Neural network-based comprehensive load model parameter automatic correction method
Through the automatic correction method of comprehensive load model parameters based on neural network, the problem that traditional load models cannot effectively reflect complex power load characteristics is solved, efficient load model parameter correction is achieved, and the safety and stability of power grid operation are improved.
Patent Information
- Application Number
- CN202411676697.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-22
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2044-11-22
AI Technical Summary
Traditional load models cannot effectively reflect complex power load characteristics, making it difficult to ensure the accuracy and reliability of the new generation of load models, affecting the safety and stability of power grid operation.
The automatic correction method of parameter of the integrated load model based on neural network is adopted. By obtaining fault recording data, the system state is simulated when the parameters change is changed, the integral area difference of the transient voltage change curve is calculated using the Simpson's 1/3 rule, and the Levenberg-Marquardt algorithm is established. The optimized neural network trains the error function, and uses the sequential quadratic planning algorithm to obtain the parameters of the comprehensive load model after reversal normalization.
Automatic correction of load model parameters is realized, correction efficiency is improved, strict requirements for large-scale power grid analysis and calculation, reducing dependence on manual experience, and improving the accuracy and reliability of the model.
Smart Images

Figure CN119180220A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of power systems, and in particular to an automatic correction method for comprehensive load model parameters based on a neural network. Background Art
[0002] With the rapid expansion of distributed power generation, traditional load models have been unable to keep up with the times, and there is an urgent need to build a new generation of load models that adapt to the development of new power systems. Behind this new demand is the significant change in the operating environment of the power system. The limitations of traditional models are becoming increasingly prominent and cannot fully reflect the current complex characteristics of power loads. However, the accuracy of the new generation of load models still faces the challenge of insufficient verification methods. Due to the lack of effective verification methods, the reliability and accuracy of the model are difficult to guarantee. The existence of this problem may affect the safety and stability of power grid operation in practical applications. Therefore, developing and improving verification methods for the new generation of load models is one of the focuses of current research and application.
[0003] At present, there are three main methods for load model correction: statistical synthesis method, overall measurement method and fault fitting method. The basic idea of the statistical synthesis method is to regard the load connected to the substation bus node as a collection of multiple power users, and each user is also a collection of various types of power load equipment. The basic idea of the overall measurement method is to regard the comprehensive load as a black box. Under the premise of determining the load model structure, it combines the collected dynamic measurement data and optimization algorithm for identification to obtain the load model parameters. The fault fitting method adjusts the load model parameter value in the simulation system to fit the actual system fault situation until the simulation curve closest to the actual fault curve is obtained, that is, the corresponding optimal load model parameters. However, in actual operation, the traditional fault fitting method mainly fits the target by manually correcting the parameters and manually modifying the load parameters to calculate the dynamic response of the system. However, the goal of this method is relatively single, and the adjustment of parameters and the evaluation of fitting effect rely on manual experience, which is not only inefficient, but also the established model is difficult to meet the strict requirements of large-scale power grid analysis and calculation for load models.
[0004] Therefore, it is necessary to design an automatic correction method for comprehensive load model parameters based on neural network. Summary of the invention
[0005] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art and to provide a method for automatically correcting parameters of a comprehensive load model based on a neural network.
[0006] To achieve the above object, the technical solution adopted by the present invention is as follows: a method for automatically correcting parameters of a comprehensive load model based on a neural network, comprising the following steps: Step 1, obtaining actual fault recording data of the integrated load system to extract the actual value of the transient voltage; Step 2, simulating system state data of the comprehensive load model when parameters change, and extracting simulation values of transient voltages; Step 3, based on the Simpson 1 / 3 rule, calculate the Simpson integral area difference between the simulated transient voltage change curve and the original fault recording transient voltage change curve, and construct a data set; Step 4, based on the neural network optimized by the Levenberg-Marquardt algorithm, establish the change response relationship between the load parameter and the area difference; Step 5, establishing a normalized error function through the trained neural network; Step 6: Based on the error function, the sequential quadratic programming algorithm is used to minimize the Simpson integral area difference to obtain the inverse normalized comprehensive load model parameters.
[0007] Furthermore, in step 1, the transient voltage value of the busbar every 0.01s after the fault occurs is extracted from the fault recording data. , as the original fault recording transient voltage change curve.
[0008] Furthermore, in the step 2, it specifically includes: The parameters for selecting the comprehensive load model include: XL={x1,x2,x3,x4,x5,x6,x7}={stator resistance, stator reactance, magnetizing reactance, rotor resistance, rotor reactance, inertia time constant, initial active load rate}; The parameter values of the comprehensive load model are gradually modified in the form of ±20% of the original parameter value, so as to obtain the transient voltage change curve of the node when the system fails under different changes in the parameters of the comprehensive load model.
[0009] Furthermore, in step 3, it specifically includes: Step 3.1, assuming that the transient voltage change curve under the condition of comprehensive load model parameter change is , the original fault recording transient voltage change curve is: ; Calculate each The difference between the points gives the difference curve: (1); Step 3.2, As a new curve, Perform integration; assuming that Points ,in is an even number, so that the number of points is an odd number, and the difference corresponding to each point is ; Then the formula for calculating the area difference between the two curves using Simpson's 1 / 3 rule is: (2); in, In each The difference between the two curves in position; is the distance between adjacent points; Step 3.3, according to the comprehensive load model parameters in step 2, randomly change these load parameters in the simulation software as the input of the neural network, and use the Simpson integral area difference between the corresponding transient voltage change curve and the original fault recording transient voltage change curve as the output of the neural network. Construct a data set, and take 80% as the training set and 20% as the test set.
[0010] Furthermore, the step 4 specifically includes the following steps: Step 4.1, create an initialized neural network, including input layer, hidden layer and output layer; Step 4.2: The number of input neurons in the input layer is the number of comprehensive load model parameters selected in step 2, and the number of neurons in the hidden layer is set to , the output layer is the Simpson integral area difference between the simulation value and the actual value corresponding to step 3, and the number of neurons is set to 1; Step 4.3, assuming the input vector is , the output of the hidden layer Calculated by: (3); In the formula, The input layer neurons to the hidden layer The weight of the neuron, is the hidden layer The bias of a neuron, is the activation function; Step 4.4, output of the output layer It is calculated by the following formula: (4); In the formula, is the weight from the hidden layer to the output layer, is the bias of the output layer; Step 4.5, use mean square error Measuring the output of a neural network Simpson area difference with the training set The difference between Step 4.6, calculate the partial derivatives of the output layer weights and biases, first the mean square error with respect to the weights and bias The partial derivatives are: (5); (6); In the formula, ; is the derivative of the activation function; Step 4.7, calculate the mean square error with respect to weight and bias The partial derivative of : (7); (8); Step 4.8, starting from the output layer, calculate the partial derivative of the error with respect to each parameter layer by layer through step 4.7, and use these partial derivatives to update the weights and biases; the Levenberg-Marquardt algorithm combines the gradient descent method and the Gauss-Newton method. The Levenberg-Marquardt algorithm optimizes the weight and bias updates of the neural network according to the following formula: (9); In the formula, is the update amount for weights and biases, is the Jacobian matrix, representing the partial derivatives of each neural network parameter, is the transpose of the Jacobian matrix, is the adjustment parameter, is the identity matrix; is the error vector, which represents the difference between the actual output and the network output; Step 4.9, if the current iteration reduces the error, then reduce The value of is closer to the Gauss-Newton method. If the current iteration increases the error, increase The value of is closer to the gradient descent method; it is adjusted repeatedly in iteration until the mean square error When a preset minimum value is reached, the operation ends; Step 4.10, evaluate the trained neural network model, and use the coefficient of determination and mean square error to evaluate the neural network model; the coefficient of determination is recorded as , which is defined as: (10); is the residual sum of squares, which represents the sum of squares of the differences between the model's predicted values and the actual values: ,here is the Simpson area difference in the test set, is the Simpson area difference output by the neural network; is the total sum of squares, which represents the sum of squared differences between the actual values and the mean: ,here is the average of the Simpson area differences output by the neural network.
[0011] Furthermore, the step 5 specifically includes the following steps: Step 5.1, before establishing the error function, normalize the input and output parameters. Assume that the input parameter vector is , the minimum and maximum values of each feature are and , use the following formula to normalize the input feature vector to scope: (11); Step 5.2, determine the output of the network based on the weights and biases of the neural network trained in step 4: (12); in, It is The weight matrix of the layer, It is The bias vector of the layer; is the activation function; is the number of layers in the network; Step 5.4, by adjusting the input vector , so that the Simpson area difference of the output of the neural network is as close to 0 as possible, and define the error function : (13).
[0012] Furthermore, the step 6 specifically includes the following steps: Step 6.1, based on the error function in step 5, define the optimization objective as ;in, is the input parameter vector, and the goal is to minimize the Simpson area difference of the neural network output to find the optimal input parameters; Step 6.2, input parameters The uniform initialization is 0.5; Step 6.3, in each iteration, based on the current parameters , for the error function Perform Taylor expansion and take its quadratic approximation: (14); in, The objective function is The gradient vector at The objective function is The Hessian matrix of or its approximation; Step 6.4, in the sequential quadratic programming algorithm, in order to find the optimal step vector , we need to solve the following quadratic programming problem: (15); Solution is the direction and step size that should be moved at the current iteration point; Step 6.5, set the step size The boundary constraints are: (16); Step 6.6, construct the Lagrangian function: (17); in, and is the Lagrange multiplier; Step 6.7, for the Lagrangian function about , , Taking the derivative and setting it to zero, we get the following condition: about The first-order condition is: (18); Feasibility conditions for constraints: (19); Regarding the satisfaction of the boundary constraints of step size d: (20); Solving for the optimal conditions , get the next iteration point : (twenty one); Step 6.8, verify the current solution Whether the convergence criterion is met; the convergence criterion is the tolerance of the objective function value , that is, the change in parameter updates between two adjacent iterations; the default value is , the maximum number of function evaluations , the default is 5000 times; Step 6.9, when the convergence criterion is met, the evaluation is terminated and the normalized input parameters are converted back to the original scale. The denormalization formula is defined as: (twenty two); in, is the original scale value of the optimized input parameter vector after denormalization.
[0013] From the above description of the present invention, it can be seen that compared with the prior art, the automatic correction method of the comprehensive load model parameters of the present invention extracts the simulation value of the transient voltage when the comprehensive load model simulates the parameter change, and obtains the Simpson integral area difference between the simulation value and the actual value of the load system; establishes the change response relationship based on the neural network of the Levenberg-Marquardt algorithm; establishes a normalized error function through the trained neural network; and obtains the inverse normalized comprehensive load model parameters based on the sequential quadratic programming algorithm with the minimum deviation value as the goal. By automatically correcting the comprehensive load model parameters, the present invention does not rely on manual experience, has high parameter correction efficiency, and can meet the strict requirements of large-scale power grid analysis and calculation for comprehensive load models. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 The present invention is a flowchart of the steps of an automatic correction method of comprehensive load model parameters based on a neural network in a preferred embodiment of the present invention. DETAILED DESCRIPTION
[0015] The technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all of the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.
[0016] Reference Figure 1 As shown, a preferred embodiment of the present invention, a method for automatically correcting parameters of a comprehensive load model based on a neural network, comprises the following steps: Step 1, obtaining actual fault recording data of the integrated load system to extract the actual value of the transient voltage; Step 2, simulating system state data of the comprehensive load model when parameters change, and extracting simulation values of transient voltages; Step 3, based on the Simpson 1 / 3 rule, calculate the Simpson integral area difference between the simulated transient voltage change curve and the original fault recording transient voltage change curve, and construct a data set; Step 4, based on the neural network optimized by the Levenberg-Marquardt algorithm, establish the change response relationship between the load parameter and the area difference; Step 5, establishing a normalized error function through the trained neural network; Step 6: Based on the error function, the sequential quadratic programming algorithm is used to minimize the Simpson integral area difference to obtain the inverse normalized comprehensive load model parameters.
[0017] As a preferred embodiment of the present invention, it may also have the following additional technical features: In this embodiment, in step 1, the transient voltage value of the busbar every 0.01s after the fault occurs is extracted from the fault recording data. , as the original fault recording transient voltage change curve.
[0018] In this embodiment, step 2 specifically includes: The parameters for selecting the comprehensive load model include: XL={x1,x2,x3,x4,x5,x6,x7}={stator resistance, stator reactance, magnetizing reactance, rotor resistance, rotor reactance, inertia time constant, initial active load rate}; The parameter values of the comprehensive load model are gradually modified in the form of ±20% of the original parameter value, so as to obtain the transient voltage change curve of the node when the system fails under different changes in the parameters of the comprehensive load model.
[0019] In this embodiment, step 3 specifically includes: Step 3.1, assuming that the transient voltage change curve under the condition of comprehensive load model parameter change is , the original fault recording transient voltage change curve is: ; Calculate each The difference between the points gives the difference curve: (1); Step 3.2, As a new curve, Perform integration; assuming that Points ,in is an even number, so that the number of points is an odd number, and the difference corresponding to each point is ; Then the formula for calculating the area difference between the two curves using Simpson's 1 / 3 rule is: (2); in, In each The difference between the two curves in position; is the distance between adjacent points; Step 3.3, according to the comprehensive load model parameters in step 2, randomly change these load parameters in the simulation software as the input of the neural network, and use the Simpson integral area difference between the corresponding transient voltage change curve and the original fault recording transient voltage change curve as the output of the neural network. Construct a data set, and take 80% as the training set and 20% as the test set.
[0020] In this embodiment, step 4 specifically includes the following steps: Step 4.1, create an initialized neural network, including input layer, hidden layer and output layer; Step 4.2: The number of input neurons in the input layer is the number of comprehensive load model parameters selected in step 2, and the number of neurons in the hidden layer is set to , the output layer is the Simpson integral area difference between the simulation value and the actual value corresponding to step 3, and the number of neurons is set to 1; Step 4.3, assuming the input vector is , the output of the hidden layer Calculated by: (3); In the formula, The input layer neurons to the hidden layer The weight of the neuron, is the hidden layer The bias of a neuron, is the activation function; Step 4.4, output of the output layer It is calculated by the following formula: (4); In the formula, is the weight from the hidden layer to the output layer, is the bias of the output layer; Step 4.5, use mean square error Measuring the output of a neural network Simpson area difference with the training set The difference between Step 4.6, calculate the partial derivatives of the output layer weights and biases, first the mean square error with respect to the weights and bias The partial derivatives are: (5); (6); In the formula, ; is the derivative of the activation function; Step 4.7, calculate the mean square error with respect to weight and bias The partial derivative of : (7); (8); Step 4.8, starting from the output layer, calculate the partial derivative of the error with respect to each parameter layer by layer through step 4.7, and use these partial derivatives to update the weights and biases; the Levenberg-Marquardt algorithm combines the gradient descent method and the Gauss-Newton method. The Levenberg-Marquardt algorithm optimizes the weight and bias updates of the neural network according to the following formula: (9); In the formula, is the update amount for weights and biases, is the Jacobian matrix, representing the partial derivatives of each neural network parameter, is the transpose of the Jacobian matrix, is the adjustment parameter, is the identity matrix; is the error vector, which represents the difference between the actual output and the network output; Step 4.9, if the current iteration reduces the error, then reduce The value of is closer to the Gauss-Newton method. If the current iteration increases the error, increase The value of is closer to the gradient descent method; it is adjusted repeatedly in iteration until the mean square error When a preset minimum value is reached, the operation ends; Step 4.10, evaluate the trained neural network model, and use the coefficient of determination and mean square error to evaluate the neural network model; the coefficient of determination is recorded as , which is defined as: (10); is the residual sum of squares, which represents the sum of squares of the differences between the model's predicted values and the actual values: ,here is the Simpson area difference in the test set, is the Simpson area difference output by the neural network; is the total sum of squares, which represents the sum of squared differences between the actual values and the mean: ,here is the average of the Simpson area differences output by the neural network.
[0021] In this embodiment, step 5 specifically includes the following steps: Step 5.1, before establishing the error function, normalize the input and output parameters. Assume that the input parameter vector is , the minimum and maximum values of each feature are and , use the following formula to normalize the input feature vector to scope: (11); Step 5.2, determine the output of the network based on the weights and biases of the neural network trained in step 4: (12); in, It is The weight matrix of the layer, It is The bias vector of the layer; is the activation function; is the number of layers in the network; Step 5.4, by adjusting the input vector , so that the Simpson area difference of the output of the neural network is as close to 0 as possible, and define the error function : (13).
[0022] In this embodiment, step 6 specifically includes the following steps: Step 6.1, based on the error function in step 5, define the optimization objective as ;in, is the input parameter vector, and the goal is to minimize the Simpson area difference of the neural network output to find the optimal input parameters; Step 6.2, input parameters The uniform initialization is 0.5; Step 6.3, in each iteration, based on the current parameters , for the error function Perform Taylor expansion and take its quadratic approximation: (14); in, The objective function is The gradient vector at The objective function is The Hessian matrix of or its approximation; Step 6.4, in the sequential quadratic programming algorithm, in order to find the optimal step vector , we need to solve the following quadratic programming problem: (15); Solution is the direction and step size that should be moved at the current iteration point; Step 6.5, set the step size The boundary constraints are: (16); Step 6.6, construct the Lagrangian function: (17); in, and is the Lagrange multiplier; Step 6.7, for the Lagrangian function about , , Taking the derivative and setting it to zero, we get the following condition: about The first-order condition is: (18); Feasibility conditions for constraints: (19); Regarding the satisfaction of the boundary constraints of step size d: (20); Finding the optimal conditions , get the next iteration point : (twenty one); Step 6.8, verify the current solution Whether the convergence criterion is met; the convergence criterion is the tolerance of the objective function value , that is, the change in parameter updates between two adjacent iterations; the default value is , the maximum number of function evaluations , the default is 5000 times; Step 6.9, when the convergence criterion is met, the evaluation is terminated and the normalized input parameters are converted back to the original scale. The denormalization formula is defined as: (twenty two); in, is the original scale value of the optimized input parameter vector after denormalization.
[0023] The method for automatically correcting the parameters of the comprehensive load model proposed in the present invention has been put into practical application in a certain power grid. The established comprehensive load model has 15,995 busbars, 701 generators, 6,194 loads, 4,137 AC lines, and 6 DC lines. The three-phase short-circuit grounding fault of the 220kV Ganhong Bridge was simulated by the comprehensive load model. The fault process is as follows: the three-phase short-circuit grounding fault occurred in the comprehensive load model at 1s, and the fault began to recover 0.12s after the three-phase short-circuit grounding fault occurred.
[0024] The parameters of the comprehensive load model are corrected by the automatic correction method of the present invention, and a simulation curve closest to the actual fault curve is obtained, that is, the corresponding optimal parameters. The transient voltage change curve under the corrected parameters is compared with the transient voltage change curve under the original parameters, and it is obtained that the Simpson integral area difference under the original parameters is 0.03. The correction effect of the present invention is better.
[0025] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and improved concepts of the present invention within the technical scope disclosed by the present invention, and they should be covered by the protection scope of the present invention.
Claims
1. A method for automatically correcting parameters of a comprehensive load model based on a neural network, characterized in that: The following steps are involved: Step 1, obtaining actual fault recording data of the integrated load system to extract the actual value of the transient voltage; Step 2, simulating system state data of the comprehensive load model when parameters change, and extracting simulation values of transient voltages; Step 3, based on the Simpson 1 / 3 rule, calculate the Simpson integral area difference between the simulated transient voltage change curve and the original fault recording transient voltage change curve, and construct a data set; Step 4, based on the neural network optimized by the Levenberg-Marquardt algorithm, establish the change response relationship between the load parameter and the area difference; Step 5, establishing a normalized error function through the trained neural network; Step 6: Based on the error function, the sequential quadratic programming algorithm is used to minimize the Simpson integral area difference to obtain the inverse normalized comprehensive load model parameters.
2. The method for automatically correcting comprehensive load model parameters based on a neural network according to claim 1, characterized in that: In step 1, the transient voltage value of the busbar every 0.01s after the fault occurs is extracted from the fault recording data. , as the original fault recording transient voltage change curve.
3. The method for automatically correcting comprehensive load model parameters based on a neural network according to claim 2, characterized in that: In the step 2, it specifically includes: The parameters for selecting the comprehensive load model include: XL={x1,x2,x3,x4,x5,x6,x7}={stator resistance, stator reactance, magnetizing reactance, rotor resistance, rotor reactance, inertia time constant, initial active load rate}; The parameter values of the comprehensive load model are gradually modified in the form of ±20% of the original parameter value, so as to obtain the transient voltage change curve of the node when the system fails under different changes in the parameters of the comprehensive load model.
4. The method for automatically correcting parameters of a comprehensive load model based on a neural network according to claim 3, characterized in that: In the step 3, it specifically includes: Step 3.1, assuming that the transient voltage change curve under the condition of comprehensive load model parameter change is , the original fault recording transient voltage change curve is: ; Calculate each The difference between the points gives the difference curve: (1); Step 3.2, As a new curve, Perform integration; assuming that Points ,in is an even number, so that the number of points is an odd number, and the difference corresponding to each point is ; Then the formula for calculating the area difference between the two curves using Simpson's 1 / 3 rule is: (2); in, In each The difference between the two curves in position; is the distance between adjacent points; Step 3.3, according to the comprehensive load model parameters in step 2, randomly change these load parameters in the simulation software as the input of the neural network, and use the Simpson integral area difference between the corresponding transient voltage change curve and the original fault recording transient voltage change curve as the output of the neural network. Construct a data set, and take 80% as the training set and 20% as the test set.
5. The method for automatically correcting parameters of a comprehensive load model based on a neural network according to claim 4, characterized in that: The step 4 specifically comprises the following steps: Step 4.1, create an initialized neural network, including input layer, hidden layer and output layer; Step 4.2: The number of input neurons in the input layer is the number of comprehensive load model parameters selected in step 2, and the number of neurons in the hidden layer is set to , the output layer is the Simpson integral area difference between the simulation value and the actual value corresponding to step 3, and the number of neurons is set to 1; Step 4.3, assuming the input vector is , the output of the hidden layer Calculated by: (3); In the formula, The input layer neurons to the hidden layer The weight of a neuron, is the hidden layer The bias of a neuron, is the activation function; Step 4.4, output of the output layer It is calculated by the following formula: (4); In the formula, is the weight from the hidden layer to the output layer, is the bias of the output layer; Step 4.5, use mean square error Measuring the output of a neural network Simpson area difference with the training set The difference between Step 4.6, calculate the partial derivatives of the output layer weights and biases, first the mean square error with respect to the weights and bias The partial derivatives are: (5); (6); In the formula, ; is the derivative of the activation function; Step 4.7, calculate the mean square error with respect to weight and bias The partial derivative of : (7); (8); Step 4.8, starting from the output layer, calculate the partial derivative of the error with respect to each parameter layer by layer through step 4.7, and use these partial derivatives to update the weights and biases; the Levenberg-Marquardt algorithm combines the gradient descent method and the Gauss-Newton method. The Levenberg-Marquardt algorithm optimizes the weight and bias updates of the neural network according to the following formula: (9); In the formula, is the update amount for weights and biases, is the Jacobian matrix, representing the partial derivatives of each neural network parameter, is the transpose of the Jacobian matrix, is the adjustment parameter, is the identity matrix; is the error vector, which represents the difference between the actual output and the network output; Step 4.9, if the current iteration reduces the error, then reduce The value of is closer to the Gauss-Newton method. If the current iteration increases the error, increase The value of is closer to the gradient descent method; it is adjusted repeatedly in iteration until the mean square error When a preset minimum value is reached, the operation ends; Step 4.10, evaluate the trained neural network model, and use the coefficient of determination and mean square error to evaluate the neural network model; the coefficient of determination is recorded as , which is defined as: (10); is the residual sum of squares, which represents the sum of squares of the differences between the model's predicted values and the actual values: ,here is the Simpson area difference in the test set, is the Simpson area difference output by the neural network; is the total sum of squares, which represents the sum of squared differences between the actual values and the mean: ,here is the average of the Simpson area differences output by the neural network.
6. The method for automatically correcting comprehensive load model parameters based on a neural network according to claim 5, characterized in that: The step 5 specifically comprises the following steps: Step 5.1, before establishing the error function, normalize the input and output parameters. Assume that the input parameter vector is , the minimum and maximum values of each feature are and , use the following formula to normalize the input feature vector to scope: (11); Step 5.2, determine the output of the network based on the weights and biases of the neural network trained in step 4: (12); in, It is The weight matrix of the layer, It is The bias vector of the layer; is the activation function; is the number of layers in the network; Step 5.4, by adjusting the input vector , so that the Simpson area difference of the output of the neural network is as close to 0 as possible, and define the error function : (13)。 7. The method for automatically correcting parameters of a comprehensive load model based on a neural network according to claim 6, characterized in that: The step 6 specifically comprises the following steps: Step 6.1, based on the error function in step 5, define the optimization objective as ;in, is the input parameter vector, and the goal is to minimize the Simpson area difference of the neural network output to find the optimal input parameters; Step 6.2, input parameters The uniform initialization is 0.5; Step 6.3, in each iteration, based on the current parameters , for the error function Perform Taylor expansion and take its quadratic approximation: (14); in, is the objective function The gradient vector at The objective function is The Hessian matrix of or its approximation; Step 6.4, in the sequential quadratic programming algorithm, in order to find the optimal step vector , we need to solve the following quadratic programming problem: (15); Solution is the direction and step size that should be moved at the current iteration point; Step 6.5, set the step size The boundary constraints are: (16); Step 6.6, construct the Lagrangian function: (17); in, and is the Lagrange multiplier; Step 6.7, for the Lagrangian function about , , Taking the derivative and setting it to zero, we get the following condition: about The first-order condition is: (18); Feasibility conditions for constraints: (19); Regarding the satisfaction of the boundary constraints of step size d: (20); Finding the optimal conditions , get the next iteration point : (21); Step 6.8, verify the current solution Whether the convergence criterion is met; the convergence criterion is the tolerance of the objective function value , that is, the change in parameter updates between two adjacent iterations; the default value is , the maximum number of function evaluations , the default is 5000 times; Step 6.9, when the convergence criterion is met, the evaluation is terminated and the normalized input parameters are converted back to the original scale. The denormalization formula is defined as: (22); in, is the original scale value of the optimized input parameter vector after denormalization.
Citation Information
Patent Citations
Load identification method based on improved F-score feature selection and particle swarm BP neural network
CN110570091A
Pulse load dynamic model construction method of fusion device based on BP neural network
CN115329651A
Multi-time scale load prediction method based on hybrid neural network
CN116402194A
Transient stability assessment method for an electric power system
US20220360084A1
Photovoltaic cell parameter identification method based on improved equilibrium optimizer algorithm
WO2022095265A1
Cited By
Depression assessment system based on brain-computer interface technology
CN119949834A
