PMU-based power distribution network adaptive reclosing method, apparatus and device, and medium

Abstract

The invention relates to a PMU-based power distribution network adaptive reclosing method, device and equipment and a medium, and the method comprises the steps: obtaining preprocessed multi-dimensional operation data through PMUs installed at the two sides of each circuit breaker of a power distribution network after the power distribution network breaks down; identifying a fault section of the multi-dimensional operation data, constructing a total vector difference sequence according to the voltage phasor difference between the fault section and the adjacent power frequency period, and generating a discrimination result based on the total vector difference sequence and the voltage amplitude change before and after the fault; performing stability and temperature rise evaluation on the multi-dimensional operation data corresponding to the judgment result to obtain the operation safety level of each fault section; determining a target section from the fault sections according to the judgment result and the operation safety level; and generating a fault coincidence decision based on a preset coincidence rule, and then reclosing the target section according to the fault coincidence decision. The method has the effect of improving the reclosing efficiency of the power distribution network in the fault line section.

Description

Technical Field

[0001] This invention belongs to the technical field of power system automation and relay protection, and in particular relates to a PMU-based adaptive reclosing method, device, equipment and medium for distribution networks. Background Technology

[0002] Currently, with the widespread integration of distributed power sources and large-scale power electronic equipment into the distribution network, line fault patterns exhibit characteristics such as a high proportion of transient faults, rapid fault evolution, and complex dynamic responses after reclosing. To ensure the reliability of power supply to users and the safety of grid operation, reclosing operations not only need to restore power supply as quickly as possible, but also need to consider multi-dimensional operational constraints such as voltage stability, oscillation response, and conductor temperature rise. Simply relying on fixed time limits and single electrical quantities is insufficient to reflect the true operational risks.

[0003] Existing distribution network reclosing mechanisms are mostly based on settings that rely on fixed reclosing delays and a limited number of measurements such as current and voltage amplitudes. They typically only determine whether to allow or block reclosing based on the magnitude of the fault current or the voltage recovery before and after reclosing. These schemes lack sufficient sensitivity to the detailed changes in fault phasors over time, making it difficult to distinguish between transient and permanent faults. They also fail to adequately consider voltage stability and small-signal stability characteristics under distributed generation grid connection, and do not incorporate the dynamic process of conductor temperature changes with current and environmental conditions into the reclosing decision. This makes them prone to reclosing into unresolved faults under complex operating conditions or erroneous reclosing when the operating state is unsafe.

[0004] The existing technical solutions mentioned above have the following drawbacks: the existing distribution network reclosing methods lack fault evolution discrimination and operation safety assessment based on synchronous phasors, making it difficult to identify suitable line sections for reclosing in a timely manner when the fault nature is complex and the operating conditions are variable, thus there is room for improvement. Summary of the Invention

[0005] The purpose of this invention is to provide a PMU-based adaptive reclosing method, device, equipment, and medium for distribution networks, in order to solve the technical problem that some distribution network reclosing methods lack fault evolution discrimination and operational safety assessment based on synchronous phasors, making it difficult to identify suitable line sections for reclosing in a timely manner when the fault nature is complex and the operating conditions are variable.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a PMU-based adaptive reclosing method for distribution networks, the method comprising: After a distribution network fault, pre-processed multi-dimensional operational data is obtained through PMUs installed on both sides of each circuit breaker in the distribution network. Identify the fault sections in the multidimensional operating data, construct a total vector difference sequence based on the voltage phasor difference between the fault sections and adjacent power frequency cycles, and generate a discrimination result based on the total vector difference sequence and the voltage amplitude changes before and after the fault. The stability and temperature rise of the multidimensional operating data corresponding to the discrimination results are evaluated to obtain the operating safety level of each fault section; Based on the discrimination result and the operational safety level, the target section is determined from the faulty section; A fault reclosing decision is generated based on a preset reclosing rule, and then the target section is reclosed according to the fault reclosing decision.

[0007] By adopting the above technical solution, and acquiring pre-processed multi-dimensional operational data through PMUs installed on both sides of each circuit breaker in the distribution network after a fault, key information such as voltage, current, and conductor temperature of each line can be acquired synchronously under a unified time reference. This provides a comprehensive and accurate data foundation for subsequent fault identification and operational status assessment. By identifying the fault section in the multi-dimensional operational data and constructing a total vector difference sequence based on the voltage phasor difference between the fault section and adjacent power frequency cycles, and generating a discrimination result based on the total vector difference sequence and the voltage amplitude changes before and after the fault, the evolution characteristics of the fault phase voltage over time can be precisely characterized, and permanent faults, transient faults, and the secondary arc extinction process can be distinguished. This avoids mistaking permanent faults for transient faults, thus improving the accuracy and efficiency of the assessment. This system improves the accuracy of fault diagnosis. By evaluating the stability and temperature rise of the multi-dimensional operating data corresponding to the diagnosis results, the operating safety level of each fault section can be obtained. It can comprehensively assess the operating risks before and after reclosing in three dimensions: voltage stability margin, small signal stability characteristics, and conductor temperature rise safety. This avoids the risk of system instability or conductor overheating caused by making decisions based on a single electrical quantity. By determining the target section from the fault sections based on the diagnosis results and operating safety level, and generating fault reclosing decisions based on preset reclosing rules, and then reclosing the target section according to the fault reclosing decisions, it can achieve adaptive selection and hierarchical control of reclosing objects and timing, thereby improving reclosing success rate and reducing the risk of cascading faults caused by false reclosing and blind reclosing.

[0008] In one example, the present invention can be further configured as follows: obtaining the preprocessed multidimensional runtime data includes: The synchronous phasors of each phase voltage and current are obtained by PMUs installed on both sides of each circuit breaker in the distribution network, and the conductor temperature data corresponding to the synchronous phasors are obtained. The synchronous phasor and the conductor temperature are interpolated and aligned, outliers are removed, and missing data is filled in under a unified time reference to obtain the preprocessed multidimensional operating data.

[0009] By adopting the above technical solution, and by acquiring the synchronous phasors of phase voltage and current through PMUs installed on both sides of each circuit breaker in the distribution network, and acquiring the conductor temperature data corresponding to the synchronous phasors, it is possible to spatially cover key switch locations and maintain measurement synchronization in time, thereby comprehensively reflecting the electrical and thermal state of the distribution network before, during, and after faults and during reclosing. By interpolating and aligning the synchronous phasors and conductor temperatures, removing outliers, and completing missing data under a unified time reference, the impact of measurement noise and missing data on subsequent calculations can be effectively suppressed, thereby improving the reliability and accuracy of fault identification, stability assessment, and temperature rise analysis results.

[0010] In one example, the present invention can be further configured as follows: constructing a total vector difference sequence based on the voltage phasor difference between the fault section and adjacent power frequency cycles, and generating a discrimination result based on the total vector difference sequence and the voltage amplitude change before and after the fault, includes: When the fault section is a single-phase fault, the voltage phasor difference between adjacent cycles is calculated based on the voltage synchronization phasor of the fault phase in each power frequency cycle, and the total vector difference is constructed based on the voltage phasor difference. The total vector difference is compared with a preset threshold within a preset continuous period to classify the fault segment into permanent faults and transient faults. Based on the total vector difference sequence and the voltage amplitude change before and after the instantaneous fault, the extinguishing of the secondary arc in the instantaneous fault is determined; The discrimination result is generated based on the permanent fault, the transient fault, and the extinction of the secondary arc.

[0011] By adopting the above technical solution, in the case of a single-phase fault in the fault section, the voltage phasor difference between adjacent cycles is calculated based on the synchronous phasor of the fault phase voltage in each power frequency cycle, and a total vector difference is constructed based on the voltage phasor difference. This transforms the periodic variation of the fault phase voltage from a time-domain measurement into a quantifiable and comparable phasor change index, thereby sensitively capturing subtle changes in the development of the fault arc and voltage recovery. By comparing the total vector difference with a preset threshold within a preset continuous cycle, the fault section is divided into permanent faults and transient faults. Based on statistical characteristics, it is possible to robustly distinguish whether the fault has self-recovery characteristics, thereby avoiding repeated reclosing for permanent faults. By determining the extinction of the secondary arc in the transient fault based on the total vector difference sequence and the voltage amplitude change before and after the transient fault, the time point when the fault arc truly disappears can be identified, thereby providing a reasonable reclosing window for subsequent reclosing. By generating discrimination results based on permanent faults, transient faults, and secondary arc extinction, a structured discrimination output containing fault type and arc extinction information can be formed, thereby providing accurate and directly usable pre-processing information for operational safety level assessment and reclosing rule selection.

[0012] In one example, the present invention can be further configured as follows: calculating the voltage phasor difference between adjacent cycles based on the fault phase voltage synchronization phasor of each power frequency cycle, and constructing a total vector difference based on the voltage phasor difference, includes: The real part of the fault phase voltage synchronization phasor for each power frequency cycle is obtained. V or ( n ) and imaginary part V oi ( n ); According to the preset formula for calculating the total vector difference The voltage phasor difference between adjacent periods is calculated, and then the total vector difference is constructed, wherein, V or (n) V oi (n) represents the real and imaginary parts of the fault phase voltage phasor in the nth cycle, respectively. V or (n+1) V oi (n+1) represents the real and imaginary parts of the fault phase voltage phasor in the (n+1)th cycle, respectively.

[0013] By adopting the above technical solution, by obtaining the corresponding real and imaginary parts from the fault phase voltage synchronization phasors of each power frequency cycle, the magnitude and phase angle information of the voltage phasors can be accurately represented in a rectangular coordinate system, thus providing a basis for the accurate calculation of the phasor difference between subsequent adjacent cycles. By calculating the voltage phasor difference between adjacent cycles according to the preset total vector difference calculation formula, and then constructing the total vector difference, where the total vector difference is in the form of the ratio of the phasor difference magnitude to the phasor magnitude of the current cycle, the voltage change under different nodes and different voltage levels can be normalized and measured, thereby improving the universality of threshold setting and the robustness of fault judgment.

[0014] In one example, the present invention can be further configured as follows: The stability and temperature rise assessment of the multi-dimensional operational data corresponding to the discrimination result, to obtain the operational safety level of each fault segment, includes: The synchronous phasors of each fault section are evaluated according to the voltage stability margin algorithm and the small-signal stability eigenvalue algorithm to obtain the voltage stability state and small-signal stability state of the distribution network. Based on the pre-defined conductor current-temperature relationship model The conductor temperature data is evaluated to obtain the conductor's thermal stress state, wherein, q c For convective heat dissipation rate, q r For the rate of heat dissipation by radiation, mC p For the heat capacity of a conductor,T c For conductor temperature, q s For solar thermal gain, I For conductor current, R(T c ) For conductors at temperature T c The resistance below; The operational safety level is generated based on the voltage stability state, the small signal stability state, and the thermal stress state.

[0015] By adopting the above technical solutions, the voltage stability state and small-signal stability state of the distribution network are obtained by evaluating the synchronous phasors of each fault section according to the voltage stability margin algorithm and the small-signal stability eigenvalue algorithm, respectively. This allows for the quantification of the system's distance from the voltage instability boundary and dynamic instability boundary before, during, and after the fault, as well as at the re-closing time. This enables the full consideration of voltage collapse risk and oscillation divergence risk in decision-making. By evaluating the conductor temperature data according to the preset conductor current-temperature relationship model, the thermal stress state of the conductor is obtained. Through the thermal balance equation, the dynamic changes in conductor temperature under the action of fault current and re-closing current can be accurately predicted, thereby determining whether the conductor may exceed the rated maximum operating temperature. By generating the operating safety level based on the voltage stability state, small-signal stability state, and thermal stress state, multi-dimensional safety indicators can be converted into a single comparable level quantity, which facilitates sorting and screening among multiple fault sections, making the re-closing decision take into account both voltage stability and conductor thermal safety.

[0016] In one example, the present invention can be further configured as follows: determining the target segment from the faulty segment based on the discrimination result and the operational safety level includes: Based on the discrimination results, fault sections with overlapping times are identified as candidate fault sections. Based on the operational safety level of each candidate fault section, stability margin analysis and temperature limits are performed, and the section with the largest stability margin and a temperature below the limit is selected as the target section.

[0017] By adopting the above technical solution, and by determining the fault sections with reclosing opportunities based on the discrimination results as candidate fault sections, reclosing can be considered only on lines that have been determined to be transient faults and have detected the extinction of secondary arcs. This avoids blind reclosing on permanent faults or lines with unextinguished arcs, reducing the risk of reclosing at persistent fault points. By performing stability margin analysis and temperature limits based on the operational safety level of each candidate fault section, the section with the largest stability margin and temperature below the limit is selected as the target section. This allows priority to be given to reclosing on candidate lines with larger voltage stability margins, smaller signal stability margins, and more sufficient conductor temperature rise margins. This improves the efficiency of power restoration after a fault while minimizing the adverse effects on the overall system stability and equipment lifespan.

[0018] In one example, the present invention can be further configured as follows: generating a fault reclosing decision based on a preset reclosing rule, and then reclosing the target section according to the fault reclosing decision, includes: The fault type of the target segment is obtained from the discrimination result, and the maximum number of overlaps corresponding to the fault type is obtained from the preset overlap rules; At the reclosable moment, the operational safety level of the target section is determined. When the operational safety level meets the preset operational safety level conditions and the maximum number of reclosing times has not been reached, the fault reclosing decision is generated and the reclosing operation is performed on the target section. After each reclosing operation, the updated multidimensional operating data, corresponding judgment results, and operating safety level are obtained for fault analysis. When the fault is cleared, subsequent reclosing is terminated. When the number of reclosing operations reaches the maximum number of reclosing operations or the operating safety level does not meet the preset operating safety level conditions, the reclosing blocking strategy is activated.

[0019] By adopting the above technical solution, and by obtaining the fault type of the target section from the discrimination results and obtaining the maximum number of reclosing times corresponding to the fault type from the preset reclosing rules, differentiated upper limits for the number of reclosing times can be set for single-phase transient faults, single-phase permanent or semi-permanent faults, and multi-phase faults. This avoids repeated attempts at fault types unsuitable for reclosing, which would reduce the mechanical and electrical life of equipment and increase system impact. By judging the operational safety level of the target section at the reclosing time, when the operational safety level meets the preset operational safety level conditions and the maximum number of reclosing times has not been reached, a fault reclosing decision is generated and the reclosing operation is executed. It can ensure that reclosing is only performed when voltage stability, dynamic stability, and temperature rise safety all meet the requirements, thereby improving the success rate and safety of reclosing operations. By acquiring updated multi-dimensional operating data, corresponding judgment results, and operating safety levels after each reclosing operation, fault analysis is performed. When the fault is cleared, subsequent reclosing is terminated. When the number of reclosing operations reaches the maximum number of reclosing operations or the operating safety level does not meet the preset operating safety level conditions, a reclosing strategy is triggered to block the reclosing. This enables dynamic closed-loop monitoring and adaptive blocking of the reclosing process, thereby avoiding repeated reclosing of faults that have not been cleared and reducing secondary impacts on the power grid and equipment.

[0020] In a second aspect, the present invention provides a PMU-based adaptive reclosing device for distribution networks, the device comprising: The data acquisition module is used to acquire pre-processed multi-dimensional operational data through PMUs installed on both sides of each circuit breaker in the distribution network after a distribution network fault. The fault discrimination module is used to identify the fault sections of the multi-dimensional operating data, construct a total vector difference sequence based on the voltage phasor difference between the fault sections and adjacent power frequency cycles, and generate a discrimination result based on the total vector difference sequence and the voltage amplitude change before and after the fault. The stability assessment module is used to assess the stability and temperature rise of the multi-dimensional operating data corresponding to the discrimination results, and to obtain the operating safety level of each fault section. The target selection module is used to determine the target segment from the faulty segments based on the discrimination result and the operational safety level; The reclosing control module is used to generate a fault reclosing decision based on a preset reclosing rule, and then reclosing the target section according to the fault reclosing decision.

[0021] By adopting the above technical solution, and acquiring pre-processed multi-dimensional operational data through PMUs installed on both sides of each circuit breaker in the distribution network after a fault, key information such as voltage, current, and conductor temperature of each line can be acquired synchronously under a unified time reference. This provides a comprehensive and accurate data foundation for subsequent fault identification and operational status assessment. By identifying the fault section in the multi-dimensional operational data and constructing a total vector difference sequence based on the voltage phasor difference between the fault section and adjacent power frequency cycles, and generating a discrimination result based on the total vector difference sequence and the voltage amplitude changes before and after the fault, the evolution characteristics of the fault phase voltage over time can be precisely characterized, and permanent faults, transient faults, and the secondary arc extinction process can be distinguished. This avoids mistaking permanent faults for transient faults, thus improving the accuracy and efficiency of the assessment. This system improves the accuracy of fault diagnosis. By evaluating the stability and temperature rise of the multi-dimensional operating data corresponding to the diagnosis results, the operating safety level of each fault section can be obtained. It can comprehensively assess the operating risks before and after reclosing in three dimensions: voltage stability margin, small signal stability characteristics, and conductor temperature rise safety. This avoids the risk of system instability or conductor overheating caused by making decisions based on a single electrical quantity. By determining the target section from the fault sections based on the diagnosis results and operating safety level, and generating fault reclosing decisions based on preset reclosing rules, and then reclosing the target section according to the fault reclosing decisions, it can achieve adaptive selection and hierarchical control of reclosing objects and timing, thereby improving reclosing success rate and reducing the risk of cascading faults caused by false reclosing and blind reclosing.

[0022] In a third aspect, the present invention provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, characterized in that the processor executes the computer program to implement the steps of the aforementioned PMU-based adaptive reclosing method for distribution networks.

[0023] In a fourth aspect, the present invention provides a storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the aforementioned PMU-based adaptive reclosing method for distribution networks. Attached Figure Description

[0024] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a flowchart of a PMU-based adaptive reclosing method for distribution networks in an embodiment of the present invention; Figure 2 This is a structural block diagram of a PMU-based adaptive reclosing device for distribution networks according to an embodiment of the present invention; Figure 3 This is a structural block diagram of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0025] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0026] The following detailed description is exemplary and intended to provide further detailed explanation of the invention. Unless otherwise specified, all technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention.

[0027] Example 1 like Figure 1 As shown, this invention discloses an adaptive reclosing method for distribution networks based on a PMU, which specifically includes the following steps: S10: After a distribution network fault, pre-processed multi-dimensional operational data is obtained through PMUs installed on both sides of each circuit breaker in the distribution network.

[0028] Specifically, after a fault is detected or a protection action flag appears, a time window containing several power frequency cycles before and after the fault is extracted, centered on the time of the fault occurrence. The three-phase voltage and current phasors uploaded by the PMUs on both sides of each circuit breaker within the window, as well as the conductor temperature measurement values ​​corresponding to the line segment, are coarsely aligned according to the timestamp. Obvious abnormal frames, zero values, saturation values, etc., are initially removed or marked to form a multi-dimensional operational data set for subsequent fault analysis and reclosing decisions.

[0029] S20: Identify fault sections in multi-dimensional operating data, construct a total vector difference sequence based on the voltage phasor difference between the fault section and adjacent power frequency cycles, and generate a discrimination result based on the total vector difference sequence and the voltage amplitude changes before and after the fault.

[0030] Specifically, by comparing the amplitude changes and phase abrupt changes of the three-phase voltage and current phasors of each line segment before and after the fault, the line segment with abnormal changes is identified as the fault segment. Within the fault segment, the sequence of voltage phasors of the fault phase changing with the power frequency cycle is extracted. A total vector difference sequence is constructed according to the phasor difference between adjacent power frequency cycles. Then, by combining the voltage amplitude during normal operation before the fault with the voltage amplitude change trend of each cycle after the fault, the magnitude of the total vector difference and its persistence over time are compared with a preset threshold, thereby forming a discrimination result characterizing the fault attributes and its evolution process.

[0031] S30: Evaluate the stability and temperature rise of the multi-dimensional operating data corresponding to the judgment results to obtain the operating safety level of each fault section.

[0032] Specifically, taking the fault sections indicated in the judgment results and their corresponding critical moments as the objects, the voltage and current synchronization phasors and conductor temperature of these sections before the fault, during the fault, and near the expected re-coinciding moment are selected as inputs. The voltage stability margin and small-signal stability characteristics are calculated through the stability assessment module, and the temperature change and thermal stress level of the conductor under the current and expected re-coinciding conditions are calculated through the temperature rise assessment module. The above results are normalized and weighted to obtain the operating safety level reflecting the comprehensive stability and temperature rise constraints of each fault section.

[0033] S40: Based on the judgment results and the operational safety level, determine the target section from the faulty sections.

[0034] Specifically, based on the fault type information and reclosing timing information given in the judgment results, the operational safety level of all fault sections is compared. After excluding sections that do not meet the basic stability requirements or whose conductor temperature is close to the allowable limit, the remaining fault sections are sorted from high to low according to their operational safety level. The fault section with the highest safety level and that meets the preset safety requirements is selected as the target section for performing this round of reclosing operations.

[0035] S50: Generate fault reclosing decisions based on preset reclosing rules, and then reclose the target section according to the fault reclosing decisions.

[0036] Specifically, based on a pre-configured reclosing rule table divided by fault type, and combined with the fault nature, reclosing opportunity, and historical reclosing count of the target section, the maximum allowable reclosing count, reclosing interval, and blocking conditions are read from the rule table. At each allowable reclosing time, it is checked whether the operating safety level of the target section meets the safety threshold. If it does, a decision to allow reclosing is generated and the reclosing operation of the corresponding circuit breaker is triggered. If it does not meet the threshold, a blocking or delay decision is generated. When the maximum reclosing count is reached or continuous evaluation indicates that the safe reclosing conditions are no longer met, the blocking state is maintained.

[0037] In one embodiment, step S10, namely obtaining the preprocessed multidimensional operational data, includes: S11: Obtain the synchronous phasors of each phase voltage and current by using PMUs installed on both sides of each circuit breaker in the distribution network, and obtain the conductor temperature data corresponding to the synchronous phasors.

[0038] Specifically, PMUs with synchronous sampling and phasor calculation functions are configured on both sides of the circuit breaker of each distribution line. The three-phase voltage and three-phase current are sampled once or more per power frequency cycle, and the voltage synchronous phasor and current synchronous phasor with uniform time stamp are calculated using internal algorithms. At the same time, conductor temperature monitoring devices, such as fiber optic temperature measuring devices or infrared temperature measuring devices, are deployed at the locations corresponding to the line conductors. The conductor temperature is periodically collected and each temperature measurement value is timestamped. The synchronous phasor data of each PMU and the temperature data of each temperature monitoring device are uploaded to the upper processing unit through the communication network. In the upper processing unit, the data are archived according to the line number, phase, and timestamp, thus forming multi-dimensional raw operating data including voltage synchronous phasor, current synchronous phasor, and conductor temperature.

[0039] S12: Under a unified time reference, interpolate and align the synchronous phasor and conductor temperature, remove outliers, and complete missing data to obtain preprocessed multidimensional operating data.

[0040] Specifically, raw data from different PMUs and temperature monitoring devices are uniformly projected onto a time axis with power frequency cycles as intervals. Minor time deviations between multiple devices are corrected by linear interpolation or by keeping the most recent value, so that each power frequency cycle corresponds to complete three-phase voltage phasors, three-phase current phasors, and conductor temperature data. Obvious erroneous values ​​detected, such as measured values ​​exceeding physical limits, zero values ​​for several consecutive cycles, and signal spikes, are identified and removed or replaced by the average value of adjacent cycles. Short-term missing data segments can be estimated by interpolation of adjacent cycles or supplemented by historical operating curves, thereby obtaining preprocessed multidimensional operating data that is aligned in time, filtered in quality, and suitable for subsequent calculations.

[0041] In one embodiment, in step S20, a total vector difference sequence is constructed based on the voltage phasor difference between the fault section and adjacent power frequency cycles. Based on this total vector difference sequence and the voltage amplitude changes before and after the fault, a discrimination result is generated, including: S21: When the fault section is a single-phase fault, calculate the voltage phasor difference between adjacent cycles based on the voltage synchronization phasor of the fault phase in each power frequency cycle, and construct the total vector difference based on the voltage phasor difference.

[0042] Specifically, after identifying the faulty phase in the faulty section, the voltage phasor of that phase in several power frequency cycles before and after the fault is extracted cycle by cycle. The voltage phasor of each cycle is split into real and imaginary parts in rectangular coordinate form and arranged in chronological order. Then, the phasor of the (n+1)th cycle and the phasor of the nth cycle are subtracted to obtain the phasor difference. The phasor difference is then normalized so that the change during the cycle is compared with the phasor magnitude of the current cycle. This forms a set of total vector differences that reflect the intensity of the change of the voltage phasor of the faulty phase over time. These total vector differences are used as elements to form a total vector difference sequence ordered by cycle.

[0043] S22: Compare the total vector difference with a preset threshold within a preset continuous period to classify the faulty segment into permanent faults and transient faults.

[0044] Specifically, a sliding window of length N is selected on the total vector difference sequence, where N can be set to 5 power frequency cycles. The total vector difference within each sliding window is compared with a preset threshold, for example, the total vector difference threshold can be set to 5%. When the total vector difference is less than the threshold for N consecutive power frequency cycles after the fault occurs and the voltage of the faulted phase does not recover to a level close to that before the fault, the fault segment is determined to be a permanent fault. When there is a segment in the total vector difference that continuously exceeds the threshold during the fault evolution process and then gradually decreases and is accompanied by voltage recovery, the fault segment is determined to be a transient fault. In practical applications, N and the threshold can be appropriately adjusted according to the system noise level and measurement accuracy.

[0045] S23: Determine the extinction of the secondary arc in the instantaneous fault based on the total vector difference sequence and the voltage amplitude changes before and after the instantaneous fault.

[0046] Specifically, in the fault section that has been determined to be an instantaneous fault, the total vector difference sequence of the fault phase voltage and the voltage amplitude change of each cycle are continuously tracked. When the total vector difference is lower than the preset threshold within N consecutive power frequency cycles and the ratio of the current cycle fault phase voltage amplitude to the voltage amplitude of the initial cycle for fault type determination is greater than the preset amplitude ratio threshold, the corresponding time point is determined as the time of secondary arc extinction. The preset amplitude ratio threshold can be 1.5, that is, the voltage amplitude at the time of arc extinction determination is required to be at least 1.5 times the initial fault voltage amplitude, so as to avoid misjudgment caused by the change of total vector difference alone, and make the determination of secondary arc extinction more accurate.

[0047] S24: Generate a judgment result based on permanent faults, transient faults, and secondary arc extinction.

[0048] Specifically, the fault type labels of each fault segment obtained from the total vector difference and voltage amplitude analysis, as well as the extinction time of the secondary arc corresponding to the instantaneous fault, are recorded together. For each fault segment, a judgment result is formed that includes information such as whether it is a permanent fault or an instantaneous fault, whether a secondary arc occurs during the instantaneous fault, and the specific time when the secondary arc is extinguished.

[0049] In one embodiment, step S21, namely, calculating the voltage phasor difference between adjacent cycles based on the fault phase voltage synchronization phasor of each power frequency cycle, and constructing a total vector difference based on the voltage phasor difference, includes: S211: Obtain the real part of the fault phase voltage synchronization phasor from each power frequency cycle. V or ( n ) and imaginary part V oi ( n ).

[0050] Specifically, the fault phase voltage synchronization phasor is represented in complex form, and the real part of the phasor is read for the nth power frequency cycle. V or ( n ) and imaginary part V oi ( n ), and store them in the storage structure in the order of time from before the fault to after the fault, according to n.

[0051] S212: Calculate according to the preset total vector difference formula The voltage phasor difference between adjacent cycles is calculated, and then the total vector difference is constructed, where, V or (n) V oi (n) represents the real and imaginary parts of the fault phase voltage phasor in the nth cycle, respectively. V or (n+1) V oi (n+1) represents the real and imaginary parts of the fault phase voltage phasor in the (n+1)th cycle, respectively.

[0052] Specifically, for each pair of adjacent periods n and n+1, the total vector difference is calculated using the formula for calculating the total vector difference. The numerator represents the magnitude of the voltage phasor difference between the two periods, and the denominator is the magnitude of the voltage phasor in the nth period. This normalization process eliminates the influence of voltage amplitude differences at different nodes, allowing the total vector difference to reflect the relative degree of change. The calculated values ​​for each period are then... TVD (n) Arrange them in chronological order to construct the total vector difference sequence.

[0053] In one embodiment, step S30 involves evaluating the stability and temperature rise of the multidimensional operational data corresponding to the judgment result to obtain the operational safety level of each fault section, including: S31: The synchronous phasors of each fault section are evaluated according to the voltage stability margin algorithm and the small-signal stability eigenvalue algorithm to obtain the voltage stability state and small-signal stability state of the distribution network.

[0054] Specifically, based on the synchronous phasors of node voltages and branch currents before, during, and at expected overlap times of the fault, the steady-state operating point of the system is calculated using a PMU-based voltage stability assessment method. A voltage stability margin algorithm, such as one based on PV curves or sensitivity matrices, is used to calculate the percentage margin of critical nodes from the voltage instability point. A PMU-based small-signal stability assessment method is then used to obtain the eigenvalues ​​of the Jacobian matrix from the linearized equivalent model of the system, analyzing the minimum damping and the magnitude of the real parts of the eigenvalues. When the voltage stability margin is large and all eigenvalues ​​have negative real parts with absolute values ​​greater than a preset threshold, the system is evaluated as having good voltage stability and good small-signal stability; otherwise, it is evaluated as having poor stability. Through the above assessment process, the voltage stability and small-signal stability of each fault section under the current operating conditions are given.

[0055] S32: Based on the preset conductor current-temperature relationship model The conductor temperature data is evaluated to obtain the conductor's thermal stress state, whereby... q c For convective heat dissipation rate, q r For the rate of heat dissipation by radiation, mC p For the heat capacity of a conductor, T c For conductor temperature, q s For solar thermal gain, I For conductor current, R(T c ) For conductors at temperature T c The resistance below.

[0056] Specifically, the temperature measurements of the conductors in each fault section before and during the fault, along with the amplitude of the current phasor, are used as inputs and substituted into the conductor current-temperature relationship model. The convective heat dissipation rate of the conductor's surface is then considered. q c and radiative heat dissipation rate q r The product of conductor mass and specific heat capacity mC p Current conductor temperature Tc Solar radiation heat gain q s and by current I Temperature-dependent resistance R(T c ) The generated resistance heat is used to solve the rate of change of conductor temperature over time and to estimate the temperature evolution process under expected coincidence conditions. The conductor operating temperature is compared with the allowable limit, i.e. the rated maximum operating temperature, to obtain quantitative results characterizing the magnitude of thermal stress and temperature rise margin of the conductor.

[0057] S33: Generates the operational safety level based on voltage stability, small-signal stability, and thermal stress.

[0058] Specifically, the voltage stability state, small-signal stability state, and thermal stress state are normalized into numerical stability indicators and temperature rise indicators, respectively. The indicators are weighted and summed according to preset weights or comprehensively evaluated through a multi-indicator decision-making method to obtain the operational safety level score corresponding to each fault section. The higher the score, the better the comprehensive stability and the greater the thermal safety margin under the current and expected overlapping conditions, thus forming an operational safety level result that can be used for sorting and screening.

[0059] In one embodiment, step S40, namely determining the target segment from the faulty segments based on the discrimination result and the operational safety level, includes: S41: Based on the discrimination results, the fault sections with coincident times are identified as candidate fault sections.

[0060] Specifically, the judgment results of all fault sections are traversed and checked. Fault sections that are judged as permanent faults or where the time of secondary arc extinction is not detected are excluded. Fault sections that are judged as instantaneous faults and where the time of secondary arc extinction is determined are marked as sections with overlapping times. Sections with overlapping times are included in the candidate fault sections.

[0061] S42: Based on the operational safety level of each candidate fault section, perform stability margin analysis and temperature limits, and select the section with the largest stability margin and temperature below the limit as the target section.

[0062] Specifically, among the candidate fault sections, based on the stability analysis results and temperature limit requirements, the voltage stability margin and small signal stability margin, as well as the safe distance between the conductor temperature and the allowable limit, are compared among all the sections that meet the requirements of temperature being below the limit and having sufficient stability margin. The section with the highest operating safety level, that is, the largest comprehensive stability margin and the largest temperature safety margin, is selected as the target section and is the priority execution target for this round of reclosing operations.

[0063] In one embodiment, step S50, namely generating a fault reclosing decision based on a preset reclosing rule, and then reclosing the target section according to the fault reclosing decision, includes: S51: Obtain the fault type of the target segment from the discrimination result, and obtain the maximum number of overlaps corresponding to the fault type from the preset overlap rules.

[0064] Specifically, the system reads the judgment result record corresponding to the target section, parses the fault type information given therein, including single-phase instantaneous fault, single-phase permanent fault, semi-permanent fault or multi-phase fault, etc., uses the fault type as an index, and looks up parameters such as the maximum allowable number of overlaps, whether secondary or multiple overlaps are allowed, and overlap interval corresponding to the fault type in the preset overlap rule table, so as to provide a rule basis for generating overlap decisions that conform to the characteristics of the fault type.

[0065] S52: At the time when reclosing is possible, the operational safety level of the target section is determined. When the operational safety level meets the preset operational safety level conditions and the maximum number of reclosing times has not been reached, a fault reclosing decision is generated and a reclosing operation is performed on the target section.

[0066] Specifically, at the reclosing time indicated by the judgment result or the corresponding nearby time point, the current operating safety level of the target section is called and compared with the pre-set operating safety level threshold or classification standard. When the operating safety level is higher than the threshold and the current reclosing count has not reached the maximum reclosing count, the current operation is judged as allowed reclosing, a corresponding fault reclosing decision is generated, and a reclosing control command is issued to the circuit breaker to which the target section belongs, so that it closes at the reclosing time to realize the reclosing operation; when the operating safety level is lower than the threshold or the maximum reclosing count has been reached, no allowed reclosing decision is generated.

[0067] S53: After each reclosing operation, obtain the updated multi-dimensional operating data, the corresponding judgment results, and the operating safety level for fault analysis. When the fault is cleared, terminate subsequent reclosing. When the number of reclosing operations reaches the maximum number of reclosing operations or the operating safety level does not meet the preset operating safety level conditions, respond to the reclosing blocking strategy.

[0068] Specifically, after completing a reclosing operation, multi-dimensional operating data for subsequent periods is collected and preprocessed. Fault section identification, total vector difference calculation, and fault nature judgment are re-executed to obtain updated judgment results. At the same time, the stability and temperature rise of the synchronous phasor and conductor temperature of the target section are re-evaluated to obtain a new operating safety level. When the updated judgment results show that the fault current has disappeared, the voltage has returned to normal, and the operating safety level remains above the safety threshold, the fault is determined to be cleared, further reclosing operations are stopped, and the existing operating mode is maintained. When the updated judgment results still show a fault and the number of reclosing operations has reached the maximum number of reclosing operations or the operating safety level has dropped below the preset operating safety level condition, the reclosing blocking strategy is triggered, prohibiting the continued sending of reclosing commands to the target section, and issuing alarms or triggering subsequent protection actions as needed.

[0069] Example 2 like Figure 2 As shown, based on the same inventive concept as the above embodiments, the present invention also provides a PMU-based adaptive reclosing device for distribution networks, comprising: The data acquisition module is used to acquire pre-processed multi-dimensional operational data through PMUs installed on both sides of each circuit breaker in the distribution network after a distribution network fault. The fault discrimination module is used to identify fault sections in multi-dimensional operating data. It constructs a total vector difference sequence based on the voltage phasor difference between the fault section and adjacent power frequency cycles, and generates discrimination results based on the total vector difference sequence and the voltage amplitude changes before and after the fault. The stability assessment module is used to assess the stability and temperature rise of the multi-dimensional operating data corresponding to the judgment results, and obtain the operating safety level of each fault section. The target selection module is used to determine the target segment from the faulty segments based on the judgment results and the operational safety level. The reclosing control module is used to generate fault reclosing decisions based on preset reclosing rules, and then reclosing the target section according to the fault reclosing decisions.

[0070] Optionally, the data acquisition module includes: The multidimensional acquisition submodule is used to acquire the synchronous phasors of each phase voltage and current through the PMU installed on both sides of each circuit breaker in the distribution network, and to acquire the conductor temperature data corresponding to the synchronous phasors. The data preprocessing submodule is used to interpolate and align synchronous phasors and conductor temperatures, remove outliers, and complete missing data under a unified time reference to obtain preprocessed multidimensional operational data.

[0071] Optionally, the fault diagnosis module includes: The single-phase processing submodule is used to calculate the voltage phasor difference between adjacent cycles based on the voltage synchronization phasor of the fault phase in each power frequency cycle when the fault section is a single-phase fault, and to construct the total vector difference based on the voltage phasor difference. The classification and discrimination submodule is used to compare the total vector difference with a preset threshold within a preset continuous period to classify the fault segment into permanent faults and instantaneous faults. The arc extinction determination submodule is used to determine the extinction of the secondary arc in a transient fault based on the total vector difference sequence and the voltage amplitude changes before and after the transient fault. The result generation submodule is used to generate discrimination results based on permanent faults, transient faults, and secondary arc extinction.

[0072] Optional, the single-phase processing submodule includes: The phasor decomposition unit is used to obtain the real part of the fault phase voltage synchronization phasor from each power frequency cycle. V or ( n ) and imaginary part V oi ( n ); The vector difference calculation unit is used to calculate the total vector difference according to the preset formula. The voltage phasor difference between adjacent cycles is calculated, and then the total vector difference is constructed, where, V or (n) V oi (n) represents the real and imaginary parts of the fault phase voltage phasor in the nth cycle, respectively. V or (n+1) V oi (n+1) represents the real and imaginary parts of the fault phase voltage phasor in the (n+1)th cycle, respectively.

[0073] Optional, the stability assessment module includes: The stability calculation submodule is used to evaluate the synchronization phasors of each fault section according to the voltage stability margin algorithm and the small-signal stability characteristic value algorithm, respectively, to obtain the voltage stability state and small-signal stability state of the distribution network. The thermal stress calculation submodule is used to calculate the current-temperature relationship of a conductor based on a preset conductor current-temperature model. The conductor temperature data is evaluated to obtain the conductor's thermal stress state, whereby... q c For convective heat dissipation rate, q r For the rate of heat dissipation by radiation, mC p For the heat capacity of a conductor, T c For conductor temperature,q s For solar thermal gain, I For conductor current, R(T c ) For conductors at temperature T c The resistance below; The level generation submodule is used to generate the operating safety level based on the voltage stability state, small signal stability state, and thermal stress state.

[0074] Optionally, the target selection module includes: The candidate screening submodule is used to determine the fault segments with overlapping times as candidate fault segments based on the discrimination results. The target determination submodule is used to perform stability margin analysis and temperature limits based on the operational safety level of each candidate fault section, and select the section with the largest stability margin and temperature below the limit as the target section.

[0075] Optionally, the overlap control module includes: The rule acquisition submodule is used to obtain the fault type of the target segment from the discrimination result and obtain the maximum number of overlaps corresponding to the fault type from the preset overlap rules; The condition judgment submodule is used to judge the operating safety level of the target section at the time when reclosing is possible. When the operating safety level meets the preset operating safety level conditions and the maximum number of reclosing times has not been reached, a fault reclosing decision is generated and a reclosing operation is performed on the target section. The interlocking control submodule is used to obtain updated multi-dimensional operating data, corresponding judgment results, and operating safety level after each reclosing operation for fault analysis. When the fault is cleared, subsequent reclosing is terminated. When the number of reclosing operations reaches the maximum number of reclosing operations or the operating safety level does not meet the preset operating safety level conditions, the interlocking reclosing strategy is activated.

[0076] Example 3 like Figure 3 As shown, the present invention also provides an electronic device 100 for implementing a PMU-based adaptive reclosing method for distribution networks; The electronic device 100 includes a memory 101, at least one processor 102, a computer program 103 stored in the memory 101 and executable on at least one processor 102, and at least one communication bus 104.

[0077] The memory 101 can be used to store the computer program 103. The processor 102 implements the steps of the PMU-based adaptive reclosing method for distribution networks in Embodiment 1 by running or executing the computer program stored in the memory 101 and calling the data stored in the memory 101.

[0078] The memory 101 may primarily include a program storage area and a data storage area. The program storage area may store the operating system, application programs required for at least one function (such as sound playback function, image playback function, etc.), etc.; the data storage area may store data created based on the use of the electronic device 100 (such as audio data), etc. In addition, the memory 101 may include non-volatile memory, such as hard disk, RAM, plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, at least one disk storage device, flash memory device, or other non-volatile solid-state storage device.

[0079] At least one processor 102 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. Processor 102 may be a microprocessor or any conventional processor. Processor 102 is the control center of electronic device 100, connecting various parts of electronic device 100 via various interfaces and lines.

[0080] The memory 101 in the electronic device 100 stores multiple instructions to implement a PMU-based adaptive reclosing method for distribution networks, and the processor 102 can execute multiple instructions to achieve the following: After a distribution network fault, pre-processed multi-dimensional operational data is obtained through PMUs installed on both sides of each circuit breaker in the distribution network. Identify fault sections in multidimensional operational data, construct a total vector difference sequence based on the voltage phasor difference between the fault section and adjacent power frequency cycles, and generate a discrimination result based on the total vector difference sequence and the voltage amplitude change before and after the fault. The stability and temperature rise of the multidimensional operating data corresponding to the judgment results are evaluated to obtain the operating safety level of each fault section; Based on the judgment results and the operational safety level, the target section is determined from the faulty section; Based on preset overlap rules, a fault overlap decision is generated, and then the target section is overlapped according to the fault overlap decision.

[0081] Example 4 If the modules / units integrated in the electronic device 100 are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, and read-only memory (ROM).

[0082] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0083] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0084] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0085] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0086] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A PMU-based adaptive reclosing method for distribution networks, characterized in that, The method includes: After a distribution network fault, pre-processed multi-dimensional operational data is obtained through PMUs installed on both sides of each circuit breaker in the distribution network. Identify the fault sections in the multidimensional operating data, construct a total vector difference sequence based on the voltage phasor difference between the fault sections and adjacent power frequency cycles, and generate a discrimination result based on the total vector difference sequence and the voltage amplitude changes before and after the fault. The stability and temperature rise of the multidimensional operating data corresponding to the discrimination results are evaluated to obtain the operating safety level of each fault section; Based on the discrimination result and the operational safety level, the target section is determined from the faulty section; A fault reclosing decision is generated based on a preset reclosing rule, and then the target section is reclosed according to the fault reclosing decision.

2. The PMU-based adaptive reclosing method for distribution networks according to claim 1, characterized in that, The acquisition of preprocessed multidimensional operational data includes: The synchronous phasors of each phase voltage and current are obtained by PMUs installed on both sides of each circuit breaker in the distribution network, and the conductor temperature data corresponding to the synchronous phasors are obtained. The synchronous phasor and the conductor temperature are interpolated and aligned, outliers are removed, and missing data is filled in under a unified time reference to obtain the preprocessed multidimensional operating data.

3. The PMU-based adaptive reclosing method for distribution networks according to claim 1, characterized in that, The step of constructing a total vector difference sequence based on the voltage phasor difference between the fault section and adjacent power frequency cycles, and generating a discrimination result based on the total vector difference sequence and the voltage amplitude changes before and after the fault, includes: When the fault section is a single-phase fault, the voltage phasor difference between adjacent cycles is calculated based on the voltage synchronization phasor of the fault phase in each power frequency cycle, and the total vector difference is constructed based on the voltage phasor difference. The total vector difference is compared with a preset threshold within a preset continuous period to classify the fault segment into permanent faults and transient faults. Based on the total vector difference sequence and the voltage amplitude change before and after the instantaneous fault, the extinguishing of the secondary arc in the instantaneous fault is determined; The discrimination result is generated based on the permanent fault, the transient fault, and the extinction of the secondary arc.

4. The PMU-based adaptive reclosing method for distribution networks according to claim 3, characterized in that, The step of calculating the voltage phasor difference between adjacent cycles based on the fault phase voltage synchronization phasor of each power frequency cycle, and constructing the total vector difference based on the voltage phasor difference, includes: The real part of the fault phase voltage synchronization phasor for each power frequency cycle is obtained. V or ( n ) and imaginary part V oi ( n ); According to the preset formula for calculating the total vector difference The voltage phasor difference between adjacent periods is calculated, and then the total vector difference is constructed, wherein, V or (n) V oi (n) represents the real and imaginary parts of the fault phase voltage phasor in the nth cycle, respectively. V or (n+1) V oi (n+1) represents the real and imaginary parts of the fault phase voltage phasor in the (n+1)th cycle, respectively.

5. The PMU-based adaptive reclosing method for distribution networks according to claim 2, characterized in that, The stability and temperature rise assessment of the multidimensional operating data corresponding to the discrimination result is performed to obtain the operating safety level of each fault section, including: The synchronous phasors of each fault section are evaluated according to the voltage stability margin algorithm and the small-signal stability eigenvalue algorithm to obtain the voltage stability state and small-signal stability state of the distribution network. Based on the pre-defined conductor current-temperature relationship model The conductor temperature data is evaluated to obtain the conductor's thermal stress state, wherein, q c For convective heat dissipation rate, q r For the rate of heat dissipation by radiation, mC p For the heat capacity of a conductor, T c For conductor temperature, q s For solar thermal gain, I For conductor current, R(T c ) For conductors at temperature T c The resistance below; The operational safety level is generated based on the voltage stability state, the small signal stability state, and the thermal stress state.

6. The PMU-based adaptive reclosing method for distribution networks according to claim 5, characterized in that, The step of determining the target segment from the faulty segments based on the discrimination result and the operational safety level includes: Based on the discrimination results, fault sections with overlapping times are identified as candidate fault sections. Based on the operational safety level of each candidate fault section, stability margin analysis and temperature limits are performed, and the section with the largest stability margin and a temperature below the limit is selected as the target section.

7. The PMU-based adaptive reclosing method for distribution networks according to claim 6, characterized in that, The step of generating a fault reclosing decision based on preset reclosing rules, and then performing reclosing on the target section according to the fault reclosing decision, includes: The fault type of the target segment is obtained from the discrimination result, and the maximum number of overlaps corresponding to the fault type is obtained from the preset overlap rules; At the reclosable moment, the operational safety level of the target section is determined. When the operational safety level meets the preset operational safety level conditions and the maximum number of reclosing times has not been reached, the fault reclosing decision is generated and the reclosing operation is performed on the target section. After each reclosing operation, the updated multidimensional operating data, corresponding judgment results, and operating safety level are obtained for fault analysis. When the fault is cleared, subsequent reclosing is terminated. When the number of reclosing operations reaches the maximum number of reclosing operations or the operating safety level does not meet the preset operating safety level conditions, the reclosing blocking strategy is activated.

8. A PMU-based adaptive reclosing device for distribution networks, characterized in that, The device includes: The data acquisition module is used to acquire pre-processed multi-dimensional operational data through PMUs installed on both sides of each circuit breaker in the distribution network after a distribution network fault. The fault discrimination module is used to identify the fault sections of the multi-dimensional operating data, construct a total vector difference sequence based on the voltage phasor difference between the fault sections and adjacent power frequency cycles, and generate a discrimination result based on the total vector difference sequence and the voltage amplitude change before and after the fault. The stability assessment module is used to assess the stability and temperature rise of the multi-dimensional operating data corresponding to the discrimination results, and to obtain the operating safety level of each fault section. The target selection module is used to determine the target segment from the faulty segments based on the discrimination result and the operational safety level; The reclosing control module is used to generate a fault reclosing decision based on a preset reclosing rule, and then reclosing the target section according to the fault reclosing decision.

9. An electronic device, characterized in that, It includes a processor and a memory, the processor being used to execute a computer program stored in the memory to implement the steps of the PMU-based adaptive reclosing method for distribution networks as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores at least one instruction, which, when executed by a processor, implements the steps of the PMU-based adaptive reclosing method for distribution networks as described in any one of claims 1 to 7.

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