A rural low-voltage transformer area photovoltaic cooperative voltage regulation and fault self-healing system and method

Abstract

The present application relates to the technical field of low-voltage power distribution, and particularly relates to a rural low-voltage transformer area photovoltaic coordinated voltage regulation and fault self-healing system and method, which comprises normal voltage regulation, fault sensing, state switching, fusion positioning, precise isolation, topology reconstruction and power recovery interlocking modules. The normal voltage regulation module collects electrical parameters and performs over-limit adjustment; the fault sensing module collects multi-source electrical quantities to generate fault data; the state switching module enters the self-healing mode when the conditions are met; the fusion positioning module determines the fault section; the precise isolation module issues a disconnection instruction; the topology reconstruction module restores power supply in the non-fault area; and the power recovery interlocking module closes and restores normal voltage regulation after the conditions are met. The present application constructs a state-driven closed-loop control link of the low-voltage transformer area through multi-module coordinated linkage, realizes continuous control of fault identification, section positioning, switch isolation, area reconstruction and power recovery, and solves the problems of fragmented processing and discontinuous control link caused by independent control of traditional fault processing.

Description

Technical Field

[0001] This invention relates to the field of low-voltage power distribution technology, and in particular to a photovoltaic-coordinated voltage regulation and fault self-healing system and method for rural low-voltage distribution areas. Background Technology

[0002] Rural low-voltage distribution areas are a crucial component of the distribution network's end point, typically consisting of distribution transformers, low-voltage outgoing lines, branch lines, and numerous single-phase or three-phase loads. With the widespread integration of distributed photovoltaic (PV) systems in rural areas, low-voltage distribution areas are gradually evolving into an operational mode where loads and power sources coexist. In this mode, PV inverters convert DC power to AC power and connect it to low-voltage distribution lines. Simultaneously, the distribution network's operational status can be characterized and analyzed using electrical quantities such as voltage, current, zero-sequence current, and line impedance. Current technologies typically integrate distribution automation devices, communication networks, and monitoring and acquisition equipment to achieve data acquisition and operational scheduling. Centralized or distributed methods are used to control and regulate line switching equipment and distributed power sources to maintain the basic stability of the distribution area's operation.

[0003] Traditional fault handling in rural low-voltage distribution areas mostly adopts segmented manual judgment and independent control strategies. Due to the lack of a continuous state-driven control link, the fault handling process is fragmented and the control link is discontinuous. Summary of the Invention

[0004] To overcome the above shortcomings, this invention provides a photovoltaic-coordinated voltage regulation and fault self-healing system and method for rural low-voltage distribution areas. It aims to improve the traditional fault handling in rural low-voltage distribution areas, which mostly adopts segmented manual judgment and independent control strategies, easily causing the fault handling process to be fragmented and the control link to be discontinuous.

[0005] In a first aspect, the present invention provides the following technical solution: a rural low-voltage distribution area photovoltaic coordinated voltage regulation and fault self-healing system, comprising: The normal voltage regulation module is used by the edge computing terminal to obtain the distribution transformer outlet voltage, photovoltaic grid connection point voltage and three-phase load current. When the voltage exceeds the limit or the three-phase imbalance exceeds the limit, it sends a reactive power regulation command or an active power limit command to the photovoltaic collaborative voltage regulation unit. The fault perception module is used to collect line voltage, current, zero-sequence current, arc signal and conductor temperature data through the multi-source electrical quantity acquisition unit, and generate fault status data based on the corresponding characteristics. The state switching module is used to send a voltage regulation stop command to the photovoltaic coordinated voltage regulation unit when the fault state data meets the fault triggering conditions, thereby stopping the normal voltage regulation module and switching to the fault self-healing mode. The fusion positioning module is used to initiate characteristic impedance spectroscopy scanning to obtain the reflection impedance characteristics of each branch in fault self-healing mode, and to obtain the HPLC (High-speed Power Line Communication) communication delay parameters of each terminal node. Based on the transformer area topology map generated by the communication delay parameters and reflection impedance characteristics, the reflection impedance characteristics and the HPLC communication delay parameters, the fault section is determined. The precision isolation module is used to send disconnection commands to the intelligent branch switches of the corresponding faulty sections; The topology reconfiguration module is used to determine, based on the transformer area topology map, non-faulty power supply areas that have a reachable power supply path to the low-voltage side busbar of the distribution transformer after the smart branch switch is disconnected, and to send a closing command to the corresponding smart branch switch. The power restoration interlocking module is used to send a closing command to the disconnected intelligent branch switch when the fault characteristics are continuously detected to disappear within the delayed verification window, the line voltage, current, and zero-sequence current are restored to the normal operating range, and the number of reclosing times does not exceed the preset upper limit. After successful closing, the normal voltage regulation module is restored to operation.

[0006] By adopting the above technical solution, through the coordinated linkage of the normal voltage regulation module, fault perception module, state switching module, fusion positioning module, and power restoration interlocking module, a closed-loop control link is formed. Starting from normal photovoltaic coordinated voltage regulation, after fault-triggered state switching, it enters impedance spectrum and communication delay fusion positioning, then completes power restoration through fault section isolation and non-fault area topology reconstruction, and finally returns to normal voltage regulation through safety power restoration interlocking. This achieves continuous control of active adjustment of transformer area voltage quality and automatic fault recovery, thereby improving the problem that traditional rural low-voltage transformer area fault handling mostly adopts segmented manual judgment and independent control strategies. Due to the lack of a through-type state-driven control link, the fault handling process is fragmented and the control link is discontinuous.

[0007] Furthermore, in the fault perception module, the steps of the multi-source electrical quantity acquisition unit acquiring line voltage, current, zero-sequence current, arc signal, and conductor temperature data include: The voltage sampling signal is obtained by sampling the three-phase voltage of the line through a voltage sampling circuit; The current sampling signal and the zero-sequence current sampling signal are obtained by sampling the three-phase current of the line through a current transformer. Arc light acquisition signal is obtained by acquiring arc light signal of line through arc light sensor; Temperature acquisition signals are obtained by acquiring the temperature of the conductor using a temperature sensor.

[0008] Furthermore, in the fault perception module, the step of generating fault status data based on corresponding features includes: Voltage characteristics are obtained by calculating the abrupt changes in line voltage; The current characteristics are obtained by calculating the rate of change of the current; The zero-sequence current characteristics are obtained by performing fluctuation analysis on the zero-sequence current. Fault status data is generated by combining voltage characteristics, current characteristics, zero-sequence current characteristics, arcing characteristics, and temperature characteristics.

[0009] Furthermore, in the fusion positioning module, the step of initiating characteristic impedance spectrum scanning to obtain the reflection impedance characteristics of each branch includes: The edge computing terminal injects a low-amplitude scanning excitation signal in a preset frequency band into the low-voltage line; The response voltage signal and response current signal are collected synchronously on each branch line; The edge computing terminal calculates the impedance spectrum data of each branch line based on the response voltage signal and the response current signal; Edge computing terminals extract the reflection impedance characteristics of each branch line based on impedance spectrum data.

[0010] Furthermore, in the fusion positioning module, the step of obtaining the HPLC communication delay parameters of each terminal node includes: The edge computing terminal sends HPLC handshake signals to each terminal node; Each terminal node returns an HPLC response message to the edge computing terminal; The edge computing terminal records the HPLC handshake signal transmission time and the HPLC response message reception time. The edge computing terminal calculates the HPLC communication delay parameters of each terminal node based on the time difference between the sending time and the receiving time.

[0011] Furthermore, in the fusion positioning module, the step of determining the faulty section based on the station topology map generated by communication delay parameters and reflection impedance characteristics, the reflection impedance characteristics, and the HPLC communication delay parameters includes: A node connection matrix is ​​constructed based on the HPLC communication delay parameters of each terminal node; A line impedance distribution model is constructed based on the reflection impedance characteristics of each branch line. Generate a transformer area topology map based on the node connection matrix and line impedance distribution model; The fault section was determined based on the matching results of the reflection impedance characteristics of each branch path in the transformer area topology map and the HPLC communication delay parameters.

[0012] Furthermore, in the precision isolation module, the step of sending a disconnection command to the intelligent branch switch corresponding to the faulty section includes: Determine the set of intelligent branch switch nodes corresponding to the fault section based on the transformer area topology map; Based on the set of intelligent branch switch nodes, generate the disconnection command corresponding to each intelligent branch switch and bind the node address information; The transmission path of the break-off command is determined based on the HPLC communication link; Disconnection commands are sent to the intelligent branch switches corresponding to each node in the set of intelligent branch switch nodes via the HPLC communication link.

[0013] Furthermore, in the topology reconfiguration module, the steps of determining the non-faulty power supply area with a reachable power supply path to the low-voltage side busbar of the distribution transformer based on the transformer area topology map, and sending a closing command to the corresponding intelligent branch switch include: Based on the transformer area topology map, the nodes corresponding to the disconnected smart branch switches are marked as isolated nodes, and the remaining nodes are marked as unisolated nodes, forming a set of isolated nodes and a set of unisolated nodes; Based on the set of unisolated nodes, a connectivity traversal is performed on the topology graph of the transformer area to generate a connected subgraph; Extract the set of nodes in the non-faulty power supply area based on the connected subgraph, and map the set of nodes in the non-faulty power supply area to the smart branch switch nodes; The closing command is generated based on the intelligent branch switch node and sent to the intelligent branch switch corresponding to the non-faulty power supply area through the HPLC communication link. The area where there is no accessible power supply path from the low-voltage side busbar of the distribution transformer is kept blocked and an alarm is sent.

[0014] Furthermore, in the power restoration interlocking module, the step of sending a closing command to the disconnected intelligent branch switch when the fault characteristics are continuously detected to disappear within the delayed verification window, the line voltage, current, and zero-sequence current return to the normal operating range, and the number of reclosing attempts does not exceed the preset upper limit includes: Within the delayed verification window, the line voltage data, current data, zero-sequence current data, and arc signal data output by the multi-source electrical quantity acquisition unit are continuously detected; When the fault characteristics disappear and the electrical quantities return to the normal operating range, check whether the zero-sequence current of the line exceeds the preset insulation leakage threshold. If it does, stop closing the circuit and send an alarm. The system detects whether the conductor temperature data exceeds the preset temperature safety threshold. If it does, it suspends the closing of the circuit and sends an alarm. When both the insulation verification and temperature rise verification are passed and the number of reclosing attempts does not exceed the preset limit, a closing command is sent to the disconnected intelligent branch switch. When the number of reclosing attempts reaches the preset secondary limit but is lower than the permanent blocking limit, a manual confirmation request is sent to the cloud platform. After confirmation, the reclosing is executed. When the number of reclosing attempts exceeds the permanent lockout limit, the automatic reclosing of that section will be permanently locked out, and a lockout alarm will be sent to the cloud platform.

[0015] Secondly, the present invention provides the following technical solution: a method for photovoltaic coordinated voltage regulation and fault self-healing in rural low-voltage distribution areas, the method comprising the following steps: Fault detection steps: Collect line voltage, current, zero-sequence current, arc signal and conductor temperature data through multi-source electrical quantity acquisition unit, and generate fault status data based on the corresponding characteristics; State switching steps: When the fault status data meets the fault triggering conditions, a voltage regulation stop command is sent to the photovoltaic coordinated voltage regulation unit to stop the normal voltage regulation step and switch to the fault self-healing step. Fault location steps: Start characteristic impedance spectroscopy scanning to obtain the reflection impedance characteristics of each branch, and obtain the HPLC communication delay parameters of each terminal node. Based on the station topology map generated by the communication delay parameters and reflection impedance characteristics, the reflection impedance characteristics and the HPLC communication delay parameters, determine the fault section. Fault isolation steps: Send a disconnect command to the intelligent branch switch of the corresponding fault section; Power restoration steps: After the intelligent branch switch is disconnected, the non-faulty power supply area with a reachable power supply path to the low-voltage side bus of the distribution transformer is determined according to the transformer area topology map, and a closing command is sent to the corresponding intelligent branch switch; the area with no reachable power supply path to the low-voltage side bus of the distribution transformer is kept blocked and an alarm is sent. Safe power restoration procedure: If, within the delayed verification window, the fault characteristics are continuously detected to have disappeared and the line voltage, current, and zero-sequence current have returned to normal operating ranges, and both the insulation verification and temperature rise verification have passed, and the number of reclosing attempts has not exceeded the preset upper limit, a closing command is sent to the disconnected intelligent branch switch; if the number of reclosing attempts reaches the preset secondary upper limit but is lower than the permanent blocking upper limit, a manual confirmation request is sent to the cloud platform, and closing is executed after confirmation; if the number of reclosing attempts exceeds the permanent blocking upper limit, automatic reclosing of this section is permanently blocked and a blocking alarm is sent to the cloud platform; after successful closing, return to the normal voltage regulation procedure.

[0016] The present invention has the following beneficial effects: 1. In this invention, through the coordinated linkage of the normal voltage regulation module, fault perception module, state switching module, fusion positioning module, and power restoration interlocking module, a closed-loop control link is formed. Starting from normal photovoltaic coordinated voltage regulation, after fault-triggered state switching, it enters impedance spectrum and communication delay fusion positioning, then completes power restoration through fault section isolation and non-fault area topology reconstruction, and finally returns to normal voltage regulation through safety power restoration interlocking. This achieves continuous control of active adjustment of transformer area voltage quality and automatic fault recovery, thereby improving the problem that traditional rural low-voltage transformer area fault handling mostly adopts segmented manual judgment and independent control strategies. Due to the lack of a continuous state-driven control link, the fault handling process is fragmented and the control link is discontinuous.

[0017] 2. In this invention, by integrating characteristic impedance spectroscopy scanning results with HPLC communication delay parameters in fault self-healing mode to construct a transformer area topology map and using it to determine fault sections, joint fault location based on the consistency of impedance distribution and communication delay is achieved. This improves the problem that traditional rural low-voltage transformer area fault location mostly relies on a single electrical quantity or manual ledger. Since the line topology depends on manual maintenance and the electrical path and communication path information are inconsistent, the fault location accuracy is insufficient.

[0018] 3. In this invention, reactive power regulation commands or active power limiting commands are sent to the photovoltaic collaborative voltage regulation unit through the normal voltage regulation module, thereby utilizing the user's photovoltaic inverter to participate in the voltage support and three-phase imbalance management of the distribution area. This improves the problem that in traditional rural low-voltage distribution areas, photovoltaic power consumption mostly only performs grid-connected power generation without participating in distribution area voltage regulation. Since the reactive power regulation capability of the photovoltaic inverter is not utilized, the problem of voltage exceeding the limit and photovoltaic curtailment coexisting is caused.

[0019] 4. In this invention, the topology reconstruction module divides the connectivity of isolated nodes and non-isolated nodes based on the transformer area topology map and generates a set of non-faulty power supply areas. This drives the intelligent branch switch to perform segmented closing control, thereby improving the traditional rural low-voltage transformer area fault restoration method, which mostly adopts the unified restoration method after the entire transformer area is shut down. Due to the lack of regional power supply reconstruction capability based on topology structure, the power outage restoration range is too large and the power supply restoration efficiency is limited.

[0020] 5. In this invention, the power restoration interlocking module continuously detects the disappearance of fault characteristics, the restoration of electrical quantities, and the number of reclosing operations within the delayed verification window, thereby realizing automatic reclosing control with multiple safety constraints. This improves the problem that traditional rural low-voltage distribution area power restoration after a fault mostly relies on manual judgment or unconditional automatic reclosing. Due to the lack of delayed verification, insulation temperature rise detection, and reclosing operation limit, secondary fault risks and equipment safety hazards are caused. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the architecture of a photovoltaic-coordinated voltage regulation and fault self-healing system for rural low-voltage distribution areas proposed in this invention; Figure 2 This is a flowchart illustrating a method for photovoltaic-coordinated voltage regulation and fault self-healing in rural low-voltage distribution areas proposed in this invention. Figure 3 This is a schematic diagram of the structure and processing flow of the fusion positioning module proposed in this invention; Figure 4 This is a schematic diagram of the collaborative control process between the precise isolation module and the topology reconstruction module proposed in this invention; Figure 5 This is a schematic diagram of the determination and control process of the power restoration interlocking module proposed in this invention. Detailed Implementation

[0022] The technical solutions in 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.

[0023] Example 1: In the first embodiment of the present invention, the present invention provides a rural low-voltage distribution area photovoltaic coordinated voltage regulation and fault self-healing system, such as... Figure 1 As shown, it includes: The normal voltage regulation module is used by the edge computing terminal to obtain the distribution transformer outlet voltage, photovoltaic grid connection point voltage and three-phase load current. When the voltage exceeds the limit or the three-phase imbalance exceeds the limit, it sends a reactive power regulation command or an active power limit command to the photovoltaic collaborative voltage regulation unit. The fault perception module is used to collect line voltage, current, zero-sequence current, arc signal and conductor temperature data through the multi-source electrical quantity acquisition unit, and generate fault status data based on the corresponding characteristics. Furthermore, in the fault perception module, the steps for the multi-source electrical quantity acquisition unit to acquire line voltage, current, zero-sequence current, arcing signal, and conductor temperature data include: The voltage sampling signal is obtained by sampling the three-phase voltage of the line through a voltage sampling circuit; The current sampling signal and the zero-sequence current sampling signal are obtained by sampling the three-phase current of the line through a current transformer. Arc light acquisition signal is obtained by acquiring arc light signal of line through arc light sensor; Temperature acquisition signals are obtained by acquiring the temperature of the conductor using a temperature sensor.

[0024] Specifically, the multi-source electrical quantity acquisition unit employs a multi-channel sampling structure consisting of a voltage sampling circuit, a current transformer, an arc sensor, and a temperature sensor for different physical quantities. The three-phase line voltage is sampled phase-by-phase by the voltage sampling circuit to obtain voltage sampling signals. The three-phase line current is sampled synchronously by the current transformer to obtain current sampling signals. The zero-sequence current sampling signal is obtained by synthesizing the three-phase current sampling signals according to the zero-sequence relationship. The arc light acquisition signal is obtained by sampling the local arc intensity changes of the line using an arc sensor. The conductor temperature acquisition signal is obtained by continuously sampling the conductor surface temperature using a temperature sensor. This sampling process forms the original multi-source electrical quantity input set. In this scheme, the three-phase line voltage sampling signal is denoted as... The current sampling signal is denoted as The zero-sequence current sampling signal is obtained by linearly combining the output current signals of the current transformer, and is expressed as follows under discrete sampling conditions: The arc light acquisition signal is denoted as The conductor temperature acquisition signal is recorded as The above signals are uniformly represented as multi-source electrical quantity input vectors as follows: Each sampled signal originates from the real-time acquisition and output of the corresponding sensor regarding the operating status of the low-voltage line. In the data processing link, voltage and current sampled signals are used for subsequent voltage and current characteristic generation, zero-sequence current sampled signal is used to reflect the three-phase unbalanced operating state, arc acquisition signal is used to characterize local arc abnormal behavior, and conductor temperature acquisition signal is used to reflect the changing trend of line thermal effects. Finally, the input vector is processed... The fault state data is represented by feature mapping. The fault state data is generated by combining voltage characteristics, current characteristics, zero-sequence current characteristics, arcing characteristics, and temperature characteristics. Specifically, a fault state vector is constructed. ;in This is a characteristic of voltage abrupt change. Characteristic of current change rate The zero-sequence current fluctuation characteristic is represented by A, the arc characteristic by T, and the temperature characteristic by T. When any feature exceeds its corresponding preset threshold, the corresponding bit in the fault state data S is marked as 1; otherwise, it is marked as 0, forming a five-dimensional fault state vector.

[0025] Furthermore, in the fault perception module, the step of generating fault status data based on corresponding features includes: Voltage characteristics are obtained by calculating the abrupt changes in line voltage; The current characteristics are obtained by calculating the rate of change of the current; The characteristics of zero-sequence current are obtained by performing fluctuation analysis on zero-sequence current; Fault status data is generated by combining voltage characteristics, current characteristics, zero-sequence current characteristics, arcing characteristics, and temperature characteristics.

[0026] Specifically, the line voltage data consists of the three-phase voltage signals output by the voltage sampling circuit, denoted as... The voltage characteristics are extracted using a mutation rate calculation method, which is expressed as follows: ; wherein, the three-phase voltage amplitude vector at the current sampling moment is further expressed as ; , , Let a, b, and c represent the voltage amplitudes of phases a, b, and c at the current sampling time, respectively; the three-phase voltage amplitude vector at the previous sampling time is represented as: The calculated voltage characteristics, i.e., voltage abrupt changes. It is actually a three-dimensional vector, and its specific expansion is as follows: In the formula, , , These are the scalar values ​​representing the sudden changes in the three-phase voltages A, B, and C, respectively. Used to characterize the degree of voltage transient changes; in the fault triggering judgment of the subsequent state switching module, the specific fault triggering condition is: the three-dimensional vector is used to characterize the voltage transient changes; The absolute values ​​of the voltage fluctuation scalars for each phase are taken. When the absolute value of the voltage fluctuation of any one or more phases exceeds the preset voltage fluctuation threshold... When, that is, satisfied That is, it is determined that the fault triggering condition is met; by retaining The three-dimensional vector form enables the system to not only detect faults but also pinpoint the specific phase where a sudden change occurred, providing fundamental data support for subsequent fusion localization and phase management. Current data consists of current sampling signals, and current characteristics are calculated using the rate of change, expressed as... ;in This represents the current vector at the current sampling moment. This represents the current vector at the previous sampling time. Indicates the sampling time interval and the rate of change of current. Used to characterize load changes and short-time impact characteristics; zero-sequence current data is obtained by synthesizing three-phase currents through zero-sequence processing, and is expressed as follows: The zero-sequence current characteristics are obtained through sliding wave analysis of the zero-sequence current sequence, and are expressed as follows: ;in and These represent the zero-sequence current values ​​at adjacent sampling times, respectively. The arc light characteristics are directly represented by the output signal of the arc light sensor. The temperature characteristic is represented by the temperature signal from the output wire of the temperature sensor. In this scheme, both the arc light signal and the temperature signal are used as independent physical quantity inputs to participate in state construction; finally, the voltage characteristics are... Current characteristics Zero-sequence current characteristics Arc characteristics and temperature characteristics Vectorized combination is performed to generate fault state data representation as follows: ; including fault status data As a unified state input, it is used for fault trigger judgment of the subsequent fusion positioning module, and further drives the start of characteristic impedance spectroscopy scanning and HPLC communication delay acquisition process, thereby completing the construction of input conditions from multi-source sampling to fault trigger control.

[0027] The state switching module is used to send a voltage regulation stop command to the photovoltaic coordinated voltage regulation unit when the fault state data meets the fault triggering conditions, thereby stopping the normal voltage regulation module and switching to the fault self-healing mode. The fusion positioning module is used to initiate characteristic impedance spectroscopy scanning to obtain the reflection impedance characteristics of each branch and the HPLC communication delay parameters of each terminal node in fault self-healing mode. Based on the station topology map generated by the communication delay parameters and reflection impedance characteristics, the reflection impedance characteristics and HPLC communication delay parameters are used to determine the fault section. Furthermore, in the fusion positioning module, the steps for initiating characteristic impedance spectrum scanning to obtain the reflection impedance characteristics of each branch include: The edge computing terminal injects a low-amplitude scanning excitation signal in a preset frequency band into the low-voltage line; The response voltage signal and response current signal are collected synchronously on each branch line; The edge computing terminal calculates the impedance spectrum data of each branch line based on the response voltage signal and the response current signal; Edge computing terminals extract the reflection impedance characteristics of each branch line based on impedance spectrum data.

[0028] The processing procedure of the fusion positioning module is as follows: Figure 3 As shown, specifically, the edge computing terminal first injects a low-amplitude scanning excitation signal of a preset frequency band into the low-voltage line. This excitation signal can be represented as... ;in Indicates the amplitude of the excitation voltage. This represents the scan frequency variable, and the time variable is... The scanning frequency band continuously varies within a preset frequency set to cover the line impedance response range, and each branch line synchronously acquires the response voltage signal under excitation. With response current signal The response signal is obtained from the outputs of the voltage sampling circuits and current transformers of each branch; the impedance spectrum data of each branch line is calculated based on the response voltage signal and the response current signal, and the calculation relationship is as follows: ;in This represents the spectral components of the response voltage signal after frequency domain transformation. This represents the spectral components of the response current signal after frequency domain transformation, and the frequency variable. The set of frequency points corresponding to the scanning excitation signal, impedance spectrum data This is used to characterize the equivalent impedance distribution characteristics of each branch line at different frequencies; further, based on the impedance spectrum data, the reflection impedance characteristics of each branch line are extracted, and the reflection impedance characteristics can be expressed as follows: ;in The reference impedance spectrum model is defined as the reference impedance spectrum data of the transformer substation, acquired through characteristic impedance spectrum scanning and stored in the edge computing terminal under historical fault-free operation conditions. The reference impedance spectrum data is initially calibrated through a full-line characteristic impedance spectrum scan during the initial commissioning of the substation and is updated at preset intervals during normal operation to compensate for slow line impedance drift caused by changes in ambient temperature and load. Represents the set of scanning frequencies and the characteristics of reflection impedance. Used to characterize the location of impedance abrupt changes in branch lines and the characteristics of reflection boundaries.

[0029] In this scheme, the low-amplitude scanning excitation signal is generated by an impedance scanning injection unit installed on the edge computing terminal side, and the injection position is located at the main outgoing line on the low-voltage side of the distribution transformer; the scanning frequency band range is [f min ,f max ], f min The value is taken as an integer multiple of the fundamental frequency of the line to avoid overlap with the power frequency and its harmonics. maxThe signal amplitude at the end of the line is determined based on the line length and distribution parameters to ensure that there is still a detectable amplitude. The amplitude V0 of the scanning excitation signal does not exceed a preset percentage of the line's rated voltage to ensure that it does not affect the power quality and the normal operation of the protection device. The response voltage and response current signals of each branch line are time-aligned and acquired through the synchronous sampling module built into the multi-source electrical quantity acquisition unit, and the sampling synchronization error is not greater than the preset time window. When the HPLC communication link is interrupted due to fault isolation or the terminal node loses power, resulting in the failure to acquire communication delay parameters, the edge computing terminal performs downgraded positioning based on the most recent valid topology map and the single impedance spectrum scan result. The downgraded positioning result is marked as low confidence and sent to the cloud platform. When there is a risk of short-circuit arc or insulation breakdown in the line under fault conditions, the edge computing terminal judges the fault current amplitude before the scanning excitation signal is injected. If the fault current exceeds the safe injection threshold, the scanning excitation injection is skipped, and the fault section is determined directly based on the HPLC communication delay parameters and the pre-stored topology map.

[0030] Furthermore, in the fusion positioning module, the steps for obtaining the HPLC communication delay parameters of each terminal node include: The edge computing terminal sends HPLC handshake signals to each terminal node; Each terminal node returns an HPLC response message to the edge computing terminal; The edge computing terminal records the HPLC handshake signal transmission time and the HPLC response message reception time. The edge computing terminal calculates the HPLC communication delay parameters of each terminal node based on the time difference between the sending time and the receiving time.

[0031] Specifically, the edge computing terminal first sends an HPLC handshake signal to each terminal node. This handshake signal can be represented as a sequence of control messages, used to trigger a response from the terminal nodes. After receiving the handshake signal, each terminal node returns an HPLC response message to the edge computing terminal. The response message contains node identification information and is transmitted through the existing power line carrier communication link. The edge computing terminal records the handshake signal transmission time. With response message reception time The sending time The system clock time corresponding to the moment the handshake signal is sent, and the receiving time. To determine the system clock time corresponding to the complete reception of the response message, this scheme uses a unified time base provided by the edge computing terminal. The HPLC communication delay parameters for each terminal node are calculated based on the time difference between the sending and receiving times, and the calculation relationship is as follows: ;in This represents the round-trip communication delay parameter for a single handshake, which reflects the combined result of the propagation delay and processing delay of the handshake signal in the power line carrier channel; further, it represents the HPLC communication delay parameters of each terminal node. The node delay mapping set is bound to the node identification information. This set serves as one of the inputs for generating the subsequent transformer area topology map and is used for consistency matching with the reflection impedance characteristics. This allows it to participate in the spatial location constraint calculation of the fault section in the fusion positioning module, thereby realizing the construction of input conditions for joint modeling of the communication domain and the electrical domain.

[0032] Furthermore, in the fusion positioning module, the steps for determining the faulty section based on the station topology map generated through communication delay parameters and reflection impedance characteristics, reflection impedance characteristics, and HPLC communication delay parameters include: A node connection matrix is ​​constructed based on the HPLC communication delay parameters of each terminal node; A line impedance distribution model is constructed based on the reflection impedance characteristics of each branch line. Generate a transformer area topology map based on the node connection matrix and line impedance distribution model; The fault section was determined based on the matching results of the reflection impedance characteristics of each branch path in the transformer area topology map and the HPLC communication delay parameters.

[0033] Specifically, the method for constructing the node connection matrix based on the HPLC communication delay parameters of each terminal node is a delay-symmetric normalized graph construction method. The input data is the delay set formed by the difference between the handshake signal transmission time and the response message reception time between each terminal node, where the communication delay parameter between any two nodes is defined as: ;in For edge computing terminals to the first The timestamp of each terminal node sending the HPLC handshake signal To receive the first The timestamps of each terminal node's response message are uniformly measured in seconds. In this scheme, the timestamps are generated and uniformly synchronized by the internal clock system of the edge computing terminal. A node connection relationship matrix is ​​constructed based on the latency of all nodes. ;in The matrix represents the communication connectivity strength between nodes, and its physical meaning is an inverse mapping of the communication link response speed. This matrix is ​​used to characterize the HPLC communication path structure in the low-pressure station area and serves as input for topology construction. Secondly, the implementation method for constructing a line impedance distribution model based on the reflection impedance characteristics of each branch line is the impedance spectrum mapping modeling method. Its input data is the frequency domain impedance data obtained from characteristic impedance spectrum scanning. The reflection impedance characteristics are defined as: ;in For the first Branch lines at frequency The response voltage spectrum amplitude under the condition, To correspond to the amplitude and frequency of the current spectrum. Generated from a preset frequency band covered by a low-amplitude scanning excitation signal; an impedance vector is formed based on discrete frequency sampling points: And construct a line impedance distribution model using the set of impedance vectors from all branches: ;in The number of branches is represented by this model, which characterizes the differences in electrical propagation characteristics among different branch lines. Furthermore, the method for generating the transformer substation topology map based on the node connection matrix and line impedance distribution model is a graph-consistent derivation method, which constructs the topology graph by consistently mapping the communication domain structure to the electrical domain structure. ; where the node set Derived from the set of terminal nodes and the set of edges Node connection matrix The elements that satisfy the threshold condition constitute the whole, that is, when When the value exceeds a set structural association threshold, a connection edge is generated, and a corresponding branch impedance vector is attached to each edge. This forms a coupled communication and electrical topology structure. Finally, the method for determining the fault section based on the reflection impedance characteristics of each branch path in the transformer area topology map and the matching results of HPLC communication delay parameters is a multi-feature path consistency discrimination method, which is applied to any path. Define the overall matching degree: ;in This represents the characteristic vector of the impedance of the branch corresponding to the path. This is a set of path communication delay characteristics. and These are reference feature templates under fault conditions. For similarity calculation function, and The weighting coefficients are used to balance the contributions of the electrical and communication domains; finally, the segment corresponding to the path with the highest matching degree is selected as the fault segment output, and the result of this segment is passed to the subsequent disconnection control process for selective disconnection and isolation control of the intelligent branch switch.

[0034] like Figure 4 As shown, the precise isolation module is used by the edge computing terminal to send disconnection commands to the intelligent branch switches of the corresponding faulty section; Furthermore, in the precision isolation module, the steps for sending a disconnection command to the intelligent branch switch corresponding to the faulty section include: Determine the set of intelligent branch switch nodes corresponding to the fault section based on the transformer area topology map; Based on the set of intelligent branch switch nodes, generate the disconnection command corresponding to each intelligent branch switch and bind the node address information; The transmission path of the break-off command is determined based on the HPLC communication link; Disconnection commands are sent to the corresponding intelligent branch switches of each node in the intelligent branch switch node set via the HPLC communication link.

[0035] Specifically, based on the transformer area topology map The method for determining the set of intelligent branch switch nodes corresponding to the fault section is a graph structure node mapping method, with the input being a topological graph structure: ;in Represents the set of intelligent branch switch nodes. This represents the set of connections between nodes, with the input being a set of fault segment identifiers. This set is obtained from the output of the fusion positioning module; the node mapping relationship is defined as follows: ;in This represents the set of intelligent branch switch nodes corresponding to the faulty section. This set is used to limit the scope of subsequent control commands. Secondly, the method for generating disconnection commands for each intelligent branch switch based on the set of intelligent branch switch nodes and binding node address information is an instruction encoding and address binding method, with the node set as the input. and a unique communication identifier for each node. The break command is defined as a control state variable: ;in Indicates the first The disconnection control quantity of each intelligent branch switch, with a value of 0 indicating an open state, is combined with the node communication address to form a command pair: This structure ensures that control commands correspond to physical switching devices. Furthermore, the method for determining the transmission path of the disconnection command based on the HPLC communication link is a power line carrier routing method, with the communication network diagram as the input. ;in This represents the set of reachable links formed based on HPLC handshake communication, combined with communication delay parameters. Construct the path cost function: ;in This indicates the communication path from the edge computing terminal to the target node. This represents the cumulative delay cost of the path, and the path selection adopts the minimum cost path: This path is used to determine the actual transmission link for the break command; finally, the means of sending the break command to the intelligent branch switch corresponding to each node in the intelligent branch switch node set through the HPLC communication link is a group broadcast and point-to-point confirmation transmission method, which transmits the command set. According to the path Each node is encapsulated into an HPLC data frame and sent sequentially to the corresponding node ID. After receiving the data, the node executes the switch disconnection control logic and returns a response message for status confirmation, thereby completing the selective isolation control of the faulty section.

[0036] like Figure 4 As shown, the topology reconfiguration module is used to determine, according to the transformer area topology map, the non-faulty power supply area that has a reachable power supply path to the low-voltage side bus of the distribution transformer after the intelligent branch switch is disconnected, and send a closing command to the corresponding intelligent branch switch. Furthermore, in the topology reconfiguration module, the steps of determining the non-faulty power supply area with a reachable power supply path to the low-voltage side busbar of the distribution transformer based on the transformer area topology map, and sending a closing command to the corresponding intelligent branch switch include: Based on the transformer area topology map, the nodes corresponding to the disconnected smart branch switches are marked as isolated nodes, and the remaining nodes are marked as unisolated nodes, forming a set of isolated nodes and a set of unisolated nodes; Based on the set of unisolated nodes, a connectivity traversal is performed on the topology graph of the transformer area to generate a connected subgraph; Extract the set of nodes in the non-faulty power supply area based on the connected subgraph, and map the set of nodes in the non-faulty power supply area to the smart branch switch nodes; The closing command is generated based on the intelligent branch switch node and sent to the intelligent branch switch corresponding to the non-faulty power supply area through the HPLC communication link. The area where there is no accessible power supply path from the low-voltage side busbar of the distribution transformer is kept blocked and an alarm is sent.

[0037] Specifically, based on the transformer substation topology map, the nodes corresponding to the disconnected smart branch switches are marked as isolated nodes, and the remaining nodes are marked as unisolated nodes. The method for forming the isolated node set and the unisolated node set is a node state re-labeling method, with the topology map as the input: ;in This represents the set of all intelligent branch switch nodes, and integrates the fault section node set output by the positioning module and the precise isolation module. Define the node state function: ;in Indicates an isolated node. This represents unisolated nodes, thus forming a set of isolated nodes: ; and the set of unisolated nodes: This state division is used to limit the scope of subsequent power supply connectivity analysis; secondly, based on the set of unisolated nodes, the connectivity traversal of the transformer area topology graph is performed to generate a connected subgraph. The implementation method is a graph traversal constraint reconstruction method, with the subgraph as the input: ;in This indicates that only the set of edges connecting unisolated nodes is retained, and the connectivity propagation function is defined through the graph traversal process: ;in This indicates that there are reachable paths between nodes, and the set of all nodes that satisfy the connectivity relation constitutes a connected subgraph. This structure is used to characterize the powerable network structure after fault isolation. Furthermore, the method for extracting the set of nodes in the non-faulty power supply area based on the connected subgraph and mapping this set to intelligent branch switch nodes is the connected component mapping method. This method extracts the maximum connected component or all reachable components from the connected subgraph set to form the set of nodes in the non-faulty power supply area. ;in This represents the set of nodes in the recoverable power supply area, and is expressed through a node mapping function: The node set is mapped to the corresponding intelligent branch switch communication identifier set for subsequent control command encapsulation. Finally, the method for generating a closing command based on the intelligent branch switch node and sending the closing command to the intelligent branch switch corresponding to the non-faulty power supply area through the HPLC communication link is the state recovery control issuance method, where the control state variable is defined as: ;in This represents the closing control quantity, combined with the node identifier. Generate control command pairs: And through the HPLC communication link, it sends and responds node by node according to the pre-established communication path set, thereby completing the selective power restoration control of the non-faulty power supply area.

[0038] It should be noted that this scheme is applicable to the typical radial topology of rural low-voltage distribution areas. Restoration of power supply to non-faulty power supply areas refers to the restoration of power supply to the line segment from the main outgoing line on the low-voltage side of the distribution transformer to the upstream of the fault point, as well as to the non-faulty branch lines, after the faulty section is isolated. The power source is the same distribution transformer within the same area. The constraint for power restoration is that there must be a reachable path between each node in the node set of the non-faulty power supply area and the low-voltage side busbar of the distribution transformer in the isolated distribution area topology.

[0039] like Figure 5 As shown, the power restoration interlocking module is used to send a closing command to the disconnected intelligent branch switch when the fault characteristics are continuously detected to disappear within the delay verification window, the line voltage, current, and zero-sequence current are restored to the normal operating range, and the number of reclosing times does not exceed the preset upper limit. After successful closing, the normal voltage regulation module is restored to operation. Furthermore, in the power restoration interlocking module, when the fault characteristics are continuously detected to have disappeared and the line voltage, current, and zero-sequence current have returned to normal operating range within the delay verification window, and the number of reclosing operations has not exceeded the preset upper limit, the steps for sending a closing command to the disconnected intelligent branch switch include: Within the delayed verification window, the line voltage data, current data, zero-sequence current data, and arc signal data output by the multi-source electrical quantity acquisition unit are continuously detected; When the fault characteristics disappear and the electrical quantities return to the normal operating range, check whether the zero-sequence current of the line exceeds the preset insulation leakage threshold. If it does, stop closing the circuit and send an alarm. The system detects whether the conductor temperature data exceeds the preset temperature safety threshold. If it does, it suspends the closing of the circuit and sends an alarm. When both the insulation verification and temperature rise verification are passed and the number of reclosing attempts does not exceed the preset limit, a closing command is sent to the disconnected intelligent branch switch. When the number of reclosing attempts reaches the preset secondary upper limit and the preset secondary upper limit is less than the permanent blocking upper limit, a manual confirmation request is sent to the cloud platform, and the closing is executed after confirmation. When the number of reclosing attempts exceeds the permanent lockout limit, the automatic reclosing of that section will be permanently locked out, and a lockout alarm will be sent to the cloud platform.

[0040] Specifically, the method for acquiring line voltage data, current data, zero-sequence current data, and arc signal data output by the multi-source electrical quantity acquisition unit, and extracting features from the arc signal data to form real-time fault characteristic states, is a multi-channel signal feature extraction method. The input data includes a sampling sequence of the arc acquisition signal A changing over time; real-time feature quantities are obtained by performing sliding window feature extraction on the arc signal. ;in For the first Arc amplitude at each sampling point Given the number of sampling points in the window, output the real-time fault feature state vector: ;in For line voltage data, For line current data, The zero-sequence current data, where I represents the current line current amplitude, is used to characterize the current set of abnormal operating features. Secondly, the real-time fault feature state is compared with the fault state data at the time of fault triggering to generate the fault feature disappearance determination result. This is achieved using a time-series feature distance discrimination method, with the input being the state vector at the time of fault triggering. ;in These represent the line voltage data, line current data, zero-sequence current data, and arc characteristics at the moment of fault triggering; and the current state vector. Construct the feature difference function: ;in This indicates the degree of deviation of fault characteristics, reflecting the difference in consistency between the current state and the fault state. This result is used to generate a fault characteristic disappearance determination identifier. Furthermore, the line voltage data, current data, and zero-sequence current data undergo interval mapping processing to generate the electrical quantity recovery determination result. The implementation method is the operating interval constraint mapping method, with the input being the current voltage, current, and zero-sequence current sample values. The standard operating interval boundary is defined as: The interval determination function is defined as: ;in This indicates that the electrical quantity has recovered to its operating range, and this result is used as one of the conditions for power restoration. Finally, based on the fault characteristic disappearance judgment result and the electrical quantity recovery judgment result, the disconnected intelligent branch switch is determined, and a closing command is generated. The method of sending the closing command to the disconnected intelligent branch switch through the HPLC communication link is a dual-condition logic control and command encapsulation and issuance method, which combines the judgment results into logical variables: ;in This is the fault characteristic difference index obtained after normalizing the degree of deviation of fault characteristics D1. This indicates that the power restoration conditions are met; when Timely generation of closing control quantity: ; and combined with the corresponding intelligent branch switch communication identifier Encapsulated as control command pairs: The closing command is transmitted to the device via the HPLC communication link. The signal is sent to the disconnected intelligent branch switch to perform the closing action, thereby completing the selective power restoration control closed loop after the fault is recovered.

[0041] In this scheme, automatic reclosing is controlled by a power restoration interlocking logic for safety constraints. The power restoration interlocking logic includes: Delayed verification: Both the fault characteristic disappearance judgment result and the electrical quantity recovery judgment result must remain in the "satisfied" state for a continuous preset number of sampling cycles before the closing preparation can begin; Fault feature threshold verification: Within the delayed verification window, the real-time fault feature deviation degree D1 must remain below the preset fault feature disappearance threshold. Insulation verification: Before closing the circuit, the edge computing terminal detects the zero-sequence current of the line. If the zero-sequence current exceeds the preset insulation leakage threshold, it is determined that the line insulation has not been restored, the closing is suspended and an alarm is sent. Temperature rise verification: Before closing the circuit, the edge computing terminal detects the conductor temperature data. If the temperature is higher than the preset temperature safety threshold, closing the circuit is paused and an alarm is sent. Reclosing count limit: The number of automatic reclosings in the same fault section within a preset time window is counted. If the number of automatic reclosings in the same fault section is exceeded, the automatic reclosing of the section will be permanently blocked and a blocking alarm will be sent to the cloud platform. Manual confirmation: If the number of reclosing attempts reaches the preset secondary upper limit and the preset secondary upper limit is less than the permanent blocking upper limit, the edge computing terminal will suspend automatic reclosing and send a manual confirmation request to the cloud platform. The reclosing can only be performed after the maintenance personnel confirm the request.

[0042] In this system, the intelligent branch switch and the multi-source electrical quantity acquisition unit are powered by the CT induction power supply and the energy storage unit. The CT induction power supply unit is mounted on the low-voltage conductor and uses the alternating magnetic field generated by the line current to obtain electrical energy through the principle of electromagnetic induction. After being converted into DC voltage by the rectification and voltage regulation module, one path powers the electric opening and closing mechanism of the intelligent branch switch and the HPLC communication module, and the other path powers the various sensors and sampling circuits of the multi-source electrical quantity acquisition unit. The supercapacitor energy storage module provides short-term energy support when the CT power supply is insufficient, ensuring that the power supply is not interrupted during the execution of the disconnection command and communication.

[0043] Example 2: This invention provides a method for photovoltaic-coordinated voltage regulation and fault self-healing in rural low-voltage distribution areas, such as... Figure 2 As shown, in this embodiment, the method includes a normal voltage regulation stage and a fault self-healing stage, both of which are uniformly scheduled and executed by the edge computing terminal.

[0044] Normal pressure regulation phase: The edge computing terminal acquires the distribution transformer outlet voltage, the voltage of each photovoltaic grid connection point, and the three-phase load current in real time, and calculates the three-phase unbalance based on the three-phase current.

[0045] When the voltage in a distribution area exceeds the upper limit, falls below the lower limit, or the three-phase imbalance exceeds the limit, the edge computing terminal executes first-level voltage regulation, i.e., sending reactive power regulation commands to the photovoltaic collaborative voltage regulation unit to control the photovoltaic inverter's reactive power output. When the voltage in a distribution area exceeds the upper limit, the inverter is controlled to output inductive reactive power; when the voltage in a distribution area falls below the lower limit, the inverter is controlled to output capacitive reactive power. The reactive power regulation command is preferentially sent to the photovoltaic collaborative voltage regulation unit corresponding to the photovoltaic grid-connected point with the closest electrical distance to the voltage-limit-exceeding node.

[0046] If the voltage or three-phase imbalance still does not return to the allowable range after the first-level voltage regulation, the edge computing terminal performs the second-level voltage regulation, that is, according to the branch priority, photovoltaic installed capacity or line end location, it sends active power limiting instructions to the photovoltaic collaborative voltage regulation unit in sequence to limit the active power output of the corresponding photovoltaic inverter.

[0047] If the three-phase imbalance still exceeds the limit after the secondary voltage regulation, the edge computing terminal sends a commutation command to the intelligent commutation switch to adjust the access phase of some single-phase loads.

[0048] When the voltage in the transformer area returns to the allowable range and the three-phase imbalance returns to the allowable range, the edge computing terminal sends an active power recovery command to the photovoltaic collaborative voltage regulation unit to release the active power limitation and restore the maximum active power output, while maintaining dynamic adjustment of reactive power.

[0049] Fault self-healing phase: During normal voltage regulation operation, the edge computing terminal continuously collects line voltage, current, zero-sequence current, arc signal and conductor temperature data through the multi-source electrical quantity acquisition unit, and generates fault status data based on voltage characteristics, current characteristics, zero-sequence current characteristics, arc signal characteristics and temperature characteristics.

[0050] When the fault status data meets the fault triggering conditions, the edge computing terminal suspends the normal voltage regulation phase and enters the fault self-healing phase. The edge computing terminal initiates characteristic impedance spectroscopy scanning to obtain the reflection impedance characteristics of each branch and obtains the HPLC communication delay parameters of each terminal node; based on the transformer area topology map, reflection impedance characteristics, and HPLC communication delay parameters generated by the communication delay parameters and reflection impedance characteristics, the fault section is determined.

[0051] After identifying the faulty section, the edge computing terminal determines the set of intelligent branch switch nodes corresponding to the faulty section based on the transformer area topology map, generates disconnection commands for each intelligent branch switch and binds the node address information, and sends disconnection commands to the corresponding intelligent branch switches through the HPLC communication link to control the intelligent branch switches to disconnect and isolate the faulty section.

[0052] After the smart branch switch is disconnected, the edge computing terminal marks the node corresponding to the disconnected smart branch switch as an isolated node and the remaining nodes as unisolated nodes, forming a set of isolated nodes and a set of unisolated nodes. Based on the set of unisolated nodes, the edge computing terminal performs a connectivity traversal of the transformer area topology to extract the set of nodes in the non-faulty power supply area and maps the set of nodes in the non-faulty power supply area to the corresponding smart branch switch. The edge computing terminal generates a closing command and sends the closing command to the smart branch switch corresponding to the non-faulty power supply area through the HPLC communication link to restore power supply to the non-faulty area.

[0053] When the edge computing terminal detects that the fault characteristics have disappeared and the line voltage, current, and zero-sequence current have returned to normal operating range, it sends a closing command to the disconnected smart branch switch to achieve automatic reclosing. After successful reclosing, the edge computing terminal resumes the monitoring and voltage regulation control process of the normal voltage regulation phase, and the system returns to normal operating status.

[0054] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A photovoltaic-coordinated voltage regulation and fault self-healing system for rural low-voltage distribution areas, characterized in that, include: The normal voltage regulation module is used by the edge computing terminal to obtain the distribution transformer outlet voltage, photovoltaic grid connection point voltage and three-phase load current. When the voltage exceeds the limit or the three-phase imbalance exceeds the limit, it sends a reactive power regulation command or an active power limit command to the photovoltaic collaborative voltage regulation unit. The fault perception module is used to collect line voltage, current, zero-sequence current, arc signal and conductor temperature data through the multi-source electrical quantity acquisition unit, and generate fault status data based on the corresponding characteristics. The state switching module is used to send a voltage regulation stop command to the photovoltaic coordinated voltage regulation unit when the fault state data meets the fault triggering conditions, thereby stopping the normal voltage regulation module and switching to the fault self-healing mode. The fusion positioning module is used to initiate characteristic impedance spectroscopy scanning to obtain the reflection impedance characteristics of each branch and the HPLC communication delay parameters of each terminal node in fault self-healing mode. Based on the station topology map generated by the communication delay parameters and reflection impedance characteristics, the reflection impedance characteristics and the HPLC communication delay parameters, the fault section is determined. The precision isolation module is used to send disconnection commands to the intelligent branch switches in the corresponding faulty sections; The topology reconfiguration module is used to determine, based on the transformer area topology map, non-faulty power supply areas that have a reachable power supply path to the low-voltage side busbar of the distribution transformer after the smart branch switch is disconnected, and to send a closing command to the corresponding smart branch switch. The power restoration interlocking module is used to send a closing command to the disconnected intelligent branch switch when the fault characteristics are continuously detected to disappear within the delayed verification window, the line voltage, current, and zero-sequence current are restored to the normal operating range, and the number of reclosing times does not exceed the preset upper limit. After successful closing, the normal voltage regulation module is restored to operation.

2. The photovoltaic-coordinated voltage regulation and fault self-healing system for rural low-voltage distribution areas according to claim 1, characterized in that, In the fault detection module: The steps of the multi-source electrical quantity acquisition unit to acquire line voltage, current, zero-sequence current, arc signal and conductor temperature data include: sampling the three-phase voltage of the line through a voltage sampling circuit to obtain a voltage sampling signal; sampling the three-phase current of the line through a current transformer to obtain a current sampling signal and a zero-sequence current sampling signal; acquiring the arc signal of the line through an arc sensor to obtain an arc acquisition signal; and acquiring the conductor temperature through a temperature sensor to obtain a temperature acquisition signal. The step of generating fault state data based on corresponding features includes: calculating the sudden change of line voltage to obtain voltage features, calculating the rate of change of current to obtain current features, performing fluctuation analysis on zero-sequence current to obtain zero-sequence current features, and combining voltage features, current features, zero-sequence current features, arcing features, and temperature features to generate fault state data.

3. The photovoltaic-coordinated voltage regulation and fault self-healing system for rural low-voltage distribution areas according to claim 1, characterized in that, When the voltage in the distribution area exceeds the upper limit, the normal voltage regulation module sends an inductive reactive power regulation command to the photovoltaic collaborative voltage regulation unit that is electrically closest to the voltage limit node; when the voltage in the distribution area is below the lower limit, it sends a capacitive reactive power regulation command to the photovoltaic collaborative voltage regulation unit that is electrically closest to the voltage limit node; when the voltage or three-phase imbalance still does not return to the allowable range after reactive power regulation, it sends an active power limiting command to the corresponding photovoltaic collaborative voltage regulation unit according to branch priority, photovoltaic installed capacity, or line end location; when the voltage and three-phase imbalance return to the allowable range, it sends an active power recovery command to the corresponding photovoltaic collaborative voltage regulation unit.

4. The photovoltaic-coordinated voltage regulation and fault self-healing system for rural low-voltage distribution areas according to claim 1, characterized in that, In the fusion positioning module, the step of initiating characteristic impedance spectrum scanning to obtain the reflection impedance characteristics of each branch includes: The edge computing terminal injects a low-amplitude scanning excitation signal in a preset frequency band into the low-voltage line; The response voltage signal and response current signal are collected synchronously on each branch line; The edge computing terminal calculates the impedance spectrum data of each branch line based on the response voltage signal and the response current signal; Edge computing terminals extract the reflection impedance characteristics of each branch line based on impedance spectrum data.

5. A rural low-voltage distribution area photovoltaic coordinated voltage regulation and fault self-healing system according to claim 1, characterized in that, In the fusion positioning module, the step of obtaining the HPLC communication delay parameters of each terminal node includes: The edge computing terminal sends HPLC handshake signals to each terminal node; Each terminal node returns an HPLC response message to the edge computing terminal; The edge computing terminal records the HPLC handshake signal transmission time and the HPLC response message reception time. The edge computing terminal calculates the HPLC communication delay parameters of each terminal node based on the time difference between the sending time and the receiving time.

6. A rural low-voltage distribution area photovoltaic coordinated voltage regulation and fault self-healing system according to claim 1, characterized in that, In the fusion positioning module, the step of determining the fault segment based on the station topology map generated by communication delay parameters and reflection impedance characteristics, the reflection impedance characteristics, and the HPLC communication delay parameters includes: A node connection matrix is ​​constructed based on the HPLC communication delay parameters of each terminal node; A line impedance distribution model is constructed based on the reflection impedance characteristics of each branch line. Generate a transformer area topology map based on the node connection matrix and line impedance distribution model; The fault section was determined based on the matching results of the reflection impedance characteristics of each branch path in the transformer area topology map and the HPLC communication delay parameters.

7. A rural low-voltage distribution area photovoltaic coordinated voltage regulation and fault self-healing system according to claim 1, characterized in that, In the precision isolation module, the step of sending a disconnection command to the intelligent branch switch corresponding to the faulty section includes: Determine the set of intelligent branch switch nodes corresponding to the fault section based on the transformer area topology map; Based on the set of intelligent branch switch nodes, generate the disconnection command corresponding to each intelligent branch switch and bind the node address information; The transmission path of the break-off command is determined based on the HPLC communication link; Disconnection commands are sent to the intelligent branch switches corresponding to each node in the set of intelligent branch switch nodes via the HPLC communication link.

8. A rural low-voltage distribution area photovoltaic coordinated voltage regulation and fault self-healing system according to claim 1, characterized in that, In the topology reconfiguration module, the steps of determining the non-faulty power supply area with a reachable power supply path to the low-voltage side busbar of the distribution transformer based on the transformer area topology map, and sending a closing command to the corresponding smart branch switch include: Based on the transformer area topology map, the nodes corresponding to the disconnected smart branch switches are marked as isolated nodes, and the remaining nodes are marked as unisolated nodes, forming a set of isolated nodes and a set of unisolated nodes; Based on the set of unisolated nodes, a connectivity traversal is performed on the topology graph of the transformer area to generate a connected subgraph; Extract the set of nodes in the non-faulty power supply area based on the connected subgraph, and map the set of nodes in the non-faulty power supply area to the smart branch switch nodes; The closing command is generated based on the intelligent branch switch node and sent to the intelligent branch switch corresponding to the non-fault power supply area through the HPLC communication link. The area where there is no accessible power supply path from the low-voltage side busbar of the distribution transformer is kept blocked and an alarm is sent.

9. A rural low-voltage distribution area photovoltaic coordinated voltage regulation and fault self-healing system according to claim 1, characterized in that, In the power restoration interlocking module, the step of sending a closing command to the disconnected intelligent branch switch when the fault characteristics are continuously detected to disappear within the delayed verification window, the line voltage, current, and zero-sequence current return to the normal operating range, and the number of reclosing attempts does not exceed the preset upper limit includes: Within the delayed verification window, the line voltage data, current data, zero-sequence current data, and arc signal data output by the multi-source electrical quantity acquisition unit are continuously detected; When the fault characteristics disappear and the electrical quantities return to the normal operating range, check whether the zero-sequence current of the line exceeds the preset insulation leakage threshold. If it does, stop closing the circuit and send an alarm. The system detects whether the conductor temperature data exceeds the preset temperature safety threshold. If it does, it suspends the closing of the circuit and sends an alarm. When both the insulation verification and temperature rise verification are passed and the number of reclosing attempts does not exceed the preset limit, a closing command is sent to the disconnected intelligent branch switch. When the number of reclosing attempts reaches the preset secondary limit but is lower than the permanent blocking limit, a manual confirmation request is sent to the cloud platform. After confirmation, the reclosing is executed. When the number of reclosing attempts exceeds the permanent lockout limit, the automatic reclosing of that section will be permanently locked out, and a lockout alarm will be sent to the cloud platform.

10. A method for photovoltaic-coordinated voltage regulation and fault self-healing in rural low-voltage distribution areas, characterized in that, The method for a rural low-voltage distribution photovoltaic coordinated voltage regulation and fault self-healing system according to any one of claims 1-9 includes the following steps: Normal voltage regulation steps: The edge computing terminal obtains the distribution transformer outlet voltage, photovoltaic grid connection point voltage and three-phase load current. When the voltage exceeds the limit or the three-phase imbalance exceeds the limit, it sends a reactive power regulation command or an active power limit command to the photovoltaic collaborative voltage regulation unit. Fault detection steps: Collect line voltage, current, zero-sequence current, arc signal and conductor temperature data through multi-source electrical quantity acquisition unit, and generate fault status data based on the corresponding characteristics; State switching steps: When the fault status data meets the fault triggering conditions, a voltage regulation stop command is sent to the photovoltaic coordinated voltage regulation unit to stop the normal voltage regulation step and switch to the fault self-healing step. Fault location steps: Start characteristic impedance spectroscopy scanning to obtain the reflection impedance characteristics of each branch, and obtain the HPLC communication delay parameters of each terminal node. Based on the station topology map generated by the communication delay parameters and reflection impedance characteristics, the reflection impedance characteristics and the HPLC communication delay parameters, determine the fault section. Fault isolation steps: Send a disconnect command to the intelligent branch switch of the corresponding fault section; Power restoration steps: After the intelligent branch switch is disconnected, the non-faulty power supply area with a reachable power supply path to the low-voltage side busbar of the distribution transformer is determined according to the transformer area topology map, and a closing command is sent to the corresponding intelligent branch switch; the area with no reachable power supply path to the low-voltage side busbar of the distribution transformer is kept blocked and an alarm is sent. Safe power restoration procedure: If, within the delayed verification window, the fault characteristics are continuously detected to have disappeared and the line voltage, current, and zero-sequence current have returned to normal operating ranges, and both the insulation verification and temperature rise verification have passed, and the number of reclosing attempts has not exceeded the preset upper limit, a closing command is sent to the disconnected intelligent branch switch; if the number of reclosing attempts reaches the preset secondary upper limit but is lower than the permanent blocking upper limit, a manual confirmation request is sent to the cloud platform, and closing is executed after confirmation; if the number of reclosing attempts exceeds the permanent blocking upper limit, automatic reclosing of this section is permanently blocked and a blocking alarm is sent to the cloud platform; after successful closing, return to the normal voltage regulation procedure.

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