory 1109 and executable on the processor 1110. When the program or instructions are executed by the processor 1110, they implement the various processes of the above-described circuit protection method embodiments and achieve the same technical effects. To avoid repetition, they will not be described again here.

[0156] Optionally, the processor 1110 is used to acquire historical load data and current parameters of at least one protection terminal;

[0157] Optionally, the processor 1110 is also used to determine a threshold value based on historical load data;

[0158] Optionally, the processor 1110 is also configured to determine protection judgment parameters corresponding to the protection terminal based on the threshold value and the current parameters;

[0159] Optionally, the processor 1110 is also configured to transmit at least one protection judgment parameter between adjacent protection terminals, and transmit it to the second protection terminal through the first protection terminal.

[0160] Optionally, the processor 1110 is further configured to determine the difference in protection judgment parameters between the first protection terminal and the second protection terminal, and to determine the location of the fault section corresponding to the protection terminal based on the difference.

[0161] Optionally, the processor 1110 is also used to control the protection terminal located on the power supply side at both ends of the fault section to perform the three-phase tripping action of the circuit breaker.

[0162] Optionally, the processor 1110 is also used to control the circuit breaker that has completed the three-phase tripping action to perform a reclosing action.

[0163] Optionally, the processor 1110 is also used to determine the reclosing result of the reclosing action.

[0164] The memory 1109 can be used to store software programs and various data. The memory 1109 may primarily include a first storage area for storing programs or instructions and a second storage area for storing data. The first storage area may store the operating system, application programs or instructions required for at least one function (such as sound playback, image playback, etc.). Furthermore, the memory 1109 may include volatile memory or non-volatile memory, or both. The non-volatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory can be random access memory (RAM), static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDRSDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct memory bus RAM (DRRAM). The memory 1109 in this embodiment includes, but is not limited to, these and any other suitable types of memory.

[0165] This application also provides a readable storage medium storing a program or instructions. When executed by a processor, the program or instructions implement the various processes of the circuit protection method embodiments described above, achieving the same technical effects. To avoid repetition, these will not be repeated here. Furthermore, the readable storage medium improves the data storage capacity and data processing speed of the circuit protection method in this application.

[0166] A computer-readable storage medium can be a tangible device that holds and stores instructions for use by an instruction execution device. A computer-readable storage medium can be an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing, but is not limited thereto. A non-exhaustive list of more specific examples of computer-readable storage media includes: portable computer floppy disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable optical disc read-only memory (CD-ROM), digital universal disk (DVD), memory cards, floppy disks, encoding mechanical devices (e.g., punched cards or grooves with raised structures for recording instructions), and any suitable combination of the foregoing. The computer-readable storage medium used herein should not be construed as the transmission of signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media, or electrical signals transmitted through wires.

[0167] The processor is the processor in the electronic device described in the above embodiments. The readable storage medium includes computer-readable storage media, such as computer read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk.

[0168] This application also provides a chip, which includes a processor and a communication interface. The communication interface and the processor are coupled. The processor is used to run programs or instructions to implement the various processes of the circuit protection method embodiments described above, and can achieve the same technical effect. To avoid repetition, it will not be described again here. In addition, the chip improves the data processing speed corresponding to the circuit protection method in this application.

[0169] It should be understood that the chip mentioned in the embodiments of this application may also be referred to as a system-on-a-chip, system chip, chip system, or system-on-a-chip, etc.

[0170] In this invention, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term "multiple" refers to two or more unless otherwise explicitly defined. The terms "install," "connect," "link," and "fix" should be interpreted broadly. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "link" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0171] In the description of this invention, it should be understood that the terms "upper," "lower," "left," "right," "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0172] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0173] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A circuit protection method, characterized in that, include: Acquire historical load data and current parameters of at least one protection terminal; The threshold value is determined based on the historical load data; The protection judgment parameters corresponding to the protection terminal are determined based on the threshold value and the current parameter, and each protection judgment parameter is set with a time stamp. At least one of the protection judgment parameters is transmitted between adjacent protection terminals, and each protection terminal receives the protection judgment parameter corresponding to another protection terminal and transmits it to the second protection terminal through the first protection terminal. Determine the difference between the protection judgment parameters between the first protection terminal and the second protection terminal; The location of the fault section corresponding to the protection terminal is determined based on the difference. Control the protection terminal located on the power supply side at both ends of the fault section to perform the three-phase tripping action of the circuit breaker; Control the circuit breaker that has completed the three-phase tripping action to perform a reclosing action; Determine the reclosing result of the reclosing action, wherein the reclosing result includes a first result and a second result; When the reclosing result is the first result, the protection terminal on the load side of the fault section is determined to be in a protection off state; When the reclosing result is the second result, the protection terminal on the load side in the fault section is determined to be in protection execution state; The difference includes a first difference, a second difference, and a third difference; When the difference is the first difference, it is determined that the protection terminal is located at both ends of the non-faulty section; When the difference is the second difference, it is determined that the protection terminal is located on the power supply side at both ends of the fault section; When the difference is the third difference, it is determined that the protection terminal is located on the load side at both ends of the fault section.

2. The circuit protection method according to claim 1, characterized in that, The determination of the reclosing result of the reclosing action includes: Obtain the current information of the first protection terminal and the second protection terminal, wherein the current information includes first current information and second current information; If both the values ​​corresponding to the first current information and the values ​​corresponding to the second current information change, the reclosing result is determined as the first result. If the value corresponding to the first current information or the value corresponding to the second current information does not change, the reclosing result is determined to be the second result.

3. The circuit protection method according to claim 1, characterized in that, Determining the threshold value based on the historical load data includes: The maximum load current and maximum output current are determined based on the historical load data. When the maximum load current is greater than the maximum output current, the threshold value is determined to be the maximum load current; Otherwise, the threshold value is determined to be the maximum output current.

4. The circuit protection method according to any one of claims 1 to 3, characterized in that, The step of determining the protection judgment parameters corresponding to the protection terminal based on the threshold value and the current parameters includes: Determine the effective value amplitude corresponding to the effective value of the three-phase current of at least one of the protection terminals; The current imbalance coefficient and setting value of each protection terminal are determined based on the current parameters. When the current imbalance coefficient is less than or equal to the setting value, the protection judgment parameter corresponding to the protection terminal is determined to be the first parameter; When the current imbalance coefficient is greater than the setting value and the effective value amplitude is greater than the threshold value, the protection judgment parameter corresponding to the protection terminal is determined to be the second parameter. When the current imbalance coefficient is greater than the setting value and the effective value amplitude is less than or equal to the threshold value, the protection judgment parameter corresponding to the protection terminal is determined to be the third parameter. The second parameter is a fixed positive value, and the third parameter is a fixed negative value with the same absolute value as the second parameter but opposite sign.

5. The circuit protection method according to claim 4, characterized in that, Determining the difference in the protection judgment parameters between the first protection terminal and the second protection terminal includes: Obtain at least one protection judgment parameter transmitted from the first protection terminal to the second protection terminal; Obtain the time stamp corresponding to the protection judgment parameter; The difference between at least one protection judgment parameter of the first protection terminal and the protection judgment parameter of the second protection terminal is determined based on the timestamp.

6. The circuit protection method according to claim 5, characterized in that, Determining the location of the fault section corresponding to the protection terminal based on the difference includes: When the protection judgment parameters of the first protection terminal and the protection judgment parameters of the second protection terminal are the same, the difference is determined to be the first difference. When the protection judgment parameter of the first protection terminal is the second parameter, and the protection judgment parameter of the second protection terminal is the third parameter, the difference is determined to be the second difference. When the protection judgment parameter of the first protection terminal is the third parameter and the protection judgment parameter of the second protection terminal is the second parameter, the difference is determined to be the third difference.

7. A circuit protection device, characterized in that, include: The acquisition module is used to acquire historical load data and the current parameters of at least one protection terminal; The determination module is used to determine a threshold value based on the historical load data; The fault judgment module is used to determine the protection judgment parameters corresponding to the protection terminal based on the threshold value and the current parameters, and each of the protection judgment parameters is set with a time stamp. The transmission module is used to transmit at least one protection judgment parameter between adjacent protection terminals, and each protection terminal receives the protection judgment parameter corresponding to another protection terminal and transmits it to the second protection terminal through the first protection terminal. The section determination module is used to determine the difference between the protection judgment parameters between the first protection terminal and the second protection terminal, and to determine the location of the fault section corresponding to the protection terminal based on the difference. The control module is used to control the protection terminal located on the power supply side at both ends of the fault section to perform the three-phase tripping action of the circuit breaker; and to control the circuit breaker that has completed the three-phase tripping action to perform the reclosing action. The protection module is used to determine the reclosing result of the reclosing action, the reclosing result including a first result and a second result; when the reclosing result is the first result, the protection terminal on the load side in the fault section is determined to be in a protection off state; When the reclosing result is the second result, the protection terminal on the load side in the fault section is determined to be in protection execution state; The difference includes a first difference, a second difference, and a third difference; When the difference is the first difference, it is determined that the protection terminal is located at both ends of the non-faulty section; When the difference is the second difference, it is determined that the protection terminal is located on the power supply side at both ends of the fault section; When the difference is the third difference, it is determined that the protection terminal is located on the load side at both ends of the fault section.

8. The circuit protection device according to claim 7, characterized in that, The protection module is further configured to: acquire current information of the first protection terminal and the second protection terminal, the current information including first current information and second current information; determine the reclosing result as a first result when both the value corresponding to the first current information and the value corresponding to the second current information have changed; and determine the reclosing result as a second result when neither the value corresponding to the first current information nor the value corresponding to the second current information has changed.

9. An electronic device, characterized in that, It includes a processor, a memory, and a program or instructions stored in the memory and executable on the processor, wherein the program or instructions, when executed by the processor, implement the steps of the circuit protection method as described in any one of claims 1 to 6.

10. A readable storage medium, characterized in that, The readable storage medium stores a program or instructions that, when executed by a processor, implement the steps of the circuit protection method as described in any one of claims 1 to 6.

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