An optimized dispatching method and system for post-disaster recovery of distribution network

Abstract

The present invention discloses an optimization scheduling method and system for post-disaster recovery of a distribution network, which specifically relates to the technical field of power grid control, and is used to solve the existing problem that potential safety hazards of grid connection cannot be discovered in advance before grid connection; real-time electrical parameter data of an isolated island area and a main power grid are obtained, and the phase difference and frequency deviation between the two are calculated based on a phasor measurement algorithm; the output power and load state of distributed power sources in the isolated island area are adjusted in real time according to the detected deviation, so that the electrical parameters of the isolated island area gradually converge with those of the main power grid; the energy conversion process between the isolated island area and the main power grid is analyzed, and the stability margin before grid connection is evaluated; the complex characteristics of electrical signals are extracted using multi-scale signal processing technology, and the complexity of phase signals of the isolated island area and the main power grid is evaluated in combination with fractal dimension analysis; based on the stability margin and signal complexity, the degree of potential hidden dangers of grid connection is judged, and when safety conditions are met, grid connection operation is allowed to be executed.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid control, and more specifically, to an optimization dispatching method and system for post-disaster recovery of a distribution network. Background Art

[0002] The stable operation of the power system is an important guarantee for the normal operation of the country's economic development and social life; however, natural disasters such as typhoons, earthquakes, floods and other natural disasters often cause serious damage to the power system, causing some areas of the distribution network to lose contact with the main power grid, forming an "island" operation phenomenon; island operation not only causes power supply interruptions in some areas, but also poses a huge challenge to the recovery and reconstruction of the power system after the disaster; how to quickly and stably connect the island area to the main power grid after a disaster is a key issue to ensure the recovery of power supply after a disaster.

[0003] During the disaster recovery process, the electrical parameters (such as voltage phase, frequency, etc.) of the isolated island area are significantly different from those of the main grid due to its isolation from the main grid. If the phase and frequency of the two are not accurately adjusted before grid connection, forced grid connection will cause drastic fluctuations in system voltage and current, and even cause damage to power equipment, threatening the safety and stability of the entire power system. In addition, if potential grid safety hazards are not discovered in advance before grid connection, these islands may cause grid connection failure or equipment damage when they are reconnected to the grid, affecting the efficiency and safety of power restoration.

[0004] In order to solve the above problems, a technical solution is now provided. Summary of the invention

[0005] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides an optimization scheduling method and system for post-disaster recovery of a distribution network to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an optimization scheduling method for post-disaster recovery of distribution networks, comprising the following steps: S1: obtaining real-time electrical parameter data of the isolated area and the main power grid, and using a phasor measurement algorithm to calculate the phase difference and frequency deviation between the isolated area and the main power grid based on the electrical parameter data when the accuracy of the electrical parameter data meets a preset threshold; S2: adjusting the output power and load state of the distributed power sources in the isolated area in real time according to the detected phase difference and frequency deviation, so that the electrical parameters of the isolated area are gradually consistent with those of the main power grid; S3: analyzing the phase difference and frequency deviation between the isolated area and the main power grid, The difference between energy conversion and critical energy of the power system during state changes is used to evaluate the stability margin before grid connection. Through multi-scale signal processing, wavelet transform is used to extract the complex characteristics of electrical signals, and combined with fractal dimension analysis, the complexity of the phase signals of the island area and the main grid is evaluated. S4: Based on the stability margin before grid connection and the complexity of the phase signals of the island area and the main grid, it is determined whether the potential hidden danger of grid connection between the island area and the main grid is too large. S5: When the electrical parameters of the island area tend to be consistent with those of the main grid, and the potential hidden danger of grid connection between the island area and the main grid is not too large, the grid connection operation is allowed.

[0007] In a preferred embodiment, S1 specifically includes: real-time collection of electrical parameter data of the island area and the main power grid, the electrical parameter data including voltage, frequency and phase; preprocessing the collected electrical parameter data to remove abnormal values ​​to ensure that the data accuracy meets the preset threshold; and using a phasor measurement algorithm to calculate the phase difference and frequency deviation between the island area and the main power grid.

[0008] In a preferred embodiment, S2 specifically includes: S201: analyzing the calculated phase difference and frequency deviation to determine the adjustment direction and amplitude; S202: formulating an adjustment strategy for the output power and load status of distributed power sources based on the phase difference and frequency deviation; S203: adjusting the output power of distributed power sources in the island area in real time according to the adjustment strategy to reduce the phase difference and frequency deviation; S204: adjusting the load status in the island area according to the adjustment strategy to promote the consistency of electrical parameters with the main power grid; S205: during the adjustment process, continuously monitoring the phase difference and frequency deviation, and adjusting the adjustment strategy in a timely manner according to the changes.

[0009] In a preferred embodiment, by analyzing the difference between energy conversion and critical energy in the power system of the isolated area and the main grid during the state change, the stability margin before grid connection is evaluated, specifically including: constructing a power system model of the isolated area and the main grid, including power generation, transmission, distribution and load links: the power system model of the isolated area is recorded as , the main power grid model is recorded as ;in, Defined as a directed graph: ;in, represents the set of nodes in the island area, Represents the directed edge set between nodes; Based on the power system model, define the transient energy function that describes the energy conversion during the state change process: Define the transient energy function , whose expression is: ;in, Representation Node The inertia coefficient, For Node The voltage phase angle, For Node The voltage phase angle, Representation Node With Node The equivalent elastic coefficient of the line between the two; analyze the critical stability state of the power system before grid connection, and calculate the corresponding critical energy value: the total energy of the system when it is in the critical stability state is marked as , determine the critical stability point Corresponding to the saddle point of the energy function, is the number of nodes; Substitution The critical energy value is obtained ; Use the transient energy function to calculate the actual energy conversion value and compare it with the critical energy value to obtain the energy difference. Based on the energy difference, the stability margin before grid connection is evaluated: Through the transient energy function , calculate the actual energy conversion value at the current moment By comparison and , evaluate the stability margin before grid connection : ;when When , it is determined that the stability margin before grid connection is sufficient; when When , it is determined that the stability margin before grid connection is insufficient.

[0010] In a preferred embodiment, multi-scale signal processing is performed, wavelet transform is used to extract complex features of electrical signals, and combined with fractal dimension analysis, the complexity of phase signals of the island area and the main power grid is evaluated, specifically: the electrical phase signals of the island area and the main power grid are collected to construct a signal sequence; the signal sequence is subjected to multi-scale decomposition and feature extraction using wavelet transform; multi-scale wavelet coefficients are extracted to construct a feature matrix to characterize signal complexity: the wavelet coefficients are arranged according to different scales and time displacements to construct a feature matrix, and the feature matrix is ​​normalized; the feature matrix is ​​calculated based on the fractal dimension to quantify the signal complexity: the feature matrix is ​​divided into several sub-matrices, and the size of each box is ,in is the scale parameter of the segmentation; get the The submatrix set at each scale and calculate the number of non-zero elements in each submatrix ; With the scale parameter , counting the number of non-zero elements at different scales , calculate the fractal dimension of the signal: ;in, is the fractal dimension of the signal; compare and analyze the signal complexity and evaluate the difference in characteristics between the isolated island area and the main power grid: the fractal dimension of the signal in the isolated island area is obtained through the fractal dimension formula of the signal and the fractal dimension of the main power grid signal ;calculate : ;when Not exceeding critical threshold When , the signal feature matching degree is high; when Exceeding critical threshold When , it is determined that the matching degree of the signal characteristics is low.

[0011] In a preferred embodiment, based on the stability margin before grid-connection and the complexity of the phase signal between the island area and the main grid, it is judged whether the potential hidden danger level of the grid-connection between the island area and the main grid is too large. Specifically, when the stability margin before grid-connection is sufficient and the matching degree of the signal characteristics is high, it is judged that the potential hidden danger level of the grid-connection between the island area and the main grid is normal; otherwise, it is judged that the potential hidden danger level of the grid-connection between the island area and the main grid is too large.

[0012] On the other hand, the present invention provides an optimization dispatching system for post-disaster recovery of distribution networks, including an electrical parameter acquisition module, a power load adjustment module, a margin complex analysis module, a grid-connected hidden danger assessment module, and a grid-connected execution judgment module; the electrical parameter acquisition module: acquires real-time electrical parameter data of the isolated island area and the main power grid, and when the accuracy of the electrical parameter data meets a preset threshold, the phase difference and frequency deviation between the isolated island area and the main power grid are calculated based on the electrical parameter data using a phasor measurement algorithm; the power load adjustment module: adjusts the output power and load state of the distributed power source in the isolated island area in real time according to the detected phase difference and frequency deviation, so that the electrical parameters of the isolated island area gradually converge to the same as those of the main power grid; the margin Complex analysis module: By analyzing the difference between energy conversion and critical energy of the power system of the isolated area and the main grid during the state change, the stability margin before grid connection is evaluated; through multi-scale signal processing, the complex characteristics of electrical signals are extracted by wavelet transform, and combined with fractal dimension analysis, the complexity of the phase signals of the isolated area and the main grid is evaluated; Grid connection hidden danger assessment module: Based on the stability margin before grid connection and the complexity of the phase signals of the isolated area and the main grid, it is judged whether the potential hidden danger of grid connection between the isolated area and the main grid is too large; Grid connection execution judgment module: When the electrical parameters of the isolated area are consistent with those of the main grid, and the potential hidden danger of grid connection between the isolated area and the main grid is not too large, the grid connection operation is allowed.

[0013] The technical effects and advantages of the optimization scheduling method and system for post-disaster recovery of distribution networks of the present invention are as follows: 1. By acquiring the real-time electrical parameter data of the isolated island area and the main power grid, the phase difference and frequency deviation between the two are accurately calculated using the phasor measurement algorithm, and the power output power and load state of the isolated island area can be adjusted in real time, so that its electrical parameters gradually become consistent with those of the main power grid. This precise real-time adjustment significantly reduces the risk of grid connection failure or equipment damage, and ensures the accuracy and safety of grid connection operation.

[0014] 2. By analyzing the energy conversion process between the isolated island area and the main power grid, the stability margin before grid connection is evaluated, and the stable operation after grid connection is further guaranteed; the complex characteristics of electrical signals are extracted by multi-scale signal processing technology, and combined with fractal dimension analysis, the nonlinear characteristics and dynamic change laws of the signals can be fully revealed. By comparing and analyzing the complexity of the phase signals of the isolated island area and the main power grid, the potential hidden dangers of grid connection can be accurately judged; based on the stability margin before grid connection and the complexity of the phase signals of the isolated island area and the main power grid, it is ensured that the grid connection operation is performed only when the safety conditions are met, which greatly improves the reliability and efficiency of power supply restoration. This method can quickly restore power supply after a disaster, shorten the recovery time, and is applicable to various complex power system environments, providing a practical technical means for the restoration of power systems after disasters. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of an optimization scheduling method for post-disaster recovery of a distribution network according to the present invention.

[0016] Figure 2 The schematic diagram is a structural diagram of an optimization dispatching system for post-disaster recovery of a distribution network according to the present invention. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Embodiment 1: Figure 1 The present invention provides an optimization scheduling method for post-disaster recovery of a distribution network, which includes the following steps: S1: acquiring real-time electrical parameter data of an isolated area and a main power grid, and, under the condition that the accuracy of the electrical parameter data meets a preset threshold, using a phasor measurement algorithm based on the electrical parameter data to calculate the phase difference and frequency deviation between the isolated area and the main power grid.

[0019] S2: According to the detected phase difference and frequency deviation, the output power and load status of the distributed power sources in the island area are adjusted in real time, so that the electrical parameters of the island area gradually converge with those of the main power grid.

[0020] S3: By analyzing the differences in energy conversion and critical energy during state changes between the power systems of the island area and the main grid, the stability margin before grid connection is evaluated. Through multi-scale signal processing, the complex features of electrical signals are extracted using wavelet transform, and combined with fractal dimension analysis, the complexity of the phase signals of the island area and the main grid is evaluated.

[0021] S4: Based on the stability margin before grid connection and the complexity of the phase signal between the island area and the main grid, determine whether the potential risk level of grid connection between the island area and the main grid is too large.

[0022] S5: When the electrical parameters of the island area are consistent with those of the main grid and the potential risk of grid connection between the island area and the main grid is not too great, grid connection operation is allowed.

[0023] S1 specifically includes: real-time collection of electrical parameter data of the island area and the main power grid, including voltage, frequency and phase: electrical parameter data mainly include voltage, frequency and phase; these data are collected in real time by high-precision sensors, and the sensors need to have high sensitivity and high stability to ensure the accuracy of the collected data; during the collection process, the sensors need to be calibrated regularly to eliminate their own errors; at the same time, the collection system should have data caching and breakpoint resumption functions to deal with possible data transmission interruptions or losses.

[0024] Preprocess the collected electrical parameter data to remove outliers and ensure that the data accuracy meets the preset threshold: Due to the influence of various factors, the collected electrical parameter data may contain outliers; in order to ensure the accuracy of the data, the collected data needs to be preprocessed; the preprocessing process includes data cleaning, data correction and data screening; data cleaning is used to remove obvious outliers, such as erroneous data caused by sensor failure or external interference; data correction is used to correct data deviations caused by errors in the sensor itself or errors in the data transmission process; data screening is used to select data that meets the preset conditions for subsequent calculations, such as selecting data segments with stable voltage and frequency.

[0025] During the data preprocessing process, a preset threshold is set to determine whether the accuracy of the electrical parameter data meets the requirements. This preset threshold can be adjusted according to actual conditions, such as the accuracy of the sensor, the stability of data transmission, and the needs of subsequent calculations.

[0026] The phase difference and frequency deviation between the island area and the main grid are calculated using the phasor measurement algorithm: the preprocessed electrical parameter data will be used to calculate the phase difference and frequency deviation between the island area and the main grid; the phasor measurement algorithm is an algorithm based on complex number operations, which can accurately calculate the phase difference and frequency deviation between two electrical signals.

[0027] When calculating the phase difference, the collected voltage signal is first converted into a phasor form, that is, the time domain signal is converted into a frequency domain signal using Fourier transform or discrete Fourier transform (DFT), and the phasor of the corresponding frequency is extracted. Then, by comparing the phasors of the island area and the main grid at the same frequency, the phase difference between them can be calculated. Specifically, the phase difference is equal to the phase of the phasor in the island area minus the phase of the phasor in the main grid.

[0028] When calculating the frequency deviation, it is also necessary to convert the collected signal into a phasor form and extract the phasor of the corresponding frequency. Then, by comparing the phasor frequencies of the island area and the main grid, the frequency deviation between them can be calculated. Specifically, the frequency deviation is equal to the frequency of the phasor in the island area minus the frequency of the phasor in the main grid.

[0029] S2 specifically includes: S201: Analyze the calculated phase difference and frequency deviation to determine the adjustment direction and amplitude: First, the calculated phase difference and frequency deviation need to be analyzed in detail; the phase difference reflects the relative position of the voltage waveform between the island area and the main power grid, while the frequency deviation reflects the difference in the rate of change of the voltage waveforms of the two; the direction and amplitude of the adjustment are determined by analyzing these two parameters.

[0030] Specifically, if the phase difference is positive, it means that the voltage waveform in the island area lags behind the main grid. Therefore, it is necessary to increase the output power of the distributed power source or reduce the load to speed up the rate of change of the voltage waveform in the island area and synchronize it with the main grid. On the contrary, if the phase difference is negative, it means that the voltage waveform in the island area is ahead of the main grid. At this time, it is necessary to reduce the output power of the distributed power source or increase the load to slow down the rate of change of the voltage waveform in the island area.

[0031] For frequency deviation, if the frequency of the island area is higher than that of the main grid, it is necessary to reduce the output power of the distributed power source or increase the load to lower the frequency of the island area; if the frequency of the island area is lower than that of the main grid, it is necessary to increase the output power of the distributed power source or reduce the load to increase the frequency of the island area.

[0032] S202: Formulate a regulation strategy for the output power and load status of the distributed power source based on the phase difference and frequency deviation: The formulation of the regulation strategy needs to comprehensively consider the actual situation of the island area, such as the type, capacity, regulation range of the distributed power source, and the characteristics and adjustability of the load.

[0033] Generally speaking, the regulation strategy includes the following aspects: first, determine the output power regulation amount of the distributed power source, which needs to be determined based on the size of the phase difference and frequency deviation and the regulation capability of the distributed power source; second, determine the adjustment plan for the load state, including which loads can be adjusted and how much the adjustment amount is; finally, formulate a timetable and steps for adjustment to ensure that the adjustment process proceeds smoothly and orderly.

[0034] S203: According to the regulation strategy, the output power of the distributed power sources in the island area is adjusted in real time to reduce the phase difference and frequency deviation: According to the formulated regulation strategy, the output power of the distributed power sources in the island area is adjusted in real time; the output of the distributed power sources needs to be precisely controlled to ensure the accuracy and effectiveness of the regulation; during the regulation process, it is necessary to pay close attention to the changes in the output power of the distributed power sources, as well as the response of the phase difference and frequency deviation; if it is found that the regulation effect is not good or over-regulation occurs, it is necessary to adjust the regulation strategy in time to ensure the stability and accuracy of the regulation process.

[0035] S204: Adjust the load state in the island area according to the regulation strategy to further promote the consistency of electrical parameters with the main power grid: this is achieved by adjusting the power of the controllable load or switching on and off part of the load.

[0036] When adjusting the load state, it is necessary to consider the characteristics of the load and the degree of adjustability. For adjustable loads, such as motors and lighting, their power can be adjusted to match the output of distributed power sources. For non-adjustable loads, such as residential electricity, it is necessary to balance the electrical parameters by switching on and off part of the load. In the process of adjusting the load state, it is also necessary to pay close attention to the changes in phase difference and frequency deviation, as well as the response of the load state. If the adjustment effect is not good or over-adjustment occurs, it is also necessary to adjust the adjustment strategy in time.

[0037] S205: During the adjustment process, the phase difference and frequency deviation are continuously monitored, and the adjustment strategy is adjusted in time according to the changes: During the adjustment process, it is necessary to continuously monitor the changes in the phase difference and frequency deviation, as well as the response of the distributed power output power and load status; if any abnormal situation is found or the adjustment effect is not good, the adjustment strategy needs to be adjusted in time to ensure the stability and accuracy of the adjustment process.

[0038] In addition, the dynamic changes between the isolated area and the main power grid need to be considered; since disasters may cause changes in the topology and electrical parameters of the distribution network, these changes need to be monitored in real time and the regulation strategy needs to be adjusted in a timely manner according to the changes.

[0039] In summary, by precisely controlling the output power and load status of distributed power sources, the electrical parameters of the island area can be gradually consistent with those of the main grid, providing a strong guarantee for the smooth grid connection between the island area and the main grid.

[0040] By analyzing the difference between energy conversion and critical energy in the state change process of the power system of the isolated area and the main grid, the stability margin before grid connection is evaluated, which includes: constructing the power system model of the isolated area and the main grid, including power generation, transmission, distribution and load links: First, for the power system of the isolated area and the main grid, construct the model of its power generation, transmission, distribution and load links; this model will include the operating status, topology and parameters of different links, such as generator output power, line impedance, distribution transformer, etc.; assuming that the power system model of the isolated area is recorded as , the main power grid model is recorded as ;in, It is composed of various power generation nodes, transmission lines and load nodes, and is defined as a directed graph: ;in, Represents the set of nodes in the island area; Represents a set of directed edges between nodes, describing the direction and path of power flow.

[0041] Similarly, the topology of the main grid and the island area are constructed in the same way and will not be described here; each element in the node set represents a power generation, load or transfer node, while the elements of the edge set represent power transmission lines.

[0042] Based on the power system model, a transient energy function is defined to describe the energy conversion during the state change process: In order to quantify the energy conversion behavior between the island area and the main grid during the grid connection process, a transient energy function is defined Used to describe the state of a system over time The energy characteristics of the change; the definition of this energy function is based on the Lagrangian mechanical system, and the transient energy of the system is described by constructing the energy balance equation; the transient energy function of the power system is assumed to be: ;in, Representation Node The inertia coefficient, in kg·m², reflects the Inertial properties within the system; For Node The voltage phase angle is in radians (rad); For Node The voltage phase angle; Representation Node With Node The equivalent elastic modulus of the line between the two nodes, with the unit of N·m / rad², which measures the strength of the electrical coupling between the two nodes.

[0043] Analyze the critical stability state of the power system before grid connection and calculate the corresponding critical energy value: Calculate the critical energy value of the system before grid connection to determine the maximum energy disturbance that the system can withstand under the most unfavorable state; Assume that the total energy of the system in the critical stability state is , first determine the critical stability point Corresponding to the saddle point of the energy function, is the number of nodes.

[0044] Will Substitution The critical energy value can be obtained : ;in, Representation Node Phase angle at the critical state.

[0045] The actual energy conversion value is calculated using the transient energy function and compared with the critical energy value to obtain the energy difference. The stability margin before grid connection is evaluated based on the energy difference: , calculate the actual energy conversion value at the current moment , whose expression is similar to the energy function above, but is calculated based on real-time data; the calculation result is: ;in, and Respectively represent the nodes in the actual state The phase angle and the rate of change of the phase angle.

[0046] Finally, by comparing and , evaluate the stability margin before grid connection : .

[0047] when When , it is determined that the stability margin before grid connection is sufficient, indicating that the system has sufficient stability margin in the current state and can be safely connected to the grid; when When the system is connected to the grid, it is determined that the stability margin before grid connection is insufficient, the system stability is at risk, and further measures need to be taken.

[0048] Through multi-scale signal processing, wavelet transform is used to extract the complex characteristics of electrical signals, and combined with fractal dimension analysis, the complexity of the phase signals of the island area and the main power grid is evaluated. Specifically, the electrical phase signals of the island area and the main power grid are collected to construct a signal sequence: the electrical phase signals of the island area and the main power grid are collected respectively to establish a signal sequence for analysis.

[0049] In the actual acquisition process, factors such as electromagnetic interference and environmental noise need to be considered, so the collected signals are preprocessed, including denoising and normalization.

[0050] Use wavelet transform to perform multi-scale decomposition and feature extraction on the signal sequence: During the wavelet transform process, select a suitable mother wavelet function to perform multi-scale decomposition on the signal sequence; the core idea of ​​wavelet transform is to decompose the signal sequence into different scales through scaling and translation operations, thereby revealing the characteristics of the signal in each frequency band.

[0051] Extract multi-scale wavelet coefficients and construct a feature matrix to characterize signal complexity: Arrange the wavelet coefficients according to different scales and time displacements to construct a feature matrix. The feature matrix completely retains the signal change information at different time scales and reflects the complexity and nonlinear characteristics of the signal.

[0052] In order to improve the extraction efficiency of signal features, the feature matrix can be further normalized. The feature matrix constructed in this way helps to avoid excessive amplification or reduction of features at a specific scale or time period.

[0053] Calculate the characteristic matrix based on the fractal dimension and quantify the signal complexity: Use the fractal dimension to analyze the characteristic matrix to quantify the complexity of the signal; the fractal dimension is an indicator that describes the self-similarity of the signal at different scales and can reflect the complexity and detailed characteristics of the signal; the commonly used box-counting dimension is used as the calculation method of the fractal dimension.

[0054] Divide the feature matrix into several sub-matrices (boxes), each box has a size of ,in is the scale parameter of the segmentation.

[0055] Get the The submatrix set at each scale and calculate the number of non-zero elements in each submatrix .

[0056] With the scale parameter , counting the number of non-zero elements at different scales , finally according to the formula: ;in, is the fractal dimension of the signal, The value range is between [0, 2]. The larger the value, the higher the complexity of the signal.

[0057] Compare and analyze the signal complexity and evaluate the difference in characteristics between the island area and the main power grid: The fractal dimension of the signal in the island area is obtained by the fractal dimension formula of the signal. and the fractal dimension of the main power grid signal , to evaluate the difference between the two in terms of phase signal complexity.

[0058] if , indicating that the phase signal in the island area is more complex, and may be subject to more interference or have more obvious nonlinear characteristics.

[0059] On the contrary, if , the complexity of the main grid phase signal is higher; based on this analysis result, reasonable grid-connected strategies and protection measures can be further formulated to ensure the stability and safety of system operation.

[0060] Calculate the difference between the two : .

[0061] when Not exceeding critical threshold When , it is determined that the matching degree of the signal characteristics is high, indicating that the phase signal complexity of the island area and the main power grid is similar, the matching degree of the signal characteristics is high, and the grid-connected operation can be performed.

[0062] when Exceeding critical threshold When , it is determined that the matching degree of the signal characteristics is low, indicating that the difference between the signal characteristics of the two is too large. Direct grid connection will cause system instability, and it is necessary to further adjust the operating parameters of the island area or take buffer measures.

[0063] in, is based on The size of the grid and other actual safety requirements and standards for grid connection are set according to the actual situation, which will not be elaborated here.

[0064] Based on the stability margin before grid-connection and the complexity of the phase signals of the island area and the main grid, it is judged whether the potential hidden danger level of the grid-connection of the island area and the main grid is too large. Specifically, when the stability margin before grid-connection is sufficient and the matching degree of the signal characteristics is high, it is judged that the potential hidden danger level of the grid-connection of the island area and the main grid is normal; otherwise, it is judged that the potential hidden danger level of the grid-connection of the island area and the main grid is too large.

[0065] This judgment logic is set based on ensuring the safety and stability of grid-connected operations. Before grid connection, the stability margin indicates the ability of the system to withstand disturbances. Sufficient stability margin means that the island area and the main power grid have good anti-interference capabilities and can maintain relative stability during the grid connection process. At the same time, the complexity matching of the phase signal reflects the consistency of the dynamic characteristics and energy characteristics of the two. A high matching degree indicates that the dynamic responses of the two are similar and can be better coordinated. Therefore, when the stability margin is sufficient and the signal feature matching degree is high, it means that the grid-connected risk is low and the system can transition smoothly. If any condition is not met, the grid connection may cause instability, with potential risks and requires further adjustment.

[0066] When the electrical parameters of the island area are consistent with those of the main grid, and the potential risks of the connection between the island area and the main grid are not too great, the grid connection operation is allowed: open the grid-connected circuit breaker or grid-connected switch, and confirm that its status is normal, ensuring that the grid-connected equipment has the execution conditions.

[0067] During the grid-connected operation, a phasor regulation device (such as a synchronous phasor controller) is used to continuously monitor the phase, frequency and voltage of the island area and the main grid to ensure continuous synchronization of the parameters.

[0068] Gradually adjust the closing speed of the grid-connected circuit breaker and adopt the "soft grid-connected" method (such as gradually adjusting the reactive power and active power) to avoid instantaneous current shocks and ensure a smooth grid-connected process.

[0069] When it is confirmed that the phase difference and frequency deviation are within the allowable range, the circuit breaker closing operation is performed to connect the island area to the main power grid and complete the grid connection.

[0070] After being connected to the grid, the current, voltage and power changes at the connection point are monitored in real time to ensure that the power system is in a stable state after being connected to the grid.

[0071] After the grid connection operation is completed, the grid operation status is continuously monitored to ensure that the parameters of the island area and the main grid remain stable within 10-15 seconds after grid connection to avoid abnormal conditions such as voltage fluctuations and frequency jumps.

[0072] If the system operates stably during the observation period after grid connection, the grid connection operation is judged to be successful, and the island area is officially merged with the main grid for operation.

[0073] Adjust the control strategy of the isolated island area to the grid-connected operation mode, gradually restore normal load and power generation plans, and ensure the operating efficiency and stability of the power supply system.

[0074] Save parameter data during grid-connected operation as a reference for subsequent grid-connected optimization and scheduling.

[0075] Embodiment 2: Embodiment 2 of the present invention differs from Embodiment 1 in that this embodiment introduces an optimization dispatching system for post-disaster recovery of distribution networks.

[0076] Figure 2 A structural schematic diagram of an optimization dispatching system for post-disaster recovery of a distribution network according to the present invention is given, which includes an electrical parameter acquisition module, a power load adjustment module, a margin complexity analysis module, a grid-connected hidden danger assessment module, and a grid-connected execution judgment module.

[0077] Electrical parameter acquisition module: obtains real-time electrical parameter data of the island area and the main power grid. When the accuracy of the electrical parameter data meets the preset threshold, the phase difference and frequency deviation between the island area and the main power grid are calculated based on the electrical parameter data using the phasor measurement algorithm.

[0078] Power load regulation module: Based on the detected phase difference and frequency deviation, the output power and load status of the distributed power sources in the island area are adjusted in real time, so that the electrical parameters of the island area gradually converge with those of the main power grid.

[0079] Margin complexity analysis module: By analyzing the difference between energy conversion and critical energy during the state change of the power system of the island area and the main grid, the stability margin before grid connection is evaluated; through multi-scale signal processing, the complex characteristics of electrical signals are extracted using wavelet transform, combined with fractal dimension analysis, the complexity of the phase signal of the island area and the main grid is evaluated.

[0080] Grid connection hidden danger assessment module: Based on the stability margin before grid connection and the complexity of the phase signal between the island area and the main grid, it is determined whether the potential hidden danger of grid connection between the island area and the main grid is too great.

[0081] Grid connection execution judgment module: When the electrical parameters of the island area are consistent with those of the main grid, and the potential hidden dangers of the grid connection between the island area and the main grid are not too great, the grid connection operation is allowed to be executed.

[0082] The above formulas are all dimensionless and numerical calculations. The formula is a formula for the most recent real situation obtained by collecting a large amount of data and performing software simulation. The preset parameters and thresholds in the formula are set by technicians in this field according to actual conditions.

[0083] The above embodiments can be implemented in whole or in part by software, hardware, firmware or any other combination thereof; when implemented by software, the above embodiments can be implemented in whole or in part in the form of a computer program product; the computer program product includes one or more computer instructions or computer programs; when the computer instructions or computer programs are loaded or executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part; the computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device; the computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center by wired (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that contains one or more available media sets. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium; the semiconductor medium can be a solid-state hard disk.

[0084] Those of ordinary skill in the art will appreciate that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware; whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution; professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0085] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and modules described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0086] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways; for example, the device embodiments described above are merely schematic, for example, the division of the modules is merely a logical function division, and there may be other division methods in actual implementation, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed; another point, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0087] The modules described as separate components may or may not be physically separated, and the components displayed as modules may or may not be physical modules. They may be located in one place or distributed on multiple network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment.

[0088] In addition, each functional module in each embodiment of the present application may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module.

[0089] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can essentially be embodied in the form of a software product, or in other words, the part that contributes to the prior art or the part of the technical solution. The computer software product is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0090] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application; therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0091] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An optimization scheduling method for post-disaster recovery of distribution networks, characterized in that: The method comprises the following steps: S1: acquiring real-time electrical parameter data of the isolated island area and the main power grid, and, under the condition that the accuracy of the electrical parameter data meets a preset threshold, using a phasor measurement algorithm based on the electrical parameter data to calculate the phase difference and frequency deviation between the isolated island area and the main power grid; S2: According to the detected phase difference and frequency deviation, the output power and load status of the distributed power sources in the isolated island area are adjusted in real time, so that the electrical parameters of the isolated island area gradually converge with those of the main power grid; S3: By analyzing the difference between energy conversion and critical energy in the state change process of the power system of the island area and the main grid, the stability margin before grid connection is evaluated; through multi-scale signal processing, the complex characteristics of electrical signals are extracted by wavelet transform, combined with fractal dimension analysis, the complexity of the phase signal of the island area and the main grid is evaluated; S4: Based on the stability margin before grid connection and the complexity of the phase signals of the island area and the main grid, determine whether the potential hidden dangers of grid connection between the island area and the main grid are too great; S5: When the electrical parameters of the island area tend to be consistent with the main grid and the potential hidden dangers of grid connection between the island area and the main grid are not too great, the grid connection operation is allowed.

2. The optimization scheduling method for post-disaster recovery of distribution network according to claim 1 is characterized in that: S1 specifically includes: real-time collection of electrical parameter data of the island area and the main power grid, the electrical parameter data including voltage, frequency and phase; preprocessing the collected electrical parameter data to remove abnormal values ​​to ensure that the data accuracy meets the preset threshold; and using the phasor measurement algorithm to calculate the phase difference and frequency deviation between the island area and the main power grid.

3. The optimization scheduling method for post-disaster recovery of distribution network according to claim 2 is characterized in that: S2 specifically includes: S201: analyzing the calculated phase difference and frequency deviation to determine the adjustment direction and amplitude; S202: formulating an adjustment strategy for the output power and load status of distributed power sources based on the phase difference and frequency deviation; S203: adjusting the output power of distributed power sources in the island area in real time according to the adjustment strategy to reduce the phase difference and frequency deviation; S204: adjusting the load status in the island area according to the adjustment strategy to promote the consistency of electrical parameters with the main power grid; S205: during the adjustment process, continuously monitoring the phase difference and frequency deviation, and adjusting the adjustment strategy in a timely manner according to the changes.

4. The optimization scheduling method for post-disaster recovery of distribution network according to claim 3 is characterized in that: By analyzing the difference between energy conversion and critical energy in the power system of the isolated area and the main grid during the state change, the stability margin before grid connection is evaluated, which includes: constructing the power system model of the isolated area and the main grid, including power generation, transmission, distribution and load links: the power system model of the isolated area is recorded as , the main power grid model is recorded as ;in, Defined as a directed graph: ;in, represents the set of nodes in the island area, Represents the directed edge set between nodes; Based on the power system model, define the transient energy function that describes the energy conversion during the state change process: Define the transient energy function , whose expression is: ;in, Representation Node The inertia coefficient, For Node The voltage phase angle, For Node The voltage phase angle, Representation Node With Node The equivalent elastic coefficient of the line between the two; analyze the critical stability state of the power system before grid connection, and calculate the corresponding critical energy value: the total energy of the system when it is in the critical stability state is marked as , determine the critical stability point Corresponding to the saddle point of the energy function, is the number of nodes; Substitution The critical energy value is obtained ; Use the transient energy function to calculate the actual energy conversion value and compare it with the critical energy value to obtain the energy difference. According to the energy difference, the stability margin before grid connection is evaluated: Through the transient energy function , calculate the actual energy conversion value at the current moment By comparison and , evaluate the stability margin before grid connection : ;when When , it is determined that the stability margin before grid connection is sufficient; when When , it is determined that the stability margin before grid connection is insufficient.

5. The optimization scheduling method for post-disaster recovery of distribution network according to claim 4 is characterized in that: Through multi-scale signal processing, wavelet transform is used to extract the complex features of electrical signals, and combined with fractal dimension analysis, the complexity of the phase signals of the island area and the main power grid is evaluated. Specifically, the electrical phase signals of the island area and the main power grid are collected to construct a signal sequence; the signal sequence is decomposed and features are extracted by wavelet transform at multiple scales; multi-scale wavelet coefficients are extracted and a feature matrix is ​​constructed to characterize the signal complexity: the wavelet coefficients are arranged according to different scales and time displacements, a feature matrix is ​​constructed, and the feature matrix is ​​normalized; Calculate the characteristic matrix based on the fractal dimension and quantify the signal complexity: divide the characteristic matrix into several sub-matrices, and the size of each box is ,in is the scale parameter of the segmentation; get the The submatrix set at each scale and calculate the number of non-zero elements in each submatrix ; With the scale parameter , counting the number of non-zero elements at different scales , calculate the fractal dimension of the signal: ;in, is the fractal dimension of the signal; compare and analyze the signal complexity and evaluate the difference in characteristics between the isolated island area and the main power grid: the fractal dimension of the signal in the isolated island area is obtained through the fractal dimension formula of the signal and the fractal dimension of the main power grid signal ;calculate : ;when Not exceeding critical threshold When , the signal feature matching degree is high; when Exceeding critical threshold When , it is determined that the matching degree of the signal characteristics is low.

6. The optimization scheduling method for post-disaster recovery of distribution network according to claim 5, characterized in that: Based on the stability margin before grid-connection and the complexity of the phase signals of the island area and the main grid, it is judged whether the potential hidden danger level of the grid-connection of the island area and the main grid is too large. Specifically, when the stability margin before grid-connection is sufficient and the matching degree of the signal characteristics is high, it is judged that the potential hidden danger level of the grid-connection of the island area and the main grid is normal; otherwise, it is judged that the potential hidden danger level of the grid-connection of the island area and the main grid is too large.

7. An optimized dispatching system for post-disaster recovery of a distribution network, used to implement an optimized dispatching method for post-disaster recovery of a distribution network as described in any one of claims 1 to 6, characterized in that: It includes an electrical parameter acquisition module, a power load adjustment module, a margin complex analysis module, a grid-connected hidden danger assessment module, and a grid-connected execution judgment module; the electrical parameter acquisition module: acquires real-time electrical parameter data of the isolated island area and the main grid, and uses a phasor measurement algorithm to calculate the phase difference and frequency deviation between the isolated island area and the main grid based on the electrical parameter data when the accuracy of the electrical parameter data meets the preset threshold; the power load adjustment module: adjusts the output power and load status of the distributed power supply in the isolated island area in real time according to the detected phase difference and frequency deviation, so that the electrical parameters of the isolated island area gradually converge to the same as those of the main grid; Margin complexity analysis module: By analyzing the difference between energy conversion and critical energy in the state change process of the power system of the island area and the main grid, the stability margin before grid connection is evaluated; through multi-scale signal processing, the complex characteristics of electrical signals are extracted by wavelet transform, combined with fractal dimension analysis, the complexity of the phase signal of the island area and the main grid is evaluated; Grid-connection hidden danger assessment module: Based on the stability margin before grid-connection and the complexity of the phase signal between the island area and the main grid, it is judged whether the potential hidden danger level of the grid-connection between the island area and the main grid is too large; Grid-connection execution judgment module: When the electrical parameters of the island area are consistent with those of the main grid, and the potential hidden danger level of the grid-connection between the island area and the main grid is not too large, the grid-connection operation is allowed.

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