Self-healing system and method for adaptive power distribution network topology changes

Abstract

The application discloses a self-healing system and method adaptive to network topology change of a power distribution network, and belongs to the field of self-healing of the power distribution network. The self-healing system and method adaptive to network topology change of the power distribution network comprise an intelligent terminal, a self-healing host and a tie switch. The application solves the problems of topology complication and fault recovery delay caused by high proportion of distributed power supply access. The application deploys the intelligent terminal at a power distribution site, transmits topology search information, switch state information and electrical quantity information through a differential channel, dynamically constructs network connection relationship in combination with an improved BFS algorithm, realizes real-time automatic identification of topology change, discriminates the switch type in the fault isolation stage, realizes fault isolation and power supply recovery in combination with a virtual tripping-physical tripping collaborative mechanism, generates a load transfer path by using a bidirectional Dijkstra algorithm after successful isolation of the fault, and locks the self-healing when the path load is greater than a set threshold. When the power condition is met, a multi-tie switch self-healing sequence operation is performed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power distribution network self-healing, in particular to a self-healing system and method for adaptive power distribution network topology changes. BACKGROUND

[0002] With more and more distributed power sources connected to the power distribution network, the network topology becomes more and more complex, and the fault isolation time and power supply recovery time become longer when the system fails. However, the reliability of power supply is increasingly required by power users, so the conventional power distribution automation cannot meet the requirements of modern society for power supply reliability.

[0003] Traditional power distribution network self-healing aims to improve the reliability and stability of the power grid by quickly detecting, isolating faults and restoring power supply. However, these technologies still have the following defects and limitations in practical application:

[0004] 1. The recovery strategy of traditional self-healing technology is often simple, and it is difficult to cope with complex and variable network topology structure, and it cannot quickly and accurately identify and adapt to topology changes, cannot adapt to complex scenarios, and has a high risk of misjudgment.

[0005] 2. Fault handling relies on centralized decision-making by the main station, with multiple communication levels, long fault isolation and power supply recovery time, and overall recovery time exceeding 500ms, which cannot meet the high requirements of modern society for power supply reliability.

[0006] 3. Path calculation relies on fixed rules, ignores real-time power balance and device capacity constraints, and load transfer paths are not optimized, which may lead to unreasonable power distribution.

[0007] 4. The switching coordination of multiple tie self-healing switches is not good, and there is no dynamic priority strategy when multiple tie switches are switched, which may cause conflicts and affect the overall self-healing effect.

[0008] Therefore, the existing needs are not met, and for this purpose, we propose a self-healing system and method for adaptive power distribution network topology changes. SUMMARY

[0009] The purpose of the present application is to provide a self-healing system and method for adaptive power distribution network topology changes, which deploys intelligent terminals at the power distribution site, transmits topology search information, switch state information and electrical quantity information through differential channels, dynamically constructs network connection relationships by improving the BFS algorithm, realizes real-time identification of topology changes, discriminates switch types during fault isolation, and realizes fault isolation and power supply recovery by combining the virtual tripping-physical tripping coordination mechanism. When the fault is successfully isolated, the bidirectional Dijkstra algorithm is used to generate the load transfer path, and when the path load is greater than the set threshold, the self-healing is locked. When the power condition is met, the multi-tie switch self-healing sequence operation is performed, solving the problems raised in the above background technology.

[0010] To achieve the above object, the present application provides the following technical solutions: an adaptive power distribution network topology change self-healing system, comprising:

[0011] The intelligent terminal is configured to periodically exchange communication messages through the differential protection communication channel of the interconnection line, and the messages include voltage, current, switch type, switch state, node type, topology search identifier and self-healing judgment state;

[0012] The self-healing host is configured to automatically convert the intelligent terminal corresponding to the switch into a self-healing host when the switch is set as a self-healing switch;

[0013] The tie switch is configured to perform a multi-tie switch self-healing sequence operation after fault isolation;

[0014] The intelligent terminal and the self-healing host both have a differential protection module built-in and support 5G and optical fiber dual-mode communication.

[0015] Further, the intelligent terminal and the self-healing host communicate through the differential protection communication channel.

[0016] Further, the operation quality of the differential protection communication channel is monitored in real time, and an abnormal alarm is given when the operation is abnormal, including:

[0017] The operation parameters of the differential protection communication channel are monitored in real time;

[0018] The bit error rate and the differential delay asymmetry corresponding to each unit time of the differential protection communication channel operation are retrieved from the operation parameters;

[0019] The bit error rate and the differential delay asymmetry corresponding to each unit time are normalized to obtain the normalized bit error rate and the normalized differential delay asymmetry corresponding to each unit time;

[0020] The normalized bit error rate and the normalized differential delay asymmetry corresponding to each unit time are used to obtain the average value of the normalized bit error rate and the average value of the normalized differential delay asymmetry;

[0021] The average value of the normalized bit error rate and the average value of the normalized differential delay asymmetry are compared;

[0022] When the difference between the average value of the normalized bit error rate and the average value of the normalized differential delay asymmetry exceeds the preset difference threshold, the operation quality of the differential protection communication channel is evaluated using the average value of the normalized bit error rate and the average value of the normalized differential delay asymmetry, and a channel abnormal alarm is given when the operation is abnormal.

[0023] Further, the running quality of the differential protection communication channel is evaluated by using the normalized average bit error rate and the normalized average differential delay asymmetry, and an abnormal channel alarm is given when abnormality occurs, including:

[0024] retrieve a signal phase change amplitude parameter from the running parameters;

[0025] retrieve a preset phase parameter reference value from the database;

[0026] perform a ratio processing of the signal phase change amplitude parameter and the preset phase parameter reference value to obtain a phase ratio parameter;

[0027] retrieve a normalized average bit error rate and a normalized average differential delay asymmetry;

[0028] use the normalized average bit error rate and the normalized average differential delay asymmetry to obtain a running evaluation coefficient corresponding to the differential protection communication channel in combination with the phase ratio parameter;

[0029] compare the running evaluation coefficient with a preset coefficient threshold value;

[0030] when the running evaluation coefficient is lower than the preset coefficient threshold value, it is determined that the channel running is abnormal, and an abnormal alarm is given.

[0031] Further, the tie switch includes:

[0032] switch failure, no charging, communication interruption and device abnormality are all considered as not meeting the self-healing condition;

[0033] if the optimal self-healing tie switch does not meet the condition, search for a backup self-healing tie switch in descending order of priority.

[0034] A self-healing method for adaptive power distribution network topology changes, for implementing a self-healing system for adaptive power distribution network topology changes, including the following steps:

[0035] According to the smart terminal configured by the power distribution site, each smart terminal in the region periodically transmits communication messages through the differential protection communication channel of the interconnection line;

[0036] According to the topology search identifier, a dynamic node correlation matrix is constructed based on the improved BFS algorithm to analyze the message and identify the topology change of the power distribution system in real time. If no message of a certain node is received within a certain number of consecutive periods, it is determined that the node is disconnected from the network, and a new node automatically joins the correlation matrix through broadcast topology node registration;

[0037] When a fault occurs, the intelligent terminal identifies the fault section switch type, if it is a load switch, a virtual trip command is sent to the adjacent circuit breaker, the upper circuit breaker executes actual opening and feeds back a trip permission signal, the load switch executes no-fault trip after receiving the trip permission signal, and the adjacent circuit breaker executes reclosing after the load switch is tripped off;

[0038] After the fault is successfully isolated, according to the load state before the fault, the optimal transfer path is calculated by using the bidirectional Dijkstra algorithm, and the maximum load of the transfer path is calculated, when it is judged that the maximum load is greater than the set threshold, the self-healing is locked, when the maximum load is less than the set threshold, the multi-linkage switch self-healing sequence operation is executed;

[0039] If the optimal self-healing linkage switch does not meet the condition, the standby self-healing linkage switch is searched in descending order of priority;

[0040] If the high-priority self-healing switch does not meet the self-healing condition, the self-healing function is handed over to the low-priority self-healing linkage switch according to the network topology state.

[0041] Further, the network topology is formed by identifying the topology state of the distribution network system in real time.

[0042] Further, after the load switch is tripped, the upper circuit breaker starts automatic reclosing after detecting that the load switch is tripped successfully.

[0043] Further, the optimal path calculation is calculated by using the bidirectional Dijkstra algorithm to calculate the optimal transfer path according to the network topology fed back by the correlation matrix after the fault is isolated.

[0044] Further, the improved BFS algorithm supports large-capacity node network to complete topology refreshing within milliseconds, and the differential protection channel is reused to transmit topology search identifiers, switch states and node types, without increasing additional communication constants.

[0045] Compared with the prior art, the beneficial effects of the present application are:

[0046] By deploying intelligent terminals at the distribution site and using differential channels to transmit topology search information, switch state information and electrical quantity information, and combining the improved BFS algorithm to dynamically build network connection relationships, the present application can identify topology changes in real time, so that when the network structure of the distribution network changes, the network connection relationships can be quickly perceived and accurately updated, providing a reliable basis for subsequent control operations.

[0047] During the fault isolation phase, this invention can accurately identify the switch type and, combined with a virtual tripping-physical tripping coordination mechanism, quickly achieve fault isolation and power restoration. This coordination mechanism can effectively avoid problems such as fault expansion or power restoration delay caused by untimely or inaccurate switch actions, thereby improving the reliability and stability of the power supply network. Through precise fault isolation, the fault area can be limited to the smallest possible range, minimizing the number of users affected by power outages and the duration of outages, thus enhancing the user's electricity experience.

[0048] This invention uses a bidirectional Dijkstra algorithm to generate the optimal transfer path after successful fault isolation, which can improve transfer efficiency and reduce power loss during the transfer process. When the path load is greater than the set threshold, self-healing is blocked to avoid system instability or even fault expansion caused by overload. Only when the power condition is met will the multi-tie switch self-healing sequence operation be executed, ensuring the safety and stability of the distribution network during the self-healing process. Attached Figure Description

[0049] Fig. 1 This is a system architecture diagram of the present invention;

[0050] Fig. 2 This is a flowchart of the automatic topology search process of the present invention;

[0051] Fig. 3 This is the logic diagram of the virtual-physical tripping coordination and self-healing of the present invention. Detailed Implementation

[0052] 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.

[0053] Please see Figs. 1-3 This embodiment provides the following technical solution:

[0054] A self-healing system for adaptive distribution network topology changes includes:

[0055] The intelligent terminal is configured to periodically transmit communication messages to each other through the differential protection communication channel of the interconnected lines. The messages include voltage, current, switch type, switch status, node type, topology search identifier and self-healing discrimination status.

[0056] The self-healing host is configured such that when the switch is set to self-healing switch, the smart terminal corresponding to the switch automatically becomes the self-healing host.

[0057] The tie switch is configured to perform a multi-tie switch self-healing sequence operation after fault isolation.

[0058] The intelligent terminal and the self-healing host are both internally provided with a differential protection module and both support 5G and optical fiber dual-mode communication.

[0059] The technical effects of the above are that the intelligent terminal periodically transmits communication messages through the differential protection communication channel, the self-healing host and the tie switch work cooperatively, the fault point can be quickly located when a fault occurs, and the fault isolation is realized through the self-healing sequence operation of the tie switch, while the power supply in the non-fault area is restored, compared with the traditional method, the self-healing action time can be shortened from minutes to milliseconds, greatly reducing the power outage time and power outage range, the intelligent terminal and the self-healing host are both internally provided with a differential protection module, which can effectively improve the protection reliability of the power distribution network after a large amount of new energy is connected, the differential protection can quickly and accurately detect faults and act, reducing the impact of faults on the power grid, and the intelligent terminal and the self-healing host both support 5G and optical fiber dual-mode communication, compared with single optical fiber communication, the deployment cost of 5G communication is lower, especially in urban and suburban areas where 5G network coverage is good, through dual-mode communication, the range and cost of optical fiber laying can be reduced on the premise of meeting system performance requirements.

[0060] The intelligent terminal and the self-healing host communicate through a differential protection communication channel, each intelligent terminal communicates with a high-priority self-healing host, and the high-priority self-healing host communicates with a low-priority self-healing host.

[0061] The technical effects of the above are that the differential protection communication channel enables the intelligent terminal to transmit current and other data to the self-healing host in real time and accurately, the self-healing host performs differential protection calculation based on these data, thereby improving the sensitivity and selectivity of relay protection, effectively avoiding problems caused by misjudgment of the fault point, and improving power supply reliability, the intelligent terminal quickly transmits fault information to the self-healing host through the differential protection communication channel, the host can quickly locate the fault section and control the corresponding equipment to isolate the fault based on the differential protection principle and self-healing algorithm, thereby minimizing the impact of the fault and reducing the power outage time, and the differential protection communication channel provides the self-healing host with timely and accurate device state and power grid operation information, enabling it to quickly make decisions and perform self-healing operations, for example, after a fault occurs in the power distribution network, the self-healing system can complete fault isolation and power supply restoration in the non-fault area within milliseconds, compared with the traditional fault handling method, the self-healing time is greatly shortened.

[0062] Specifically, the operation quality of the differential protection communication channel is monitored in real time, and an abnormal alarm is given when the operation is abnormal, including:

[0063] The operating parameters of the differential protection communication channel are monitored in real time;

[0064] retrieve, from the operation parameters, a bit error rate and a differential delay asymmetry corresponding to each unit time of operation of the differential protection communication channel;

[0065] normalize the bit error rate and the differential delay asymmetry corresponding to each unit time to obtain a normalized bit error rate and a normalized differential delay asymmetry corresponding to each unit time;

[0066] obtain a normalized bit error rate average and a normalized differential delay asymmetry average using the normalized bit error rate and the normalized differential delay asymmetry corresponding to each unit time;

[0067] compare the normalized bit error rate average and the normalized differential delay asymmetry average;

[0068] when a difference between the normalized bit error rate average and the normalized differential delay asymmetry average exceeds a preset difference threshold, evaluate the operation quality of the differential protection communication channel using the normalized bit error rate average and the normalized differential delay asymmetry average, and perform channel abnormality alarm when abnormality occurs.

[0069] The technical effects of the above technical solution are as follows: The bit error rate and the differential delay asymmetry corresponding to each unit time are first normalized. This is because the original bit error rate and the differential delay asymmetry may be in different orders of magnitude and different ranges, and normalization can map them to the same value interval (such as [0, 1]), making them comparable and eliminating the influence of dimension and numerical range difference on subsequent calculation and analysis. The normalized bit error rate average and the normalized differential delay asymmetry average are calculated to reflect the average performance of the channel in data transmission accuracy and time synchronization over a period of time. The average value can smooth out abnormal fluctuations at individual time points and reflect the overall trend of channel operation. The two average values are compared, and the operation quality is evaluated when the difference exceeds the preset threshold. Under normal circumstances, the two values should maintain a relatively stable relationship. If the difference is too large, it indicates that the channel has imbalances in data transmission accuracy and time synchronization. By comparing the sizes of the two values and the difference, the quality of the channel operation can be judged. If the bit error rate average is much higher than the differential delay asymmetry average, it indicates that the channel is severely disturbed and the number of data transmission errors increases; otherwise, if the differential delay asymmetry average is too high, there is a time synchronization related fault, such as clock deviation. According to the evaluation result, it is determined whether it is abnormal and an alarm is given, thereby achieving effective monitoring of the operation quality of the differential protection communication channel.

[0070] By monitoring the running parameters such as the bit error rate and the differential delay asymmetry of the differential protection communication channel in real time, subtle changes in the channel running state can be captured in time. Once the difference between the two average values exceeds the preset threshold, evaluation and alarm are performed, which can remind the operation and maintenance personnel before the fault occurs, so as to take measures in advance, reduce the risk of differential protection misoperation or refusal caused by channel failure, and improve the reliability and stability of the power system. The normalized bit error rate average value and the differential delay asymmetry average value are used to evaluate the channel running quality, which converts complex running parameters into quantifiable and comparable indicators. This helps the operation and maintenance personnel to intuitively understand the channel running status and distinguish between normal fluctuations and abnormal situations, providing accurate basis for channel maintenance and upgrading and improving the operation and maintenance efficiency. By comparing the indicators of the bit error rate and the differential delay asymmetry, the channel running problems can be analyzed from different angles. When an abnormality occurs, the difference between the two can help determine whether the problem is in the accuracy of data transmission (bit error rate) or the time synchronization (differential delay asymmetry), which facilitates more accurate fault location and shortens the fault troubleshooting time.

[0071] Specifically, the normalized bit error rate average value and the normalized differential delay asymmetry average value are used to evaluate the running quality of the differential protection communication channel, and channel abnormal alarm is performed when an abnormality occurs, including:

[0072] Retrieving a signal phase change amplitude parameter from the running parameter;

[0073] Retrieving a preset phase parameter reference value from the database;

[0074] Performing ratio processing on the signal phase change amplitude parameter and the preset phase parameter reference value to obtain a phase ratio parameter;

[0075] Retrieving the normalized bit error rate average value and the normalized differential delay asymmetry average value;

[0076] Using the normalized bit error rate average value and the normalized differential delay asymmetry average value in combination with the phase ratio parameter to obtain a running evaluation coefficient corresponding to the differential protection communication channel;

[0077] Wherein, the running evaluation coefficient is obtained by the following formula:

[0078]

[0079] Wherein, U represents the running evaluation coefficient; W p represents the normalized bit error rate average value; T p represents the normalized differential delay asymmetry average value; S represents the phase ratio parameter; Specifically, (1-T p) is a measure of the deviation of the delay difference from the ideal state (no delay difference, i.e., T p = 0) to some extent. 1 - S*(1 - T p ) is first calculated, and then combined with the bit error rate related term. The absolute value ensures that the result of 1 - S*(1 - T p ) is non-negative and participates in the calculation, avoiding unreasonable calculation results. The overall formula reflects the running state evaluation of the system under the comprehensive consideration of these factors, and the value of U will change according to the changes of these parameters. p W is the normalized average bit error rate. The bit error rate reflects the proportional relationship between the number of incorrectly received code elements and the total number of transmitted code elements in the data transmission process, and reflects the transmission error caused by noise, interference and other factors. 1 - S*(1 - T p ) combines the phase and delay factors. The multiplication of the two represents the correlation between the bit error rate and the degree of influence of the signal by the phase and delay, and measures the comprehensive influence of these factors on the system performance. Taking the absolute value is to ensure that the calculation result of this part is non-negative, which conforms to the physical meaning and mathematical operation logic.

[0080] The running evaluation coefficient is compared with a preset coefficient threshold.

[0081] When the running evaluation coefficient is lower than the preset coefficient threshold, it is determined that the channel is running abnormally, and an abnormal alarm is triggered.

[0082] The technical effects of the above technical solutions are: the signal phase change amplitude parameter is extracted from the running parameters, and the phase ratio parameter is obtained by ratio processing with the preset phase parameter reference value in the database, reflecting the degree of signal phase change relative to the reference. At the same time, the normalized average bit error rate and the average differential delay asymmetry are obtained, which represent the average level of data transmission accuracy and time synchronization respectively. Normalization processing eliminates the differences in the original parameter dimensions and numerical ranges, making the parameters comparable. The normalized average bit error rate, the average differential delay asymmetry, and the phase ratio parameter are combined to calculate the running evaluation coefficient. This is because the bit error rate affects data transmission accuracy, the differential delay asymmetry relates to time synchronization, and the signal phase change affects signal integrity, all of which determine the channel running quality. These parameters are fused into a numerical value through a specific calculation method (the specific formula is not given, but the principle is to consider comprehensively), which quantifies the channel running quality. The running evaluation coefficient is compared with a preset coefficient threshold. The threshold is set according to the performance indicators of the normal operation of the channel and the requirements of the differential protection for the quality of the channel. If the running evaluation coefficient is lower than the threshold, it means that the channel running quality has decreased to the extent that affects normal work, and the channel is determined to be running abnormally and an alarm is triggered, reminding the operation and maintenance personnel to take measures to maintain the channel.

[0083] The multi-dimensional parameters such as the bit error rate, the differential delay asymmetry and the signal phase change amplitude are comprehensively evaluated to evaluate the operation quality of the communication channel. Compared with single index evaluation, the actual operation condition of the channel can be more comprehensively and accurately reflected, the misjudgment and omission are reduced, and the accuracy of the evaluation is improved. The channel abnormality is determined and an alarm is given by comparing the operation evaluation coefficient with the preset threshold value, so that early warning can be given before the channel performance is reduced to affect the normal work of the differential protection. The operation and maintenance personnel can intervene in advance to avoid power system failure caused by channel failure and improve the reliability and stability of the power system. The quantitative operation evaluation coefficient enables the operation and maintenance personnel to intuitively understand the channel operation quality and determine the maintenance priority. For the channel with the operation evaluation coefficient close to the threshold value, the operation and maintenance resources are reasonably allocated, the operation and maintenance efficiency is improved, and the operation and maintenance cost is reduced.

[0084] The tie switch comprises:

[0085] The switch failure, the uncharged, the communication interruption and the device abnormality are considered as not meeting the self-healing condition, wherein:

[0086] The switch failure refers to that the switch cannot normally act when it needs to act, in this case, the tie switch cannot be closed or opened according to the self-healing strategy, so that the self-healing cannot be realized;

[0087] The uncharged refers to that the operating power of the switch is not charged, so that the switch cannot normally act;

[0088] The communication interruption refers to that the communication link between the switch and the control center or other devices is interrupted, in the self-healing process, the switch needs to receive the control instruction or report the state information, the communication interruption will cause that the information cannot be transmitted, so that the implementation of the self-healing strategy is affected;

[0089] The device abnormality refers to that the switch itself or its accessory device fails, so that the switch cannot correctly judge the fault condition or execute the self-healing operation;

[0090] If the optimal self-healing tie switch does not meet the condition, the standby self-healing tie switch is searched in descending order of priority.

[0091] The technical effect of the above is that when the tie switch has switch failure, no charging, communication interruption and device abnormality, etc., all of which are considered not to meet the self-healing condition, these abnormal conditions will cause the tie switch to fail to work normally, thereby failing to realize the self-healing function, if the optimal self-healing tie switch does not meet the condition, the system will search for a backup self-healing tie switch in descending order of priority, which means that the system will preferentially select a backup switch with higher priority to ensure the reliability and effectiveness of the self-healing operation, in this way, even if the optimal self-healing tie switch fails, the system can still realize self-healing through the backup switch, thereby improving the self-healing reliability of the entire system, and the descending order of priority search strategy can sort different switches according to their importance and reliability, so that the system is more reasonable when selecting a backup switch, thereby optimizing the self-healing strategy, and then quickly finding an available backup switch to shorten the fault recovery time and reduce the impact of power failure on users.

[0092] Specifically, the embodiment also provides a self-healing method for adaptive power distribution network topology changes, which is used for realizing a self-healing system for adaptive power distribution network topology changes and comprises the following steps:

[0093] According to the intelligent terminal configured by the power distribution site, each intelligent terminal in the region periodically transmits communication messages to each other through the differential protection communication channel of the interconnection line;

[0094] According to the topology search identifier, a dynamic node correlation matrix is constructed by analyzing the message based on the improved BFS algorithm, the topology change of the power distribution system is identified in real time, if no message of a node is received in a plurality of continuous periods, it is determined that the node is disconnected from the network, and a new node is automatically added to the correlation matrix through broadcast topology node registration;

[0095] When a fault occurs, the intelligent terminal identifies the type of the fault section switch, if it is a load switch, a virtual tripping instruction is sent to the adjacent circuit breaker, the upper circuit breaker feeds back a tripping permission signal after executing actual opening, the load switch executes fault-free tripping after receiving the tripping permission signal, and the adjacent circuit breaker executes reclosing after the load switch is tripped, and the upstream circuit breaker starts the automatic reclosing function after receiving the information that the load switch is disconnected, thereby realizing the complete fault isolation process;

[0096] When the self-healing switch is not charged or the reclosing fails, a backup tie switch is searched, the load is calculated to be lower than a threshold value, the backup tie switch is closed, and power supply is restored;

[0097] After the fault is successfully isolated, the optimal transfer path is calculated by using the bidirectional Dijkstra algorithm according to the load state before the fault, and the maximum load of the transfer path is calculated, the self-healing is locked when it is judged that the maximum load is greater than the set threshold, and the multi-tie switch self-healing sequence operation is executed when the maximum load is less than the set threshold;

[0098] If the optimal self-healing contactor does not meet the condition, search for a backup self-healing contactor in descending order of priority;

[0099] If the high-priority self-healing contactor does not meet the self-healing condition, the self-healing function is handed over to the low-priority self-healing contactor according to the network topology state.

[0100] The technical effects of the above are: through periodic mutual transmission of communication messages containing multiple key information by intelligent terminals, combined with differential protection communication channels, the changes in the distribution network topology can be quickly identified, and self-healing control can be completed within milliseconds, significantly improving the self-healing efficiency and response speed of the distribution network. Using the improved BFS algorithm to construct a dynamic node correlation matrix, the topology changes of the distribution network system can be identified in real time. New nodes can automatically join the correlation matrix through broadcast "topology node registration", and nodes that have left the network can also be identified in a timely manner, thereby adapting to the complex and variable topology structure of the distribution network, especially in the active distribution network scenario containing distributed power sources. In the event of a fault, the intelligent terminal can quickly identify the type of switch in the fault section and realize fault isolation through the virtual tripping-physical tripping coordination mechanism. After fault isolation, the optimal transfer path is calculated using the bidirectional Dijkstra algorithm to ensure that power conditions are met and power is quickly restored through multi-contactor self-healing sequence operation, improving power supply reliability. Multiple contactors can work together, and when the high-priority self-healing contactor does not meet the self-healing condition, a backup self-healing contactor can be searched in descending order of priority, avoiding self-healing failure due to single switch failure and further improving system reliability. Based on the above operations, real-time monitoring and dynamic updating of network topology reduce the risk of misjudgment due to complex network topology in traditional self-healing technology. At the same time, the path optimization engine based on the bidirectional Dijkstra algorithm can calculate the optimal transfer path according to real-time power balance and device capacity constraints, avoiding unreasonable power distribution and improving the overall performance of the system.

[0101] Real-time identification of the topology state of the distribution network system forms the network topology.

[0102] The technical effects of the above are: through real-time monitoring and dynamic updating of the topology state of the distribution network, any changes in the network can be quickly responded to, such as the addition, deletion or state change of nodes. Through fast adaptation, the system can maintain efficient operation in a complex and variable distribution network environment, especially in scenarios where distributed power sources are frequently connected, causing dynamic changes in the topology structure. In the event of a fault, the fault location and its impact on the network topology can be immediately identified, and strategies for fault isolation and power restoration can be quickly developed. Real-time topology identification significantly shortens fault handling time, reduces the range and duration of power outages, and improves power supply reliability.

[0103] After the load switch trips, the upper circuit breaker starts automatic closing after detecting the successful tripping of the load switch.

[0104] The technical effect of the above is that through the virtual tripping-physical tripping cooperative mechanism, the load switch trips without fault current, avoiding the impact of fault current caused by direct tripping of the load switch, the upper circuit breaker only closes after confirming the successful tripping of the load switch, ensuring the thoroughness and safety of fault isolation, and after the successful tripping of the load switch, the upper circuit breaker immediately starts automatic closing, which can restore power supply in the non-fault area in a very short time, significantly shortening the power outage time and improving the power supply reliability.

[0105] Optimal path calculation, after fault isolation, the network topology is fed back according to the correlation matrix, and the bidirectional Dijkstra algorithm is used to calculate the optimal transfer path.

[0106] The technical effect of the above is that the bidirectional Dijkstra algorithm can comprehensively consider network topology, path length, device capacity, and real-time power balance, etc., to select the optimal transfer path, and the optimized path selection ensures the rationality of power distribution, avoiding the problem of overload or power shortage caused by improper path selection, and through the bidirectional Dijkstra algorithm, the optimal transfer path from the power source to the load can be quickly calculated, ensuring that power supply can be quickly restored after fault isolation, and the power supply recovery time is significantly shortened through the path calculation method, improving the self-healing ability of the distribution network, and through the calculation of the optimal transfer path, the power supply strategy can be quickly adjusted when a fault occurs, ensuring the continuous power supply of important loads, thereby improving the stability of the distribution network and reducing the risk of power outage caused by faults.

[0107] The improved BFS algorithm supports large-capacity node networks to complete topology refreshing within milliseconds, and reuses differential protection channels to transmit topology search identifiers, switch states, and node types without the need to increase additional communication constants.

[0108] The technical effect of the above is that the improved BFS algorithm can complete the topology refreshing of large-capacity node networks within milliseconds, making it suitable for complex and variable distribution network scenarios, and the improved BFS algorithm enables the distribution network to better cope with dynamic changes in network topology, supports more node access and more complex network structures, and through the reuse of differential protection channels to transmit topology search identifiers, switch states, and node types, etc., additional communication constants or dedicated communication channels are not needed, which fully utilizes existing communication resources, avoids the increase in cost and complexity caused by additional communication equipment or lines, and improves the economy and implementability of the system.

[0109] The application can dynamically construct network connection relationship by transmitting topology search information through differential channels and combining improved BFS algorithm, can identify topology change in real time, can well solve the protection configuration difficulty problem in complex scenes such as multi-terminal line, can distinguish switch type in the fault isolation stage, can quickly and reliably isolate faults in combination with virtual tripping-physical tripping collaborative mechanism, can avoid user accompaniment in non-fault area, and can generate load transfer path by using bidirectional Dijkstra algorithm after successful isolation of faults, can perform multi-liaison switch self-healing sequence operation when power conditions are met, can realize power supply recovery in a short time, and improves power supply reliability.

[0110] It should be noted that, in this document, relational terms such as first and second and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0111] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, alternatives, and variations can be made in the embodiments without departing from the spirit and scope of the present application.

Claims

1. A self-healing system that adapts to network topology changes in a power distribution network, characterized by, The application relates to a self-healing intelligent terminal system, which comprises the following parts: an intelligent terminal configured to periodically exchange communication messages through a differential protection communication channel of an interconnection line, wherein the messages comprise voltage, current, switch type, switch state, node type, topology search identifier and self-healing judgment state; wherein the operation quality of the differential protection communication channel is monitored in real time, and an abnormal alarm is given when the operation is abnormal; a self-healing host configured to automatically convert the intelligent terminal corresponding to the switch into the self-healing host when the switch is set as a self-healing switch; a tie switch configured to perform a multi-tie switch self-healing sequence operation after fault isolation; the intelligent terminal and the self-healing host are both internally provided with a differential protection module and support 5G and optical fiber dual-mode communication; the operation quality of the differential protection communication channel is monitored in real time, and an abnormal alarm is given when the operation is abnormal, which comprises the following steps: monitoring the operation parameters of the differential protection communication channel in real time; obtaining the bit error rate and the differential delay asymmetry degree corresponding to each unit time of the differential protection communication channel from the operation parameters; normalizing the bit error rate and the differential delay asymmetry degree corresponding to each unit time to obtain the normalized bit error rate and the normalized differential delay asymmetry degree corresponding to each unit time; obtaining the average value of the normalized bit error rate and the average value of the normalized differential delay asymmetry degree; comparing the average value of the normalized bit error rate and the average value of the normalized differential delay asymmetry degree; when the difference between the average value of the normalized bit error rate and the average value of the normalized differential delay asymmetry degree exceeds a preset difference threshold value, the operation quality of the differential protection communication channel is evaluated by using the average value of the normalized bit error rate and the average value of the normalized differential delay asymmetry degree, and an abnormal channel alarm is given when the operation is abnormal; the operation quality of the differential protection communication channel is evaluated by using the average value of the normalized bit error rate and the average value of the normalized differential delay asymmetry degree, and an abnormal channel alarm is given when the operation is abnormal, which comprises the following steps: obtaining the signal phase change amplitude parameter from the operation parameters; obtaining the preset phase parameter reference value from a database; obtaining the phase ratio parameter by ratio processing the signal phase change amplitude parameter and the preset phase parameter reference value; obtaining the average value of the normalized bit error rate and the average value of the normalized differential delay asymmetry degree; obtaining the operation evaluation coefficient corresponding to the differential protection communication channel by combining the average value of the normalized bit error rate and the average value of the normalized differential delay asymmetry degree with the phase ratio parameter; comparing the operation evaluation coefficient with a preset coefficient threshold value; when the operation evaluation coefficient is lower than the preset coefficient threshold value, it is determined that the channel operation is abnormal, and an abnormal alarm is given.

2. The self-healing system for adaptive power grid network topology changes of claim 1, wherein: the intelligent terminal and the self-healing host communicate through the differential protection communication channel.

3. The self-healing system for adaptive power grid network topology changes of claim 1, wherein: the tie switch comprises the following parts: switch refusal, no charging, communication interruption and device abnormality are all considered as not meeting the self-healing condition. If the optimal self-healing tie switch does not meet the conditions, search for a backup self-healing tie switch in descending order of priority.

4. A self-healing method for adaptive power distribution network topology changes, used for implementing a self-healing system for adaptive power distribution network topology changes according to any one of claims 1-3, characterized in that, It comprises the following steps: According to the configuration of the intelligent terminal of the distribution network, each intelligent terminal in the region periodically transmits communication messages through the differential protection communication channel of the interconnection line. According to the topology search identifier, the dynamic node correlation matrix is constructed based on the improved BFS algorithm to identify the topology changes of the distribution network system in real time. If no message of a node is received within a certain number of periods, it is determined that the node has left the network, and a new node automatically joins the correlation matrix through broadcast topology node registration. When a fault occurs, the intelligent terminal identifies the type of the fault section switch. If it is a load switch, it sends a virtual trip command to the adjacent circuit breaker. The upper circuit breaker executes the actual opening and feeds back the trip signal. The load switch receives the trip signal and executes the fault-free trip. After the load switch is tripped, the adjacent circuit breaker executes the closing. After the fault is successfully isolated, the optimal transfer path is calculated using the bidirectional Dijkstra algorithm based on the load state before the fault, and the maximum load of the transfer path is calculated. When the maximum load is greater than the set threshold, the self-healing is locked. When the maximum load is less than the set threshold, the multi-tie switch self-healing sequence operation is executed. If the optimal self-healing tie switch does not meet the conditions, search for a backup self-healing tie switch in descending order of priority. If the high-priority self-healing switch does not meet the self-healing conditions, the self-healing function is transferred to the low-priority self-healing tie switch according to the network topology state.

5. The self-healing method of adaptive power grid network topology changes according to claim 4, characterized in that: Real-time identification of the topology state of the distribution network system forms the network topology.

6. The self-healing method of adaptive power grid network topology changes according to claim 4, characterized in that: After the load switch is tripped, the upper circuit breaker starts the automatic closing after detecting the successful tripping of the load switch.

7. The self-healing method of adaptive power grid network topology changes according to claim 4, characterized in that: Optimal path calculation: after fault isolation, the optimal transfer path is calculated using the bidirectional Dijkstra algorithm based on the network topology feedback from the correlation matrix.

8. The self-healing method of adaptive power grid network topology changes according to claim 4, characterized in that: The improved BFS algorithm supports large-capacity node networks to complete topology refresh in milliseconds and reuses the differential protection channel to transmit topology search identifiers, switch states, and node types without the need for additional communication settings.

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