Power distribution network relay protection evaluation test method, system and equipment based on digital twinning and storage medium

Abstract

The invention discloses a digital twinning-based power distribution network relay protection evaluation test method, system and equipment and a storage medium, and relates to the technical field of intelligent power grids, and the method comprises the steps: carrying out the site selection optimization according to a distribution network topological structure and load distribution, configuring a data collection terminal, and building a data transmission network to collect the operation data of a power distribution network; preprocessing operation data of the power distribution network, constructing a digital twinning model, and realizing twinning synchronous updating through data mapping; simulation and fault test verification are carried out, and analysis and optimization feedback are carried out on verification data. According to the digital twinborn-based power distribution network relay protection evaluation test method provided by the invention, the problems are effectively solved by optimizing data acquisition distribution points, constructing a twinborn model in real time and performing multi-scene simulation verification, and an innovative solution is provided for relay protection strategy evaluation and optimization of a complex power distribution network.

Description

Technical Field

[0001] The present invention relates to the field of smart grid technology, and specifically to a distribution network relay protection evaluation and testing method, system, equipment and storage medium based on digital twins. Background Art

[0002] With the rapid development of power systems, the structure of distribution networks has become increasingly complex, and the proportion of distributed power generation access has continued to increase, resulting in new challenges to the operation mode and protection strategy of traditional distribution networks. In recent years, relay protection technology has developed from traditional electromechanical protection to microcomputer protection, and more accurate fault detection and isolation have been achieved through real-time monitoring of grid parameters. However, due to the randomness and volatility of distributed energy, traditional relay protection equipment has shown problems such as untimely response and high frequency of false operation when facing a high proportion of renewable energy access and complex fault conditions. At the same time, the widespread application of digital technology has gradually attracted attention to protection strategies based on sensor networks and high-precision measurement devices (such as PMUs). These technologies can capture the state of the power system more quickly, but they still have certain limitations in data processing efficiency, system dynamic response, and fault simulation accuracy.

[0003] In the context of the new power system, the access of renewable energy to the distribution network leads to bidirectional flow of power flow and large operational fluctuations, which restrict the effective absorption of highly intermittent and highly volatile renewable energy. The control objectives of isolated distributed power sources connected to the grid or connected through microgrids focus on autonomous management. Due to capacity limitations, they cannot completely solve the absorption problems brought about by the large-scale application of high-penetration renewable energy in the distribution network. In response to the above problems, the project conducts research from three aspects: dynamic regional division, collaborative interactive control, and source-grid-load-storage operation optimization from a global interactive perspective, and achieves breakthroughs in related technologies such as regional dynamic networking, intermittent energy fluctuation smoothing, and coordinated operation of multiple types of distributed energy equipment. However, from the perspective of source-grid-load-storage coordinated control function testing and verification, the original project has limited scenario construction capabilities, and the testing and verification work is time-consuming and labor-intensive. Therefore, it is urgent to build a source-grid-load-storage coordinated control function verification platform with strong scenario construction capabilities and simple testing and verification. A verification platform is needed. Based on the system-level control performance verification platform of typical equipment on the distribution network side, and based on the technical concept of distribution network stratification and grouping, it is planned to be implemented by arranging multiple regional coordination controllers and a main coordination controller. The regional coordination controller realizes the verification of the regional coordination control function, and the main coordination controller realizes the verification of the source-grid-load-storage global coordination control function. The coordination controller supports multiple communication methods such as Can, optical fiber, 485, etc. to ensure the issuance of coordination control instructions. Summary of the invention

[0004] In view of the above-mentioned problems, the present invention is proposed.

[0005] Therefore, the technical problem solved by the present invention is: how to implement the verification of the regional coordination control function of the existing technical regional coordination controller and the verification of the source-grid-load-storage global coordination control function of the main coordination controller.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a distribution network relay protection evaluation and testing method based on digital twin, comprising: Optimize the site selection according to the distribution network topology and load distribution, configure data acquisition terminals, and build a data transmission network to collect distribution network operation data; Preprocess the distribution network operation data and build a digital twin model. Achieve twin synchronization updates through data mapping; Conduct simulation and fault test verification, analyze and optimize the verification data; The distribution network operation data includes the topological structure, load distribution, node information, and sensor data of the distribution network; the sensor data includes current and voltage data and synchronous phasor data.

[0007] As a preferred solution of the distribution network relay protection evaluation and testing method based on digital twins described in the present invention, wherein: the site selection optimization based on the distribution network topology and load distribution includes determining the key nodes of the distribution network, the substation bus, the distributed power access point, the sensitive load node, deploying multifunctional sensors, and comprehensively using the site optimization algorithm to reduce redundant equipment; Arrange data acquisition equipment, and the optimization model formula for the collection point arrangement is expressed as: ; The constraint formula is expressed as: ; ; ; in, represents the total layout cost, Indicates The cost of arranging voltage transformers at each point is: Indicates The cost of current transformers arranged at each point is Indicates The cost of PMUs deployed at each point is Indicates Voltage and current at the point; Indicates the safe threshold range of voltage and current. Indicates Point power and distance parameters, Coverage Indicates the coverage effect of the collection points. Indicates the minimum requirement for coverage effect.

[0008] As a preferred solution of the distribution network relay protection evaluation and testing method based on digital twins described in the present invention, wherein: the preprocessing of the distribution network operation data includes using linear interpolation for missing values, low-pass filtering for harmonic noise, and filtering using a Butterworth filter; Synchronous data acquisition, the time accuracy of synchronous acquisition is controlled by the synchronous phasor measurement device, and the formula is expressed as: ; in, Indicates The phase angle of the point, Indicates The current and voltage at the point, represents the power frequency angular velocity, Indicates time.

[0009] As a preferred solution of the distribution network relay protection evaluation and testing method based on digital twins described in the present invention, wherein: the construction of the digital twin model includes constructing a dynamic power grid model and defining the calculation equation of the dynamic model, which is expressed as follows: ; in, Representation Node The active power and reactive power of Representation Node The voltage, Representation Node The real part of the admittance matrix parameter between Representation Node The imaginary part of the admittance matrix parameter between Representation Node The voltage phase angle difference, Represents the total set of nodes in the network.

[0010] As a preferred solution of the distribution network relay protection evaluation and testing method based on digital twins described in the present invention, wherein: the twin synchronization update through data mapping includes performing data mapping, collecting data through sensors and PMUs, and transmitting it to the twin model, combining the collected data with the simulation output of the twin model, and dynamically adjusting the weights and ; The data mapping formula is expressed as: ; in, Indicates the first The current state of the node, Represents physical data collected in real time, represents the predicted data output by the simulation model, Represents the dynamic weight of data fusion; Perform dynamic simulation, and update the formula based on node voltage as follows: ; in, represents the node voltage after iteration, Representation Node and The admittance parameter, Indicates the active and reactive power of the node; Initial voltage Collect data from real-time Initialize the admittance matrix Calculate in advance based on the distribution network topology and line parameters; in the initial state, use the collected data as input ; Update the node voltage according to the dynamic formula until the convergence condition is met: ; in, Indicates the convergence accuracy threshold; The dynamic simulation formula uses the real-time collected active and reactive power as input and iteratively updates the voltage of each node to ensure that the model state is consistent with the physical system.

[0011] As a preferred solution of the distribution network relay protection evaluation and testing method based on digital twins described in the present invention, the simulation and fault test verification include typical faults, single-phase grounding fault, three-phase short circuit, overload operation; fault injection, simulated fault current formula is expressed as: ; in, Indicates positive sequence, negative sequence, and zero sequence impedance, represents the fault point impedance; Dynamic response test, protection device response, triggering relay protection action, recording action time and logic: ; in, Indicates the fault detection time, Indicates the logic operation time of the protection device. Indicates the switch operation time; transmits the fault simulation results to the twin model, verifies the model's dynamic response capability to the fault scenario, and makes local adjustments and incremental updates to the faulty area; When a single-phase grounding fault occurs, the voltage and power of the node where the fault occurs are locally adjusted, the status of the affected node and the neighboring nodes are corrected, and the phase angle and current value of the fault location are updated. The voltage and power distribution of the fault area are locally adjusted by simulating the current change when the fault occurs. The fault detection algorithm is used to identify the fault point, calculate and adjust the current values ​​of other phases, and prevent the system from mistakenly marking the non-fault area as the fault area. When a three-phase short circuit occurs, the node voltage, power and phase angle of all fault points are locally adjusted for the three-phase short circuit fault, and the data of the current measurement point is updated at the same time; the short-circuit current path is adjusted through incremental simulation to identify the area affected by the short circuit; the power loss and current flow direction of the relevant lines are updated, and the calculation overhead is reduced through local power flow calculation and rapid correction of the fault current value.

[0012] When a part of the power grid is overloaded, some equipment will be overloaded; local updates will be made to the current and power in the overloaded area, the power dispatch of the load equipment will be adjusted, the power flow direction in the overloaded area will be adjusted, the system load distribution will be optimized, and the widespread chain reaction caused by overload will be avoided; When a harmonic fault occurs, harmonics may be generated due to nonlinear loads or equipment failures, affecting the voltage waveform of the power grid. The voltage and current waveforms of the affected area are adjusted through local filtering and harmonic compensation. Dynamic voltage control and filtering algorithms are used to locally adjust the power parameters of the harmonic-affected area to reduce the propagation impact of harmonics.

[0013] As a preferred solution of the distribution network relay protection evaluation and testing method based on digital twins described in the present invention, the data analysis and optimization feedback include updating the parameters in the twin model by the gradient descent method after each optimization iteration to optimize the parameters. The optimization target formula is expressed as: ; in, Represents the sum of squares of node errors in the entire network, represents the single node error; The optimization method is to use the gradient descent method to adjust the parameters in the twin model, the admittance matrix or load value ; Perform dynamic updates and update the model status in real time according to the optimization results: ; in, represents the optimized model parameter adjustment value, Optimize model parameters; the optimized model is immediately used for the next round of simulation to achieve adaptive improvement of the twin model.

[0014] As a preferred solution of the distribution network relay protection evaluation and testing system based on digital twin described in the present invention, wherein: Data collection and transmission module, which optimizes the site selection according to the distribution network topology and load distribution, configures data collection terminals and sensor equipment, and establishes a reliable data transmission network; The data preprocessing module cleans and preprocesses the operating data, builds a digital twin model, and realizes high-precision distribution network status simulation; Data mapping and synchronization update module, which realizes real-time synchronization update of twin models through data mapping to ensure the consistency of the state of the simulation model and the physical system; The simulation optimization module performs simulation and fault test verification, analyzes test data and provides feedback on the optimization model.

[0015] A computer device includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement a step of a distribution network relay protection evaluation and testing method based on digital twins.

[0016] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of a distribution network relay protection evaluation and testing method based on digital twins.

[0017] Beneficial effects of the invention: The distribution network relay protection evaluation and testing method based on digital twins provided by the invention has the problems of unreasonable data collection points, insufficient model dynamic synchronization capability, and single fault simulation and verification methods in the existing distribution network relay protection evaluation technology. The distribution network relay protection evaluation and testing method based on digital twins proposed by our invention effectively solves the above problems by optimizing data collection points, building twin models in real time, and multi-scenario simulation verification. It provides an innovative solution for the evaluation and optimization of relay protection strategies for complex distribution networks. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0019] Figure 1 An overall flow chart of a distribution network relay protection evaluation and testing method based on digital twins provided for the first embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0021] Example 1, reference Figure 1 , as an embodiment of the present invention, provides a distribution network relay protection evaluation and testing method based on digital twin, comprising: S1: Optimize the site selection according to the distribution network topology and load distribution, configure the data acquisition terminal, and build a data transmission network to collect distribution network operation data.

[0022] Furthermore, the distribution network operation data includes the topological structure, load distribution, node information, and sensor data of the distribution network; the sensor data includes current and voltage data and synchronous phasor data.

[0023] Furthermore, the site selection optimization based on the distribution network topology and load distribution includes determining the key nodes of the distribution network, substation busbars, distributed power access points, sensitive load nodes, deploying multifunctional sensors, and using a comprehensive point optimization algorithm to reduce redundant equipment. Data acquisition equipment layout formula: The optimization model for the collection point layout can be expressed as: ; Constraints: ; in, represents the total layout cost, Represents the The cost of arranging voltage transformers, current transformers and PMUs at each point, Indicates Voltage and current at a point Indicates the allowable range of voltage and current. Indicates The power and distance parameters of the points, Indicates the coverage effect of the collection points. Indicates the minimum requirement for coverage effect.

[0024] S2: Preprocess the distribution network operation data and build a digital twin model.

[0025] Furthermore, the distribution network operation data preprocessing includes using linear interpolation for missing values, low-pass filtering for harmonic noise, and filtering using a Butterworth filter; Data acquisition synchronization, the time accuracy of synchronous acquisition is defined by the formula of synchronized phasor measurement unit (PMU): ; in, Indicates The phase angle of the point, Indicates The current and voltage at the point, Indicates the power frequency angular velocity (usually Hz or Hz), Indicates time.

[0026] Establish a dynamic equivalent electromagnetic transient model of distributed power sources, energy storage devices and flexible loads to simulate the electromagnetic transient characteristics of the new distribution network. The digital twin model of relay protection is established based on the technical parameters, action logic and operation mechanism of the relay protection device to create a virtual relay protection model. Provide real-time synchronization and dynamic simulation functions to evaluate the response capability of the protection device.

[0027] The construction of the digital twin model includes the construction of a dynamic power grid model and the power flow calculation equation of the dynamic model: ; in, Representation Node The active power and reactive power of Representation Node The voltage, Representation Node The real part of the admittance matrix parameter between Representation Node The imaginary part of the admittance matrix parameter between Representation Node The voltage phase angle difference, Represents the total set of nodes in the network.

[0028] It should be noted that the test environment is set up to provide an AC / DC load simulation environment, including multiple types of distributed power supplies and power electronic devices. It supports harmonic injection and impedance simulation to simulate complex fault scenarios.

[0029] S3: Realize twin synchronization update through data mapping.

[0030] Furthermore, the twin synchronization update through data mapping includes performing data mapping, collecting data through sensors and PMUs, and transmitting them to the twin model, combining the collected data with the simulation output of the twin model, and dynamically adjusting the weights. and Balance real-time performance and reliability.

[0031] The data mapping formula is expressed as: ; in, Indicates the first The current state of the node, Represents physical data collected in real time, represents the predicted data output by the simulation model, Represents the dynamic weight of data fusion.

[0032] Dynamic simulation formula, based on node voltage update formula: ; in, represents the node voltage after iteration, Representation Node and The admittance parameter, Represents the active and reactive power of the node.

[0033] Perform initialization, initial voltage Collect data from real-time Initialize the admittance matrix Based on the distribution network topology and line parameters, the collected data is used as input in the initial state. ; Update the node voltage according to the dynamic formula until the convergence condition is met: ; in, Indicates the convergence accuracy threshold.

[0034] The connection logic is a dynamic simulation formula that uses the real-time collected active and reactive power as input, iteratively updates the voltage of each node to ensure that the model state is consistent with the physical system.

[0035] It should be noted that the collected data is combined with the twin model through data mapping, and the node voltage update is calculated based on the dynamic simulation formula. The data synchronization and error correction mechanism is introduced to ensure the consistency of the state of the physical system and the twin model. The model responsiveness is tested using fault simulation, and the model performance is continuously improved through parameter optimization and dynamic update.

[0036] S4: Perform simulation and fault test verification, analyze the verification data and provide optimization feedback.

[0037] The simulation and fault test verification include typical faults, single-phase grounding fault, three-phase short circuit, overload operation; fault injection, the simulated fault current formula is expressed as: ; in, Indicates positive sequence, negative sequence, and zero sequence impedance, represents the fault point impedance; Dynamic response test, protection device response, triggering relay protection action, recording action time and logic: ; in, Indicates the fault detection time, Indicates the logic operation time of the protection device. Indicates the switch operation time; transmits the fault simulation results to the twin model, verifies the model's dynamic response capability to fault scenarios, and makes local adjustments and incremental updates to the faulty area.

[0038] When a single-phase grounding fault occurs, the voltage and power of the faulty node are locally adjusted, the status of the affected node and the neighboring nodes are corrected, and the phase angle and current value of the fault location are updated. By simulating the current change when the fault occurs, the voltage and power distribution in the fault area are locally adjusted. The fault detection algorithm is used to identify the fault point, and the current values ​​of other phases are calculated and adjusted to prevent the system from mistakenly marking the non-fault area as the fault area.

[0039] When a three-phase short circuit occurs, the node voltage, power and phase angle of all fault points are locally adjusted for the three-phase short circuit fault, and the data of the current measurement point is updated at the same time; the short-circuit current path is adjusted through incremental simulation to identify the area affected by the short circuit; the power loss and current flow direction of the relevant lines are updated, and the calculation overhead is reduced through local power flow calculation and rapid correction of the fault current value.

[0040] When a part of the power grid is overloaded, some equipment will be overloaded. Locally update the current and power in the overloaded area, adjust the power dispatch of the load equipment, adjust the power flow in the overloaded area, optimize the system load distribution, and avoid widespread chain reactions caused by overload.

[0041] When a harmonic fault occurs, harmonics may be generated due to nonlinear loads or equipment failures, affecting the voltage waveform of the power grid. The voltage and current waveforms of the affected area are adjusted through local filtering and harmonic compensation. Dynamic voltage control and filtering algorithms are used to locally adjust the power parameters of the harmonic-affected area to reduce the propagation impact of harmonics.

[0042] Data analysis and optimization feedback include parameter optimization. The optimization target formula is expressed as: ; in, Represents the sum of squares of node errors in the entire network, Represents the single node error.

[0043] Optimization method, using gradient descent method to adjust the parameters in the twin model, the admittance matrix or load value .

[0044] Perform dynamic updates and update the model status in real time according to the optimization results: ; in, It represents the adjusted value of the optimized model parameters. The optimized model is immediately used in the next round of simulation to achieve adaptive improvement of the twin model.

[0045] It should be noted that the protection strategy optimization, combined with the results of electromagnetic transient analysis, adjusts the action threshold and response logic of the relay protection device. Verify the reliability and coordination of the protection device in a complex grid. Study the coordinated protection mechanism, analyze the interaction between protection and distributed power sources in the distribution network, and optimize the coordination mechanism. Solve the interference and malfunction problems between multiple protection devices. Platform verification, use the evaluation test platform built to conduct multiple rounds of simulation tests on the optimized protection strategy. Submit a performance report to verify the effectiveness of the strategy under different operating conditions.

[0046] Example 2 is an embodiment of the present invention, which provides a distribution network relay protection evaluation and testing method based on digital twins. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments.

[0047] First, the test preparation, this embodiment is aimed at the operation status of a regional distribution network, with a high penetration rate of distributed power access environment as the background, to design and verify the distribution network relay protection evaluation test method based on digital twins. The key nodes selected include a 110kV substation, two distributed photovoltaic power station access points and three sensitive load nodes, and the sensor layout plan is determined by the point optimization algorithm. Multifunctional sensors (voltage transformer, current transformer, PMU) are selected to configure the data acquisition terminal, and a low-latency communication network is used to build a data transmission platform.

[0048] Implementation steps: The site selection of key nodes in the distribution network is optimized by utilizing the distribution network topology and load distribution data and applying the site optimization formula. After calculation, 4 points are selected from 6 candidate points to arrange the equipment.

[0049] Data acquisition and transmission,Sensors are installed at optimized locations and transmit data through IEC 61850 protocol.,The acquisition frequency is set to 50 Hz and the PMU synchronization error does not exceed 1 µs.

[0050] The data is transferred to a central platform for storage and analysis.

[0051] Data preprocessing and twin model construction, linear interpolation method is used to process missing data, and Butterworth filter is used to filter harmonic noise. The filtering parameters are third-order and the cutoff frequency is 300 Hz.

[0052] Build a dynamic model based on the power flow equation, map and synchronize data, dynamically fuse collected data and simulation model output, and adjust weights to achieve high-precision real-time synchronization.

[0053] Simulation and fault testing, setting typical fault scenarios: single-phase grounding fault, three-phase short circuit and overload operation, simulating fault current and verifying the response time of relay protection, and recording the action logic.

[0054] Optimize feedback, analyze test data, and use the gradient descent method to adjust the twin model parameters to optimize the target.

[0055] Table 1 Test data record table ; According to the test data in Table 1, it can be observed that through the dynamic simulation and synchronous update of digital twin technology, the operating parameters of each key node can quickly respond to changes in the external environment and remain within a reasonable range. The error between the initial state and the dynamic synchronization dropped from 0.5% to 0.3%, indicating that data mapping and weight adjustment significantly improved the fit between the twin model and the physical system. Compared with the traditional fixed weight data fusion technology, dynamic weight adjustment makes the model more adaptable to load changes and fault disturbances.

[0056] The single-phase ground fault response time is 25 ms, and the three-phase short-circuit fault response time is 30 ms, which is significantly better than the 50 ms average response time of traditional relay protection devices. The error between the model prediction and the actual collected data is within 1.2%, which fully verifies the dynamic response capability of the twin model to fault scenarios.

[0057] Embodiment 3 is an embodiment of the present invention, which provides a distribution network relay protection evaluation and testing system based on digital twin, including: The data acquisition and transmission module optimizes the site selection according to the distribution network topology and load distribution, configures data acquisition terminals and sensor equipment, and establishes a reliable data transmission network.

[0058] The data preprocessing module cleans and preprocesses the operating data, builds a digital twin model, and realizes high-precision distribution network status simulation.

[0059] The data mapping and synchronization update module realizes the real-time synchronization update of the twin model through data mapping, ensuring the consistency of the state of the simulation model and the physical system.

[0060] The simulation optimization module performs simulation and fault test verification, analyzes test data and provides feedback on the optimization model.

[0061] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0062] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0063] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk case (magnetic devices), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0064] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0065] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A distribution network relay protection evaluation and testing method based on digital twins, characterized in that: include: Optimize the site selection according to the distribution network topology and load distribution, configure data acquisition terminals, and build a data transmission network to collect distribution network operation data; Preprocess distribution network operation data and build a digital twin model; Achieve twin synchronization updates through data mapping; Conduct simulation and fault test verification, analyze and optimize the verification data; The distribution network operation data includes the topological structure, load data, node information, and sensor data of the distribution network; the sensor data includes current and voltage data and synchronous phasor data.

2. The distribution network relay protection evaluation and testing method based on digital twin according to claim 1, characterized in that: The site selection optimization based on the distribution network topology and load distribution includes determining the key nodes of the distribution network, substation busbars, distributed power access points, sensitive load nodes, deploying multifunctional sensors, and comprehensively using the site optimization algorithm to reduce redundant equipment; Arrange data acquisition equipment, and the optimization model formula for the collection point arrangement is expressed as: ； The constraint formula is expressed as: ； ； ； in, represents the total layout cost, Indicates The cost of arranging voltage transformers at each point is: Indicates The cost of current transformers arranged at each point is Indicates The cost of PMUs deployed at each point is Indicates Voltage and current at the point; Indicates the safe threshold range of voltage and current. Indicates Point power and distance parameters, Coverage Indicates the coverage effect of the collection points. Indicates the minimum requirement for coverage effect.

3. The distribution network relay protection evaluation and testing method based on digital twin according to claim 2, characterized in that: The preprocessing of the distribution network operation data includes using linear interpolation for missing values, low-pass filtering for harmonic noise, and filtering with a Butterworth filter; Synchronous data acquisition, the time accuracy of synchronous acquisition is controlled by the synchronous phasor measurement device, and the formula is expressed as: ； in, Indicates The phase angle of the point, Indicates The current and voltage at the point, represents the power frequency angular velocity, Indicates time.

4. The distribution network relay protection evaluation and testing method based on digital twin according to claim 3 is characterized in that: The construction of the digital twin model includes constructing a dynamic power grid model and defining a calculation equation of the dynamic model, which is expressed as follows: ； in, Representation Node The active power and reactive power of Representation Node The voltage, Representation Node The real part of the admittance matrix parameter between Representation Node The imaginary part of the admittance matrix parameter between Representation Node The voltage phase angle difference, Represents the total set of nodes in the network.

5. The distribution network relay protection evaluation and testing method based on digital twin according to claim 4, characterized in that: The twin synchronization update through data mapping includes performing data mapping, collecting data through sensors and PMUs, and transmitting them to the twin model, combining the collected data with the simulation output of the twin model, and dynamically adjusting the weights. and ; The data mapping formula is expressed as: ； in, Indicates the first The current state of the node, Represents physical data collected in real time, represents the predicted data output by the simulation model, Represents the dynamic weight of data fusion; Perform dynamic simulation, and update the formula based on node voltage as follows: ； in, represents the node voltage after iteration, Representation Node and The admittance parameter, Indicates the active and reactive power of the node; Initial voltage Collect data from real-time Initialize the admittance matrix Calculate in advance based on the distribution network topology and line parameters; in the initial state, use the collected data as input ; Update the node voltage according to the dynamic formula until the convergence condition is met: ； in, Indicates the convergence accuracy threshold; The dynamic simulation formula uses the real-time collected active and reactive power as input and iteratively updates the voltage of each node to ensure that the model state is consistent with the physical system.

6. The distribution network relay protection evaluation and testing method based on digital twin according to claim 5, characterized in that: The simulation and fault test verification include typical faults, single-phase grounding fault, three-phase short circuit, overload operation; fault injection, the simulated fault current formula is expressed as: ； in, Indicates positive sequence, negative sequence, and zero sequence impedance, represents the fault point impedance; Dynamic response test, protection device response, triggering relay protection action, recording action time and logic: ； in, Indicates the fault detection time, Indicates the logic operation time of the protection device. Indicates the switch operation time; transmits the fault simulation results to the twin model, verifies the model's dynamic response capability to the fault scenario, and makes local adjustments and incremental updates to the faulty area; When a single-phase grounding fault occurs, the voltage and power of the node where the fault occurs are locally adjusted, the status of the affected node and the neighboring nodes are corrected, and the phase angle and current value of the fault location are updated. The voltage and power distribution of the fault area are locally adjusted by simulating the current change when the fault occurs. The fault detection algorithm is used to identify the fault point, calculate and adjust the current values ​​of other phases, and prevent the system from mistakenly marking the non-fault area as the fault area. When a three-phase short circuit occurs, the node voltage, power and phase angle of all fault points are locally adjusted for the three-phase short circuit fault, and the data of the current measurement point is updated at the same time; the short circuit current path is adjusted through incremental simulation to identify the area affected by the short circuit; the power loss and current flow direction of the relevant lines are updated, and the calculation overhead is reduced through local power flow calculation and rapid correction of the fault current value; When a part of the power grid is overloaded, some equipment will be overloaded; local updates will be made to the current and power in the overloaded area, the power dispatch of the load equipment will be adjusted, the power flow direction in the overloaded area will be adjusted, the system load distribution will be optimized, and the widespread chain reaction caused by overload will be avoided; When a harmonic fault occurs, harmonics may be generated due to nonlinear loads or equipment failures, affecting the voltage waveform of the power grid. The voltage and current waveforms of the affected area are adjusted through local filtering and harmonic compensation. Dynamic voltage control and filtering algorithms are used to locally adjust the power parameters of the harmonic-affected area to reduce the propagation impact of harmonics.

7. The distribution network relay protection evaluation and testing method based on digital twin according to claim 6, characterized in that: The analysis and optimization feedback of the verification data includes updating the parameters in the twin model by the gradient descent method after each optimization iteration to optimize the parameters. The optimization target formula is expressed as: ； in, represents the sum of squares of node errors in the entire network, represents the single node error; The optimization method is to use the gradient descent method to adjust the parameters in the twin model, the admittance matrix or load value ; Perform dynamic updates and update the model status in real time according to the optimization results: ； in, represents the optimized model parameter adjustment value, Optimize model parameters; the optimized model is immediately used in the next round of simulation to achieve adaptive improvement of the twin model.

8. A system using the distribution network relay protection evaluation and testing method based on digital twins as described in any one of claims 1 to 7, characterized in that: Data collection and transmission module, which optimizes the site selection according to the distribution network topology and load distribution, configures data collection terminals and sensor equipment, and establishes a reliable data transmission network; The data preprocessing module cleans and preprocesses the operating data, builds a digital twin model, and realizes high-precision distribution network status simulation; Data mapping and synchronization update module, which realizes real-time synchronization update of twin models through data mapping to ensure the consistency of the state of the simulation model and the physical system; The simulation optimization module performs simulation and fault test verification, analyzes test data and provides feedback on the optimization model.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the distribution network relay protection evaluation and testing method based on digital twins described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the distribution network relay protection evaluation and testing method based on digital twin described in any one of claims 1 to 7 are implemented.

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