Digital Twin-Based Relay Protection Evaluation and Testing Method, System, Equipment and Storage Medium for Distribution Network

Abstract

The present invention discloses a relay protection evaluation and testing method, system, device and storage medium for a distribution network based on digital twin, which relates to the technical field of smart grids. It includes optimizing the site selection according to the distribution network topology structure and load distribution, configuring data acquisition terminals, building a data transmission network to collect the operation data of the distribution network; preprocessing the operation data of the distribution network, constructing a digital twin model, and realizing twin synchronous update through data mapping; conducting simulation and fault test verification, and analyzing and optimizing the feedback on the verification data. The relay protection evaluation and testing method for the distribution network based on digital twin proposed by the method of the present invention effectively solves the above problems through optimizing the data acquisition point layout, real-time constructing the twin model and multi-scenario simulation verification, and provides an innovative solution for the evaluation and optimization of relay protection strategies for complex distribution networks.

Description

Technical Field

[0001] The present invention relates to the technical field of smart grids, and specifically to a relay protection evaluation and test method, system, device, and storage medium for a distribution network based on digital twins. Background Art

[0002] With the rapid development of the power system, the structure of the distribution network has become more complex, and the proportion of distributed power sources connected has been continuously increasing, resulting in new challenges for the operation mode and protection strategy of the traditional distribution network. In recent years, relay protection technology has developed from traditional electromechanical protection to microcomputer protection, achieving more accurate fault detection and isolation through real-time monitoring of grid parameters. However, due to the randomness and volatility of distributed energy, traditional relay protection devices show problems such as untimely response and high misoperation frequency when facing high proportions of renewable energy access and complex fault conditions. At the same time, the wide application of digital technologies has made protection strategies based on sensor networks and high-precision measurement devices (such as PMUs) gradually attract attention. These technologies can capture the state of the power system faster, but they still have certain limitations in terms of data processing efficiency, system dynamic response, and fault simulation accuracy.

[0003] Under the background of the new power system, the access of renewable energy in the distribution network leads to two-way power flow, large operation fluctuations, and restricts the effective consumption of highly intermittent and strongly volatile renewable energy. The control objectives for the grid connection of isolated distributed power sources or through microgrids focus on autonomous management, and due to capacity limitations, they cannot fully solve the consumption 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 area division, collaborative interactive control, and source-network-load-storage operation optimization from a global interaction perspective, achieving breakthroughs in related technologies such as regional dynamic networking, suppression of intermittent energy fluctuations, and coordinated operation of multiple types of distributed energy devices. However, from the perspective of testing and verifying the source-network-load-storage coordinated control function, the original project's scenario construction ability is limited, and the testing and verification work is time-consuming and laborious. Therefore, there is an urgent need to build a source-network-load-storage coordinated control function verification platform with strong scenario construction ability and easy testing and verification. Based on the technical concept of hierarchical and grouped distribution networks, it is planned to achieve this by arranging multiple regional coordination controllers and a main coordination controller. The regional coordination controllers verify the regional coordination control function, and the main coordination controller verifies the source-network-load-storage global coordination control function. The coordination controllers support multiple communication methods such as Can, optical fiber, and 485 to ensure the issuance function of coordination control instructions. Summary of the Invention

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

[0005] Therefore, the technical problem to be solved by the present invention is: the problem of how to verify the implementation of the regional coordination control function by the existing technical regional coordination controller and the problem of verifying the implementation of the source-network-load-storage global coordination control function by the main coordination controller.

[0006] To solve the above technical problem, the present invention provides the following technical solution: a method for evaluating and testing the relay protection of a distribution network based on digital twin, including

[0007] Conduct site selection optimization according to the distribution network topology and load distribution, configure data acquisition terminals, and build a data transmission network to collect the operation data of the distribution network;

[0008] Preprocess the operation data of the distribution network and build a digital twin model,

[0009] Realize twin synchronous update through data mapping;

[0010] Conduct simulation and fault test verification, and analyze and optimize the feedback of the verification data;

[0011] The operation data of the distribution network includes the topology of the distribution network, load distribution, node information, and sensor data; the sensor data includes current and voltage data and synchronized phasor data.

[0012] As a preferred solution of the method for evaluating and testing the relay protection of a distribution network based on digital twin according to the present invention, wherein: the site selection optimization according to the distribution network topology and load distribution includes determining the key nodes of the distribution network, substation buses, distributed power access points, and sensitive load nodes, deploying multifunctional sensors, and comprehensively using the layout optimization algorithm to reduce redundant equipment;

[0013] Arrange data acquisition equipment, and the optimization model formula for the layout of the acquisition points is expressed as:

[0014] ;

[0015] The constraint condition formula is expressed as:

[0016] ;

[0017] ;

[0018] ;

[0019] Among them, represents the total layout cost, represents the cost of arranging a voltage transformer at the th point, represents the cost of arranging a current transformer at the th point, represents the The cost of PMUs arranged at the voltage and current at point represents the safety threshold range of voltage and current, the power and distance parameter at point represents the coverage effect of the collection point, represents the minimum requirement for the coverage effect.

[0020] As a preferred solution of the digital twin-based relay protection evaluation and testing method for distribution networks according to the present invention, wherein: the preprocessing of distribution network operation data includes using linear interpolation for missing values, performing low-pass filtering on harmonic noise, and filtering using a Butterworth filter;

[0021] Synchronous data acquisition, the time accuracy of synchronous acquisition is controlled by a synchronous phasor measurement unit, and the formula is expressed as:

[0022] ;

[0023] wherein, the phase angle at point the current and voltage at point represents the power frequency angular velocity, represents time.

[0024] As a preferred solution of the digital twin-based relay protection evaluation and testing method for distribution networks according to 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, and the formula is expressed as:

[0025] ;

[0026] wherein, represents the active power and reactive power of node represents the voltage of node represents the real part of the admittance matrix parameter between nodes represents the imaginary part of the admittance matrix parameter between nodes represents the voltage phase angle difference between nodes represents the total node set in the network.

[0027] ​​​​​As a preferred solution of the digital-twin-based relay protection evaluation and testing method for distribution networks described in the present invention, wherein: the realization of twin synchronous 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 ;

[0028] The data mapping formula is expressed as:

[0029] ;

[0030] wherein, represents the current state of the th node in the twin model, represents the physical data collected in real time, represents the predicted data output by the simulation model, represents the dynamic weight of data fusion;

[0031] Performing dynamic simulation, the node voltage update formula based on it is expressed as:

[0032] ;

[0033] wherein, represents the node voltage after iteration, represents the admittance parameters of nodes and , represents the active and reactive powers of the node;

[0034] Initial voltage is initialized from the real-time collected data The admittance matrix is calculated in advance based on the distribution network topology and line parameters; in the initial state, the collected data is used as the input ; The node voltage is updated according to the dynamic formula until the convergence condition is met:

[0035] ;

[0036] wherein, represents the convergence accuracy threshold;

[0037] The dynamic simulation formula uses the active and reactive powers collected in real time as the input, and iteratively updates the voltage of each node to ensure that the model state is consistent with the physical system.

[0038] As a preferred solution of the digital-twin-based relay protection evaluation and testing method for a distribution network according to the present invention, wherein: the simulation and fault testing verification includes typical faults, single-phase grounding faults, three-phase short circuits, and overload operation; fault injection, the formula for simulating the fault current is expressed as:

[0039] ;

[0040] Wherein, represents the positive-sequence, negative-sequence, and zero-sequence impedances, represents the impedance at the fault point;

[0041] Dynamic response test, the protection device responds, triggers the relay protection action, and records the action time and logic:

[0042] ;

[0043] Wherein, represents the fault detection time, represents the logic operation time of the protection device, represents the switch operation time; transmit the fault simulation results to the twin model, verify the dynamic response ability of the model to the fault scenario, and perform local adjustment and incremental update on the fault-occurring area;

[0044] When a single-phase grounding fault occurs, locally adjust the voltage and power of the fault-occurring node, correct the states of the affected nodes and neighboring nodes, and at the same time, update the phase angle and current value at the fault location; by simulating the current change during the fault occurrence, locally adjust the voltage and power distribution in the fault area; use the fault detection algorithm to identify the fault point, calculate and adjust the current values of other phases to prevent the system from mislabeling the non-fault area as the fault area;

[0045] When a three-phase short circuit occurs, for the three-phase short circuit fault, locally adjust the node voltage, power, and phase angle of all fault points, and at the same time update the data at the current measurement points; adjust the short-circuit current path through incremental simulation to identify the area affected by the short circuit; update the power loss and current flow direction of the relevant lines, and reduce the calculation overhead by local power flow calculation and rapid correction of the fault current value.

[0046] When a part of the power grid is overloaded, resulting in overload of some equipment; locally update the current and power in the overloaded area of the load, adjust the power scheduling of the load equipment, adjust the power flow direction in the overloaded area, optimize the system load distribution, and avoid the widespread chain reaction caused by overload;

[0047] When a harmonic fault occurs, harmonics may be generated due to non-linear loads or equipment failures, affecting the voltage waveform of the power grid; through local filtering and harmonic compensation, the voltage and current waveforms in the affected area are adjusted; dynamic voltage control and filtering algorithms are used to locally adjust the power parameters in the harmonic-affected area and reduce the propagation impact of harmonics.

[0048] As a preferred solution of the digital twin-based relay protection evaluation and testing method for distribution networks according to the present invention, wherein: the data analysis and optimization feedback includes, after each optimization iteration, updating the parameters in the twin model by the gradient descent method for parameter optimization, and the optimization objective formula is expressed as:

[0049] ;

[0050] Wherein, represents the sum of the squares of the errors of all network nodes, represents the single-node error;

[0051] The optimization method is to use the gradient descent method to adjust the parameters in the twin model, and the admittance matrix or the load value ;

[0052] is dynamically updated, and the model state is updated in real time according to the optimization result:

[0053] ;

[0054] Wherein, represents the adjusted value of the optimized model parameters, the optimized model parameters; the optimized model is immediately used for the next round of simulation to achieve the adaptive improvement of the twin model.

[0055] As a preferred solution of the digital twin-based relay protection evaluation and testing system for distribution networks according to the present invention, wherein:

[0056] The data acquisition and transmission module optimizes the site selection according to the distribution network topology structure and load distribution, configures data acquisition terminals and sensor devices, and establishes a reliable data transmission network;

[0057] The data preprocessing module cleans and preprocesses the operation data, constructs a digital twin model, and realizes the high-precision simulation of the distribution network state;

[0058] The data mapping and synchronous update module realizes the real-time synchronous update of the twin model through data mapping to ensure the consistency of the state between the simulation model and the physical system;

[0059] The simulation optimization module performs simulation and fault test verification, analyzes the test data and feeds back to optimize the model.

[0060] A computer device includes a memory and a processor. The memory stores a computer program, and the execution of the computer program by the processor realizes the steps of a digital-twin-based relay protection evaluation and testing method for a distribution network.

[0061] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of a digital-twin-based relay protection evaluation and testing method for a distribution network are realized.

[0062] Advantages of the present invention: In the existing relay protection evaluation technology for distribution networks, there are problems such as unreasonable data acquisition point layout, insufficient model dynamic synchronization ability, and single fault simulation and verification means. The digital-twin-based relay protection evaluation and testing method proposed by the present invention effectively solves the above problems through optimizing data acquisition point layout, real-time constructing a twin model, and multi-scenario simulation verification. It provides an innovative solution for the relay protection strategy evaluation and optimization of complex distribution networks. Description of the Drawings

[0063] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0064] Figure 1 It is the overall flowchart of a digital-twin-based relay protection evaluation and testing method provided for the first embodiment of the present invention. Detailed Embodiments

[0065] To make the above objects, features, and advantages of the present invention more obvious and understandable, the detailed embodiments of the present invention will be described below with reference to the drawings of the specification. Obviously, the described embodiments are some, rather than all, embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0066] Embodiment 1, referring to Figure 1 , which is an embodiment of the present invention, provides a digital-twin-based relay protection evaluation and testing method for a distribution network, including:

[0067] S1: Optimize the site selection according to the distribution network topology structure and load distribution, configure data acquisition terminals, and build a data transmission network to collect the operation data of the distribution network.

[0068] Furthermore, the operation data of the distribution network includes the topological structure of the distribution network, load distribution, node information, and sensor data; the sensor data includes current and voltage data and synchronized phasor data.

[0069] Furthermore, the site selection optimization based on the distribution network topological structure and load distribution includes determining the key nodes of the distribution network, substation buses, distributed power access points, and sensitive load nodes, deploying multi-functional sensors, and comprehensively using the point layout optimization algorithm to reduce redundant devices. The formula for arranging data acquisition devices: The optimization model for arranging acquisition points can be expressed as:

[0070] ;

[0071] Constraint conditions:

[0072] ;

[0073] Among them, represents the total layout cost, represents the costs of arranging voltage transformers, current transformers, and PMUs at the th point respectively, represents the voltage and current at the th point represents the allowable range of voltage and current, represents the power and distance parameters at the th point, represents the coverage effect of the acquisition point, represents the minimum requirement for the coverage effect.

[0074] S2: Preprocess the operation data of the distribution network and construct a digital twin model.

[0075] Furthermore, the preprocessing of the operation data of the distribution network includes using linear interpolation for missing values, performing low-pass filtering on harmonic noise, and filtering using a Butterworth filter;

[0076] Data acquisition synchronization. The time accuracy of synchronous acquisition is defined by the formula of the synchronized phasor measurement unit (PMU) as:

[0077] ;

[0078] Among them, represents the phase angle at the th point, represents the current and voltage at the th point, represents the power frequency angular velocity (usually Hz or Hz), represents time.

[0079] Build a dynamic equivalent electromagnetic transient model for distributed power sources, energy storage devices, and flexible loads to simulate the electromagnetic transient characteristics during the operation of a new-type distribution network. The digital twin model of relay protection is established based on the technical parameters, action logic, and operation mechanism of relay protection devices to create a virtual relay protection model. Provide real-time synchronization and dynamic simulation functions to evaluate the response ability of protection devices.

[0080] The construction of the digital twin model includes the construction of a dynamic power grid model. The power flow calculation equation of the dynamic model is as follows:

[0081] ;

[0082] Where, represents the active power and reactive power of node , represents the voltage of node , represents the real part of the admittance matrix parameter between nodes and represents the imaginary part of the admittance matrix parameter between nodes , represents the voltage phase angle difference between nodes , represents the total node set in the network.

[0083] It should be noted that the test environment is built to provide an AC / DC load simulation environment, including various types of distributed power sources and power electronic devices. Support harmonic injection and impedance simulation for simulating complex fault scenarios.

[0084] S3: Achieve twin synchronous update through data mapping.

[0085] Furthermore, the achieving of twin synchronous 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 to balance real-time performance and reliability.

[0086] The data mapping formula is expressed as:

[0087] ;

[0088] Where, represents the current state of the th node in the twin model, represents the physical data collected in real time, represents the predicted data output by the simulation model, represents the dynamic weight of data fusion.

[0089] Dynamic simulation formula, based on the node voltage update formula:

[0090] ;

[0091] Wherein, represents the node voltage after iteration, represents node and admittance parameters, represents the active and reactive power of the node.

[0092] Execute initialization, initial voltage from real-time acquisition data Initialize the admittance matrix Pre-calculate based on the distribution network topology and line parameters. In the initial state, use the acquisition data as input ; Update the node voltage according to the dynamic formula until the convergence condition is met:

[0093] ;

[0094] Wherein, represents the convergence accuracy threshold.

[0095] The connection logic is that the dynamic simulation formula uses the active and reactive power collected in real time as input, iteratively updates the voltage of each node, and ensures that the model state is consistent with the physical system.

[0096] It should be noted that the acquisition data is combined with the twin model through data mapping, and the node voltage update is calculated based on the dynamic simulation formula. A data synchronization and error correction mechanism is introduced to ensure the consistency of the state between the physical system and the twin model. The fault simulation is used to test the response ability of the model, and the model performance is continuously improved through parameter optimization and dynamic update.

[0097] S4: Conduct simulation and fault test verification, and analyze and optimize the feedback on the verification data.

[0098] The simulation and fault test verification include typical faults, single-phase ground fault, three-phase short circuit, overload operation; fault injection, the simulated fault current formula is expressed as:

[0099] ;

[0100] Wherein, represents the positive sequence, negative sequence, and zero sequence impedances, represents the fault point impedance;

[0101] Dynamic response test, the protection device responds, triggers the relay protection action, and records the action time and logic:

[0102] ;

[0103] Among them, represents the fault detection time, represents the logical operation time of the protection device, represents the switch operation time; transmit the fault simulation results to the twin model, verify the dynamic response ability of the model to the fault scenario, and perform local adjustment and incremental update on the fault-occurring area.

[0104] When a single-phase grounding fault occurs, locally adjust the voltage and power of the faulty node, correct the states of the affected nodes and neighboring nodes. At the same time, update the phase angle and current value at the fault location; by simulating the current change during the fault occurrence, locally adjust the voltage and power distribution in the fault area; use the fault detection algorithm to identify the fault point, calculate and adjust the current values of other phases to prevent the system from mislabeling the non-fault area as the fault area.

[0105] When a three-phase short circuit occurs, for the three-phase short circuit fault, locally adjust the node voltage, power and phase angle of all fault points, and at the same time update the data at the current measurement points; adjust the short-circuit current path through incremental simulation to identify the area affected by the short circuit; update the power loss and current flow direction of the relevant lines, and reduce the calculation overhead by local power flow calculation and rapid correction of the fault current value.

[0106] When a certain part of the power grid is overloaded, it causes some equipment to be overloaded; locally update the current and power in the overloaded area of the load, adjust the power scheduling of the load equipment, adjust the power flow direction in the overloaded area, optimize the system load distribution, and avoid the widespread chain reaction caused by overload.

[0107] When a harmonic fault occurs, due to nonlinear loads or equipment failures, harmonics may be generated, affecting the voltage waveform of the power grid; adjust the voltage and current waveforms in the affected area through local filtering and harmonic compensation; adopt dynamic voltage control and filtering algorithms to locally adjust the power parameters in the harmonic-affected area and reduce the propagation impact of harmonics.

[0108] Performing data analysis and optimization feedback includes performing parameter optimization, and the optimization objective formula is expressed as:

[0109] ;

[0110] Among them, represents the sum of the squares of the errors of all nodes in the network, represents the error of a single node.

[0111] Optimization method, use the gradient descent method to adjust the parameters in the twin model, the admittance matrix or the load value .

[0112] Perform dynamic updates and update the model status in real time according to the optimization results:

[0113] ;

[0114] Among them, represents the adjusted value of the optimized model parameters. The optimized model is immediately used for the next round of simulation to achieve the adaptive improvement of the twin model.

[0115] It should be noted that for the protection strategy optimization, in combination with the electromagnetic transient analysis results, the action thresholds and response logics of the relay protection devices are adjusted. Verify the reliability and coordination of the protection devices in the complex grid. For the research on the coordination protection mechanism, analyze the interaction between the protection and distributed power sources in the distribution network and optimize the coordination mechanism. Solve the interference and misoperation problems among multiple protection devices. For the platform verification, use the built evaluation and test platform 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.

[0116] Embodiment 2 is an embodiment of the present invention, which provides a method for evaluating and testing the relay protection of a distribution network based on digital twins. In order to verify the beneficial effects of the present invention, scientific demonstrations are carried out through economic benefit calculations and simulation experiments.

[0117] First, for the test preparation, in this embodiment, aiming at the operation status of a regional distribution network and with the background of a high-penetration distributed power source access environment, a method for evaluating and testing the relay protection of a distribution network based on digital twins is designed and verified. Select key nodes including an 110 kV substation, two distributed photovoltaic power station access points, and three sensitive load nodes, and determine the sensor layout scheme through a layout optimization algorithm. Select multifunctional sensors (voltage transformers, current transformers, PMUs) to configure data acquisition terminals, and build a data transmission platform using a low-latency communication network.

[0118] Implementation steps:

[0119] Optimize the location selection of the key nodes of the distribution network. Using the distribution network topology and load distribution data, apply the layout optimization formula to calculate and select 4 points out of 6 candidate points to arrange equipment.

[0120] Data acquisition and transmission. Install sensors at the optimized locations and transmit data through the IEC 61850 protocol. The acquisition frequency is set to 50 Hz, and the PMU synchronization error does not exceed 1 μs.

[0121] After the data is transmitted to the central platform, it is stored and analyzed.

[0122] Data preprocessing and twin model construction. For missing data, linear interpolation method is used for processing, and for harmonic noise, Butterworth filter is used for filtering. The filter parameters are third order and the cut-off frequency is 300 Hz.

[0123] Build a dynamic model based on power flow equations, data mapping and synchronous update, dynamically fuse the acquired data and the output of the simulation model, and adjust the weights to achieve high-precision real-time synchronization.

[0124] Simulation and fault testing. Set typical fault scenarios: single-phase ground fault, three-phase short circuit and overload operation, simulate the fault current and verify the response time of the relay protection, and record the action logic.

[0125] Optimization feedback. Analyze the test data, and use the gradient descent method to adjust the parameters of the twin model for the optimization objective.

[0126] Table 1 Test data record form

[0127] ;

[0128] It can be observed from the test data in Table 1 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 state after dynamic synchronization drops from 0.5% to 0.3%, indicating that data mapping and weight adjustment significantly improve the fitness between the twin model and the physical system. Compared with the traditional fixed-weight data fusion technology, dynamically adjusting the weights makes the model more adaptable to load changes and fault disturbances.

[0129] The response time of the single-phase ground fault is 25 ms, and the response time of the three-phase short circuit fault is 30 ms, which is significantly better than the average response time of 50 ms of the traditional relay protection device. The error between the model prediction and the actual acquired data is within 1.2%, fully verifying the dynamic response ability of the twin model to the fault scenario.

[0130] Embodiment 3, an embodiment of the present invention, provides a digital twin-based relay protection evaluation and test system for a distribution network, including:

[0131] Data acquisition and transmission module. Optimize the site selection according to the distribution network topology structure and load distribution, configure data acquisition terminals and sensor devices, and establish a reliable data transmission network.

[0132] Data preprocessing module. Clean and preprocess the operation data, build a digital twin model, and realize high-precision distribution network state simulation.

[0133] Data mapping and synchronous update module. Achieve real-time synchronous update of the twin model through data mapping, and ensure the consistency of the state between the simulation model and the physical system.

[0134] The simulation optimization module performs simulation and fault test verification, analyzes the test data and feeds back the optimization model.

[0135] 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, in essence, or the part that contributes to the prior art, or a 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 and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods of the various embodiments of the present invention. The foregoing storage medium includes: USB flash drives, mobile hard disks, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical discs, etc., all of which can store program codes.

[0136] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a definite sequence list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or in combination with these instruction execution systems, apparatuses, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.

[0137] More specific examples (non-exhaustive list) of computer-readable media include the following: electrical connection parts (electronic devices) having one or more wirings, portable computer disk cartridges (magnetic devices), random access memories (RAMs), read-only memories (ROMs), erasable programmable read-only memories (EPROMs or flash memories), optical fiber devices, and portable compact disc read-only memories (CDROMs). Additionally, the computer-readable medium can even be paper or other suitable media on which a program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or other suitable processing as necessary, and then stored in a computer memory.

[0138] It should be understood that each part of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above 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, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

[0139] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered by 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; 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 weight W real and W sim Balance real-time performance and reliability; The data mapping formula is expressed as: M i (t)=W real ·D i (t)+W sim ·S i (t) Among them, M i (t) represents the current state of the i-th node in the twin model, D i (t) represents the physical data collected in real time, S i (t) represents the predicted data output by the simulation model, W real ,W sim 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, Y ii ,Y ij represents the admittance parameter of nodes i and j, P i ,Q i Indicates the active and reactive power of the node; Initialization conditions, initial voltage Collect data from real-time i (t) Initialize the admittance matrix Y based on the distribution network topology and line parameters in advance. In the initial state, the collected data is used as input. Update the node voltage according to the dynamic formula until the convergence condition is met: Among them, ∈ represents the convergence accuracy threshold; The dynamic simulation formula 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; Conduct simulation and fault test verification, analyze and optimize the verification data; 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: Among them, Z1, Z2, Z0 represent positive sequence, negative sequence, and zero sequence impedances, and Z f represents the fault point impedance; Dynamic response test, protection device response, triggering relay protection action, recording action time and logic: T action =T detect +T compute +T operate Among them, T detect represents the fault detection time, T compute Indicates the logic operation time of the protection device, T operate Indicates the switch operation time; transmits the fault simulation results to the twin model to verify the model's dynamic response capability to fault scenarios; The analysis and optimization feedback includes parameter optimization, and the optimization target formula is expressed as: Among them, J represents the sum of squares of the errors of all nodes in the network, E i 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 Y ij Or load value P i ,Q i ; Perform dynamic updates and update the model status in real time according to the optimization results: Among them, ΔM i 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.

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: Where C represents the total layout cost, represents the cost of arranging the voltage transformer at the i-th point, represents the cost of the current transformer arranged at the i-th point, represents the cost of the PMU deployed at the i-th point, V i ,I i represents the voltage and current at the i-th point; Indicates the safety threshold range of voltage and current, P i ,D i represents the power and distance parameters of the i-th point, Coverage(P i ,D i ) represents the coverage effect of the collection points, η represents the minimum requirement for the coverage effect, and N represents the total set of nodes in the network.

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: Among them, θ i (t) represents the phase angle of the i-th point, I i ,V i represents the current and voltage at the i-th point, ω represents the industrial frequency angular velocity, and t represents 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: Among them, P i ,Q i represents the active power and reactive power of node i, V i ,V j represents the voltage of node i,j, G ij represents the real part of the admittance matrix parameter between nodes i and j, B ij represents the imaginary part of the admittance matrix parameter between nodes i and j, θ ij represents the voltage phase angle difference between nodes i and j, and N represents the total set of nodes in the network.

5. 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 4, 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 real-time synchronous update of the twin model through data mapping includes performing data mapping, collecting data through sensors and PMUs, and transmitting the data to the twin model, combining the collected data with the simulation output of the twin model, and dynamically adjusting the weight W. real and W sim Balance real-time performance and reliability; The data mapping formula is expressed as: M i (t)=W real ·D i (t)+W sim ·S i (t) Among them, M i (t) represents the current state of the i-th node in the twin model, D i (t) represents the physical data collected in real time, S i (t) represents the predicted data output by the simulation model, W real ,W sim 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, Y ii ,Y ij represents the admittance parameters of nodes i and j, P i ,Q i Indicates the active and reactive power of the node; Initialization conditions, initial voltage Collect data from real-time i (t) Initialize the admittance matrix Y based on the distribution network topology and line parameters in advance. In the initial state, the collected data is used as input. Update the node voltage according to the dynamic formula until the convergence condition is met: Among them, ∈ represents the convergence accuracy threshold; The dynamic simulation formula 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; The simulation optimization module performs simulation and fault test verification, analyzes test data and provides feedback on the optimization model; 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: Among them, Z1, Z2, Z0 represent positive sequence, negative sequence, and zero sequence impedances, and Z f represents the fault point impedance; Dynamic response test, protection device response, triggering relay protection action, recording action time and logic: T action =T detect +T compute +T operate Among them, T detect represents the fault detection time, T compute Indicates the logic operation time of the protection device, T operate Indicates the switch operation time; transmits the fault simulation results to the twin model to verify the model's dynamic response capability to fault scenarios; The analyzing test data and feeding back the optimization model includes performing parameter optimization, and the optimization target formula is expressed as: Among them, J represents the sum of squares of the errors of all nodes in the network, E i 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 Y ij Or load value P i ,Q i ; Perform dynamic updates and update the model status in real time according to the optimization results: Among them, ΔM i 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.

6. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: 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 4 are implemented.

7. 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 twins described in any one of claims 1 to 4 are implemented.

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