A power distribution network self-healing method and system based on inverter and broadband network analysis

Abstract

The application discloses a power distribution network self-healing method and system based on an inverter and broadband network analysis, and belongs to the technical field of power distribution network self-healing. The application obtains a candidate transfer scheme and topology configuration data, then performs broadband network modeling on the candidate transfer scheme according to the topology configuration data to obtain a broadband network node admittance matrix; then broadband impedance analysis and resonance characteristic extraction are performed on the broadband network node admittance matrix; on the basis, an inverter output control model is constructed with the topology configuration data, and coupling analysis is performed in combination with broadband impedance data and resonance characteristic data to obtain a safety risk analysis result; finally, the candidate transfer scheme is verified for inverter control based on the safety risk analysis result, and a self-healing transfer scheme is screened, so that the power distribution network is self-healed and recovered, and the stability of the power distribution network self-healing recovery is improved.

Description

Technical Field

[0001] This invention belongs to the field of distribution network self-healing technology, and particularly relates to a distribution network self-healing method and system based on inverter and broadband network analysis. Background Technology

[0002] Distribution network self-healing refers to the technical means by which a power distribution system, after a fault occurs, automatically restores power supply to non-faulty areas by locating the fault, isolating the faulty section, and so on. It is a core function for improving power supply reliability. Traditional distribution network self-healing methods are usually based on the basic logic of fault location, fault isolation, interconnection and power transfer, and power restoration. They change the network topology through switching operations to transfer the out-of-power load to the backup power source, thereby restoring power supply to non-faulty areas in a relatively short time.

[0003] Traditional distribution network self-healing solutions typically focus on the steady-state feasibility of the distribution network, addressing switch reconfiguration and load restoration issues. They treat inverters in the distribution network as constant power sources or simple reactive power compensation nodes, considering only the inverter's own operational performance. However, with the large-scale integration of inverters into the distribution network, this disconnect between inverter control and network topology easily leads to network impedance reconfiguration problems during temporary topology changes in the self-healing process. Furthermore, it can cause control coupling issues during actual inverter operation, resulting in harmonic amplification, local resonance, weak network oscillations, inverter control mismatch, and protection malfunctions during distribution network self-healing, thus reducing the stability of the distribution network self-healing process. Summary of the Invention

[0004] The present invention aims to provide a distribution network self-healing method and system based on inverter and broadband network analysis to solve the above-mentioned technical problems and improve the stability of distribution network self-healing.

[0005] To address the aforementioned technical problems, embodiments of the present invention provide a distribution network self-healing method based on inverter and broadband network analysis, comprising: Obtain several candidate power transfer schemes for the power distribution network and the topology configuration data of each candidate power transfer scheme; Based on the topology configuration data, broadband network modeling is performed on each of the candidate power transfer schemes to obtain the broadband network node admittance matrix of each candidate power transfer scheme; Based on the broadband network node admittance matrix, broadband impedance analysis and resonance feature extraction are performed on each of the candidate power transfer schemes to obtain broadband impedance data and resonance feature data of each candidate power transfer scheme. Based on the topology configuration data, an inverter output control model is constructed for each of the candidate power transfer schemes. Combined with the wideband impedance data and resonant characteristic data, a coupled analysis is performed on each of the candidate power transfer schemes to obtain the safety risk analysis results of each candidate power transfer scheme. Based on the safety risk analysis results, the inverter control is verified for the candidate power transfer scheme to obtain the self-healing power transfer scheme of the distribution network, and the distribution network is self-healed and restored based on the self-healing power transfer scheme.

[0006] Understandably, compared to existing technologies, this invention acquires candidate power transfer schemes and their topology configuration data, then performs broadband network modeling on the candidate power transfer schemes based on the topology configuration data to obtain broadband network node admittance matrices. Next, broadband impedance analysis and resonance feature extraction are performed using the broadband network node admittance matrices, thereby achieving a comprehensive characterization of the broadband impedance characteristics and resonance risks of each candidate power transfer scheme at the network topology level. Based on this, an inverter output control model is constructed using the topology configuration data, and coupled analysis is performed using broadband impedance data and resonance feature data. This enables interactive evaluation of the fragmented inverter control and network topology characteristics, resulting in more accurate safety risk analysis results. Finally, based on these safety risk analysis results, inverter control verification is performed on the candidate power transfer schemes, and self-healing power transfer schemes are selected. This ensures that the distribution network self-healing recovery fully considers the interaction between the inverter and the network topology, effectively avoiding problems such as harmonic amplification, local resonance, and control mismatch caused by neglecting the interaction between the inverter and the network topology in traditional methods, thus improving the stability of the distribution network self-healing recovery.

[0007] As a preferred embodiment, the topology configuration data includes: line configuration parameters, transformer configuration parameters, capacitor configuration parameters, compensation device configuration parameters, and load configuration parameters; the broadband network modeling of each candidate power transfer scheme based on the topology configuration data, to obtain the broadband network node admittance matrix of each candidate power transfer scheme, includes: Based on the line configuration parameters, construct the line frequency domain admittance matrix for each candidate power transfer scheme at each preset wideband scanning angle frequency; Based on the transformer configuration parameters, construct the transformer frequency domain admittance matrix for each of the candidate power transfer schemes at each of the wideband scanning angular frequencies; Based on the capacitor configuration parameters, construct the capacitor frequency domain admittance matrix for each candidate power transfer scheme at each wideband scanning angular frequency; Based on the configuration parameters of the compensation device, construct the frequency domain admittance matrix of the compensation device for each candidate power transfer scheme at each wideband scanning angular frequency; Based on the load configuration parameters, construct the load frequency domain admittance matrix for each of the candidate power transfer schemes at each of the wideband scanning angular frequencies; The frequency domain admittance matrices of the line, transformer, capacitor, compensation device, and load are summed to obtain the broadband network node admittance matrix of each candidate power transfer scheme at each broadband scanning angular frequency.

[0008] The above scheme constructs corresponding frequency domain admittance matrices for lines, transformers, capacitors, compensation devices, and loads based on line configuration parameters, transformer configuration parameters, capacitor configuration parameters, compensation device configuration parameters, and load configuration parameters, respectively. This ensures that the broadband network node admittance matrix accurately reflects the differentiated frequency response characteristics of different devices in the distribution network over a wide frequency range, avoiding modeling distortion caused by simply equating various devices to power frequency parameters. It ensures that each candidate power transfer scheme has a broadband network node admittance matrix that strictly matches its network topology, resulting in high accuracy in subsequent broadband impedance analysis and resonance feature extraction of candidate power transfer schemes. This provides reliable data support for subsequent safety risk assessment, thereby improving the stability of the distribution network's self-healing recovery.

[0009] As a preferred embodiment, the step of performing broadband impedance analysis and resonance feature extraction on each of the candidate power transfer schemes based on the broadband network node admittance matrix to obtain broadband impedance data and resonance feature data for each of the candidate power transfer schemes includes: Based on the topology configuration data, identify the set of key nodes in each of the candidate transfer schemes, and form a set of elimination nodes based on other nodes in the candidate transfer schemes that do not belong to the set of key nodes; Based on the elimination node set, the broadband network node admittance matrix of each candidate transfer scheme is subjected to equivalent elimination processing to obtain the broadband equivalent admittance matrix corresponding to the key node set of each candidate transfer scheme. Inverting the broadband equivalent admittance matrix yields the broadband equivalent impedance matrix corresponding to the key node set of each candidate power transfer scheme; Based on the number of key nodes in the key node set of each candidate power transfer scheme, the broadband impedance spectrum of each candidate power transfer scheme is extracted from the broadband equivalent impedance matrix; Broadband impedance data for each candidate power transfer scheme is formed based on the broadband equivalent impedance matrix and broadband impedance spectrum. Based on the broadband impedance data, resonant features are extracted from each of the candidate power transfer schemes to obtain the main resonant frequency band and predicted total harmonic distortion rate of the voltage for each candidate power transfer scheme, thereby forming resonant feature data for each candidate power transfer scheme.

[0010] In the above scheme, nodes in the candidate power transfer schemes are classified to form a set of key nodes and a set of nodes to be eliminated. The set of nodes to be eliminated is then subjected to equivalent elimination processing to obtain a broadband equivalent admittance matrix and a broadband equivalent impedance matrix that retain only the set of key nodes. The elimination method significantly reduces the dimensionality of the broadband network node admittance matrix, which not only reduces the computational requirements but also allows the calculated broadband impedance data and resonance characteristic data to directly reflect the electrical characteristics of key nodes in the actual execution of the candidate power transfer scheme. Then, by extracting the broadband impedance spectrum and combining it with the broadband equivalent impedance matrix to form broadband impedance data, resonance characteristics are extracted using the broadband impedance data to obtain the main resonant frequency band and the predicted total harmonic distortion rate of the voltage. This achieves multi-dimensional and accurate quantification of the resonance risk of the candidate power transfer scheme, thereby improving the stability and accuracy of the distribution network's self-healing recovery.

[0011] As a preferred embodiment, the resonant feature extraction of each candidate power transfer scheme based on the broadband impedance data is performed to obtain the main resonant frequency band and predicted total harmonic distortion rate of the voltage for each candidate power transfer scheme, thereby forming the resonant feature data of each candidate power transfer scheme, including: Within a preset wideband scanning angular frequency range, the wideband impedance spectrum of each candidate power transfer scheme is searched to obtain several local peak frequency points for each candidate power transfer scheme. Based on preset peak value judgment conditions, the local peak frequency points are filtered to obtain the main resonant frequency band of each candidate power supply scheme; Obtain harmonic current injection data for each of the candidate power transfer schemes, and determine the harmonic voltage prediction data corresponding to the key node set of each candidate power transfer scheme based on the harmonic current injection data and the broadband equivalent impedance matrix. The total harmonic distortion rate of the predicted voltage for each of the candidate power transfer schemes is determined based on the harmonic voltage prediction data. The resonant characteristic data of each candidate power transfer scheme are formed based on the main resonant frequency band and the predicted total harmonic distortion of the voltage for each candidate power transfer scheme.

[0012] In the above scheme, the broadband impedance spectrum is scanned to identify all local peak frequency points, and the main resonant frequency band with real risk significance is screened according to the preset peak judgment conditions. This can avoid the overly conservative evaluation results that lead to the wrong elimination of a large number of feasible schemes, which is conducive to maintaining the sufficiency of self-healing schemes. Then, using the harmonic current injection data and the broadband equivalent impedance matrix, the harmonic voltage prediction data of key nodes and the total harmonic distortion rate of the predicted voltage are calculated. This can truly reflect the degree of harmonic amplification of the network topology under the candidate power transfer scheme under the actual harmonic source excitation, providing reliable resonance characteristic data for subsequent safety risk assessment, thereby improving the accuracy and stability of self-healing recovery.

[0013] As a preferred embodiment, the inverter output control model for each candidate power transfer scheme is constructed based on the topology configuration data. Coupled analysis is then performed on each candidate power transfer scheme using the wideband impedance data and resonant characteristic data to obtain the safety risk analysis results for each candidate power transfer scheme, including: Based on the topology configuration data, the control fingerprint of each inverter in each of the candidate power transfer schemes is determined; Based on the topology configuration data, construct the current disturbance vector and voltage disturbance vector for each inverter in each candidate power transfer scheme; The signal output admittance of each inverter within each candidate power transfer scheme is determined based on the ratio of the current disturbance vector to the voltage disturbance vector. The signal output admittance of each inverter in each candidate power transfer scheme is aggregated to obtain the aggregated output admittance of the inverter for each candidate power transfer scheme. An inverter output control model for each candidate power transfer scheme is formed based on the inverter aggregated output admittance for each candidate power transfer scheme and the control fingerprint of each inverter. Based on the inverter output control model, wideband impedance data, and resonance characteristic data, a coupled analysis is performed on each of the candidate power transfer schemes to obtain the stability risk index, control compatibility risk index, harmonic amplification risk index, and weak grid risk index for each candidate power transfer scheme. The stability risk index, control compatibility risk index, harmonic amplification risk index, and weak network risk index are weighted and summed to obtain the security risk analysis results for each candidate power transfer scheme.

[0014] In the above scheme, the inverter's control fingerprint is determined by topology configuration data and characterized as a small-signal output admittance. This allows the inverter's dynamic control characteristics to participate in subsequent frequency domain coupling analysis in the form of admittance, avoiding the problem of traditional methods treating the inverter as an ideal power source or a simple reactive power compensation node and ignoring its dynamic control characteristics. Based on this, coupling analysis using the inverter output control model, wideband impedance data, and resonance characteristic data enables interactive evaluation of the fragmented inverter control and network topology characteristics, resulting in more accurate stability risk, control compatibility risk, harmonic risk, and weak network risk. Finally, the stability risk, control compatibility risk, harmonic risk, and weak network risk are weighted and summed to obtain the safety risk analysis results. This achieves a multi-dimensional comprehensive evaluation of the dynamic safety of candidate power transfer schemes, effectively avoiding the risk omission caused by the one-sidedness of single-dimensional evaluation, thereby improving the accuracy and stability of the distribution network's self-healing recovery.

[0015] As a preferred embodiment, the coupling analysis of each candidate power transfer scheme based on the inverter output control model, wideband impedance data, and resonant characteristic data yields stability risk indicators, control compatibility risk indicators, harmonic amplification risk indicators, and weak grid risk indicators for each candidate power transfer scheme, including: The inverter aggregate output admittance of each candidate power transfer scheme is mapped to each key node in the set of key nodes to obtain the inverter aggregate output admittance mapping matrix of each candidate power transfer scheme. The return ratio matrix of each candidate power transfer scheme is constructed based on the inverter aggregated output admittance mapping matrix and the broadband equivalent impedance matrix of each candidate power transfer scheme. Extract the minimum singular value from the return ratio matrix of each candidate transfer scheme, and determine the stability risk index of each candidate transfer scheme based on the minimum singular value; Based on the main resonant frequency band and the control fingerprint of each inverter in each candidate power transfer scheme, the control compatibility risk index of each candidate power transfer scheme is determined. The harmonic amplification risk index for each candidate power transfer scheme is determined based on the preset voltage total harmonic distortion rate limit, the predicted voltage total harmonic distortion rate, the preset impedance spectrum amplitude discrimination threshold, and the broadband impedance spectrum. The equivalent short-circuit capacity of each candidate power transfer scheme is determined based on the broadband equivalent impedance matrix, and the weak network risk index of each candidate power transfer scheme is determined based on the equivalent short-circuit capacity.

[0016] In the above scheme, the inverter aggregated output admittance is mapped to each key node in the set of key nodes, so that the inverter aggregated output admittance mapping matrix and the broadband equivalent impedance matrix have the same dimension, ensuring that the return ratio matrix can conform to the actual network topology of the distribution network. Then, the minimum singular value of the return ratio matrix is ​​extracted as a stability margin index, making the stability risk index more accurate. Subsequently, based on the main resonant frequency band and control fingerprint, a control compatibility risk index is obtained, which can identify the problem of interaction mismatch between inverter control parameters and network topology. On this basis, the voltage total harmonic distortion rate limit and prediction are used as the basis for further analysis. The total harmonic distortion rate of voltage, the preset impedance spectrum amplitude discrimination threshold, and the broadband impedance spectrum are used to determine the harmonic amplification risk index, which can accurately identify the network topology harmonic problems of the distribution network. Then, the broadband equivalent impedance matrix is ​​used to obtain the weak network risk index, which can accurately assess the degree of weakness in the distribution network during the self-healing process. The stability risk index, control compatibility risk index, harmonic amplification risk index, and weak network risk index together constitute a complete dynamic security evaluation system from different dimensions, which enables the risk assessment to cover various instability forms that may occur after power transfer, thereby improving the accuracy and stability of the distribution network self-healing recovery.

[0017] As a preferred embodiment, the step of performing inverter control verification on the candidate power transfer schemes based on the safety risk analysis results to obtain a self-healing power transfer scheme for the distribution network, and performing self-healing recovery of the distribution network based on the self-healing power transfer scheme, includes: Based on the security risk analysis results, each of the candidate transfer schemes is risk-classified to obtain the risk level of each candidate transfer scheme. If the risk level of the candidate power transfer scheme is the preset first level, then the candidate power transfer scheme will be used as the alternative power transfer scheme for the distribution network. If the risk level of the candidate power transfer scheme is the preset second level, then the inverter control verification is performed on the candidate power transfer scheme based on the safety risk analysis results to update the risk level of the candidate power transfer scheme; If the risk level of the candidate transfer scheme is the preset third level, then the candidate transfer scheme is eliminated; Each of the alternative power transfer schemes is evaluated based on a preset self-healing comprehensive benefit model to obtain the self-healing power transfer scheme of the distribution network, and the distribution network is self-healed and restored based on the self-healing power transfer scheme.

[0018] In the above scheme, risk classification is performed based on the results of safety risk analysis. This tiered approach allows first-tier candidate power transfer schemes to be considered without additional inverter control verification, reducing computational burden. The risk level of first-tier candidate power transfer schemes is updated through inverter control verification, preventing direct elimination due to high risk and retaining more recoverable schemes. Third-tier candidate power transfer schemes are directly eliminated, effectively preventing non-compliant schemes from entering the final selection. Furthermore, a self-healing comprehensive benefit model is used for evaluation, ensuring that the final selected self-healing scheme not only has good load recovery performance at the steady-state level but also meets the requirements for safe and stable operation at the dynamic level, thereby improving the success rate and stability of the distribution network's self-healing recovery.

[0019] As a preferred embodiment, if the risk level of the candidate supply transfer scheme is a preset second level, then based on the safety risk analysis results, inverter control verification is performed on the candidate supply transfer scheme to update the risk level of the candidate supply transfer scheme, including: If the risk level of the candidate power transfer scheme is the preset second level, then obtain the adjustable range of the control parameters of each inverter in the candidate power transfer scheme; Based on the adjustable range of the control parameters and the results of the safety risk analysis, the control fingerprint of each inverter is adjusted to obtain the temporary control fingerprint of each inverter. The security risk analysis results of the candidate power transfer schemes are updated based on the temporary control fingerprints of each inverter to obtain the first security risk analysis result of the candidate power transfer schemes. The risk level of the candidate transfer scheme is updated based on the first security risk analysis results.

[0020] In the above scheme, the adjustable range of control parameters of each inverter is obtained, and a temporary control parameter range is generated by combining the control fingerprint. The inverter control fingerprint is then adjusted within this range to obtain a temporary control fingerprint. Based on the adjusted control fingerprint, a new safety risk assessment and risk level update are performed. Without changing the topology, adjusting the inverter control parameters increases the number of executable self-healing schemes, thereby increasing the number of optional schemes for distribution network self-healing. At the same time, the accuracy and reliability of control parameter adjustment are ensured by the temporary control parameter range and the results of safety risk analysis, thereby improving the success rate and stability of distribution network self-healing recovery.

[0021] Accordingly, this embodiment provides a distribution network self-healing system based on inverter and broadband network analysis, including: a candidate power transfer scheme acquisition module, a broadband network modeling module, a broadband network analysis module, an inverter broadband network coupling analysis module, and a distribution network self-healing module; The candidate power transfer scheme acquisition module is used to acquire several candidate power transfer schemes of the distribution network and the topology configuration data of each candidate power transfer scheme; The broadband network modeling module is used to perform broadband network modeling on each of the candidate transfer schemes based on the topology configuration data, and to obtain the broadband network node admittance matrix of each of the candidate transfer schemes. The broadband network analysis module is used to perform broadband impedance analysis and resonance feature extraction on each of the candidate power transfer schemes based on the broadband network node admittance matrix, so as to obtain broadband impedance data and resonance feature data of each of the candidate power transfer schemes. The inverter wideband network coupling analysis module is used to construct an inverter output control model for each candidate power transfer scheme based on the topology configuration data, and to perform coupling analysis on each candidate power transfer scheme in combination with the wideband impedance data and resonance characteristic data to obtain the safety risk analysis results of each candidate power transfer scheme. The distribution network self-healing module is used to perform inverter control verification on the candidate power transfer scheme based on the safety risk analysis results, obtain the self-healing power transfer scheme of the distribution network, and perform self-healing recovery of the distribution network based on the self-healing power transfer scheme.

[0022] As a preferred embodiment, the broadband network modeling module includes: a broadband network modeling unit; In the broadband network modeling unit, the topology configuration data includes: line configuration parameters, transformer configuration parameters, capacitor configuration parameters, compensation device configuration parameters, and load configuration parameters; Based on the line configuration parameters, construct the line frequency domain admittance matrix for each candidate power transfer scheme at each preset wideband scanning angle frequency; Based on the transformer configuration parameters, construct the transformer frequency domain admittance matrix for each of the candidate power transfer schemes at each of the wideband scanning angular frequencies; Based on the capacitor configuration parameters, construct the capacitor frequency domain admittance matrix for each candidate power transfer scheme at each wideband scanning angular frequency; Based on the configuration parameters of the compensation device, construct the frequency domain admittance matrix of the compensation device for each candidate power transfer scheme at each wideband scanning angular frequency; Based on the load configuration parameters, construct the load frequency domain admittance matrix for each of the candidate power transfer schemes at each of the wideband scanning angular frequencies; The frequency domain admittance matrices of the line, transformer, capacitor, compensation device, and load are summed to obtain the broadband network node admittance matrix of each candidate power transfer scheme at each broadband scanning angular frequency.

[0023] Understandably, compared to existing technologies, this invention acquires candidate power transfer schemes and their topology configuration data, then performs broadband network modeling on the candidate power transfer schemes based on the topology configuration data to obtain broadband network node admittance matrices. Next, broadband impedance analysis and resonance feature extraction are performed using the broadband network node admittance matrices, thereby achieving a comprehensive characterization of the broadband impedance characteristics and resonance risks of each candidate power transfer scheme at the network topology level. Based on this, an inverter output control model is constructed using the topology configuration data, and coupled analysis is performed using broadband impedance data and resonance feature data. This enables interactive evaluation of the fragmented inverter control and network topology characteristics, resulting in more accurate safety risk analysis results. Finally, based on these safety risk analysis results, inverter control verification is performed on the candidate power transfer schemes, and self-healing power transfer schemes are selected. This ensures that the distribution network self-healing recovery fully considers the interaction between the inverter and the network topology, effectively avoiding problems such as harmonic amplification, local resonance, and control mismatch caused by neglecting the interaction between the inverter and the network topology in traditional methods, thus improving the stability of the distribution network self-healing recovery. Attached Figure Description

[0024] Figure 1 A flowchart illustrating the steps of a distribution network self-healing method based on inverter and broadband network analysis, provided in an embodiment of the present invention; Figure 2This is a schematic diagram of a distribution network self-healing system based on inverter and broadband network analysis, provided as an embodiment of the present invention. Detailed Implementation

[0025] 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.

[0026] Example 1 Please refer to Figure 1 , Figure 1 The flowchart of a distribution network self-healing method based on inverter and broadband network analysis provided in this embodiment of the invention includes steps S101 to S105.

[0027] Step S101: Obtain several candidate power transfer schemes for the distribution network and the topology configuration data of each candidate power transfer scheme.

[0028] Step S102: Based on the topology configuration data, perform broadband network modeling on each of the candidate transfer schemes to obtain the broadband network node admittance matrix of each candidate transfer scheme.

[0029] Step S103: Based on the broadband network node admittance matrix, perform broadband impedance analysis and resonance feature extraction on each of the candidate power transfer schemes to obtain broadband impedance data and resonance feature data of each candidate power transfer scheme.

[0030] Step S104: Based on the topology configuration data, construct the inverter output control model for each candidate power transfer scheme, and perform a coupling analysis on each candidate power transfer scheme by combining the wideband impedance data and resonance characteristic data to obtain the safety risk analysis results of each candidate power transfer scheme.

[0031] Step S105: Based on the safety risk analysis results, perform inverter control verification on the candidate power transfer scheme to obtain the self-healing power transfer scheme of the distribution network, and perform self-healing recovery of the distribution network based on the self-healing power transfer scheme.

[0032] This embodiment acquires candidate power transfer schemes and their topology configuration data, then performs broadband network modeling on the candidate schemes based on the topology configuration data to obtain broadband network node admittance matrices. Next, broadband impedance analysis and resonance feature extraction are performed using the broadband network node admittance matrices, thus achieving a comprehensive characterization of the broadband impedance characteristics and resonance risks of each candidate power transfer scheme at the network topology level. Based on this, an inverter output control model is constructed using the topology configuration data, and coupled analysis is performed using broadband impedance data and resonance feature data. This enables interactive evaluation of the fragmented inverter control and network topology characteristics, resulting in more accurate safety risk analysis results. Finally, based on the safety risk analysis results, inverter control verification is performed on the candidate power transfer schemes, and self-healing power transfer schemes are selected. This ensures that the distribution network self-healing recovery fully considers the interaction between the inverter and the network topology, effectively avoiding problems such as harmonic amplification, local resonance, and control mismatch caused by neglecting the interaction between the inverter and the network topology in traditional methods, thereby improving the stability of the distribution network self-healing recovery.

[0033] In an optional embodiment, obtaining a plurality of candidate power transfer schemes for the distribution network and the topology configuration data of each candidate power transfer scheme includes: This embodiment represents the power distribution network as a graphical structure. ,in Represents a set of nodes. This represents the branch circuit and the set of switches. The state of each switch is defined as follows: ;in, Indicates the first One switch is closed. Indicates the first One switch is off. This is a set of operable switches. Before a distribution network can perform self-healing recovery, fault isolation is required. A distribution network with completed fault isolation is defined as... ;in, For the network before the failure, A set of switches that are disconnected to isolate faults.

[0034] For distribution networks that have completed fault isolation, the traditional method for generating self-healing schemes for distribution networks currently generates several initial power transfer schemes, which are represented as follows: ; Indicates the first An initial supply transfer plan This represents the total number of initial power transfer schemes. Simultaneously, the topology configuration data for each initial power transfer scheme can be determined. This topology configuration data includes, but is not limited to, the relevant configuration data for each node, power equipment, and line within the initial power transfer scheme. Specifically, this embodiment defines the topology configuration data as including: line configuration parameters, transformer configuration parameters, capacitor configuration parameters, compensation device configuration parameters, and load configuration parameters. It should be noted that generating the initial power transfer scheme and its corresponding topology configuration data is a common preliminary step in current distribution network self-healing; therefore, this embodiment will not elaborate on its specific implementation process.

[0035] Based on this, it is necessary to verify the three-phase power flow constraints of each initial power transfer scheme to ensure that the subsequent candidate power transfer schemes can meet the steady-state feasibility after fault isolation of the distribution network; specifically, the three-phase power flow constraints include the following formulas (1) to (5), (1); (2); (3); (4); (5); In formulas (1) to (5), Indicates separation, , which represent phase a, phase b and phase c respectively; and These represent the upstream and downstream nodes at both ends of the line, respectively. Indicates power is generated by the node Flowing along the line to the node Reference direction; Represented by node The downstream neighbor of the upstream node; and Representing branch roads In phase The active and reactive power transmitted upstream; and Representing branch roads In phase The active and reactive power transmitted upstream; and Representing nodes respectively In phase The active power and reactive power of the load; and Representing nodes respectively In phase The active and reactive power injected into the distribution network by distributed power sources, energy storage converters or other controllable power electronic devices; in particular, the above active power, reactive power, load active power and load reactive power are all defined with positive values ​​for inflow into the load and positive values ​​for injection into the distribution network by distributed power sources; and Representing branch roads In phase The equivalent resistance and equivalent reactance on the surface; and Representing nodes respectively and nodes In phase The voltage amplitude variable (in this embodiment, a linearized three-phase DistFlow power flow model is used, therefore...) and (Take the square of the corresponding phase voltage amplitude). and These represent the lower and upper limits of the allowable node voltage, respectively. Indicates a branch In phase The maximum current allowed to pass through is usually determined by the line thermal stability limit, the rated current of the switch, or the protection setting. If the initial power transfer scheme satisfies the three-phase power flow constraints of formulas (1) to (5), then the initial power transfer scheme is taken as a candidate power transfer scheme, and its corresponding topology configuration data is recorded as the topology configuration data of the candidate power transfer scheme; thus, in this embodiment, the candidate power transfer scheme is defined as follows: .

[0036] In this embodiment, the topology configuration data includes: line configuration parameters, transformer configuration parameters, capacitor configuration parameters, compensation device configuration parameters, and load configuration parameters; the broadband network modeling of each candidate power transfer scheme based on the topology configuration data to obtain the broadband network node admittance matrix of each candidate power transfer scheme includes: Based on the line configuration parameters, construct the line frequency domain admittance matrix for each candidate power transfer scheme at each preset wideband scanning angle frequency; Based on the transformer configuration parameters, construct the transformer frequency domain admittance matrix for each of the candidate power transfer schemes at each of the wideband scanning angular frequencies; Based on the capacitor configuration parameters, construct the capacitor frequency domain admittance matrix for each candidate power transfer scheme at each wideband scanning angular frequency; Based on the configuration parameters of the compensation device, construct the frequency domain admittance matrix of the compensation device for each candidate power transfer scheme at each wideband scanning angular frequency; Based on the load configuration parameters, construct the load frequency domain admittance matrix for each of the candidate power transfer schemes at each of the wideband scanning angular frequencies; The frequency domain admittance matrices of the line, transformer, capacitor, compensation device, and load are summed to obtain the broadband network node admittance matrix of each candidate power transfer scheme at each broadband scanning angular frequency.

[0037] In an alternative embodiment, for the first For each candidate transfer scheme, this embodiment performs broadband network modeling. Broadband network modeling requires broadband scanning; therefore, this embodiment defines the broadband scanning angular frequency set as follows: ;in, , For each wideband scan angular frequency; Next, establish candidate supply transfer schemes. The corresponding broadband network node admittance matrix; specifically, the topology configuration data needs to be clarified, including: line configuration parameters, transformer configuration parameters, capacitor configuration parameters, compensation device configuration parameters, and load configuration parameters; The line configuration parameters include, but are not limited to, the nodes at both ends of the line, the line phase, the type of overhead line or cable, the line length, the resistance per unit length, the reactance, the susceptance to ground, the grounding method, and the status of the line switches; next, in this embodiment, the three-phase frequency domain... Equivalent model of the line, phase domain conversion algorithm of line parameters, and branch stamping algorithm of node admittance matrix are used to construct candidate transfer schemes. Line frequency domain admittance matrix at each broadband scanning angular frequency. In particular, if the line configuration parameters need to include the phase domain parameters given by the equipment ledger or line parameter library in the actual distribution network self-healing and restoration, the phase domain frequency domain branch admittance assembly algorithm can be directly used to construct them; if the line is given with positive sequence, negative sequence, and zero sequence parameters, the phase domain parameters can be obtained by first using the symmetric component-phase component conversion algorithm, and then matrix assembly can be performed. Transformer configuration parameters include, but are not limited to, rated capacity, rated voltage, turns ratio, short-circuit impedance, excitation admittance, winding connection group, tap position, neutral grounding method, and grounding impedance. This embodiment employs a phase-domain multi-winding transformer equivalent circuit algorithm, a transformer phase shift matrix algorithm, and a node admittance matrix stamping algorithm to construct the transformer frequency domain admittance matrix. ; Capacitor configuration parameters include, but are not limited to, the rated capacity of the parallel capacitor bank, connection node, wiring method, switching position, series reactor parameters, discharge resistor parameters, and current operating status. This embodiment uses either the parallel capacitor branch frequency domain admittance algorithm or the series RLC branch frequency domain admittance algorithm to construct the capacitor frequency domain admittance matrix. ; The configuration parameters of the compensation device include, but are not limited to, the rated capacity, grid connection point location, interface reactance, filter parameters, control mode, control bandwidth, limiting parameters, and frequency response data of SVG (Static Var Generator), SVC (Static Var Compensator), or other dynamic reactive power compensation devices. In this embodiment, a linearized Norton equivalent small-signal admittance model or frequency response fitting algorithm is used to construct the capacitor frequency domain admittance matrix. ; Load configuration parameters include, but are not limited to, node active power, reactive power, node voltage, load type, ZIP load ratio, induction motor ratio, and historical operating curves. This embodiment uses a ZIP load model operating point linearization algorithm, a constant impedance equivalent algorithm, or an induction motor small-signal admittance equivalent algorithm to construct the load frequency domain admittance matrix. ; Finally, the frequency domain admittance matrix of the line... Transformer frequency domain admittance matrix Capacitor frequency domain admittance matrix Frequency domain admittance matrix of compensation device and load frequency domain admittance matrix By summing the results, we obtain the broadband network node admittance matrix for each candidate transfer scheme at each broadband scanning angular frequency. The broadband network node admittance matrix is ​​expressed as shown in the following formula: .

[0038] It should be noted that the above-mentioned construction of the line frequency domain admittance matrix... Transformer frequency domain admittance matrix Capacitor frequency domain admittance matrix Frequency domain admittance matrix of compensation device and load frequency domain admittance matrix The specific configuration data used can be limited according to actual needs, and other mature modeling algorithms can also be used for construction.

[0039] The above embodiments construct corresponding frequency domain admittance matrices for lines, transformers, capacitors, compensation devices, and loads based on line configuration parameters, transformer configuration parameters, capacitor configuration parameters, compensation device configuration parameters, and load configuration parameters, respectively. This ensures that the broadband network node admittance matrix accurately reflects the differentiated frequency response characteristics of different devices in the distribution network over a wide frequency range, avoiding modeling distortion caused by simply equating various devices to power frequency parameters. It ensures that each candidate power transfer scheme has a broadband network node admittance matrix that strictly matches its network topology, resulting in high accuracy in subsequent broadband impedance analysis and resonance feature extraction of candidate power transfer schemes. This provides reliable data support for subsequent safety risk assessment, thereby improving the stability of the distribution network's self-healing recovery.

[0040] In this embodiment, the step of performing broadband impedance analysis and resonance feature extraction on each of the candidate power transfer schemes based on the broadband network node admittance matrix to obtain broadband impedance data and resonance feature data for each candidate power transfer scheme includes: Based on the topology configuration data, identify the set of key nodes in each of the candidate transfer schemes, and form a set of elimination nodes based on other nodes in the candidate transfer schemes that do not belong to the set of key nodes; Based on the elimination node set, the broadband network node admittance matrix of each candidate transfer scheme is subjected to equivalent elimination processing to obtain the broadband equivalent admittance matrix corresponding to the key node set of each candidate transfer scheme. Inverting the broadband equivalent admittance matrix yields the broadband equivalent impedance matrix corresponding to the key node set of each candidate power transfer scheme; Based on the number of key nodes in the key node set of each candidate power transfer scheme, the broadband impedance spectrum of each candidate power transfer scheme is extracted from the broadband equivalent impedance matrix; Broadband impedance data for each candidate power transfer scheme is formed based on the broadband equivalent impedance matrix and broadband impedance spectrum. Based on the broadband impedance data, resonant features are extracted from each of the candidate power transfer schemes to obtain the main resonant frequency band and predicted total harmonic distortion rate of the voltage for each candidate power transfer scheme, thereby forming resonant feature data for each candidate power transfer scheme.

[0041] In the above embodiments, by classifying the nodes in the candidate power transfer schemes to form a set of key nodes and a set of elimination nodes, and performing equivalent elimination processing on the elimination node set, a broadband equivalent admittance matrix and a broadband equivalent impedance matrix are obtained, retaining only the set of key nodes. This elimination method significantly reduces the dimensionality of the broadband network node admittance matrix, which not only reduces the computational requirements but also allows the calculated broadband impedance data and resonance characteristic data to directly reflect the electrical characteristics of key nodes in the actual execution of the candidate power transfer scheme. Next, by extracting the broadband impedance spectrum and combining it with the broadband equivalent impedance matrix to form broadband impedance data, resonance characteristics are extracted using the broadband impedance data to obtain the main resonant frequency band and the predicted total harmonic distortion rate of the voltage. This achieves multi-dimensional and accurate quantification of the resonance risk of the candidate power transfer scheme, thereby improving the stability and accuracy of the distribution network's self-healing recovery.

[0042] In this embodiment, the resonant feature extraction of each candidate power transfer scheme based on the broadband impedance data to obtain the main resonant frequency band and predicted total harmonic distortion of voltage for each candidate power transfer scheme, thereby forming the resonant feature data of each candidate power transfer scheme, includes: Within a preset wideband scanning angular frequency range, the wideband impedance spectrum of each candidate power transfer scheme is searched to obtain several local peak frequency points for each candidate power transfer scheme. Based on preset peak value judgment conditions, the local peak frequency points are filtered to obtain the main resonant frequency band of each candidate power supply scheme; Obtain harmonic current injection data for each of the candidate power transfer schemes, and determine the harmonic voltage prediction data corresponding to the key node set of each candidate power transfer scheme based on the harmonic current injection data and the broadband equivalent impedance matrix. The total harmonic distortion rate of the predicted voltage for each of the candidate power transfer schemes is determined based on the harmonic voltage prediction data. The resonant characteristic data of each candidate power transfer scheme are formed based on the main resonant frequency band and the predicted total harmonic distortion of the voltage for each candidate power transfer scheme.

[0043] In the above embodiments, the broadband impedance spectrum is scanned to identify all local peak frequency points, and the main resonant frequency band with real risk significance is screened according to the preset peak judgment conditions. This can avoid the overly conservative evaluation results that lead to the wrong elimination of a large number of feasible solutions, which is conducive to maintaining the sufficiency of self-healing solutions. Then, using the harmonic current injection data and the broadband equivalent impedance matrix, the harmonic voltage prediction data of key nodes and the total harmonic distortion rate of the predicted voltage are calculated. This can truly reflect the degree of harmonic amplification of the network topology under the candidate power transfer scheme under the actual harmonic source excitation, providing reliable resonant characteristic data for subsequent safety risk assessment, thereby improving the accuracy and stability of self-healing recovery.

[0044] In an alternative embodiment, after obtaining Subsequently, in order to calculate the broadband impedance spectrum of the candidate power transfer schemes at the critical nodes, this embodiment selects critical nodes to form a critical node set. Other nodes in the candidate transfer scheme that do not belong to the set of key nodes form the elimination node set. Critical nodes are defined as key tie points or key buses in a distribution network. Their specific configuration can be pre-configured or dynamically selected based on actual power transfer tasks, operational monitoring needs, and protection and control requirements of the distribution master station or edge controller. Critical nodes include, but are not limited to: nodes on both sides of a tie switch to be closed, the power supply inlet bus of the target restoration area, important load buses, distributed generation grid connection points, energy storage converter grid connection points, SVG grid connection points, parallel capacitor bank access buses, and the deployment of online power quality monitoring devices. In particular, the specific selection of critical tie points or key buses is an engineering configuration object in distribution network equivalent modeling and operational monitoring, and can be determined according to the actual application scenario.

[0045] Next, the admittance matrices of the broadband network nodes in the candidate transfer schemes undergo Kron elimination, the specific process of which is shown below. In this embodiment, [the following is defined]. and Representing the sets of key nodes respectively The node voltage vector and the injected current vector; and Represent the sets of elimination nodes respectively The node voltage vector and injected current vector; then based on the key node set Set of elimination nodes The admittance matrix of the broadband network nodes is reordered and divided into blocks, and the result is shown in formula (6). (6); In formula (6), For the self-admittance submatrix of key nodes; The self-admittance submatrix of the elimination nodes; and This is the coupling admittance submatrix between the critical node and the elimination node.

[0046] It should be noted that the Kron reduction method used in this embodiment is a standard method in power engineering for simplifying the analysis of large networks. It eliminates internal nodes in the network through an algebraic elimination process while preserving the electrical behavior of a specific target node (port), thereby reducing the dimensionality of system equations (such as the node admittance matrix).

[0047] Therefore, the equivalent elimination process in this embodiment is performed at each wideband scanning angular frequency. Below, the admittance matrix of broadband network nodes. Perform Kron equivalence on all elimination nodes except for critical nodes. When the set of elimination nodes... When there is no external harmonic current injection, let To obtain the set of key nodes The corresponding broadband equivalent admittance matrix is ​​shown in the specific form of formula (7). (7); For the broadband equivalent admittance matrix Inverse the equation to obtain the broadband equivalent impedance matrix corresponding to the key node set of each candidate power transfer scheme. ; If there is only a single critical bus or a single tie point in the self-healing of the distribution network, then the number of critical nodes is defined as 1. In this embodiment, a broadband equivalent impedance matrix is ​​used. The corresponding diagonal elements are used as the equivalent impedance of the driving point of the critical node, which is also used as the broadband impedance spectrum. If the coupling effect between multiple critical nodes is considered in the self-healing of the distribution network, then multiple critical nodes are defined. In this embodiment, a broadband equivalent impedance matrix is ​​used. The maximum singular value of the matrix is ​​taken as the broadband impedance spectrum; therefore, the broadband impedance spectrum can be expressed as shown in formula (8); ; in, Indicates key nodes The corresponding equivalent impedance at the driving point; This represents the largest singular value of the matrix.

[0048] This embodiment sets a wideband scanning angular frequency range. Equivalent to the wideband scanning angular frequency set mentioned above; next, the wideband impedance spectrum is searched to obtain several local peak frequency points for each candidate power supply scheme; local peak frequency points that meet the peak judgment conditions are selected as the main resonant frequency band; the peak judgment conditions include: the impedance amplitude of the local peak frequency point exceeds the first threshold, the peak prominence of the adjacent frequency band of the local peak frequency point exceeds the second threshold, and the amplification factor of the local peak frequency point relative to the fundamental equivalent impedance exceeds the third threshold; the specific values ​​of the first threshold, the second threshold and the third threshold can be limited according to actual needs, and will not be elaborated here in this embodiment. Thus, the main resonant frequency band is expressed as shown in the following formula (9), (9); Harmonic current injection data for candidate power transfer schemes is obtained using common techniques such as online monitoring data of the distribution network, parameters of harmonic source equipment, or typical harmonic current models. In this embodiment, harmonic current injection data is defined as... , which indicates the first The first candidate supply transfer scheme The second harmonic current; Therefore, the harmonic voltage prediction data corresponding to the set of key nodes is expressed as follows: ; The fundamental angular frequency is derived from the broadband scanning angular frequency set. ; For key nodes The predicted total harmonic distortion rate of the voltage is expressed as shown in formula (10). (10); In formula (10), For the set of harmonic orders involved in the calculation, For candidate supply solutions Internal critical nodes The Predicted data for subharmonic voltage. For candidate supply solutions Internal critical nodes The fundamental voltage; The predicted total harmonic distortion (THD) of the voltage at all critical nodes is used to determine the predicted THD of the candidate power supply schemes. Finally, the main resonant frequency band and the predicted THD are used as the resonant characteristic data of the candidate power supply schemes.

[0049] In this embodiment, the inverter output control model for each candidate power transfer scheme is constructed based on the topology configuration data. Coupled analysis is then performed on each candidate power transfer scheme using the wideband impedance data and resonant characteristic data to obtain the safety risk analysis results for each candidate power transfer scheme, including: Based on the topology configuration data, the control fingerprint of each inverter in each of the candidate power transfer schemes is determined; Based on the topology configuration data, construct the current disturbance vector and voltage disturbance vector for each inverter in each candidate power transfer scheme; The signal output admittance of each inverter within each candidate power transfer scheme is determined based on the ratio of the current disturbance vector to the voltage disturbance vector. The signal output admittance of each inverter in each candidate power transfer scheme is aggregated to obtain the aggregated output admittance of the inverter for each candidate power transfer scheme. An inverter output control model for each candidate power transfer scheme is formed based on the inverter aggregated output admittance for each candidate power transfer scheme and the control fingerprint of each inverter. Based on the inverter output control model, wideband impedance data, and resonance characteristic data, a coupled analysis is performed on each of the candidate power transfer schemes to obtain the stability risk index, control compatibility risk index, harmonic amplification risk index, and weak grid risk index for each candidate power transfer scheme. The stability risk index, control compatibility risk index, harmonic amplification risk index, and weak network risk index are weighted and summed to obtain the security risk analysis results for each candidate power transfer scheme.

[0050] In the above embodiments, the inverter's control fingerprint is determined by topology configuration data and characterized as a small-signal output admittance. This allows the inverter's dynamic control characteristics to participate in subsequent frequency domain coupling analysis in the form of admittance, avoiding the problem of traditional methods treating the inverter as an ideal power source or a simple reactive power compensation node and ignoring its dynamic control characteristics. Based on this, coupling analysis using the inverter output control model, wideband impedance data, and resonance characteristic data enables interactive evaluation of the fragmented inverter control and network topology characteristics, resulting in more accurate stability risks, control compatibility risks, harmonic risks, and weak network risks. Finally, the stability risks, control compatibility risks, harmonic risks, and weak network risks are weighted and summed to obtain the safety risk analysis results. This achieves a multi-dimensional comprehensive evaluation of the dynamic safety of candidate power transfer schemes, effectively avoiding risk omissions caused by the one-sidedness of single-dimensional evaluation, thereby improving the accuracy and stability of distribution network self-healing recovery.

[0051] In this embodiment, the coupled analysis of each candidate power transfer scheme based on the inverter output control model, wideband impedance data, and resonant characteristic data yields stability risk indicators, control compatibility risk indicators, harmonic amplification risk indicators, and weak grid risk indicators for each candidate power transfer scheme, including: The inverter aggregate output admittance of each candidate power transfer scheme is mapped to each key node in the set of key nodes to obtain the inverter aggregate output admittance mapping matrix of each candidate power transfer scheme. The return ratio matrix of each candidate power transfer scheme is constructed based on the inverter aggregated output admittance mapping matrix and the broadband equivalent impedance matrix of each candidate power transfer scheme. Extract the minimum singular value from the return ratio matrix of each candidate transfer scheme, and determine the stability risk index of each candidate transfer scheme based on the minimum singular value; Based on the main resonant frequency band and the control fingerprint of each inverter in each candidate power transfer scheme, the control compatibility risk index of each candidate power transfer scheme is determined. The harmonic amplification risk index for each candidate power transfer scheme is determined based on the preset voltage total harmonic distortion rate limit, the predicted voltage total harmonic distortion rate, the preset impedance spectrum amplitude discrimination threshold, and the broadband impedance spectrum. The equivalent short-circuit capacity of each candidate power transfer scheme is determined based on the broadband equivalent impedance matrix, and the weak network risk index of each candidate power transfer scheme is determined based on the equivalent short-circuit capacity.

[0052] In the above embodiments, the inverter aggregated output admittance is mapped to each key node in the key node set, so that the inverter aggregated output admittance mapping matrix and the broadband equivalent impedance matrix have the same dimension, ensuring that the return ratio matrix can conform to the actual network topology of the distribution network. Then, the minimum singular value of the return ratio matrix is ​​extracted as a stability margin index, making the stability risk index more accurate. Subsequently, based on the main resonant frequency band and control fingerprint, a control compatibility risk index is obtained, which can identify the problem of interactive mismatch between inverter control parameters and network topology. On this basis, the voltage total harmonic distortion rate limit and pre- By measuring the total harmonic distortion rate of voltage, setting a threshold for impedance spectrum amplitude discrimination, and determining the harmonic amplification risk index using a broadband impedance spectrum, the network topology harmonic problems of the distribution network can be accurately identified. Then, the weak network risk index is obtained using a broadband equivalent impedance matrix, which can accurately assess the degree of weakness in the distribution network during the self-healing process. The stability risk index, control compatibility risk index, harmonic amplification risk index, and weak network risk index together constitute a complete dynamic security evaluation system from different dimensions, enabling the risk assessment to cover various instability forms that may occur after power transfer, thereby improving the accuracy and stability of the distribution network's self-healing recovery.

[0053] In an optional embodiment, the control fingerprint of each inverter within each candidate power transfer scheme is determined from the topology configuration data. The control fingerprint of an inverter refers to the control parameter vector of the inverter. Specifically, the set of inverters participating in the support under each candidate power transfer scheme is defined as follows: For any inverter The control fingerprint is represented as follows: ; in, Indicates the inverter control mode. Indicates the bandwidth of the phase-locked loop. Indicates the current loop bandwidth. and These represent the Volt / VAr control slope and the Volt / Watt control slope, respectively. and Represents the virtual impedance parameter. and These represent the active frequency droop factor and the reactive frequency droop factor of the GFM, respectively. This refers to the rated capacity of the inverter.

[0054] Specifically, Volt / Var control refers to voltage-reactive power control, Volt / Watt control refers to voltage-active power control, and GFM (Grid-Forming) refers to grid-based control; all of these are conventional control modes for inverters.

[0055] Construct the current perturbation vector for each inverter within each candidate power transfer scheme. and voltage disturbance vector Current disturbance vector This refers to the vector of difference between the inverter output current and the current reference value; voltage disturbance vector. This refers to the vector difference between the inverter's output voltage and the voltage reference value; therefore, the inverter's signal output admittance is expressed as: Aggregate the signal output admittances to obtain the aggregated inverter output admittance for each selected power supply scheme, which is specifically expressed as follows: Therefore, the inverter aggregated output admittance and the control fingerprint of each inverter form an inverter output control model for candidate power transfer schemes.

[0056] The signal output admittance of each inverter in the aggregated output admittance of the candidate supply scheme inverters is used to calculate the signal output admittance of each inverter. According to the grid connection node, phase, and other data of the inverter, the key node set is mapped. For each key node, obtain the equivalent impedance matrix for broadband. Inverter aggregated output admittance mapping matrix of the same dimension ; Based on this, the return ratio matrix of the candidate power transfer scheme is constructed according to the product of the inverter aggregated output admittance mapping matrix and the broadband equivalent impedance matrix, which is expressed as: ;in, Refers to candidate supply transfer schemes At angular frequency The return ratio matrix below can also be called the multiple-input multiple-output small-signal loop gain matrix; It is a dimensionless matrix used to reflect the dynamic coupling strength between the candidate power transfer topology and the inverter group control characteristics; Next, this embodiment introduces an identity matrix with the same dimension as the returned ratio matrix. The small-signal stability margin index of the candidate supply transfer scheme is calculated and expressed as: ;in, The wideband scanning angular frequency set used for stability evaluation is set in this embodiment to be the same as the wideband scanning angular frequency set used in the previous wideband network modeling. It can also be set separately according to the inverter control bandwidth and resonant sensitive frequency band. This represents the minimum singular value of the matrix. The smaller, the more... The closer a candidate transfer scheme is to a singularity, the closer it is to the small-signal instability boundary. Furthermore, to facilitate weighting with other indicators, this embodiment first introduces a small positive number to prevent the denominator from being zero. Then, the stability risk index is calculated, which is expressed as: ; The main resonant frequency band has been obtained in the previous section. Its specific form can be expressed as: ; Indicates candidate supply transfer schemes The The main resonant frequency band can be represented as: ; and These are the lower and upper boundary frequencies of the main resonant frequency band, respectively. For candidate supply solutions The number of main resonant frequency bands obtained from the identification; To measure the closeness between the inverter control bandwidth and the main resonant frequency band, this embodiment defines a frequency. To the main resonant frequency band set Distance function: More specifically, the distance function can be expressed as shown in formula (11); (11); when The smaller the value, the closer the control bandwidth is to the main resonant frequency band of the candidate topology; when... When this occurs, it indicates that the control bandwidth falls within the main resonant frequency band, posing a high risk of control coupling. Next, since not all inverters participate in power support, and only those inverters that participate in power support are at risk of control coupling, this embodiment further defines the set of inverters participating in power support in the candidate power transfer scheme as follows: For any inverter The details of its fingerprint control have been described above and will not be repeated here. The distance function is used to measure the proximity between the parameters in the control fingerprint and the main resonant frequency band, thereby obtaining the control compatibility risk index, which is expressed as shown in the following formula (12); (12); in, For inverter The weight of the inverter can be determined based on its rated capacity, grid connection location, support for the target recovery area, or historical operational reliability. , , , , To control the weighting coefficients of each item in the compatibility risk; This is the frequency normalization constant; To prevent small positive numbers with a denominator of zero; For candidate supply solutions The target Volt / VAr slope is calculated based on the voltage support requirements. The Volt / VAr slope normalization baseline value; For candidate supply solutions The target virtual impedance vector is determined based on impedance shaping requirements. This serves as the reference value for virtual impedance normalization. For candidate supply solutions The recommended inverter control modes include, but are not limited to, GFL mode, GFM mode, or voltage support enhancement mode. This is an indicator function; it takes the value 1 if the condition inside the parentheses is true, and 0 otherwise. Among the aforementioned control compatibility risk indicators, Used to evaluate whether the bandwidth of the inverter's phase-locked loop is close to or falls within the main resonant frequency band; Used to evaluate whether the current loop bandwidth is close to or falls within the main resonant frequency band; Used to evaluate the deviation between the current Volt / VAr curve slope and the target voltage support requirement; Used to evaluate the deviation between the current virtual impedance parameter and the target impedance shaping parameter; This is due to the inconsistency between the current inverter control mode and the recommended control mode of the candidate power transfer scheme; therefore, the control compatibility risk index... The larger the value, the better the candidate supply transfer plan. The worse the match between the inverter control parameters and the impedance characteristics of the network after power transfer, the better.

[0057] Next, the voltage total harmonic distortion rate limit is defined. Refers to candidate supply transfer schemes Next critical node The permissible total harmonic distortion (THD) limit for the corresponding voltage level; defining the predicted THD. Refers to candidate supply transfer schemes Next critical node The predicted total harmonic distortion rate of the voltage; therefore, the harmonic amplification risk index is expressed as: ;in, The threshold for impedance spectrum amplitude discrimination; This is the impedance peak risk weighting coefficient; Furthermore, regarding key nodes Its equivalent short-circuit capacity can be expressed as: ;in, As a key node The rated voltage; The fundamental angular frequency Key nodes in the lower broadband equivalent impedance matrix Driving point impedance element; candidate power supply scheme The equivalent short-circuit capacity can be taken as the minimum equivalent short-circuit capacity of the critical node. ; For inverter Rated capacity; The smaller the value, the higher the degree of network weakness exhibited by the candidate transfer scheme in the target recovery area; therefore, the network weakness risk index is expressed as: ; To prevent small positive numbers with a denominator of zero; Finally, the stability risk index, control compatibility risk index, harmonic amplification risk index, and weak network risk index are weighted and summed to obtain the security risk analysis results for each candidate power transfer scheme, which are expressed as follows: ;in, , , and These are the weighting coefficients for stability risk indicators, control compatibility risk indicators, harmonic amplification risk indicators, and weak network risk indicators, respectively.

[0058] In this embodiment, the step of performing inverter control verification on the candidate power transfer scheme based on the safety risk analysis results to obtain the self-healing power transfer scheme of the distribution network, and performing self-healing recovery of the distribution network based on the self-healing power transfer scheme, includes: Based on the security risk analysis results, each of the candidate transfer schemes is risk-classified to obtain the risk level of each candidate transfer scheme. If the risk level of the candidate power transfer scheme is the preset first level, then the candidate power transfer scheme will be used as the alternative power transfer scheme for the distribution network. If the risk level of the candidate power transfer scheme is the preset second level, then the inverter control verification is performed on the candidate power transfer scheme based on the safety risk analysis results to update the risk level of the candidate power transfer scheme; If the risk level of the candidate transfer scheme is the preset third level, then the candidate transfer scheme is eliminated; Each of the alternative power transfer schemes is evaluated based on a preset self-healing comprehensive benefit model to obtain the self-healing power transfer scheme of the distribution network, and the distribution network is self-healed and restored based on the self-healing power transfer scheme.

[0059] In the above embodiments, risk classification is performed based on the results of safety risk analysis. This tiered processing approach allows first-tier candidate power transfer schemes to be considered without additional inverter control verification, reducing computational burden. The risk level of the first-tier candidate power transfer schemes is updated through inverter control verification, preventing direct elimination due to high risk and retaining more recoverable schemes. Third-tier candidate power transfer schemes are directly eliminated, effectively preventing non-compliant schemes from entering the final selection. Based on this, a self-healing comprehensive benefit model is used for evaluation, ensuring that the finally selected self-healing scheme not only has good load recovery performance at the steady-state level but also meets the requirements for safe and stable operation at the dynamic level, thereby improving the success rate and stability of the distribution network's self-healing recovery.

[0060] In this embodiment, if the risk level of the candidate power transfer scheme is a preset second level, then based on the safety risk analysis results, inverter control verification is performed on the candidate power transfer scheme to update the risk level of the candidate power transfer scheme, including: If the risk level of the candidate power transfer scheme is the preset second level, then obtain the adjustable range of the control parameters of each inverter in the candidate power transfer scheme; Based on the adjustable range of the control parameters and the results of the safety risk analysis, the control fingerprint of each inverter is adjusted to obtain the temporary control fingerprint of each inverter. The security risk analysis results of the candidate power transfer schemes are updated based on the temporary control fingerprints of each inverter to obtain the first security risk analysis result of the candidate power transfer schemes. The risk level of the candidate transfer scheme is updated based on the first security risk analysis results.

[0061] In the above embodiments, by obtaining the adjustable range of control parameters for each inverter, a temporary control parameter range is generated by combining the control fingerprint, and the inverter control fingerprint is adjusted within this range to obtain a temporary control fingerprint. Then, based on the adjusted control fingerprint, a new safety risk assessment and risk level update are performed. Without changing the topology, adjusting the inverter control parameters increases the number of executable self-healing schemes, thereby increasing the number of optional schemes for distribution network self-healing. At the same time, the accuracy and reliability of control parameter adjustment are ensured by the temporary control parameter range and the safety risk analysis results, thereby improving the success rate and stability of distribution network self-healing recovery.

[0062] In an optional embodiment, this embodiment normalizes the stability risk index, control compatibility risk index, harmonic amplification risk index, and weak network risk index for candidate power transfer schemes. The stability risk index is defined as follows: The normalized control compatibility risk indicator is: The normalized harmonic amplification risk index is: The normalized weak network risk index is: ;in, To determine the lower bound of the stability margin, in this embodiment, we take... ; To control compatibility risk limits, in this embodiment, we take... ; As the lower limit of the short-circuit ratio, in this embodiment, we take... Therefore, candidate supply transfer schemes The normalized composite risk index is expressed as: ;in, In this embodiment, .

[0063] The candidate supply transfer schemes are risk-classified to obtain the risk level of each candidate supply transfer scheme. It is represented as: ; in, Indicates the first level. Indicates the second level. Indicates the third level; If the risk level of a candidate supply transfer scheme is level three, it indicates that its risk is unacceptable, and no temporary control parameters will be generated; the candidate supply transfer scheme will be directly eliminated. Specifically, if the candidate supply transfer scheme meets the following conditions... , or If any constraint in the code is found to be unsafe to execute, it should also be removed.

[0064] If the risk level of a candidate supply transfer scheme is Level 1, then it will be directly used as an alternative supply transfer scheme. If the risk level of the candidate power transfer solution is level two, then inverter control verification is required. In this case, the adjustable range of the control parameters is set as follows: Next, the control fingerprints of each inverter are adjusted. The specific process is as follows: First, the inverter is initialized using its control fingerprint. The initial control parameters are: ; in, This indicates the initial inverter control mode. This represents the initial phase-locked loop bandwidth. Indicates the initial current loop bandwidth. and These represent the initial Volt / VAr control slope and the initial Volt / Watt control slope, respectively. and Indicates the initial virtual resistance and initial virtual reactance. and These represent the initial GFM active frequency droop coefficient and the initial GFM reactive frequency droop coefficient, respectively. Next, when the initial phase-locked loop bandwidth is too close to the main resonant frequency band, it satisfies... season ;in, This is the minimum allowed phase-locked loop bandwidth for the inverter; This indicates the temporary phase-locked loop bandwidth adjustment amount; if the requirements are still not met after adjustment... Then continue according to The compression coefficient is adjusted iteratively, but the number of iterations does not exceed 3. When the initial current loop bandwidth is too close to the main resonant frequency band, adjust the initial current loop bandwidth, i.e., when the following conditions are met... season: ;in, This is the minimum allowable current loop bandwidth for the inverter. This indicates the bandwidth of the temporary current loop; if it still does not meet the requirements after adjustment. Then continue according to The compression coefficient is adjusted iteratively, but the number of iterations does not exceed 3. At the same time, obtain the maximum virtual resistance of the inverter. Maximum virtual reactance and capacitance reference impedance Then, the initial virtual resistance and initial virtual reactance of the inverter are adjusted to obtain the temporary virtual resistance. and temporary virtual reactance It is represented by the following formulas (13) and (14), (13); (14); Therefore, the temporary voltage reference value of the inverter can be calculated, which is expressed as: ;in, This is the output current value of the inverter; This indicates the voltage reference value before adjustment; Indicates the temporary voltage reference value; When candidate power transfer schemes have insufficient voltage support or reactive power support requirements, the initial Volt / VAr control slope is adjusted to obtain the temporary Volt / VAr control slope, which is expressed as follows: ;in, and These are the minimum Volt / VAr slope and the maximum Volt / VAr slope of the inverter, respectively; after obtaining the temporary Volt / VAr control slope, the corresponding Volt / VAr control law is shown in formula (15); (15); in, This is the temporary reactive power output of the inverter; This is the reference value for the inverter's grid connection point voltage; This refers to the inverter's grid connection point voltage. This is the maximum reactive power of the inverter; This is a limiting function; When a candidate power transfer scheme has the risk of voltage exceeding limits due to local overvoltage or reverse power flow, the active power output of the inverter and the initial Volt / Watt control slope are adjusted. In this embodiment, the power derating trigger threshold is set to... And set the minimum active power output as ; Let be the rated active capacity of the inverter; therefore, the Volt / Watt control law is expressed as: ;in, This is the temporary active power output of the inverter; This is the original active power reference value; Temporary Volt / Watt control slope; ; When the weak network risk of the candidate transfer scheme is high, that is, when the following conditions are met... Furthermore, the state of charge of the energy storage inverter satisfy Some inverters (of energy storage type) in the candidate power transfer scheme will be switched to GFM control mode, wherein the sum of the capacities of these inverters meets the following requirements. ; Indicates candidate supply transfer schemes The set of inverters that are switched to GFM control; Indicates inverter The rated capacity; based on this, the GFM control mode is expressed as: and In this embodiment, take ; The rated angular frequency; This is the rated voltage amplitude; and These are the active power reference value and the reactive power reference value, respectively. This is the temporary angular frequency; This refers to the active frequency droop factor of the temporary GFM. This is the temporary voltage amplitude; This is the reactive frequency droop factor for temporary GFM; The above-mentioned reactive frequency droop coefficient of GFM is obtained. Temporary GFM active frequency droop factor Temporary phase-locked loop bandwidth adjustment Temporary current loop bandwidth Temporary virtual resistor Temporary virtual reactor Temporary Volt / VAr control slope Temporary Volt / Watt control slope Subsequently, a temporary control fingerprint was formed. ; It needs to be explained that, Still satisfied ,in, This refers to the initial control parameters. This refers to the adjustment amount of the initial control parameters; For inverter The range of permissible control parameters; This indicates a limiting operator that projects control parameters onto the allowable range of the device; Next, the temporary control fingerprint is reintroduced into the aforementioned steps, the security risk analysis results are updated, and the first security risk analysis result of the candidate transfer scheme is obtained, thereby updating the risk level of the candidate transfer scheme.

[0065] Specifically, this embodiment also introduces a secondary verification constraint. If a candidate transfer scheme simultaneously satisfies the secondary verification constraint, it can be directly used as an alternative transfer scheme. The secondary verification constraint is expressed as follows: , , , , and ; , and These are the predicted total harmonic distortion rate of the voltage, the small-signal stability margin index, and the minimum equivalent short-circuit capacity, respectively, obtained by recalculating after incorporating the temporary control fingerprint. After obtaining multiple alternative power transfer schemes for the distribution network, this embodiment uses a self-healing comprehensive benefit model to evaluate each of the alternative power transfer schemes, thereby obtaining the self-healing power transfer scheme for the distribution network; wherein, the definition is... It is a set of alternative supply transfer schemes, which includes several alternative supply transfer schemes; The self-healing comprehensive benefit model is expressed as shown in formula (16); (16); in, A self-healing resupply solution; For the set of load nodes; This is the load priority coefficient; For load recovery state variables; Active power of node load; As an alternative supply transfer solution Down switch The state; This represents the initial switching state after a fault. This is the switching operation cost coefficient; This is the risk penalty coefficient; To control the adjustment cost coefficient.

[0066] After determining the self-healing power transfer scheme for the distribution network, this embodiment defines the inverter control parameters for the self-healing power transfer scheme as follows: Then, following the self-healing recovery method of "control first, then switch", the power distribution master station or edge controller first adjusts the inverter control parameters. The parameters are sent to the corresponding inverters. After receiving the parameters, the inverters return confirmation information and the actual effective parameters to the distribution master station or edge controller. When satisfied And parameter confirmation time If the time is less than 5 seconds, it is determined that the inverter control parameters of the self-healing power supply scheme have taken effect. To prevent small positive numbers with a denominator of zero; Next, wait for the control to stabilize. Subsequently, according to the topology configuration data of the self-healing power transfer scheme, the distribution network is subjected to tie switch closure, sectional switch adjustment and topology reconstruction, so that the recovery area forms a power supply topology that meets the radial constraints.

[0067] Specifically, if the set of alternative supply transfer solutions is empty, it is determined that there is no supply transfer solution that meets the safety requirements under the current fault recovery scenario, and the fault isolation status is maintained, or manual review mode is entered. If there is a parameter confirmation time... Devices exceeding 5 seconds, or those with a relative deviation between the actual effective parameters and the inverter control parameters exceeding [a certain threshold], are considered faulty. If the self-healing transfer plan fails, the execution of the self-healing transfer plan will be suspended, and the selection of a self-healing transfer plan from the alternative transfer plans will continue until no self-healing transfer plan is available. Then, the fault isolation status will be maintained and the manual review mode will be entered.

[0068] After the self-healing power transfer scheme is implemented, in order to avoid cold load shocks and transient overshoots, this embodiment adopts a graded recovery strategy: ;in, for Level load target recovery power, This corresponds to the recovery time constant.

[0069] After the power supply is switched, the total harmonic distortion rate of the voltage, the oscillation amplitude of the sensitive frequency band, the frequency deviation and the number of inverters disconnected from the grid are continuously monitored. If the formula (17) is met, it is determined that there is an instability risk and a rollback is triggered. (17); in, The total harmonic distortion of voltage. This is the upper limit of harmonic distortion. For the amplitude of sensitive frequency band oscillation, The oscillation threshold, For frequency deviation, For frequency deviation threshold, The number of inverters disconnected from the grid. This sets a maximum allowed number of disconnections. When a rollback is triggered, the distribution network reverts to the alternative topology or switches to the suboptimal solution to ensure a closed-loop safety during the power restoration process.

[0070] Example 2 Please refer to Figure 2 , Figure 2 A schematic diagram of a distribution network self-healing system based on inverter and broadband network analysis provided in an embodiment of the present invention includes: a candidate power transfer scheme acquisition module 201, a broadband network modeling module 202, a broadband network analysis module 203, an inverter broadband network coupling analysis module 204, and a distribution network self-healing module 205. The candidate power transfer scheme acquisition module 201 is used to acquire several candidate power transfer schemes of the distribution network and the topology configuration data of each candidate power transfer scheme; The broadband network modeling module 202 is used to perform broadband network modeling on each of the candidate transfer schemes based on the topology configuration data, and obtain the broadband network node admittance matrix of each of the candidate transfer schemes; The broadband network analysis module 203 is used to perform broadband impedance analysis and resonance feature extraction on each of the candidate power transfer schemes based on the broadband network node admittance matrix, so as to obtain broadband impedance data and resonance feature data of each of the candidate power transfer schemes. The inverter wideband network coupling analysis module 204 is used to construct an inverter output control model for each of the candidate power transfer schemes based on the topology configuration data, and to perform coupling analysis on each of the candidate power transfer schemes in combination with the wideband impedance data and resonance characteristic data to obtain the safety risk analysis results of each candidate power transfer scheme. The distribution network self-healing module 205 is used to perform inverter control verification on the candidate power transfer scheme based on the safety risk analysis results, obtain the self-healing power transfer scheme of the distribution network, and perform self-healing recovery of the distribution network based on the self-healing power transfer scheme.

[0071] In this embodiment, the broadband network modeling module 202 includes: a broadband network modeling unit; In the broadband network modeling unit, the topology configuration data includes: line configuration parameters, transformer configuration parameters, capacitor configuration parameters, compensation device configuration parameters, and load configuration parameters; Based on the line configuration parameters, construct the line frequency domain admittance matrix for each candidate power transfer scheme at each preset wideband scanning angle frequency; Based on the transformer configuration parameters, construct the transformer frequency domain admittance matrix for each of the candidate power transfer schemes at each of the wideband scanning angular frequencies; Based on the capacitor configuration parameters, construct the capacitor frequency domain admittance matrix for each candidate power transfer scheme at each wideband scanning angular frequency; Based on the configuration parameters of the compensation device, construct the frequency domain admittance matrix of the compensation device for each candidate power transfer scheme at each wideband scanning angular frequency; Based on the load configuration parameters, construct the load frequency domain admittance matrix for each of the candidate power transfer schemes at each of the wideband scanning angular frequencies; The frequency domain admittance matrices of the line, transformer, capacitor, compensation device, and load are summed to obtain the broadband network node admittance matrix of each candidate power transfer scheme at each broadband scanning angular frequency.

[0072] In this embodiment, the broadband network analysis module 203 includes: a broadband network analysis unit; The broadband network analysis unit is used to identify the set of key nodes in each candidate transfer scheme based on the topology configuration data, and to form a set of elimination nodes based on other nodes in the candidate transfer scheme that do not belong to the set of key nodes. Based on the elimination node set, the broadband network node admittance matrix of each candidate transfer scheme is subjected to equivalent elimination processing to obtain the broadband equivalent admittance matrix corresponding to the key node set of each candidate transfer scheme. Inverting the broadband equivalent admittance matrix yields the broadband equivalent impedance matrix corresponding to the key node set of each candidate power transfer scheme; Based on the number of key nodes in the key node set of each candidate power transfer scheme, the broadband impedance spectrum of each candidate power transfer scheme is extracted from the broadband equivalent impedance matrix; Broadband impedance data for each candidate power transfer scheme is formed based on the broadband equivalent impedance matrix and broadband impedance spectrum. Based on the broadband impedance data, resonant features are extracted from each of the candidate power transfer schemes to obtain the main resonant frequency band and predicted total harmonic distortion rate of the voltage for each candidate power transfer scheme, thereby forming resonant feature data for each candidate power transfer scheme.

[0073] In this embodiment, the broadband network analysis unit includes: a resonance feature extraction subunit; The resonant feature extraction subunit is used to search the broadband impedance spectrum of each candidate power transfer scheme in a preset broadband scanning angular frequency range to obtain several local peak frequency points of each candidate power transfer scheme. Based on preset peak value judgment conditions, the local peak frequency points are filtered to obtain the main resonant frequency band of each candidate power supply scheme; Obtain harmonic current injection data for each of the candidate power transfer schemes, and determine the harmonic voltage prediction data corresponding to the key node set of each candidate power transfer scheme based on the harmonic current injection data and the broadband equivalent impedance matrix. The total harmonic distortion rate of the predicted voltage for each of the candidate power transfer schemes is determined based on the harmonic voltage prediction data. The resonant characteristic data of each candidate power transfer scheme are formed based on the main resonant frequency band and the predicted total harmonic distortion of the voltage for each candidate power transfer scheme.

[0074] In this embodiment, the inverter broadband network coupling analysis module 204 includes: an inverter broadband network coupling analysis unit; The inverter broadband network coupling analysis unit is used to determine the control fingerprint of each inverter in each of the candidate power transfer schemes based on the topology configuration data. Based on the topology configuration data, construct the current disturbance vector and voltage disturbance vector for each inverter in each candidate power transfer scheme; The signal output admittance of each inverter within each candidate power transfer scheme is determined based on the ratio of the current disturbance vector to the voltage disturbance vector. The signal output admittance of each inverter in each candidate power transfer scheme is aggregated to obtain the aggregated output admittance of the inverter for each candidate power transfer scheme. An inverter output control model for each candidate power transfer scheme is formed based on the inverter aggregated output admittance for each candidate power transfer scheme and the control fingerprint of each inverter. Based on the inverter output control model, wideband impedance data, and resonance characteristic data, a coupled analysis is performed on each of the candidate power transfer schemes to obtain the stability risk index, control compatibility risk index, harmonic amplification risk index, and weak grid risk index for each candidate power transfer scheme. The stability risk index, control compatibility risk index, harmonic amplification risk index, and weak network risk index are weighted and summed to obtain the security risk analysis results for each candidate power transfer scheme.

[0075] In this embodiment, the inverter broadband network coupling analysis unit includes: an inverter broadband network coupling analysis subunit; The inverter broadband network coupling analysis subunit is used to map the inverter aggregated output admittance of each candidate power transfer scheme to each key node in the key node set, so as to obtain the inverter aggregated output admittance mapping matrix of each candidate power transfer scheme. The return ratio matrix of each candidate power transfer scheme is constructed based on the inverter aggregated output admittance mapping matrix and the broadband equivalent impedance matrix of each candidate power transfer scheme. Extract the minimum singular value from the return ratio matrix of each candidate transfer scheme, and determine the stability risk index of each candidate transfer scheme based on the minimum singular value; Based on the main resonant frequency band and the control fingerprint of each inverter in each candidate power transfer scheme, the control compatibility risk index of each candidate power transfer scheme is determined. The harmonic amplification risk index for each candidate power transfer scheme is determined based on the preset voltage total harmonic distortion rate limit, the predicted voltage total harmonic distortion rate, the preset impedance spectrum amplitude discrimination threshold, and the broadband impedance spectrum. The equivalent short-circuit capacity of each candidate power transfer scheme is determined based on the broadband equivalent impedance matrix, and the weak network risk index of each candidate power transfer scheme is determined based on the equivalent short-circuit capacity.

[0076] In this embodiment, the power distribution network self-healing module 205 includes: a power distribution network self-healing unit; The power distribution network self-healing unit is used to classify the risk of each candidate power transfer scheme based on the safety risk analysis results, and obtain the risk level of each candidate power transfer scheme. If the risk level of the candidate power transfer scheme is the preset first level, then the candidate power transfer scheme will be used as the alternative power transfer scheme for the distribution network. If the risk level of the candidate power transfer scheme is the preset second level, then the inverter control verification is performed on the candidate power transfer scheme based on the safety risk analysis results to update the risk level of the candidate power transfer scheme; If the risk level of the candidate transfer scheme is the preset third level, then the candidate transfer scheme is eliminated; Each of the alternative power transfer schemes is evaluated based on a preset self-healing comprehensive benefit model to obtain the self-healing power transfer scheme of the distribution network, and the distribution network is self-healed and restored based on the self-healing power transfer scheme.

[0077] In this embodiment, the power distribution network self-healing unit includes: an inverter control verification subunit; The inverter control verification subunit is used to obtain the adjustable range of control parameters of each inverter in the candidate power transfer scheme if the risk level of the candidate power transfer scheme is a preset second level. Based on the adjustable range of the control parameters and the results of the safety risk analysis, the control fingerprint of each inverter is adjusted to obtain the temporary control fingerprint of each inverter. The security risk analysis results of the candidate power transfer schemes are updated based on the temporary control fingerprints of each inverter to obtain the first security risk analysis result of the candidate power transfer schemes. The risk level of the candidate transfer scheme is updated based on the first security risk analysis results.

[0078] This embodiment acquires candidate power transfer schemes and their topology configuration data, then performs broadband network modeling on the candidate schemes based on the topology configuration data to obtain broadband network node admittance matrices. Next, broadband impedance analysis and resonance feature extraction are performed using the broadband network node admittance matrices, thus achieving a comprehensive characterization of the broadband impedance characteristics and resonance risks of each candidate power transfer scheme at the network topology level. Based on this, an inverter output control model is constructed using the topology configuration data, and coupled analysis is performed using broadband impedance data and resonance feature data. This enables interactive evaluation of the fragmented inverter control and network topology characteristics, resulting in more accurate safety risk analysis results. Finally, based on the safety risk analysis results, inverter control verification is performed on the candidate power transfer schemes, and self-healing power transfer schemes are selected. This ensures that the distribution network self-healing recovery fully considers the interaction between the inverter and the network topology, effectively avoiding problems such as harmonic amplification, local resonance, and control mismatch caused by neglecting the interaction between the inverter and the network topology in traditional methods, thereby improving the stability of the distribution network self-healing recovery.

[0079] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A self-healing method for distribution networks based on inverter and broadband network analysis, characterized in that, include: Obtain several candidate power transfer schemes for the power distribution network and the topology configuration data of each candidate power transfer scheme; Based on the topology configuration data, broadband network modeling is performed on each of the candidate power transfer schemes to obtain the broadband network node admittance matrix of each candidate power transfer scheme; Based on the broadband network node admittance matrix, broadband impedance analysis and resonance feature extraction are performed on each of the candidate power transfer schemes to obtain broadband impedance data and resonance feature data of each candidate power transfer scheme. Based on the topology configuration data, an inverter output control model is constructed for each of the candidate power transfer schemes. Combined with the wideband impedance data and resonant characteristic data, a coupled analysis is performed on each of the candidate power transfer schemes to obtain the safety risk analysis results of each candidate power transfer scheme. Based on the safety risk analysis results, the inverter control is verified for the candidate power transfer scheme to obtain the self-healing power transfer scheme of the distribution network, and the distribution network is self-healed and restored based on the self-healing power transfer scheme.

2. The distribution network self-healing method based on inverter and broadband network analysis as described in claim 1, characterized in that, The topology configuration data includes: line configuration parameters, transformer configuration parameters, capacitor configuration parameters, compensation device configuration parameters, and load configuration parameters; the broadband network modeling of each candidate power transfer scheme based on the topology configuration data, to obtain the broadband network node admittance matrix of each candidate power transfer scheme, includes: Based on the line configuration parameters, construct the line frequency domain admittance matrix for each candidate power transfer scheme at each preset wideband scanning angle frequency; Based on the transformer configuration parameters, construct the transformer frequency domain admittance matrix for each of the candidate power transfer schemes at each of the wideband scanning angular frequencies; Based on the capacitor configuration parameters, construct the capacitor frequency domain admittance matrix for each candidate power transfer scheme at each wideband scanning angular frequency; Based on the configuration parameters of the compensation device, construct the frequency domain admittance matrix of the compensation device for each candidate power transfer scheme at each wideband scanning angular frequency; Based on the load configuration parameters, construct the load frequency domain admittance matrix for each of the candidate power transfer schemes at each of the wideband scanning angular frequencies; The frequency domain admittance matrices of the line, transformer, capacitor, compensation device, and load are summed to obtain the broadband network node admittance matrix of each candidate power transfer scheme at each broadband scanning angular frequency.

3. The distribution network self-healing method based on inverter and broadband network analysis as described in claim 1, characterized in that, The process of performing broadband impedance analysis and resonance feature extraction on each candidate power transfer scheme based on the broadband network node admittance matrix to obtain broadband impedance data and resonance feature data for each candidate power transfer scheme includes: Based on the topology configuration data, identify the set of key nodes in each of the candidate transfer schemes, and form a set of elimination nodes based on other nodes in the candidate transfer schemes that do not belong to the set of key nodes; Based on the elimination node set, the broadband network node admittance matrix of each candidate transfer scheme is subjected to equivalent elimination processing to obtain the broadband equivalent admittance matrix corresponding to the key node set of each candidate transfer scheme. Inverting the broadband equivalent admittance matrix yields the broadband equivalent impedance matrix corresponding to the key node set of each candidate power transfer scheme; Based on the number of key nodes in the key node set of each candidate power transfer scheme, the broadband impedance spectrum of each candidate power transfer scheme is extracted from the broadband equivalent impedance matrix; Broadband impedance data for each candidate power transfer scheme is formed based on the broadband equivalent impedance matrix and broadband impedance spectrum. Based on the broadband impedance data, resonant features are extracted from each of the candidate power transfer schemes to obtain the main resonant frequency band and predicted total harmonic distortion rate of the voltage for each candidate power transfer scheme, thereby forming resonant feature data for each candidate power transfer scheme.

4. The distribution network self-healing method based on inverter and broadband network analysis as described in claim 3, characterized in that, The resonant feature extraction of each candidate power transfer scheme based on the broadband impedance data yields the main resonant frequency band and predicted total harmonic distortion rate of each candidate power transfer scheme, forming the resonant feature data of each candidate power transfer scheme, including: Within a preset wideband scanning angular frequency range, the wideband impedance spectrum of each candidate power transfer scheme is searched to obtain several local peak frequency points for each candidate power transfer scheme. Based on preset peak value judgment conditions, the local peak frequency points are filtered to obtain the main resonant frequency band of each candidate power supply scheme; Obtain harmonic current injection data for each of the candidate power transfer schemes, and determine the harmonic voltage prediction data corresponding to the key node set of each candidate power transfer scheme based on the harmonic current injection data and the broadband equivalent impedance matrix. The total harmonic distortion rate of the predicted voltage for each of the candidate power transfer schemes is determined based on the harmonic voltage prediction data. The resonant characteristic data of each candidate power transfer scheme are formed based on the main resonant frequency band and the predicted total harmonic distortion rate of the voltage for each candidate power transfer scheme.

5. A distribution network self-healing method based on inverter and broadband network analysis as described in claim 3 or 4, characterized in that, The inverter output control model for each candidate power transfer scheme is constructed based on the topology configuration data. Coupled analysis is then performed on each candidate power transfer scheme using the wideband impedance data and resonant characteristic data to obtain the safety risk analysis results for each candidate power transfer scheme, including: Based on the topology configuration data, the control fingerprint of each inverter in each of the candidate power transfer schemes is determined; Based on the topology configuration data, construct the current disturbance vector and voltage disturbance vector for each inverter in each candidate power transfer scheme; The signal output admittance of each inverter within each candidate power transfer scheme is determined based on the ratio of the current disturbance vector to the voltage disturbance vector. The signal output admittance of each inverter in each candidate power transfer scheme is aggregated to obtain the aggregated output admittance of the inverter for each candidate power transfer scheme. An inverter output control model for each candidate power transfer scheme is formed based on the inverter aggregated output admittance for each candidate power transfer scheme and the control fingerprint of each inverter. Based on the inverter output control model, wideband impedance data, and resonance characteristic data, a coupled analysis is performed on each of the candidate power transfer schemes to obtain the stability risk index, control compatibility risk index, harmonic amplification risk index, and weak grid risk index for each candidate power transfer scheme. The stability risk index, control compatibility risk index, harmonic amplification risk index, and weak network risk index are weighted and summed to obtain the security risk analysis results for each candidate power transfer scheme.

6. The distribution network self-healing method based on inverter and broadband network analysis as described in claim 5, characterized in that, The coupling analysis of each candidate power transfer scheme based on the inverter output control model, wideband impedance data, and resonant characteristic data yields stability risk indicators, control compatibility risk indicators, harmonic amplification risk indicators, and weak grid risk indicators for each candidate power transfer scheme, including: The inverter aggregate output admittance of each candidate power transfer scheme is mapped to each key node in the set of key nodes to obtain the inverter aggregate output admittance mapping matrix of each candidate power transfer scheme. The return ratio matrix of each candidate power transfer scheme is constructed based on the inverter aggregated output admittance mapping matrix and the broadband equivalent impedance matrix of each candidate power transfer scheme. Extract the minimum singular value from the return ratio matrix of each candidate transfer scheme, and determine the stability risk index of each candidate transfer scheme based on the minimum singular value; Based on the main resonant frequency band and the control fingerprint of each inverter in each candidate power transfer scheme, the control compatibility risk index of each candidate power transfer scheme is determined. The harmonic amplification risk index for each candidate power transfer scheme is determined based on the preset voltage total harmonic distortion rate limit, the predicted voltage total harmonic distortion rate, the preset impedance spectrum amplitude discrimination threshold, and the broadband impedance spectrum. The equivalent short-circuit capacity of each candidate power transfer scheme is determined based on the broadband equivalent impedance matrix, and the weak network risk index of each candidate power transfer scheme is determined based on the equivalent short-circuit capacity.

7. The distribution network self-healing method based on inverter and broadband network analysis as described in claim 5, characterized in that, The process of performing inverter control verification on the candidate power transfer schemes based on the safety risk analysis results to obtain a self-healing power transfer scheme for the distribution network, and performing self-healing recovery of the distribution network based on the self-healing power transfer scheme, includes: Based on the security risk analysis results, each of the candidate transfer schemes is risk-classified to obtain the risk level of each candidate transfer scheme. If the risk level of the candidate power transfer scheme is the preset first level, then the candidate power transfer scheme will be used as the alternative power transfer scheme for the distribution network. If the risk level of the candidate power transfer scheme is the preset second level, then the inverter control verification is performed on the candidate power transfer scheme based on the safety risk analysis results to update the risk level of the candidate power transfer scheme; If the risk level of the candidate transfer scheme is the preset third level, then the candidate transfer scheme is eliminated; Each of the alternative power transfer schemes is evaluated based on a preset self-healing comprehensive benefit model to obtain the self-healing power transfer scheme of the distribution network, and the distribution network is self-healed and restored based on the self-healing power transfer scheme.

8. The distribution network self-healing method based on inverter and broadband network analysis as described in claim 7, characterized in that, If the risk level of the candidate power transfer scheme is a preset second level, then based on the safety risk analysis results, inverter control verification is performed on the candidate power transfer scheme to update its risk level, including: If the risk level of the candidate power transfer scheme is the preset second level, then obtain the adjustable range of the control parameters of each inverter in the candidate power transfer scheme; Based on the adjustable range of the control parameters and the results of the safety risk analysis, the control fingerprint of each inverter is adjusted to obtain the temporary control fingerprint of each inverter. The security risk analysis results of the candidate power transfer schemes are updated based on the temporary control fingerprints of each inverter to obtain the first security risk analysis result of the candidate power transfer schemes. The risk level of the candidate transfer scheme is updated based on the first security risk analysis results.

9. A distribution network self-healing system based on inverter and broadband network analysis, characterized in that, include: The module includes a candidate power transfer scheme acquisition module, a broadband network modeling module, a broadband network analysis module, an inverter broadband network coupling analysis module, and a distribution network self-healing module. The candidate power transfer scheme acquisition module is used to acquire several candidate power transfer schemes of the distribution network and the topology configuration data of each candidate power transfer scheme; The broadband network modeling module is used to perform broadband network modeling on each of the candidate transfer schemes based on the topology configuration data, and to obtain the broadband network node admittance matrix of each of the candidate transfer schemes. The broadband network analysis module is used to perform broadband impedance analysis and resonance feature extraction on each of the candidate power transfer schemes based on the broadband network node admittance matrix, so as to obtain broadband impedance data and resonance feature data of each of the candidate power transfer schemes. The inverter wideband network coupling analysis module is used to construct an inverter output control model for each candidate power transfer scheme based on the topology configuration data, and to perform coupling analysis on each candidate power transfer scheme in combination with the wideband impedance data and resonance characteristic data to obtain the safety risk analysis results of each candidate power transfer scheme. The distribution network self-healing module is used to perform inverter control verification on the candidate power transfer scheme based on the safety risk analysis results, obtain the self-healing power transfer scheme of the distribution network, and perform self-healing recovery of the distribution network based on the self-healing power transfer scheme.

10. A distribution network self-healing system based on inverter and broadband network analysis as described in claim 9, characterized in that, The broadband network modeling module includes: a broadband network modeling unit; In the broadband network modeling unit, the topology configuration data includes: line configuration parameters, transformer configuration parameters, capacitor configuration parameters, compensation device configuration parameters, and load configuration parameters; Based on the line configuration parameters, construct the line frequency domain admittance matrix for each candidate power transfer scheme at each preset wideband scanning angle frequency; Based on the transformer configuration parameters, construct the transformer frequency domain admittance matrix for each of the candidate power transfer schemes at each of the wideband scanning angular frequencies; Based on the capacitor configuration parameters, construct the capacitor frequency domain admittance matrix for each candidate power transfer scheme at each wideband scanning angular frequency; Based on the configuration parameters of the compensation device, construct the frequency domain admittance matrix of the compensation device for each candidate power transfer scheme at each wideband scanning angular frequency; Based on the load configuration parameters, construct the load frequency domain admittance matrix for each of the candidate power transfer schemes at each of the wideband scanning angular frequencies; The frequency domain admittance matrices of the line, transformer, capacitor, compensation device, and load are summed to obtain the broadband network node admittance matrix of each candidate power transfer scheme at each broadband scanning angular frequency.

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