A method and system for fast positioning and self-healing control of a rural power distribution network

Abstract

This invention discloses a method and system for fault location and self-healing control in rural power distribution networks, belonging to the field of fault location and self-healing technology. The method includes the following steps: S1, terminal configuration and data acquisition; S2, fault characteristic determination; S3, joint locking of fault sections; S4, fault isolation and load statistics; S5, power restoration of the power outage area. It aims to overcome the shortcomings of existing power distribution network fault location and self-healing control technologies, such as weak anti-anomaly capabilities. It addresses the problems of existing distributed solutions relying on single electrical quantities for fault determination, which easily leads to false or missed fault identification and inaccurate fault section locking. It also solves the problems of existing distributed solutions relying on single electrical quantities for fault determination, which easily leads to terminal-side autonomous coordination in load statistics and power restoration of the power outage area, potentially causing operational risks such as switch overload and loop-closing impact. The method achieves rapid and accurate fault location, reliable isolation, and autonomous power restoration in the power distribution network, comprehensively improving the power supply reliability and operational safety of the power distribution network.

Description

Technical Field

[0001] This invention relates to the field of fault location and self-healing technology in power distribution networks, and more specifically, to a method and system for rapid fault location and self-healing control in rural power distribution networks. Background Technology

[0002] The distribution network is the core link connecting the power generation side and end users in the power system. Its operational stability and fault handling capabilities directly determine the reliability of power supply and the safety of users' electricity consumption. According to power industry operation statistics, more than 85% of power outages on the user side are caused by distribution network faults, with rural distribution networks accounting for more than 70% of the total outage time in the entire system. As the core carrier at the end of the new power system construction, the rural distribution network undertakes the key function of ensuring electricity supply for rural residents, agricultural production, and rural industrial development. The national distribution network upgrading and transformation special plan also clearly identifies improving the self-healing capability of rural power grids and shortening the duration of outages as core construction indicators. However, rural distribution networks generally suffer from problems such as large line coverage radius, weak grid structure, complex operating environment, and insufficient operation and maintenance inspection forces. The fault incidence rate is much higher than that of urban distribution networks, and the manual investigation and handling cycle after a fault is long. Fault investigation of remote lines often takes several hours, which can easily cause large-scale and long-term power outages. This is the core difficulty of current distribution network operation and maintenance management.

[0003] Traditional fault location and self-healing control in distribution networks often employs a centralized management and control mode at the master station. Electrical data collected by field terminals is uniformly transmitted to the master station, which then performs centralized analysis to locate the fault before issuing switch opening and closing control commands level by level. This mode heavily relies on long-distance communication links between the master station and terminals. However, rural distribution networks typically use wireless public network transmission, which generally suffers from unstable signal coverage, limited bandwidth, large transmission delay fluctuations, and susceptibility to interruptions in extreme weather conditions. Once communication is interrupted or the master station crashes, the entire fault handling process completely fails. Furthermore, the multi-stage information interaction and centralized computation introduce significant processing delays, failing to meet the timeliness requirements for rapid fault isolation and self-healing in distribution networks, and easily leading to the expansion of the fault's scope.

[0004] With the continued advancement of dual-carbon goals, a large number of distributed photovoltaic and small hydropower sources have been connected to rural power distribution networks. The power flow in the distribution network has shifted from the traditional unidirectional flow to a multidirectional and complex flow, further exacerbating the difficulty of fault diagnosis. Existing distributed fault handling solutions mostly rely on a single overcurrent characteristic for fault diagnosis, which is susceptible to factors such as load fluctuations, backfeeding from distributed sources, and line harmonic interference, leading to false or missed fault diagnoses and an inability to accurately pinpoint the faulty section. At the same time, the load statistics of the power loss area, the verification of reserve capacity, and the power restoration operation after a fault still require the participation and coordination of the master station, making it impossible to achieve peer-to-peer autonomous control at the terminal side. The adaptability of power loss area restoration is poor, which can easily lead to operational risks such as overload of tie switches and loop-closing impacts, making it difficult to adapt to the operating scenarios of new distribution networks. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention aims to provide a method and system for rapid fault location and self-healing control in rural power distribution networks. This system overcomes the shortcomings of existing fault location and self-healing control technologies, such as the centralized management mode's heavy reliance on the master station and communication links, prolonged fault handling time, and weak anomaly resistance. It also solves the problems of existing distributed solutions relying on single electrical quantities for fault detection, which easily leads to false or missed faults, inaccurate fault location, and the inability to achieve autonomous coordination between the load statistics and power restoration in power-out areas at the terminal side, which can easily cause operational risks such as switch overload and loop-closing impact. The invention achieves rapid and accurate fault location, reliable isolation, and autonomous power restoration in rural power distribution networks, comprehensively improving the power supply reliability and operational safety of rural power distribution networks.

[0006] To solve the above problems, the present invention adopts the following technical solution.

[0007] A method for rapid fault location and self-healing control in rural power distribution networks includes the following steps:

[0008] S1. Terminal Configuration and Data Acquisition: Terminals are configured at the sectionalizing switches and tie switches of the distribution network, with the busbar as the power supply side and the lines between adjacent switches as independent sections; each terminal synchronizes with the distribution network topology; the master station sends short-circuit threshold, undervoltage threshold and the standby capacity of the tie switch to the terminal; the terminal collects the current amplitude, current direction, voltage amplitude and load power of the switch in real time.

[0009] S2. Fault characteristic determination: When the current amplitude collected by the terminal is greater than the short circuit threshold, it is determined that there is an overcurrent characteristic, and the current direction away from the power supply side is marked as positive; when the voltage amplitude is lower than the undervoltage threshold, it is determined that there is an undervoltage characteristic.

[0010] S3. Joint Locking of Fault Section: Adjacent terminals exchange the overcurrent characteristic, the undervoltage characteristic, and the current direction through peer-to-peer communication; when a terminal on the power supply side of the same independent section has the overcurrent characteristic and the current direction is positive, and a terminal away from the power supply side does not have the overcurrent characteristic but has the undervoltage characteristic, the adjacent terminals jointly lock the independent section as a fault section.

[0011] S4. Fault Isolation and Load Statistics: The terminals on both sides of the fault section drive the corresponding switches to open, so as to isolate the fault section; each terminal located downstream of the power supply side of the fault section marks its own independent section as a power outage area, and based on the distribution network topology, transmits and accumulates its own load power level by level through the peer-to-peer communication to obtain the total load of the power outage area;

[0012] S5. Power supply restoration in the power outage area: The terminal at the tie switch connected to the power outage area obtains the total load of the power outage area. If the reserve capacity is greater than the total load of the power outage area, the tie switch is driven to close to complete the power supply restoration. The fault section is jointly locked through terminal peer-to-peer communication, and the fault isolation and power supply restoration can be completed without the need for centralized calculation at the master station, which greatly shortens the fault handling time and significantly improves the reliability of power supply in the distribution network.

[0013] As a further technical solution of the present invention, S1 includes the following sub-steps:

[0014] S11: For the target distribution network, configure feeder terminal units one-to-one at all sectional switches and tie switches to complete the electrical wiring and full-function matching between the terminal and the switch, establish a one-to-one correspondence between the switch and the terminal, and clarify that each switch corresponds to a unique terminal. Switches and terminals without a corresponding relationship are not bound together.

[0015] S12: Taking the outgoing bus of the distribution network to the substation as the sole reference power source, the line between two adjacent switches with configured terminals is designated as an independent electrical section, the distribution network topology adjacency relationship and power direction identification are established, it is clear whether any two switches are directly connected or whether they are the first-end switches adjacent to the bus, and a unique number is assigned to each independent section.

[0016] S13: The distribution network master station constructs a complete distribution network topology model and distributes it to all terminals, and each terminal completes topology synchronization verification.

[0017] S14: The master station sends the adjusted short-circuit threshold, undervoltage threshold and tie switch backup capacity to each terminal, and the terminal completes parameter storage and solidification;

[0018] S15: Each terminal collects electrical quantities at the switch at a fixed sampling frequency, calculates the current amplitude, current direction, voltage amplitude, and load power using the full-wave Fourier algorithm, and refreshes and stores them at a fixed period. This refines the terminal configuration, topology synchronization, and data acquisition process, establishes a one-to-one correspondence between switches and terminals, ensures the accuracy of topology and sampling data, and provides a reliable foundation for subsequent fault diagnosis.

[0019] As a further technical solution of the present invention, the specific implementation process and verification logic of S13 are as follows:

[0020] Master station modeling: Based on the actual field wiring, the distribution network master station constructs a complete distribution network topology model that includes the location of bus power supply points, switch installation locations and numbers, upstream and downstream boundaries of independent sections, correspondence between switches and terminals, and power supply point information on the opposite side of tie switches;

[0021] Model distribution: The main station distributes the topology model to all terminals through the adapted communication link;

[0022] Verification and Confirmation: After receiving the topology model, each terminal stores it locally and completes the verification through topology synchronization verification logic. That is, it compares the topology adjacency information and power direction information stored locally by the terminal with the corresponding information sent by the master station. If the two are completely consistent, the verification passes; otherwise, the verification fails. After the verification is correct, the terminal sends a synchronization completion confirmation signal to the master station, which clarifies the logic of distribution network topology modeling, full transmission and verification, and ensures that the topology of each terminal is completely consistent with that of the master station. This avoids the location error caused by topology deviation and effectively improves the accuracy of fault diagnosis.

[0023] As a further technical solution of the present invention, S2 includes the following sub-steps, and the overall determination mechanism is as follows:

[0024] S21: Overcurrent characteristic determination. The terminal compares the current amplitude obtained by the acquisition and calculation with the short-circuit threshold issued by the master station in real time, cycle by cycle. The determination logic is: when the current amplitude of any phase exceeds the short-circuit threshold for one power frequency cycle or more, it is determined that it has overcurrent characteristics; otherwise, it does not have overcurrent characteristics.

[0025] S22: Current direction calibration. With the bus power supply side as the reference direction, the current direction is determined by calculating the difference between the current phase and the bus reference voltage phase. The current direction away from the power supply side is marked as positive.

[0026] S23: Undervoltage characteristic determination. The terminal compares the voltage amplitude obtained by the acquisition and calculation with the undervoltage threshold issued by the master station in real time on a cycle-by-cycle basis. The determination logic is as follows: when the voltage amplitude of any phase is lower than the undervoltage threshold for one power frequency cycle or more, it is determined that it has undervoltage characteristics; otherwise, it does not have undervoltage characteristics. The sub-determination logic of overcurrent, current direction and undervoltage characteristics is refined. Based on the continuous comparison of power frequency cycles, the characteristics are identified, which effectively avoids the problem of misjudgment of fault characteristics caused by instantaneous electrical interference.

[0027] As a further technical solution of the present invention, the specific calculation method and judgment logic of S22 are as follows:

[0028] Phase difference calculation: The terminal uses the bus power supply side as the reference direction to calculate the difference between the phase of the acquired current and the phase of the bus reference voltage in real time.

[0029] Direction determination: When the phase difference is between -90° and 90°, the current flow direction is determined to be away from the bus power supply side and towards the line load side. This direction is marked as positive, and the current direction flag is made active. When the phase difference is between 90° and 270°, the current flow direction is determined to be towards the bus power supply side. This direction is marked as negative, and the current direction flag is made inactive. This method for accurately determining the current direction based on phase difference clearly marks the positive and negative current directions, providing accurate basis for determining upstream and downstream fault sections and effectively improving the accuracy of fault location.

[0030] As a further technical solution of the present invention, S3 includes the following sub-steps, and the overall mechanism is as follows:

[0031] S31: Peer-to-peer communication interaction, each terminal predetermines adjacent upstream and downstream terminals based on the synchronized distribution network topology, and exchanges fault-related information such as its own overcurrent characteristics, current direction, undervoltage characteristics and terminal number in two directions through point-to-point peer-to-peer communication links.

[0032] S32: Fault section determination. For each independent section, the upstream and downstream terminals at both ends of the section are determined based on the bus power supply side. The determination logic is executed synchronously at both ends of the terminal. That is, the upstream terminal must have overcurrent characteristics and the current direction must be positive. At the same time, the downstream terminal does not have overcurrent characteristics but has undervoltage characteristics. If this condition is met, the section is determined to be a fault section.

[0033] S33: Joint locking. When the above judgment results of the terminals at both ends of the segment are completely consistent, the terminals at both ends jointly lock the independent segment as the faulty segment and report the locking information to the main station and adjacent terminals. Through the peer-to-peer exchange of fault information between adjacent terminals, the terminals at both ends of the segment synchronously judge and jointly lock the faulty segment, avoiding positioning deviation caused by the abnormality of a single terminal, and the fault locking result is more reliable.

[0034] As a further technical solution of the present invention, S4 includes the following sub-steps, and the overall operation flow is as follows:

[0035] S41: Fault isolation. After the terminals on both sides of the fault section confirm the fault lock, the trip control interlocking logic is executed. That is, when the fault lock is effective and the trip command is continuously output for no less than 50ms, the corresponding switch is driven to trip, thus completing the complete electrical isolation between the fault section and the upstream and downstream live lines.

[0036] S42: Power loss zone marking. Each terminal located in the fault section that is away from the downstream of the power source side marks its own independent section as a power loss zone based on the distribution network topology, and completes the boundary confirmation of the power loss zone range through communication interaction.

[0037] S43: Load statistics. All terminals in the power outage area communicate with each other and use a step-by-step transmission and accumulation method from the end of the power outage area to the tie switch side to summarize the load power of the section where all terminals are located, and finally obtain the total load of the power outage area. This refines the fault isolation blocking logic, power outage area marking and load statistics process, ensures reliable fault isolation, accurately counts the total load of the power outage area, and provides accurate load basis for subsequent power restoration.

[0038] As a further technical solution of the present invention, the specific topology search logic and marking mechanism of S42 are as follows:

[0039] Marking start point determination: Starting from the downstream terminal of the fault section, select the terminal located away from the power supply side and whose own voltage loss characteristics are in a valid state; Section marking: The selected terminal is marked by the power loss zone marking logic based on the synchronously completed distribution network topology. That is, when the terminal's voltage loss characteristics are valid and the section it is in belongs to the downstream topology range of the fault section, the section is marked as the power loss zone section;

[0040] Scope Confirmation: All terminals marked as power outage zones exchange their own undervoltage status and zone number through peer-to-peer communication to confirm the boundary of the power outage zone, clarifying all independent zones and corresponding terminals included in the power outage zone, as well as the connection boundary between the power outage zone and the tie switch; among them, the downstream topology range of the fault zone is obtained through breadth-first search, clarifying the logic of power outage zone marking and scope confirmation based on breadth-first search, accurately delineating the boundary of the power outage zone, avoiding omissions and duplications in load statistics, and ensuring the accuracy of the total load data of the power outage zone.

[0041] As a further technical solution of the present invention, S5 includes the following sub-steps, and the specific control logic is as follows:

[0042] S51: Load data verification. The terminal corresponding to the tie switch connected to the power failure area obtains the total load data of the power failure area and confirms the integrity of the data through the data verification logic. That is, the data verification passes when the total load of the power failure area is consistent with the sum of the loads of all terminals in the power failure area; otherwise, the data is incorrect.

[0043] S52: Backup capacity verification. The terminal retrieves the backup capacity corresponding to the contact switch issued by the master station and verifies the feasibility of power restoration through the power restoration feasibility verification logic. That is, if the backup capacity is greater than the product of the total load of the power failure area and the safety factor, it is determined that the power restoration conditions are met; otherwise, they are not met.

[0044] S53: Closing and Restoration. If the backup capacity verification passes, the terminal executes the closing control interlocking logic. That is, when the four conditions of power restoration feasibility, fault isolation completion, no loop risk, and no reverse power supply risk are met simultaneously, the tie switch is driven to close, completing the power restoration of the power loss area. The restoration completion signal is fed back to the main station and all terminals in the power loss area. The multiple verification and closing interlocking logic of power restoration are refined to ensure that the backup capacity of the tie switch meets the power supply demand, avoid overload and loop impact risks, and make the power restoration process safer and more reliable.

[0045] A rapid fault location and self-healing control system for rural power distribution networks includes a distribution network master station and multiple feeder terminal units;

[0046] The distribution network master station is communicatively connected to each of the feeder terminal units, and point-to-point peer-to-peer communication is supported between adjacent feeder terminal units; taking the bus of the distribution network as the power supply side, the line between adjacent sectionalizing switches and tie switches is defined as an independent section, and each sectionalizing switch and tie switch is equipped with a feeder terminal unit one-to-one;

[0047] The distribution network master station is used to send the distribution network topology, the set short-circuit threshold, the undervoltage threshold, and the standby capacity corresponding to the tie switch to all the feeder terminal units.

[0048] The feeder terminal unit is used to synchronize and store the distribution network topology issued by the distribution network master station, and to collect the current amplitude, current direction, voltage amplitude and load power at the switch in real time.

[0049] The feeder terminal unit has a built-in fault feature determination module, which is configured to: when the collected current amplitude is greater than the short circuit threshold, determine that the feeder terminal unit has overcurrent characteristics, and mark the current direction away from the power supply side as positive.

[0050] When the collected voltage amplitude is lower than the undervoltage threshold, the feeder terminal unit is determined to have undervoltage characteristics. Adjacent feeder terminal units are used to exchange their overcurrent characteristics, undervoltage characteristics, and current direction through peer-to-peer communication. When the feeder terminal unit on the power supply side of the same independent section has overcurrent characteristics and the current direction is positive, and the feeder terminal unit on the opposite side of the power supply side of the independent section has no overcurrent characteristics but has undervoltage characteristics, the feeder terminal units at both ends of the independent section jointly lock it as a fault section. The feeder terminal units on both sides of the fault section are used to drive the corresponding switch to open, so as to achieve electrical isolation of the fault section.

[0051] Each feeder terminal unit located downstream of the power source in the fault section is used to mark its own independent section as a power outage area. Based on the synchronized distribution network topology, it transmits and accumulates its own load power level by level through peer-to-peer communication to calculate the total load of the power outage area. The feeder terminal unit corresponding to the tie switch connected to the power outage area is used to obtain the total load of the power outage area. If the standby capacity corresponding to the tie switch issued by the distribution network master station is greater than the total load of the power outage area, the tie switch is driven to close, and the power supply to the power outage area is restored. This constructs a distribution network fault location and self-healing control system that supports point-to-point peer-to-peer communication. It can autonomously complete the entire fault handling process without centralized control by the master station. The system has strong anti-interference ability and high power supply reliability.

[0052] Compared with the prior art, the advantages of this invention are:

[0053] This invention addresses the core pain points of fault location and self-healing control in existing power distribution networks, especially rural power distribution networks, such as centralized management and control heavily relying on the master station and communication links, prolonged fault handling time, insufficient location accuracy, and poor security of self-healing control. Through a terminal distributed peer-to-peer collaborative technical architecture, it achieves autonomous, rapid, and precise handling of power distribution network faults throughout the entire process, bringing significant technical benefits in multiple dimensions.

[0054] This invention abandons the traditional control mode of centralized computing and hierarchical instruction issuance by the master station. It realizes fault information exchange and collaborative judgment through peer-to-peer communication between adjacent terminals. The entire process of fault location, isolation and power restoration can be completed without the full participation of the master station. It completely gets rid of the strong dependence on the master station and long-distance communication links, effectively avoids the problem of fault handling failure caused by unstable public network communication in rural power grids and communication interruption under extreme working conditions. It reduces the fault handling latency from the traditional second level to the millisecond level, greatly improves the fault handling efficiency, and avoids the expansion of the fault scope.

[0055] This invention integrates multiple electrical quantities such as overcurrent characteristics, current direction, and undervoltage characteristics to construct a fault judgment system. By matching the characteristics of upstream and downstream terminals of the fault section, the fault section is jointly located. This effectively solves the problem of misjudgment and missed judgment caused by load fluctuations, backfeeding from distributed power sources, and harmonic interference in traditional single-feature judgment. Even in the complex scenario of multi-source power flow in the distribution network, the fault section can still be accurately located, which greatly reduces the pressure of manual operation and maintenance in rural power grids.

[0056] Meanwhile, after fault isolation, this invention completes the step-by-step accumulation and statistics of the load in the power outage area through terminal peer-to-peer communication, and performs power restoration after verifying the standby capacity of the tie switch. This realizes the terminal-side autonomous collaborative control of power restoration in the power outage area, effectively avoids operational risks such as tie switch overload and loop impact, comprehensively improves the power supply reliability and operational safety of the distribution network, and meets the construction requirements of the power distribution network upgrade and transformation of the new power system. Attached Figure Description

[0057] Figure 1 This is a schematic diagram of the method flow of the present invention. Detailed Implementation

[0058] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0059] This invention provides an embodiment 1

[0060] Please see Figure 1 A method for rapid fault location and self-healing control in rural power distribution networks includes the following steps:

[0061] S1. Terminal Configuration and Data Acquisition: Terminals are configured at the sectionalizing switches and tie switches of the distribution network, with the busbar as the power supply side and the lines between adjacent switches as independent sections; each terminal synchronizes with the distribution network topology; the master station sends short-circuit threshold, undervoltage threshold and the standby capacity of the tie switch to the terminal; the terminal collects the current amplitude, current direction, voltage amplitude and load power of the switch in real time.

[0062] S2. Fault characteristic determination: When the current amplitude collected by the terminal is greater than the short circuit threshold, it is determined that there is an overcurrent characteristic, and the current direction away from the power supply side is marked as positive; when the voltage amplitude is lower than the undervoltage threshold, it is determined that there is an undervoltage characteristic.

[0063] S3. Joint Locking of Fault Section: Adjacent terminals exchange the overcurrent characteristic, the undervoltage characteristic, and the current direction through peer-to-peer communication; when a terminal on the power supply side of the same independent section has the overcurrent characteristic and the current direction is positive, and a terminal away from the power supply side does not have the overcurrent characteristic but has the undervoltage characteristic, the adjacent terminals jointly lock the independent section as a fault section.

[0064] S4. Fault Isolation and Load Statistics: The terminals on both sides of the fault section drive the corresponding switches to open, so as to isolate the fault section; each terminal located downstream of the power supply side of the fault section marks its own independent section as a power outage area, and based on the distribution network topology, transmits and accumulates its own load power level by level through the peer-to-peer communication to obtain the total load of the power outage area;

[0065] S5. Power supply restoration in the power outage area: The terminal at the tie switch connected to the power outage area obtains the total load of the power outage area. If the reserve capacity is greater than the total load of the power outage area, the tie switch is driven to close to complete the power supply restoration. The fault section is jointly locked through terminal peer-to-peer communication, and the fault isolation and power supply restoration can be completed without the need for centralized calculation at the master station, which greatly shortens the fault handling time and significantly improves the power supply reliability of the distribution network.

[0066] S1 includes the following sub-steps:

[0067] S11: For the target distribution network, configure feeder terminal units one-to-one at all sectional switches and tie switches to complete the electrical wiring and full-function matching between the terminal and the switch, establish a one-to-one correspondence between the switch and the terminal, and clarify that each switch corresponds to a unique terminal. Switches and terminals without a corresponding relationship are not bound together.

[0068] S12: Taking the outgoing bus of the distribution network to the substation as the sole reference power source, the line between two adjacent switches with configured terminals is designated as an independent electrical section, the distribution network topology adjacency relationship and power direction identification are established, it is clear whether any two switches are directly connected or whether they are the first-end switches adjacent to the bus, and a unique number is assigned to each independent section.

[0069] S13: The distribution network master station constructs a complete distribution network topology model and distributes it to all terminals, and each terminal completes topology synchronization verification.

[0070] S14: The master station sends the adjusted short-circuit threshold, undervoltage threshold and tie switch backup capacity to each terminal, and the terminal completes parameter storage and solidification;

[0071] S15: Each terminal collects electrical quantities at the switch at a fixed sampling frequency, calculates the current amplitude, current direction, voltage amplitude, and load power using the full-wave Fourier algorithm, and refreshes and stores them at a fixed cycle. This refines the terminal configuration, topology synchronization, and data acquisition process, establishes a one-to-one correspondence between switches and terminals, ensures the accuracy of topology and sampling data, and provides a reliable foundation for subsequent fault diagnosis.

[0072] The specific implementation process and verification logic of S13 are as follows:

[0073] Master station modeling: Based on the actual field wiring, the distribution network master station constructs a complete distribution network topology model that includes the location of bus power supply points, switch installation locations and numbers, upstream and downstream boundaries of independent sections, correspondence between switches and terminals, and power supply point information on the opposite side of tie switches;

[0074] Model distribution: The main station distributes the topology model to all terminals through the adapted communication link;

[0075] Verification and Confirmation: After receiving the topology model, each terminal stores it locally and completes the verification through topology synchronization verification logic. That is, it compares the topology adjacency information and power direction information stored locally by the terminal with the corresponding information sent by the master station. If the two are completely consistent, the verification passes; otherwise, the verification fails. After the verification is correct, the terminal sends a synchronization completion confirmation signal to the master station, which clarifies the distribution network topology modeling, full transmission and verification logic, and ensures that the topology of each terminal is completely consistent with that of the master station. This avoids the location error caused by topology deviation and effectively improves the accuracy of fault diagnosis.

[0076] S2 includes the following sub-steps, and the overall determination mechanism is as follows:

[0077] S21: Overcurrent characteristic determination. The terminal compares the current amplitude obtained by the acquisition and calculation with the short-circuit threshold issued by the master station in real time, cycle by cycle. The determination logic is: when the current amplitude of any phase exceeds the short-circuit threshold for one power frequency cycle or more, it is determined that it has overcurrent characteristics; otherwise, it does not have overcurrent characteristics.

[0078] S22: Current direction calibration. With the bus power supply side as the reference direction, the current direction is determined by calculating the difference between the current phase and the bus reference voltage phase. The current direction away from the power supply side is marked as positive.

[0079] S23: Undervoltage characteristic determination. The terminal compares the voltage amplitude obtained by the acquisition and calculation with the undervoltage threshold issued by the master station in real time on a cycle-by-cycle basis. The determination logic is as follows: when the voltage amplitude of any phase is lower than the undervoltage threshold for one power frequency cycle or more, it is determined that it has undervoltage characteristics; otherwise, it does not have undervoltage characteristics. The sub-determination logic of overcurrent, current direction and undervoltage characteristics is refined. Based on the continuous comparison of power frequency cycles, the characteristics are identified, which effectively avoids the problem of misjudgment of fault characteristics caused by instantaneous electrical interference.

[0080] The specific calculation method and judgment logic of S22 are as follows:

[0081] Phase difference calculation: The terminal uses the bus power supply side as the reference direction to calculate the difference between the phase of the acquired current and the phase of the bus reference voltage in real time.

[0082] Direction determination: When the phase difference is between -90° and 90°, the current flow direction is determined to be away from the bus power supply side and towards the line load side. This direction is marked as positive, and the current direction flag is set to an active state. When the phase difference is between 90° and 270°, the current flow direction is determined to be towards the bus power supply side. This direction is marked as negative, and the current direction flag is set to an inactive state. This clarifies the accurate current direction determination method based on phase difference, clearly marks the positive and negative current directions, provides accurate basis for determining upstream and downstream fault sections, and effectively improves the accuracy of fault location.

[0083] S3 includes the following sub-steps, and the overall mechanism is as follows:

[0084] S31: Peer-to-peer communication interaction, each terminal predetermines adjacent upstream and downstream terminals based on the synchronized distribution network topology, and exchanges fault-related information such as its own overcurrent characteristics, current direction, undervoltage characteristics and terminal number in two directions through point-to-point peer-to-peer communication links.

[0085] S32: Fault section determination. For each independent section, the upstream and downstream terminals at both ends of the section are determined based on the bus power supply side. The determination logic is executed synchronously at both ends of the terminal. That is, the upstream terminal must have overcurrent characteristics and the current direction must be positive. At the same time, the downstream terminal does not have overcurrent characteristics but has undervoltage characteristics. If this condition is met, the section is determined to be a fault section.

[0086] S33: Joint locking. When the above judgment results of the terminals at both ends of the segment are completely consistent, the terminals at both ends jointly lock the independent segment as the faulty segment and feed back the locking information to the main station and adjacent terminals. Through the peer-to-peer exchange of fault information between adjacent terminals, the terminals at both ends of the segment synchronously judge and jointly lock the faulty segment, avoiding positioning deviation caused by the abnormality of a single terminal, and the fault locking result is more reliable.

[0087] S4 includes the following sub-steps, and the overall operation flow is as follows:

[0088] S41: Fault isolation. After the terminals on both sides of the fault section confirm the fault lock, the trip control interlocking logic is executed. That is, when the fault lock is effective and the trip command is continuously output for no less than 50ms, the corresponding switch is driven to trip, thus completing the complete electrical isolation between the fault section and the upstream and downstream live lines.

[0089] S42: Power loss zone marking. Each terminal located in the fault section that is away from the downstream of the power source side marks its own independent section as a power loss zone based on the distribution network topology, and completes the boundary confirmation of the power loss zone range through communication interaction.

[0090] S43: Load statistics. All terminals in the power outage area communicate with each other and use a step-by-step transmission and accumulation method from the end of the power outage area to the tie switch side to summarize the load power of the section where all terminals are located, and finally obtain the total load of the power outage area. This refines the fault isolation blocking logic, power outage area marking and load statistics process to ensure reliable fault isolation and accurate statistics of the total load of the power outage area, providing accurate load basis for subsequent power restoration.

[0091] The specific topology search logic and tagging mechanism of S42 are as follows:

[0092] Marking start point determination: Starting from the downstream terminal of the fault section, select the terminal located away from the power supply side and whose own voltage loss characteristics are in a valid state; Section marking: The selected terminal is marked by the power loss zone marking logic based on the synchronously completed distribution network topology. That is, when the terminal's voltage loss characteristics are valid and the section it is in belongs to the downstream topology range of the fault section, the section is marked as the power loss zone section;

[0093] Range Confirmation: All terminals marked as power outage zones exchange their own undervoltage status and zone number through peer-to-peer communication to confirm the boundary of the power outage zone, clarifying all independent zones and corresponding terminals included in the power outage zone, as well as the connection boundary between the power outage zone and the tie switch; among them, the downstream topology range of the fault zone is obtained through breadth-first search, clarifying the power outage zone marking and range confirmation logic based on breadth-first search, accurately delineating the boundary of the power outage zone, avoiding omissions and duplications in load statistics, and ensuring the accuracy of the total load data of the power outage zone;

[0094] S5 includes the following sub-steps, and the specific control logic is as follows:

[0095] S51: Load data verification. The terminal corresponding to the tie switch connected to the power failure area obtains the total load data of the power failure area and confirms the integrity of the data through the data verification logic. That is, the data verification passes when the total load of the power failure area is consistent with the sum of the loads of all terminals in the power failure area; otherwise, the data is incorrect.

[0096] S52: Backup capacity verification. The terminal retrieves the backup capacity corresponding to the contact switch issued by the master station and verifies the feasibility of power restoration through the power restoration feasibility verification logic. That is, if the backup capacity is greater than the product of the total load of the power failure area and the safety factor, it is determined that the power restoration conditions are met; otherwise, they are not met.

[0097] S53: Closing and Restoration. If the backup capacity verification passes, the terminal executes the closing control interlocking logic. That is, when the four conditions of power restoration being feasible, fault isolation being completed, no risk of loop closure, and no risk of reverse power supply are met simultaneously, the tie switch is driven to close, completing the power restoration of the power loss area. The restoration completion signal is fed back to the main station and all terminals in the power loss area. This refines the multiple verification and closing interlocking logic for power restoration, ensuring that the backup capacity of the tie switch meets the power supply requirements, avoiding overload and loop closure impact risks, and making the power restoration process safer and more reliable.

[0098] This invention provides an embodiment 2

[0099] A rapid fault location and self-healing control system for rural power distribution networks includes a distribution network master station and multiple feeder terminal units;

[0100] The distribution network master station is communicatively connected to each of the feeder terminal units, and point-to-point peer-to-peer communication is supported between adjacent feeder terminal units; taking the bus of the distribution network as the power supply side, the line between adjacent sectionalizing switches and tie switches is defined as an independent section, and each sectionalizing switch and tie switch is equipped with a feeder terminal unit one-to-one;

[0101] The distribution network master station is used to send the distribution network topology, the set short-circuit threshold, the undervoltage threshold, and the standby capacity corresponding to the tie switch to all the feeder terminal units.

[0102] The feeder terminal unit is used to synchronize and store the distribution network topology issued by the distribution network master station, and to collect the current amplitude, current direction, voltage amplitude and load power at the switch in real time.

[0103] The feeder terminal unit has a built-in fault feature determination module, which is configured to: when the collected current amplitude is greater than the short circuit threshold, determine that the feeder terminal unit has overcurrent characteristics, and mark the current direction away from the power supply side as positive.

[0104] When the collected voltage amplitude is lower than the undervoltage threshold, the feeder terminal unit is determined to have undervoltage characteristics. Adjacent feeder terminal units are used to exchange their overcurrent characteristics, undervoltage characteristics, and current direction through peer-to-peer communication. When the feeder terminal unit on the power supply side of the same independent section has overcurrent characteristics and the current direction is positive, and the feeder terminal unit on the opposite side of the power supply side of the independent section has no overcurrent characteristics but has undervoltage characteristics, the feeder terminal units at both ends of the independent section jointly lock it as a fault section. The feeder terminal units on both sides of the fault section are used to drive the corresponding switch to open, so as to achieve electrical isolation of the fault section.

[0105] Each feeder terminal unit located downstream of the power source in the fault section is used to mark its own independent section as a power outage area. Based on the synchronized distribution network topology, it transmits and accumulates its own load power level by level through peer-to-peer communication to calculate the total load of the power outage area. The feeder terminal unit corresponding to the tie switch connected to the power outage area is used to obtain the total load of the power outage area. If the standby capacity corresponding to the tie switch issued by the distribution network master station is greater than the total load of the power outage area, the tie switch is driven to close, and the power supply to the power outage area is restored. This constructs a distribution network fault location and self-healing control system that supports point-to-point peer-to-peer communication. It can autonomously complete the entire fault handling process without centralized control by the master station. The system has strong anti-interference ability and high power supply reliability.

[0106] This invention provides an application example

[0107] S1 Terminal Configuration and Data Acquisition

[0108] S1.1 Terminals are installed at the sectionalizing switches and tie switches of the distribution network.

[0109] For the target 10kV rural radial distribution network, the first step is to complete a comprehensive inventory of all line equipment, clearly identifying the installation location and unique equipment number of all pole-mounted sectionalizing switches, branch boundary switches, and ring network interconnection switches. For each sectionalizing switch and each interconnection switch, a feeder terminal unit (FTU) is configured on a one-to-one basis, ensuring one switch corresponds to one unique terminal. Electrical wiring is then completed between the terminal and the switch's secondary control circuits, along with the associated current transformers and voltage transformers, enabling full functional matching of the terminal for electrical quantity acquisition, switch status monitoring, and opening / closing command actuation. Finally, a one-to-one mapping matrix between switches and terminals is constructed. The matrix is ​​defined as follows:

[0110]

[0111] In the formula: The total number of switches on the line is equal to the total number of terminals configured. For the elements of the mapping matrix, when hour, , representing the Switch No. and No. The terminal completes a one-to-one binding; when hour, This indicates no binding relationship;

[0112] S1.2 The busbar is the power supply side, and the lines between adjacent switches are independent sections.

[0113] Using the 10kV outgoing busbar of the substation as the sole reference power source, the main power flow direction of the outgoing power source is clearly defined. Along the outgoing power source route, the overhead or cable lines between two adjacent switches with pre-configured terminals are designated as independent electrical sections. Each independent section contains only the boundary switches at both ends, with no other branch switches with terminals within the section, ensuring each section has unique upstream and downstream boundaries. A unique section number is assigned to each independent section, completing the independent section division of the entire line. A distribution network topology adjacency matrix is ​​constructed. Vector associated with power supply direction Complete the standardized definition of independent segments:

[0114]

[0115]

[0116] In the formula: Adjacency matrix The Line 1 Column elements, matrix dimension is , This represents the total number of switches; Power direction associated vector The There are n elements, and the vector dimension is 1. The unique number of the independent section is In the corresponding adjacency matrix The lines between the switch pairs;

[0117] S1.3 Synchronous Distribution Network Topology for Each Terminal

[0118] The first step involves the distribution network master station constructing a complete distribution network topology model of the target line based on the actual field wiring. This model includes: the location of the bus power source, the installation location and numbering of all switches, the upstream and downstream boundaries of all independent sections, the terminal number corresponding to each switch, and the power source information on the opposite side of the tie switch. The second step involves the master station distributing the complete distribution network topology model to all configured terminals on the line via a 4G / fiber / LoRa wireless self-organizing network communication link adapted for rural power grids. The third step involves each terminal receiving the topology model, storing it locally, and performing a topology synchronization verification. After successful verification, the terminal sends a topology synchronization completion confirmation signal to the master station, ensuring that the topology model of all terminals is completely consistent with the actual field wiring and the master station model. A topology synchronization verification function is then constructed. Used for local verification of topology consistency on the terminal, the function is defined as:

[0119]

[0120] In the formula: For the first The topology synchronization verification result of terminal number 1 This indicates that the synchronization verification has passed. This indicates a synchronization failure. For the first The row vectors related to itself in the adjacency matrix stored locally by the terminal; The adjacency matrix issued by the main station The row vector corresponding to switch number 1; For the first The element corresponding to itself in the power direction association vector stored locally on the terminal; The power direction association vector issued by the master station The element corresponding to switch number 1;

[0121] S1.4 The master station sends short-circuit threshold, undervoltage threshold, and backup capacity of the tie switch to the terminal.

[0122] Based on historical load data of the target line, short-circuit current calculation results, and power supply capacity of the power source on the opposite side of the tie switch, the master station completes parameter tuning and point-to-point distribution: 1. For each terminal's corresponding switch, the master station tunes and distributes the corresponding line's short-circuit current threshold, completing the short-circuit threshold configuration for all terminals; 2. For all terminals on the line, the master station uniformly tunes and distributes the distribution network undervoltage judgment threshold, completing the undervoltage threshold configuration for all terminals; 3. For each tie switch's corresponding terminal, the master station individually tunes and distributes the maximum backup power supply capacity that the power source on the opposite side of the tie switch can provide, completing the backup capacity configuration for all tie switch terminals; After all parameters are distributed to the corresponding terminals, the terminals complete parameter storage and solidification, and send a parameter reception confirmation signal to the master station to ensure that there are no parameter transmission errors;

[0123] Short-circuit current threshold Tuning formula: In the formula: This is the short-circuit current threshold at the corresponding switch of the terminal, in amperes (A). For the reliability coefficient, a value of 1.5 is used in the rural power grid scenario; This represents the maximum load current of the corresponding line section, in amperes (A). To protect the compatibility factor, we take 0.8; This represents the minimum two-phase short-circuit current at the end of the corresponding line section, expressed in amperes (A).

[0124] Underpressure threshold Tuning formula:

[0125]

[0126] In the formula: The voltage threshold for determining undervoltage, in kV; is the voltage loss coefficient, which is set to 0.7 in the rural power grid scenario to avoid misjudgment caused by voltage fluctuations; is the rated line voltage of the distribution network, which is set to 10kV for a 10kV system;

[0127] Spare capacity of tie switch Setting formula:

[0128]

[0129] , where: is the spare power supply capacity that can be provided by the power source on the opposite side of the tie switch, with the unit of kVA; is the rated capacity of the distribution transformer on the opposite side of the tie switch, with the unit of kVA; is the real-time total active load of the power source on the opposite side of the tie switch, with the unit of kVA;

[0130] S1.5 The terminal collects the current amplitude, current direction, voltage amplitude and load power of the switch where it is located in real time

[0131] After all terminals complete topology synchronization and parameter solidification, they enter the real-time operation state and perform standardized collection operations: 1. Through the current transformer and voltage transformer matched with the switch, at a sampling frequency of 32 points per 50Hz power frequency cycle, collect the three-phase current instantaneous values and three-phase voltage instantaneous values at the switch where it is located in real time; 2. Based on the collected instantaneous values, through the full-wave Fourier algorithm, calculate in real time to obtain the three-phase fundamental current amplitude at the switch where it is located, the phase and direction of the current relative to the bus reference voltage, the three-phase fundamental voltage amplitude, and the real-time active load power of the downstream line of the switch where it is located; 3. The terminal locally stores the calculated real-time data, refreshes it at a fixed period of 20ms, and provides a real-time data basis for subsequent fault judgment;

[0132] Fundamental current amplitude calculation (full-wave Fourier algorithm):

[0133] , ,

[0134] In the formula: , are the real part and the imaginary part of the fundamental current respectively, with the unit of A; is the number of sampling points per cycle, which is set to 32; is the th instantaneous current value of the sampling point, with the unit of A; is the fundamental current amplitude, with the unit of A;

[0135] The fundamental voltage amplitude calculation adopts the same full-wave Fourier algorithm as above to obtain the fundamental voltage amplitude , with the unit of kV;

[0136] Real-time active load power calculation:

[0137]

[0138] In the formula: This represents the real-time active load power of the downstream lines of the switch, in kW. For the first The instantaneous voltage value at each sampling point, in kV; For the first The instantaneous current value at each sampling point, in amperes (A);

[0139] S2 Fault Characteristic Determination

[0140] S2.1 When the current amplitude collected by the terminal is greater than the short-circuit threshold, it is determined that the current has overcurrent characteristics.

[0141] The terminal compares the fundamental amplitude of the three-phase current, calculated in real time, with the short-circuit threshold issued by the master station cycle by cycle. When the fundamental amplitude of any phase current exceeds the short-circuit threshold for one power frequency cycle or more, the terminal determines that its current switch position has overcurrent characteristics, generates a local overcurrent characteristic flag, and sets it to an active state. If the current amplitude does not exceed the short-circuit threshold, the overcurrent characteristic flag remains in an inactive state. An overcurrent characteristic determination function is constructed. The function is defined as: In the formula: This is an overcurrent characteristic flag. This indicates that it possesses current-carrying characteristics. This indicates a no-overcurrent characteristic; The fundamental current amplitude of any one of the three phases A, B, and C, in amperes (A). The duration for which the current amplitude exceeds the threshold, in milliseconds; The power frequency period is set to 20ms.

[0142] S2.2 Mark the current direction away from the power supply side as positive.

[0143] The terminal uses the bus power supply side as the reference direction and calculates the difference between the phase of the acquired current and the phase of the bus reference voltage in real time to determine the current direction. When the current flow direction is away from the bus power supply side and towards the line load side, the terminal marks the current direction as positive, generates a local current direction flag, and sets it to a positive valid state. When the current flow direction is towards the bus power supply side, it is marked as reverse, and the current direction flag is set to a reverse valid state. A current direction determination function is constructed. Direction calibration is achieved based on phase difference, and the function is defined as follows: , In the formula: The phase difference between the fundamental current and the bus reference voltage is expressed in degrees (°). The phase angle of the fundamental current is expressed in degrees (°). The phase angle of the bus reference voltage, in degrees; This is a current direction flag. This indicates that the current direction is positive (away from the power supply side). This indicates that the current direction is reversed (pointing towards the power source).

[0144] S2.3 When the voltage amplitude is lower than the undervoltage threshold, it is determined that the undervoltage characteristic exists.

[0145] The terminal compares the fundamental amplitude of the three-phase voltage, calculated in real time, with the undervoltage threshold issued by the master station cycle by cycle. When the fundamental amplitude of any phase voltage is lower than the undervoltage threshold for one power frequency cycle or more, the terminal determines that its current switch position has undervoltage characteristics, generates a local undervoltage characteristic flag, and sets it to an active state. If the voltage amplitude is not lower than the undervoltage threshold, the undervoltage characteristic flag remains in an inactive state. An undervoltage characteristic determination function is constructed. The function is defined as:

[0146]

[0147] In the formula: This is a depressurization characteristic marker. This indicates that the pressure is depressurized. This indicates a lack of pressure loss. The fundamental voltage amplitude of any one of the three phases A, B, and C, in kV; The duration during which the voltage amplitude is below the threshold, in milliseconds; The power frequency period is set to 20ms.

[0148] S3 fault section joint locking

[0149] S3.1 Adjacent terminals exchange information on overcurrent characteristics, undervoltage characteristics, and current direction through peer-to-peer communication.

[0150] All terminals on the line, based on the synchronously completed distribution network topology, pre-determine their directly adjacent upstream and downstream terminals. When any terminal generates a valid local overcurrent characteristic flag signal, it immediately sends its terminal number, overcurrent characteristic flag status, current direction flag status, and undervoltage characteristic flag status to its adjacent upstream and downstream terminals in real time via a point-to-point peer-to-peer communication link. Simultaneously, it receives corresponding characteristic status information from adjacent terminals, completing bidirectional real-time exchange of fault characteristic information between adjacent terminals. Each terminal generates a local fault characteristic vector. Used for peer-to-peer communication, the vector is defined as: In the formula: This is a local fault feature vector for the terminal, with a dimension of 1×4; This is an overcurrent characteristic flag. This is a current direction flag. This is a depressurization characteristic flag. A unique identifier for the terminal itself;

[0151] S3.2 Verify that the terminals on the power supply side of the same independent section have overcurrent characteristics and the current direction is positive, while the terminals away from the power supply side do not have overcurrent characteristics but have undervoltage characteristics.

[0152] For each independently defined segment, the adjacent terminals at both ends of the segment synchronously perform fault segment determination condition verification based on the characteristic information obtained from the interaction between the two parties: 1. Taking the bus power supply side as the reference, the terminal located closer to the power supply side in the segment is defined as the upstream terminal, and the terminal located away from the power supply side in the segment is defined as the downstream terminal; 2. The terminals at both ends synchronously verify the determination conditions to confirm whether the two core conditions are met simultaneously; construct the fault determination function for the independent segment. The function is defined as: In the formula: Independent section The fault diagnosis results The representative section meets the fault determination criteria. This indicates dissatisfaction; For the first Terminal No. (upstream) and the Independent sections between terminals (downstream); This is the overcurrent characteristic flag bit for the upstream terminal; This is a current direction flag for the upstream terminal; The logical NOT operation is performed on the overcurrent characteristic flag of the downstream terminal. This is a flag indicating the pressure loss characteristic of the downstream terminal; For logical AND operation;

[0153] S3.3 Adjacent terminals jointly lock this independent segment as a faulty segment.

[0154] When the upstream and downstream terminals at both ends of an independent segment have independently completed the above-mentioned fault determination condition verification and the verification results are completely consistent, the two terminals synchronously generate the fault locking flag bit for that independent segment and jointly lock the independent segment as a faulty segment. After locking, the two terminals send the faulty segment number, locking status, and fault time information to adjacent terminals and the master station to complete the joint locking operation of the faulty segment. A joint locking function for the faulty segment is then constructed. Locking is achieved based on synchronous confirmation from both ends, and the function is defined as follows: In the formula: Independent section The fault lockout flag bit, The representative section has been jointly identified as the faulty section. This indicates that the device is not locked. The fault determination result for the section obtained independently by the upstream terminal; The fault determination result for the section is obtained independently by the downstream terminal.

[0155] S4 Fault Isolation and Load Statistics

[0156] S4.1 The terminals on both sides of the faulty section are driven to trip the corresponding switches to isolate the faulty section.

[0157] Once the fault section has been locked, the two terminals on either side of the fault section, after confirming the validity of the fault locking flag, immediately send a tripping control command to their respective switch bodies. Upon receiving the tripping command, the switch executes the tripping action and, after completion, sends a tripping completion signal back to the corresponding terminal. Upon receiving the tripping completion signal, the terminal confirms that the corresponding boundary of the fault section has been disconnected. After both terminals have completed their tripping operations, complete electrical isolation between the fault section and upstream / downstream live lines is achieved. Simultaneously, a fault isolation completion signal is sent to the main station and adjacent terminals. A tripping control interlocking function is then constructed. The function is defined as: In the formula: This is the trip control enable flag. This indicates that the tripping command has been authorized. This represents a lockout / opening operation; The duration of the trip control command output is measured in milliseconds (ms); 50ms is the anti-interference interlocking time to avoid maloperation caused by electromagnetic interference in the rural power grid.

[0158] S4.2 Each terminal located downstream of the power supply side in the fault section marks its own independent section as a power outage zone.

[0159] Starting from the downstream terminal of the faulty section, all terminals located away from the power supply side and whose own undervoltage characteristic flags are valid, based on the synchronously completed distribution network topology, mark their respective independent sections as the power outage zone. All terminals in the power outage zone exchange their undervoltage status and section number through peer-to-peer communication to confirm the boundary of the power outage zone, forming a complete power outage zone range. This clarifies all independent sections and corresponding terminals within the power outage zone, as well as the connection boundary between the power outage zone and the tie switch. A power outage zone segment marking function is then constructed. The function is defined as: In the formula: This is a marker bit for the power outage zone. This indicates that the corresponding independent section is marked as a power outage zone. Represents the non-power-loss area; For section The corresponding terminal's undervoltage characteristic flag; the downstream topology set of the fault section is a set of all independent sections that are away from the power source side, obtained by breadth-first search based on the distribution network topology;

[0160] S4.3 Based on the distribution network topology, the total load of the power outage area is obtained by transmitting and accumulating the load power level by level through peer-to-peer communication.

[0161] All terminals within the power outage zone, based on real-time collected load power data for their respective sections, accumulate and statistically analyze the load power through peer-to-peer communication links, using a step-by-step transmission method from the very end of the power outage zone towards the tie switch. Finally, at the terminal corresponding to the tie switch connected to the power outage zone, the total load of the power outage zone is calculated. A step-by-step recursive accumulation formula for the power outage zone load is constructed as follows: , In the formula: For the first The cumulative active load transmitted upstream from the terminal level, in kW; For the first Real-time active load power of the section where the terminal is located, in kW; For the first The cumulative active load received by the primary terminal from downstream adjacent terminals, in kW; This represents the total number of terminal stages from the end to the tie switch within the power outage zone. This represents the total active load of the power outage area, i.e., the total load of the power outage area, in kW.

[0162] S5 power outage area power restored

[0163] S5.1 The terminal at the tie switch connected to the power outage area obtains the total load of the power outage area.

[0164] The terminal corresponding to the interconnecting switch connected to the power outage area receives the total load data of the power outage area, which is transmitted and accumulated step by step, through a peer-to-peer communication link. After receiving the data, it stores it locally and verifies the data integrity to confirm that the total load value of the power outage area is correct; a verification function for the total load data of the power outage area is then constructed. The function is defined as: In the formula: For load data verification results, This means the data is complete and accurate. This indicates a data error; This represents the total number of terminals within the power outage zone. The first in the power outage area The real-time active load power of the section where the terminal is located, in kW;

[0165] S5.2 Verify whether the standby capacity corresponding to the tie switch is greater than the total load of the power outage area.

[0166] For the terminal corresponding to the interconnecting switch, the standby capacity corresponding to that interconnecting switch issued by the main station is retrieved, and the standby capacity is compared and verified with the total load of the confirmed power outage area to determine whether the conditions for power restoration are met; a power restoration feasibility verification function is constructed. The function is defined as: In the formula: Power restoration permission flag is set. This indicates that the backup capacity meets the requirements, and power restoration is permitted. The representative did not meet the requirements; therefore, power restoration was prohibited. For safety reasons, a coefficient of 1.2 is used in rural power grid scenarios to avoid the risk of backup power overload; This refers to the standby capacity corresponding to the tie switch, in kVA. Total load of the power outage area, in kW;

[0167] S5.3 If the standby capacity is greater than the total load of the power outage area, the tie switch will be closed to complete the power restoration.

[0168] After generating the power restoration permission flag, the terminal corresponding to the tie switch first performs a pre-closing safety check to confirm that the fault section has been completely electrically isolated, there is no risk of live looping in the power-out area, and no risk of reverse power supply. Once all pre-check conditions are met, a closing control command is immediately sent to the tie switch body. After receiving the closing command, the tie switch executes the closing action and sends a closing completion signal to the corresponding terminal. After receiving the closing completion signal, the terminal confirms that the power-out area has been connected to the backup power supply on the other side through the tie switch, completing the power restoration of the power-out area. At the same time, it sends a power restoration completion signal to the main station and all terminals in the power-out area, and the entire fault location, isolation, and self-healing process ends. The closing control interlocking function is then constructed. The function is defined as: In the formula: This is the closing control enable flag. This indicates that the system is authorized to issue a closing command. This represents the interlocking and closing operation; Enable power restoration flag; To indicate that the fault isolation is complete, the flag is set to 1 after the switches on both sides of the fault section are fully open. The closing risk interlock flag is set to 1 after all switches in the power outage zone are in the open state; This is the reverse power supply interlock flag; it is set to 1 after no other power source is connected in the power failure zone. For logical AND operation;

[0169] In summary, this invention addresses the core pain points of fault location and self-healing control in existing power distribution networks, especially rural power distribution networks, such as centralized management and control heavily relying on the master station and communication links, prolonged fault handling time, insufficient location accuracy, and poor security of self-healing control. Through a terminal distributed peer-to-peer collaborative technical architecture, it achieves autonomous, rapid, and precise handling of power distribution network faults throughout the entire process, bringing significant technical benefits in multiple dimensions.

[0170] This invention abandons the traditional control mode of centralized computing and hierarchical instruction issuance by the master station. It realizes fault information exchange and collaborative judgment through peer-to-peer communication between adjacent terminals. The entire process of fault location, isolation and power restoration can be completed without the full participation of the master station. It completely gets rid of the strong dependence on the master station and long-distance communication links, effectively avoids the problem of fault handling failure caused by unstable public network communication in rural power grids and communication interruption under extreme working conditions. It reduces the fault handling latency from the traditional second level to the millisecond level, greatly improves the fault handling efficiency, and avoids the expansion of the fault scope.

[0171] This invention integrates multiple electrical quantities such as overcurrent characteristics, current direction, and undervoltage characteristics to construct a fault judgment system. By matching the characteristics of upstream and downstream terminals of the fault section, the fault section is jointly located. This effectively solves the problem of misjudgment and missed judgment caused by load fluctuations, backfeeding from distributed power sources, and harmonic interference in traditional single-feature judgment. Even in the complex scenario of multi-source power flow in the distribution network, the fault section can still be accurately located, which greatly reduces the pressure of manual operation and maintenance in rural power grids.

[0172] Meanwhile, after fault isolation, this invention completes the step-by-step accumulation and statistics of the load in the power outage area through terminal peer-to-peer communication, and performs power restoration after verifying the standby capacity of the tie switch. This realizes the terminal-side autonomous collaborative control of power restoration in the power outage area, effectively avoids operational risks such as tie switch overload and loop impact, comprehensively improves the power supply reliability and operational safety of the distribution network, and meets the construction requirements of the power distribution network upgrade and transformation of the new power system.

[0173] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concepts, should be covered within the scope of protection of the present invention.

Claims

1. A method for rapid fault location and self-healing control in rural power distribution networks, characterized in that: Includes the following steps: S1. Terminal Configuration and Data Acquisition: Terminals are configured at the sectionalizing switches and tie switches of the distribution network, with the busbar as the power supply side and the lines between adjacent switches as independent sections; each terminal synchronizes with the distribution network topology; the master station sends short-circuit threshold, undervoltage threshold and the standby capacity of the tie switch to the terminal; the terminal collects the current amplitude, current direction, voltage amplitude and load power of the switch in real time. S2. Fault characteristic determination: When the current amplitude collected by the terminal is greater than the short circuit threshold, it is determined that there is an overcurrent characteristic, and the current direction away from the power supply side is marked as positive; when the voltage amplitude is lower than the undervoltage threshold, it is determined that there is an undervoltage characteristic. S3. Joint Locking of Fault Section: Adjacent terminals exchange the overcurrent characteristic, the undervoltage characteristic, and the current direction through peer-to-peer communication; when a terminal on the power supply side of the same independent section has the overcurrent characteristic and the current direction is positive, and a terminal away from the power supply side does not have the overcurrent characteristic but has the undervoltage characteristic, the adjacent terminals jointly lock the independent section as a fault section. S4. Fault Isolation and Load Statistics: The terminals on both sides of the fault section drive the corresponding switches to open, so as to isolate the fault section; each terminal located downstream of the power supply side of the fault section marks its own independent section as a power outage area, and based on the distribution network topology, transmits and accumulates its own load power level by level through the peer-to-peer communication to obtain the total load of the power outage area; S5. Power restoration in the power outage area: The terminal at the interconnecting switch connected to the power outage area obtains the total load of the power outage area. If the reserve capacity is greater than the total load of the power outage area, the interconnecting switch is driven to close, and power restoration is completed.

2. The method for rapid fault location and self-healing control in rural power distribution networks according to claim 1, characterized in that: S1 includes the following sub-steps: S11: For the target distribution network, configure feeder terminal units one-to-one at all sectional switches and tie switches to complete the electrical wiring and full-function matching between the terminal and the switch, establish a one-to-one correspondence between the switch and the terminal, and clarify that each switch corresponds to a unique terminal. Switches and terminals without a corresponding relationship are not bound together. S12: Taking the outgoing bus of the distribution network to the substation as the sole reference power source, the line between two adjacent switches with configured terminals is designated as an independent electrical section, the distribution network topology adjacency relationship and power direction identification are established, it is clear whether any two switches are directly connected or whether they are the first-end switches adjacent to the bus, and a unique number is assigned to each independent section. S13: The distribution network master station constructs a complete distribution network topology model and distributes it to all terminals, and each terminal completes topology synchronization verification. S14: The master station sends the adjusted short-circuit threshold, undervoltage threshold and tie switch backup capacity to each terminal, and the terminal completes parameter storage and solidification; S15: Each terminal collects electrical quantities at the switch at a fixed sampling frequency, calculates the current amplitude, current direction, voltage amplitude, and load power using the full-wave Fourier algorithm, and refreshes and stores them at a fixed period.

3. The method for rapid fault location and self-healing control in rural power distribution networks according to claim 2, characterized in that: The specific implementation process and verification logic of S13 are as follows: Master station modeling: Based on the actual field wiring, the distribution network master station constructs a complete distribution network topology model that includes the location of bus power supply points, switch installation locations and numbers, upstream and downstream boundaries of independent sections, correspondence between switches and terminals, and power supply point information on the opposite side of tie switches; Model distribution: The main station distributes the topology model to all terminals through the adapted communication link; Verification and confirmation: After receiving the topology model, each terminal stores it locally and completes the verification through the topology synchronization verification logic. That is, it compares the topology adjacency information and power direction information stored locally by the terminal with the corresponding information sent by the master station. If the two are completely consistent, the verification passes; otherwise, the verification fails. After the verification is correct, the terminal sends a synchronization completion confirmation signal to the master station.

4. The method for rapid fault location and self-healing control in rural power distribution networks according to claim 1, characterized in that: S2 includes the following sub-steps, and the overall determination mechanism is as follows: S21: Overcurrent characteristic determination. The terminal compares the current amplitude obtained by the acquisition and calculation with the short-circuit threshold issued by the master station in real time, cycle by cycle. The determination logic is: when the current amplitude of any phase exceeds the short-circuit threshold for one power frequency cycle or more, it is determined that it has overcurrent characteristics; otherwise, it does not have overcurrent characteristics. S22: Current direction calibration. With the bus power supply side as the reference direction, the current direction is determined by calculating the difference between the current phase and the bus reference voltage phase. The current direction away from the power supply side is marked as positive. S23: Voltage loss characteristic determination. The terminal compares the voltage amplitude obtained by the acquisition and calculation with the voltage loss threshold issued by the master station in real time, cycle by cycle. The determination logic is: when the voltage amplitude of any phase is lower than the voltage loss threshold for one power frequency cycle or more, it is determined that it has voltage loss characteristics; otherwise, it does not have voltage loss characteristics.

5. The method for rapid fault location and self-healing control in rural power distribution networks according to claim 4, characterized in that: The specific calculation method and judgment logic of S22 are as follows: Phase difference calculation: The terminal uses the bus power supply side as the reference direction to calculate the difference between the phase of the acquired current and the phase of the bus reference voltage in real time; Direction determination: When the phase difference is between -90° and 90°, the current flow direction is determined to be away from the bus power supply side and towards the line load side. This direction is marked as positive, and the current direction flag is made active. When the phase difference is between 90° and 270°, the current flow direction is determined to be towards the bus power supply side. This direction is marked as negative, and the current direction flag is made inactive.

6. The method for rapid fault location and self-healing control in rural power distribution networks according to claim 1, characterized in that: S3 includes the following sub-steps, and the overall mechanism is as follows: S31: Peer-to-peer communication interaction, each terminal predetermines adjacent upstream and downstream terminals based on the synchronized distribution network topology, and exchanges fault-related information such as its own overcurrent characteristics, current direction, undervoltage characteristics and terminal number in two directions through point-to-point peer-to-peer communication links. S32: Fault section determination. For each independent section, the upstream and downstream terminals at both ends of the section are determined based on the bus power supply side. The determination logic is executed synchronously at both ends of the terminal. That is, the upstream terminal must have overcurrent characteristics and the current direction must be positive. At the same time, the downstream terminal does not have overcurrent characteristics but has undervoltage characteristics. If this condition is met, the section is determined to be a fault section. S33: Joint locking. When the above judgment results of the terminals at both ends of the segment are completely consistent, the terminals at both ends jointly lock the independent segment as a faulty segment and send the locking information back to the master station and adjacent terminals.

7. The method for rapid fault location and self-healing control in rural power distribution networks according to claim 1, characterized in that: S4 includes the following sub-steps, and the overall operation flow is as follows: S41: Fault isolation. After the terminals on both sides of the fault section confirm the fault lock, the trip control interlocking logic is executed. That is, when the fault lock is effective and the trip command is continuously output for no less than 50ms, the corresponding switch is driven to trip, thus completing the complete electrical isolation between the fault section and the upstream and downstream live lines. S42: Power loss zone marking. Each terminal located in the fault section that is away from the downstream of the power source side marks its own independent section as a power loss zone based on the distribution network topology, and completes the boundary confirmation of the power loss zone range through communication interaction. S43: Load statistics. All terminals in the power outage area communicate with each other and use a step-by-step transmission and accumulation method from the end of the power outage area to the tie switch side to summarize the load power of the section where all terminals are located, and finally obtain the total load of the power outage area.

8. The method for rapid fault location and self-healing control in rural power distribution networks according to claim 7, characterized in that: The specific topology search logic and tagging mechanism of S42 are as follows: Starting point determination: Starting from the downstream terminal of the faulty section, select terminals located away from the power supply side and whose own undervoltage characteristics are valid; section Marking: The terminals selected above are marked by the power failure marking logic based on the synchronously completed distribution network topology. That is, when the terminal's voltage loss characteristics are valid and the section it is located in is within the downstream topology range of the fault section, the section is marked as a power failure section. Range confirmation: All terminals marked as power outage zones exchange their own undervoltage status and zone number through peer-to-peer communication to confirm the boundary of the power outage zone, clarifying all independent zones and corresponding terminals included in the power outage zone, as well as the connection boundary between the power outage zone and the tie switch; among them, the downstream topology range of the fault zone is obtained through breadth-first search.

9. The method for rapid fault location and self-healing control in rural power distribution networks according to claim 1, characterized in that: S5 includes the following sub-steps, and the specific control logic is as follows: S51: Load data verification. The terminal corresponding to the tie switch connected to the power failure area obtains the total load data of the power failure area and confirms the integrity of the data through the data verification logic. That is, the data verification passes when the total load of the power failure area is consistent with the sum of the loads of all terminals in the power failure area; otherwise, the data is incorrect. S52: Backup capacity verification. The terminal retrieves the backup capacity corresponding to the contact switch issued by the master station and verifies the feasibility of power restoration through the power restoration feasibility verification logic. That is, if the backup capacity is greater than the product of the total load of the power failure area and the safety factor, it is determined that the power restoration conditions are met; otherwise, they are not met. S53: Closing and Restoration. If the standby capacity verification passes, the terminal executes the closing control interlocking logic. That is, when the four conditions of power supply restoration being feasible, fault isolation being completed, no risk of loop closure, and no risk of reverse power supply are met simultaneously, the tie switch is driven to close, completing the power supply restoration of the power outage area, and a restoration completion signal is fed back to the main station and all terminals in the power outage area.

10. A rapid fault location and self-healing control system for rural power distribution networks, characterized in that: Includes the distribution network master station and multiple feeder terminal units; The distribution network master station is communicatively connected to each of the feeder terminal units, and point-to-point peer-to-peer communication is supported between adjacent feeder terminal units; taking the bus of the distribution network as the power supply side, the line between adjacent sectionalizing switches and tie switches is defined as an independent section, and each sectionalizing switch and tie switch is equipped with a feeder terminal unit one-to-one; The distribution network master station is used to send the distribution network topology, the set short-circuit threshold, the undervoltage threshold, and the standby capacity corresponding to the tie switch to all the feeder terminal units. The feeder terminal unit is used to synchronize and store the distribution network topology issued by the distribution network master station, and to collect the current amplitude, current direction, voltage amplitude and load power at the switch in real time. The feeder terminal unit has a built-in fault feature determination module, which is configured to: when the collected current amplitude is greater than the short circuit threshold, determine that the feeder terminal unit has overcurrent characteristics, and mark the current direction away from the power supply side as positive. When the collected voltage amplitude is lower than the undervoltage threshold, the feeder terminal unit is determined to have undervoltage characteristics. Adjacent feeder terminal units are used to exchange their overcurrent characteristics, undervoltage characteristics, and current direction through peer-to-peer communication. When the feeder terminal unit on the power supply side of the same independent section has overcurrent characteristics and the current direction is positive, and the feeder terminal unit on the opposite side of the power supply side of the independent section has no overcurrent characteristics but has undervoltage characteristics, the feeder terminal units at both ends of the independent section jointly lock it as a fault section. The feeder terminal units on both sides of the fault section are used to drive the corresponding switch to open, so as to achieve electrical isolation of the fault section. Each feeder terminal unit located downstream of the power source in the fault section is used to mark its own independent section as a power outage area, and to calculate the total load of the power outage area by transmitting and accumulating its own load power through peer-to-peer communication based on the synchronized distribution network topology. The feeder terminal unit corresponding to the tie switch connected to the power outage area is used to obtain the total load of the power outage area. If the standby capacity corresponding to the tie switch issued by the distribution network master station is greater than the total load of the power outage area, the tie switch is driven to close to complete the power restoration of the power outage area.

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