Emergency control method and system under distribution network failure

Abstract

The present invention discloses an emergency control method and system under distribution network faults, the method includes obtaining a candidate switch sequence set according to the topological structure information of the distribution network feeder segment switch group, screening the candidate switch sequence set for stable operation, obtaining a number of target switch action sequences, calculating the reliability results of each target switch action sequence under each fault scenario according to the target switch action sequence and the fault simulation scenario, and selecting the optimal switch action sequence, generating a distribution network emergency control scheme under different fault simulation scenarios based on the optimal switch action sequence, and executing the distribution network emergency control scheme determined by the actual fault scenario when a fault occurs in the distribution network. The present invention ensures continuous power supply to key loads under emergency conditions of the distribution network, improves the flexibility and reliability of the distribution network switching between different operation modes, and enhances the ability of the power grid to respond to emergencies.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid control, and in particular to an emergency control method and system under a distribution network failure. Background Art

[0002] With the development of power grid infrastructure, the power supply stability of the power grid has been significantly improved, and the demand for the emergency response capability and flexibility of the power grid in urban construction has also increased significantly.

[0003] In the face of emergencies, the power grid infrastructure needs to be quickly converted from the conventional grid structure to an independent power supply unit to ensure the power supply reliability of critical loads. In this process, the topological reconstruction of the distribution network feeder segment switch group plays a vital role. Different switch action sequences will have a significant impact on the transient characteristics of the system. The existing switch action method has a poor effect, resulting in poor power supply effect of the converted independent power supply unit, affecting the stability of the power grid system operation.

[0004] It can be seen that how to optimize the control process of each feeder section switch under a distribution network fault has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0005] The present invention provides an emergency control method and system under a distribution network fault, so as to optimize the control process of a feeder section switch of the distribution network.

[0006] In order to solve the above technical problems, an embodiment of the present invention provides an emergency control method under a distribution network fault, comprising:

[0007] According to the topological structure information of the feeder section switch group of the distribution network, a depth-first search algorithm is used in the simulation environment to traverse and obtain a set of candidate switch sequences that meet the transient characteristic constraints of the system.

[0008] A stable operation screening is performed on each candidate switch sequence in the candidate switch sequence set to obtain a number of target switch action sequences, wherein the stable operation screening is designed to use the key parameter change rate of each candidate switch sequence obtained by power flow calculation and transient simulation calculation as a screening evaluation indicator.

[0009] Each of the target switch action sequences is applied to all the constructed fault simulation scenarios in turn, and the simulation feedback results corresponding to each of the fault simulation scenarios are evaluated to determine all the distribution network power supply reliability results corresponding to each of the fault simulation scenarios.

[0010] All distribution network power supply reliability results corresponding to each of the fault simulation scenarios are analyzed to determine the optimal switch action sequence corresponding to each of the fault simulation scenarios, and based on the optimal switch action sequence, emergency control plans for the distribution network under different fault simulation scenarios are generated.

[0011] When a failure occurs in the distribution network, the distribution network emergency control plan determined by the actual failure scenario is executed.

[0012] Furthermore, according to the topological structure information of the distribution network feeder section switch group, a set of candidate switch sequences satisfying the system transient characteristic constraint conditions is obtained by traversing using a depth-first search algorithm in a simulation environment, including:

[0013] According to the topological structure information of the distribution network feeder segment switch group, a depth-first search algorithm is used to traverse all switch action path combinations. For each switch action path combination, a transient simulation of the switch action is performed through a transient calculator based on the terminal voltage data of the feeder section corresponding to each switch.

[0014] It is determined whether the system transient characteristic constraint conditions are met according to the simulation results. If so, the corresponding switch action path combination is stored in the switch sequence set as a candidate switch sequence.

[0015] Furthermore, the stable operation screening is performed on each candidate switch sequence in the candidate switch sequence set to obtain a plurality of target switch action sequences, including:

[0016] For each candidate switch sequence, a switch state array of the candidate switch sequence is obtained, and the power flow of the distribution network is iteratively calculated by the Newton-Raphson method according to the switch state array to obtain an initial steady-state reference value.

[0017] According to the initial steady-state reference value, the frequency change rate of the voltage and current within the switching action interval is collected by dynamic sampling. If the frequency change rate exceeds a stable change rate threshold, the corresponding target switching action sequence is screened out.

[0018] Furthermore, the reliability results include mean time between failures and mean duration of failures.

[0019] Furthermore, each of the target switch action sequences is applied to all the constructed fault simulation scenarios in turn, and the simulation feedback results corresponding to each of the fault simulation scenarios are evaluated to determine all the distribution network power supply reliability results corresponding to each of the fault simulation scenarios, including:

[0020] The probability distribution of the fault type is obtained according to each target switch action sequence, and the fault scenario parameters are extracted from the power distribution network power fault type library using a Monte Carlo sampler according to the probability distribution. According to the fault scenario parameters, several fault simulation scenarios are generated.

[0021] For each of the target switch action sequences, the corresponding target switch action sequence is applied to each of the fault simulation scenarios to simulate and obtain the power-off state of the load point of the distribution network under each of the fault simulation scenarios.

[0022] According to the power-off status of the load point, a time window algorithm is used to calculate the power supply interruption duration in the current fault simulation scenario, and a sliding time window statistical method is used to calculate the adjacent fault intervals in the current fault simulation scenario.

[0023] The average fault-free operation time and the average fault duration are obtained according to the power supply interruption time and the adjacent fault interval.

[0024] Furthermore, the power supply reliability results of all distribution networks corresponding to each of the fault simulation scenarios are analyzed to determine the optimal switch action sequence corresponding to each of the fault simulation scenarios, and the distribution network emergency control schemes under different fault simulation scenarios are generated based on the optimal switch action sequence, including:

[0025] A performance evaluation matrix under the corresponding fault simulation scenario is constructed according to the operating cost index and the reliability results corresponding to all target switch action sequences under each fault simulation scenario.

[0026] The performance evaluation matrix is ​​operated with the bus voltage deviation limit, the line current ratio limit and the load distribution imbalance as constraints to obtain the optimal switch action sequence under the corresponding fault simulation scenario.

[0027] Based on the optimal switch action sequence, a distribution network emergency control scheme under different fault simulation scenarios is generated.

[0028] Furthermore, when a failure occurs in the distribution network, executing the distribution network emergency control plan determined by the actual failure scenario includes:

[0029] During the operation of the distribution network, the distribution network operation data is acquired in real time, the operation characteristic data of the distribution network operation data is extracted, and it is determined whether a fault occurs in the distribution network according to the operation characteristic data.

[0030] If a fault occurs in the distribution network, the actual fault scenario is determined based on the operating characteristic data, the corresponding fault simulation scenario is matched based on the actual fault scenario, and the opening and closing states of the corresponding feeder section switches in the distribution network are adjusted based on the optimal switching action sequence corresponding to the fault simulation scenario.

[0031] Furthermore, in the process of adjusting the opening and closing states of corresponding feeder section switches in the distribution network according to the optimal switch action sequence corresponding to the fault simulation scenario, the operating state of the distribution network is monitored in real time, and the distribution network emergency control scheme is adaptively adjusted according to the monitoring results.

[0032] Furthermore, the real-time monitoring of the operating status of the distribution network and the adaptive adjustment of the distribution network emergency control scheme according to the monitoring results include:

[0033] The distribution network operation data is monitored in real time, and a voltage amplitude prediction value, a frequency change prediction value, and a power fluctuation prediction value are predicted based on the distribution network operation data.

[0034] A pre-adjusted switch action sequence is obtained according to the voltage amplitude prediction value, the frequency change prediction value, the power fluctuation prediction value, and the current switch state combination data.

[0035] The adjusted distribution network is simulated according to the pre-adjusted switch action sequence to obtain corresponding simulated transient response characteristic data.

[0036] The delay correction amount in the adjustment process is calculated according to the deviation between the simulated transient response characteristic data and the response characteristic data in the actual adjustment process.

[0037] The distribution network emergency control scheme is adaptively adjusted according to the delay correction amount.

[0038] Another embodiment of the present invention provides an emergency control system under a distribution network failure, comprising:

[0039] The distribution network simulation module is used to traverse the topological structure information of the distribution network feeder segment switch group using a depth-first search algorithm in a simulation environment to obtain a set of candidate switch sequences that meet the system transient characteristic constraints.

[0040] An indicator calculation module is used to perform stable operation screening on each candidate switch sequence in the candidate switch sequence set to obtain a plurality of target switch action sequences, wherein the stable operation screening is designed to use the key parameter change rate of each candidate switch sequence obtained by power flow calculation and transient simulation calculation as a screening evaluation indicator.

[0041] The fault simulation module is used to apply each of the target switch action sequences to all the constructed fault simulation scenarios in turn, and evaluate the simulation feedback results corresponding to each of the fault simulation scenarios to determine all the distribution network power supply reliability results corresponding to each of the fault simulation scenarios.

[0042] The scheme generation module is used to analyze all the distribution network power supply reliability results corresponding to each of the fault simulation scenarios, determine the optimal switch action sequence corresponding to each of the fault simulation scenarios, and generate distribution network emergency control schemes under different fault simulation scenarios based on the optimal switch action sequence.

[0043] The emergency control module is used to execute the distribution network emergency control plan determined by the actual fault scenario when a fault occurs in the distribution network.

[0044] Compared with the prior art, the embodiments of the present invention have the following advantages:

[0045] In response to the switching needs of the distribution network in normal operation and emergency situations, emergency operation modes such as independent power supply units are preset, the optimal switch disconnection plan is selected and the corresponding switch action sequence is formulated. During the morphological transformation process after a distribution network failure, the switch operation plan is dynamically adjusted through real-time monitoring and adaptive control strategies to ensure continuous power supply to critical loads, improve the flexibility and reliability of the distribution network in switching between different operation modes, and enhance the power grid's ability to respond to emergencies. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 A flowchart of the steps of the emergency control method under distribution network failure provided by an embodiment of the present invention;

[0047] Figure 2 This is a structural block diagram of an emergency control device under distribution network failure provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] In the description of this application, the terms "first", "second", "third", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", "third", etc. may explicitly or implicitly include one or more of the feature. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0050] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a connection between the two elements. The terms "vertical", "horizontal", "left", "right", "upper", "lower" and similar expressions used herein are only for illustrative purposes, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0051] In the description of this application, it should be noted that, unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood by specific circumstances.

[0052] An embodiment of the present invention provides an emergency control method under a distribution network failure. For details, see Figure 1 , Figure 1 The flowchart of the emergency control method under a distribution network fault in one embodiment of the present invention includes steps S11 to S15:

[0053] Step S11, according to the topological structure information of the distribution network feeder section switch group, a depth-first search algorithm is used in a simulation environment to traverse and obtain a set of candidate switch sequences that meet the system transient characteristic constraint conditions.

[0054] When responding to new major epidemics and public emergencies, the power grid infrastructure needs to be quickly converted from a conventional grid-type structure to an independent power supply unit to ensure the power supply reliability of critical loads. In this process, the topological reconstruction of the distribution network feeder segment switch group plays a vital role.

[0055] However, the selection and optimization of the switching action sequence faces many technical challenges. First, different switching action sequences will have a significant impact on the transient characteristics of the system, including voltage, frequency and power fluctuations. Improper switching operation sequence may cause system instability or even collapse.

[0056] Therefore, it is necessary to control the order of disconnecting switches during the rapid conversion of the power grid from a conventional grid-type structure to an independent power supply unit.

[0057] First, the topological structure information of all feeder section switch parameters in the distribution network is obtained. The topological structure information needs to include data on all feeder section switch parameters, node and feeder relationships, network connectivity, etc. In the simulation environment, based on the topological structure information, a depth-first search algorithm is used to traverse all possible switch action path combinations. During the traversal process, the state of each switch (on or off) is recorded to generate all possible switch action path combinations.

[0058] According to the system transient characteristic constraints, all candidate switch action sequences that can satisfy the system's operation as multiple independent power supply units in an emergency state are screened out from all schemes as a set of candidate switch action sequences. Among them, the system transient characteristic constraints consider the transient characteristics of the system in an emergency state, such as voltage stability, current distribution, etc., to ensure that the selected switch action sequences will not cause system instability or damage.

[0059] Preferably, on the basis of satisfying the constraints of the transient characteristics of the system, factors such as the economy and feasibility of the switching action may be further considered.

[0060] The specific process of selecting candidate switch action sequences according to the system transient characteristic constraint conditions in this embodiment is as follows:

[0061] For each switch action path combination, a transient simulation of the switch action is performed through a transient calculator based on the terminal voltage data of the feeder section corresponding to each switch. Through the simulation results, the transient characteristics of the power grid system after the switch action can be evaluated, such as voltage stability, overcurrent conditions, power balance, etc.

[0062] It is determined whether the preset system transient characteristic constraint conditions are met according to the simulation results. If so, the corresponding switch action path combination is stored in the switch sequence set as a candidate switch sequence.

[0063] Step S12, performing stable operation screening for each candidate switch sequence in the candidate switch sequence set to obtain a plurality of target switch action sequences, wherein the stable operation screening is designed to use the key parameter change rate of each candidate switch sequence obtained by power flow calculation and transient simulation calculation as a screening evaluation indicator.

[0064] Each candidate switch sequence corresponds to a specific set of switch states (on or off), which determine the topological structure of the distribution network. In order to perform power flow calculation, it is first necessary to obtain these switch state arrays, and then iteratively calculate the distribution network power flow through the Newton-Raphson method based on the switch state array to obtain the initial steady-state reference value. The initial steady-state reference value helps to determine whether the distribution network is in a stable state after the switch action, and whether there are problems such as voltage exceeding the limit and current overload.

[0065] According to the initial steady-state reference value, the frequency change rate of the voltage and current in the switching action interval is collected through dynamic sampling. The higher the frequency change rate, the greater the fluctuation of the operating state and the more unstable the operation. If the frequency change rate caused by a candidate switching sequence during the switching action exceeds the stability threshold, it means that the sequence may cause system instability or other serious problems, so it needs to be screened out to ensure that the final selected switching sequence can meet the stability and reliability requirements of the system. The screened candidate switching sequences are used as the target switching action sequences.

[0066] Step S13, applying each of the target switch action sequences to all constructed fault simulation scenarios in turn, evaluating the simulation feedback results corresponding to each of the fault simulation scenarios, so as to determine all distribution network power supply reliability results corresponding to each of the fault simulation scenarios.

[0067] By analyzing historical data or expert experience, we can understand the possible fault types and their probability distribution under different switch action sequences, and use the Monte Carlo method based on the probability distribution to randomly extract fault scenario parameters from the distribution network power fault type library according to the probability distribution of the fault type. This method can simulate the randomness and uncertainty of faults in actual distribution networks.

[0068] Each target switch action sequence is applied to the generated fault simulation scenario one by one to simulate the impact of the switch action on the distribution network. Through fault simulation, the load point power-off status of the distribution network based on the current target action switch sequence after each fault occurs is obtained.

[0069] According to the power outage status of the load point, the time window algorithm is used to calculate the power supply interruption duration in the current fault simulation scenario. The sliding time window statistical method is used to calculate the adjacent fault intervals in the current fault simulation scenario. According to the power supply interruption duration and the adjacent fault intervals, the power supply reliability results of each target switch action sequence in each fault simulation scenario are obtained, among which the power supply reliability results include the current average fault-free operation time and average fault duration.

[0070] By calculating the power supply reliability results, we can comprehensively evaluate the performance of each switching sequence in each fault simulation scenario and accurately quantify the power supply reliability, thus providing a basis for subsequently improving the operating efficiency and safety of independent power supply units.

[0071] Step S14, analyzing all distribution network power supply reliability results corresponding to each of the fault simulation scenarios, determining the optimal switch action sequence corresponding to each of the fault simulation scenarios, and generating distribution network emergency control plans under different fault simulation scenarios based on the optimal switch action sequence.

[0072] A performance evaluation matrix for the corresponding fault simulation scenario is constructed based on the operating cost index and the reliability results corresponding to all target switch action sequences under each fault simulation scenario. The performance evaluation matrix can reflect the comprehensive performance of the combined efficiency and cost of different switch action sequences under different fault simulation scenarios.

[0073] Operation constraints are set for the performance evaluation matrix. Specifically, the constraints include bus voltage deviation limit, line current ratio limit and load distribution imbalance. The optimal switch action sequence that meets the operation conditions and cost constraints is selected according to the operation results. At least one optimal switch action sequence is obtained for each fault simulation scenario.

[0074] Based on the optimal switch action sequence, emergency control schemes for the distribution network under different fault simulation scenarios are generated. By comprehensively considering the operating cost, reliability results and safety constraints, the optimal switch action sequence can be selected, and based on this, an effective emergency control scheme is generated to improve the operating efficiency and safety of the distribution network.

[0075] Step S15, when a failure occurs in the distribution network, executing the distribution network emergency control plan determined by the actual failure scenario.

[0076] After obtaining the distribution network emergency control plan, when the distribution network fails during operation, the operation characteristic data can be extracted from the distribution network operation data, and it can be judged whether the distribution network fails based on the operation characteristic data. If a failure occurs, the actual fault scenario is determined based on the operation characteristic data, and the corresponding fault simulation scenario is matched from the fault database based on the actual fault scenario. The optimal switch action sequence in the query plan is based on the fault simulation scenario, and the optimal switch action sequence is applied to determine the opening and closing of the corresponding feeder section switches in the distribution network, as well as the sequence of disconnecting switches.

[0077] However, in the actual control process, since the distribution network is in the process of failure, the power flow in the power grid is unstable and may change at any time. For example, when the selected switch to be disconnected is disconnected according to the preset emergency control plan, the disconnection of a certain switch causes the increase of the current in the surrounding branches to be greater than the preset expectation, resulting in a significant change in the data in the power grid. At this time, the power grid control according to the original preset plan obviously cannot meet the control target.

[0078] Therefore, in the process of executing the optimal switching action sequence corresponding to the current fault scenario according to the emergency control plan and adjusting the opening and closing status of the corresponding feeder section switches in the distribution network, it is necessary to monitor the operation data of the distribution network in real time. When a certain opening and closing action has an unexpected impact on the distribution network, the distribution network emergency control plan needs to be dynamically and adaptively adjusted.

[0079] The specific adaptive adjustment process is:

[0080] Monitor the distribution network operation data in real time, and predict the voltage amplitude, frequency change and power fluctuation based on the distribution network operation data;

[0081] According to the above prediction values, it is judged whether the scheme needs to be adjusted. In the actual operation process, the larger the above prediction value is, the greater the impact of the current breaking action on the stability of the distribution network is. The pre-adjusted switch action sequence is obtained based on the prediction value and the current switch state combination data.

[0082] Before applying the pre-adjustment switch action sequence, it is necessary to simulate the state after pre-adjustment, simulate the adjusted distribution network according to the pre-adjustment switch action sequence, and obtain the corresponding simulated transient response characteristic data.

[0083] The delay correction amount in the adjustment process is calculated according to the deviation between the simulated transient response characteristic data and the response characteristic data in the actual adjustment process. If the delay correction amount exceeds the fluctuation deviation in the normal adjustment process, the distribution network emergency control plan is adaptively adjusted according to the delay correction amount.

[0084] The emergency control method under distribution network failure of the present invention presets emergency operation modes such as independent power supply units according to the switching requirements of the distribution network in normal operation and emergency situations, selects the optimal switch disconnection plan and formulates the corresponding switch action sequence, and dynamically adjusts the switch operation plan through real-time monitoring and adaptive control strategy during the morphological conversion process after the distribution network failure to ensure continuous power supply to key loads, thereby improving the flexibility and reliability of the distribution network in switching between different operation modes and enhancing the ability of the power grid to respond to emergencies.

[0085] The embodiment of the present invention further provides an emergency control system under a distribution network failure, which is used to execute the emergency control method under a distribution network failure as described above. Figure 2 This is a structural block diagram of an emergency control system under a distribution network failure according to an embodiment of the present invention, and the system includes:

[0086] The distribution network simulation module 21 is used to traverse the topological structure information of the distribution network feeder segment switch group using a depth-first search algorithm in a simulation environment to obtain a set of candidate switch sequences that meet the system transient characteristic constraint conditions.

[0087] The indicator calculation module 22 is used to perform stable operation screening on each candidate switch sequence in the candidate switch sequence set to obtain a plurality of target switch action sequences, wherein the stable operation screening is designed to use the key parameter change rate of each candidate switch sequence obtained by power flow calculation and transient simulation calculation as the screening evaluation indicator.

[0088] The fault simulation module 23 is used to apply each of the target switch action sequences to all the constructed fault simulation scenarios in turn, and evaluate the simulation feedback results corresponding to each of the fault simulation scenarios to determine all the distribution network power supply reliability results corresponding to each of the fault simulation scenarios.

[0089] The solution generation module 24 is used to analyze all the distribution network power supply reliability results corresponding to each of the fault simulation scenarios, determine the optimal switch action sequence corresponding to each of the fault simulation scenarios, and generate distribution network emergency control solutions under different fault simulation scenarios based on the optimal switch action sequence.

[0090] The emergency control module 25 is used to execute the distribution network emergency control plan determined by the actual fault scenario when a fault occurs in the distribution network.

[0091] The technical features and technical effects of the system proposed in the embodiment of the present invention are the same as those of the method proposed in the embodiment of the present invention, and are not described in detail here. Each module in the above system can be implemented in whole or in part by software, hardware, and a combination thereof. Each of the above modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to each of the above modules.

[0092] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An emergency control method under distribution network failure, characterized in that: include: According to the topological structure information of the feeder section switch group of the distribution network, a depth-first search algorithm is used in the simulation environment to traverse and obtain a set of candidate switch sequences that meet the transient characteristic constraints of the system; Performing stable operation screening on each candidate switch sequence in the candidate switch sequence set to obtain a plurality of target switch action sequences, wherein the stable operation screening is designed to use the key parameter change rate of each candidate switch sequence obtained by power flow calculation and transient simulation calculation as a screening evaluation index; Apply each of the target switch action sequences to all the constructed fault simulation scenarios in turn, and evaluate the simulation feedback results corresponding to each of the fault simulation scenarios to determine all the distribution network power supply reliability results corresponding to each of the fault simulation scenarios; Analyze all the distribution network power supply reliability results corresponding to each of the fault simulation scenarios, determine the optimal switch action sequence corresponding to each of the fault simulation scenarios, and generate distribution network emergency control plans under different fault simulation scenarios based on the optimal switch action sequence; When a failure occurs in the distribution network, the distribution network emergency control plan determined by the actual failure scenario is executed.

2. The emergency control method under distribution network failure according to claim 1, characterized in that: The method of traversing the topological structure information of the feeder section switch group of the distribution network using a depth-first search algorithm in a simulation environment to obtain a set of candidate switch sequences that meet the transient characteristic constraint conditions of the system includes: According to the topological structure information of the feeder segment switch group of the distribution network, a depth-first search algorithm is used to traverse all switch action path combinations, and for each switch action path combination, a transient simulation of the switch action is performed through a transient calculator according to the terminal voltage data of the feeder segment corresponding to each switch; It is determined whether the system transient characteristic constraint conditions are met according to the simulation results. If so, the corresponding switch action path combination is stored in the switch sequence set as a candidate switch sequence.

3. The emergency control method under distribution network failure according to claim 1, characterized in that: The stable operation screening is performed on each candidate switch sequence in the candidate switch sequence set to obtain a plurality of target switch action sequences, including: For each candidate switch sequence, a switch state array of the candidate switch sequence is obtained, and according to the switch state array, the power flow of the distribution network is iteratively calculated by the Newton-Raphson method to obtain an initial steady-state reference value; According to the initial steady-state reference value, the frequency change rate of the voltage and current within the switching action interval is collected by dynamic sampling. If the frequency change rate exceeds a stable change rate threshold, the corresponding target switching action sequence is screened out.

4. The emergency control method under distribution network failure according to claim 1, characterized in that: The reliability results include mean time between failures and mean duration between failures.

5. The emergency control method under distribution network failure as claimed in claim 4, characterized in that: The method of applying each of the target switch action sequences to all the constructed fault simulation scenarios in turn, and evaluating the simulation feedback results corresponding to each of the fault simulation scenarios to determine all the distribution network power supply reliability results corresponding to each of the fault simulation scenarios, includes: Obtaining a probability distribution of the fault type according to each target switch action sequence, extracting fault scenario parameters from a distribution network power fault type library using a Monte Carlo sampler according to the probability distribution, and generating a plurality of fault simulation scenarios according to the fault scenario parameters; For each of the target switch action sequences, applying the corresponding target switch action sequence to each of the fault simulation scenarios to simulate and obtain the load point power-off state of the distribution network under each of the fault simulation scenarios; According to the power-off status of the load point, a time window algorithm is used to calculate the power supply interruption duration in the current fault simulation scenario, and a sliding time window statistical method is used to calculate the adjacent fault intervals in the current fault simulation scenario; The average fault-free operation time and the average fault duration are obtained according to the power supply interruption time and the adjacent fault interval.

6. The emergency control method under distribution network failure as claimed in claim 5, characterized in that: The method of analyzing all the power supply reliability results of the distribution network corresponding to each of the fault simulation scenarios, determining the optimal switch action sequence corresponding to each of the fault simulation scenarios, and generating the distribution network emergency control scheme under different fault simulation scenarios based on the optimal switch action sequence includes: Constructing a performance evaluation matrix under the corresponding fault simulation scenario according to the operating cost index and the reliability results corresponding to all target switch action sequences under each fault simulation scenario; The performance evaluation matrix is ​​operated with the bus voltage deviation limit, the line current ratio limit and the load distribution imbalance as constraints to obtain the optimal switch action sequence under the corresponding fault simulation scenario; Based on the optimal switch action sequence, a distribution network emergency control scheme under different fault simulation scenarios is generated.

7. The emergency control method under distribution network failure according to claim 1, characterized in that: When a failure occurs in the distribution network, executing the distribution network emergency control plan determined by the actual failure scenario includes: During the operation of the distribution network, the distribution network operation data is acquired in real time, the operation characteristic data of the distribution network operation data is extracted, and whether a fault occurs in the distribution network is determined according to the operation characteristic data; If a fault occurs in the distribution network, the actual fault scenario is determined based on the operating characteristic data, the corresponding fault simulation scenario is matched based on the actual fault scenario, and the opening and closing states of the corresponding feeder section switches in the distribution network are adjusted based on the optimal switching action sequence corresponding to the fault simulation scenario.

8. The emergency control method under distribution network failure as claimed in claim 7, characterized in that: In the process of adjusting the opening and closing states of corresponding feeder section switches in the distribution network according to the optimal switch action sequence corresponding to the fault simulation scenario, the operating state of the distribution network is monitored in real time, and the emergency control scheme of the distribution network is adaptively adjusted according to the monitoring results.

9. The emergency control method under distribution network failure as claimed in claim 8, characterized in that: The real-time monitoring of the operating status of the distribution network and adaptively adjusting the emergency control scheme of the distribution network according to the monitoring results include: Real-time monitoring of distribution network operation data, and prediction of voltage amplitude prediction value, frequency change prediction value and power fluctuation prediction value according to the distribution network operation data; Obtaining a pre-adjusted switch action sequence according to the voltage amplitude prediction value, the frequency change prediction value, the power fluctuation prediction value, and current switch state combination data; Simulating the adjusted distribution network according to the pre-adjusted switch action sequence to obtain corresponding simulated transient response characteristic data; Calculating a delay correction amount in the adjustment process according to a deviation between the simulated transient response characteristic data and the response characteristic data in the actual adjustment process; The distribution network emergency control scheme is adaptively adjusted according to the delay correction amount.

10. An emergency control system for distribution network failure, characterized in that: include: The distribution network simulation module is used to traverse the topological structure information of the distribution network feeder segment switch group using a depth-first search algorithm in a simulation environment to obtain a set of candidate switch sequences that meet the system transient characteristic constraint conditions; An index calculation module is used to perform stable operation screening on each candidate switch sequence in the candidate switch sequence set to obtain a plurality of target switch action sequences, wherein the stable operation screening is designed to use the key parameter change rate of each candidate switch sequence obtained by power flow calculation and transient simulation calculation as a screening evaluation index; A fault simulation module is used to apply each of the target switch action sequences to all the constructed fault simulation scenarios in turn, and evaluate the simulation feedback results corresponding to each of the fault simulation scenarios to determine all the distribution network power supply reliability results corresponding to each of the fault simulation scenarios; A scheme generation module is used to analyze all the power supply reliability results of the distribution network corresponding to each of the fault simulation scenarios, determine the optimal switch action sequence corresponding to each of the fault simulation scenarios, and generate the distribution network emergency control scheme under different fault simulation scenarios based on the optimal switch action sequence; The emergency control module is used to execute the distribution network emergency control plan determined by the actual fault scenario when a fault occurs in the distribution network.

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