CN-121440473-B - Short-circuit parameter calculation method considering influence of power electronic equipment

CN121440473BCN 121440473 BCN121440473 BCN 121440473BCN-121440473-B

Abstract

The invention discloses a short-circuit parameter calculation method considering the influence of power electronic equipment, which belongs to the technical field of relay protection of power systems and comprises the steps of obtaining multidimensional operation data of the power systems, fusing a system state vector model and a power electronic equipment equivalent model to obtain a layering system calculation model, executing system initialization to determine an initial state to obtain an initialized system calculation model, constructing a short-circuit parameter calculation frame, executing preliminary solution of short-circuit parameters to obtain a short-circuit parameter preliminary result, adjusting model parameters in real time through a dynamic compensation and multi-objective optimization mechanism to obtain an optimal parameter set, adopting an iterative algorithm to solve the short-circuit parameters, combining a multidimensional error evaluation to judge whether the calculation result is converged, and outputting a final short-circuit parameter according to the convergence judgment result. The invention realizes high-precision and self-adaptive calculation of the short-circuit parameters, and remarkably improves the accuracy and the robustness of short-circuit analysis of the power system containing the power electronic equipment.

Inventors

CHEN KEYANG
WANG JIAHAO
LI YUGANG
LIAO CHANG
TANG XUEYONG
LUO JINLONG
XIE WEI
JIANG SHIXIAO
XIE CAIKE
YUAN LONG
Fan Junqiu
ZHOU YIRAN
NING NAN
WANG XIUJING
Du Renren

Assignees

贵州电网有限责任公司

Dates

Publication Date: 20260505
Application Date: 20251230

Claims (7)

1. A short-circuit parameter calculation method taking into account the influence of power electronics, comprising: acquiring multidimensional operation data of the power system; Based on the preprocessed multidimensional operation data, fusing a system state vector model and a power electronic equipment equivalent model to obtain a layering system calculation model; Based on the layering system calculation model, executing system initialization, and determining an initial state to obtain an initialized system calculation model; Based on the initialized system calculation model, constructing a short-circuit parameter calculation frame, and executing preliminary solution of short-circuit parameters to obtain a preliminary short-circuit parameter result; based on the preliminary short-circuit parameter result, the model parameters are adjusted in real time through a dynamic compensation and multi-objective optimization mechanism to obtain an optimal parameter set; Based on the optimal parameter set, solving the short-circuit parameter by adopting an iterative algorithm, judging whether the calculation result is converged by combining multi-dimensional error evaluation, and outputting a final short-circuit parameter according to the convergence judgment result; the obtaining a hierarchical system computing model includes: based on the preprocessed multidimensional operation data, combining a power system topological structure and power electronic equipment parameters to construct a layered model framework, wherein the layered model framework comprises an electrical characteristic layer, a control characteristic layer and a fault characteristic layer; based on the hierarchical modular structure design, a system state vector model is established by integrating node voltage, branch current, power and equipment control parameters; Based on the real-time running state and control parameters contained in the system state vector model, combining the main loop characteristics and a control response mechanism to construct an equivalent model of the power electronic equipment; integrating the system state vector model and the power electronic equipment equivalent model into a layering model framework to obtain a layering system calculation model; The obtaining the initialized system calculation model comprises the following steps: Based on the preprocessed multidimensional operation data and the layering system calculation model, an initial voltage vector, a system impedance matrix and power electronic equipment control parameters are obtained; Based on the initial voltage vector, the system impedance matrix and the control parameters of the power electronic equipment, calling a system state equation to solve the initial current vector; based on the initial current vector, the initial voltage vector, the system impedance matrix and the control parameters of the power electronic equipment, integrating to form a complete initial working point of the system; based on the initial working point of the system, carrying out state assignment on the system calculation model to obtain an initialized system calculation model; The obtaining of the preliminary short-circuit parameter result comprises the following steps: Based on the initialized system calculation model, combining fault scene configuration, and extracting basic short circuit impedance and dynamic correction items; Based on the basic short-circuit impedance and the dynamic correction term, combining the dynamic equivalent model and the real-time running state of each power electronic device, respectively calculating the equivalent impedance of each power electronic device in the short-circuit process and determining the device weight coefficient; based on the equivalent impedance and the equipment weight coefficient of the power electronic equipment, the dynamic compensation coefficient and the equipment weight coefficient are adjusted through an iterative optimization algorithm, and finally the dynamic compensation coefficient and the equipment weight coefficient are substituted into a short-circuit parameter calculation framework to be solved, so that a short-circuit parameter preliminary result is obtained.
2. The method for calculating short-circuit parameters considering the influence of power electronic equipment according to claim 1, wherein the preprocessed multi-dimensional operation data comprises the steps of carrying out standardization processing on the multi-dimensional operation data and eliminating outliers and high-frequency noise by combining median filtering and wavelet transformation.
3. The method for calculating the short-circuit parameters considering the influence of the power electronic equipment according to claim 2, wherein the obtaining the optimal parameter set comprises the following steps: Defining a multi-objective optimization function comprising a plurality of sub-objective functions and regularization terms; Based on the multi-objective optimization function, carrying out parameter sensitivity analysis and determining key optimization parameters; based on the key optimization parameters, a dynamic compensation mechanism is designed, and a real-time error signal is utilized to generate a dynamic compensation quantity; based on the dynamic compensation quantity, adopting a sliding window self-adaptive updating strategy to iteratively update the model parameters to obtain updated parameter vectors; Based on the updated parameter vector, parameter optimization is completed through a parallel computing architecture and a dynamic weight adjustment mechanism, and an optimal parameter set is obtained.
4. A method for calculating a short-circuit parameter taking into account the effects of power electronics as recited in claim 3, wherein said outputting the final short-circuit parameter comprises: Solving nonlinear short-circuit parameters of power electronic equipment by adopting an improved Newton-Lawson iterative algorithm and combining self-adaptive step control, and generating an iterative solution vector and an objective function value; Based on the iterative solution vector and an external reference value, calculating each dimension error, and constructing a multi-dimension error evaluation function by adopting a weighted square sum mode to obtain a comprehensive error index; based on the dimension errors and the external reference values, calculating accuracy assessment is carried out by adopting a relative error algorithm, and a global accuracy value is obtained; comparing the objective function values of the current iteration and the last iteration, and judging whether the difference value between the objective function values of the current iteration and the last iteration is smaller than a preset convergence threshold value or not to obtain convergence state information; Based on the comprehensive error index, the global precision value and the convergence state information, a result tracing mechanism is established and fed back to the parameter updating and optimizing step, a calculation strategy is dynamically adjusted, and the final short-circuit parameter is output.
5. The method for calculating short-circuit parameters taking into consideration influence of power electronic equipment according to claim 4, wherein said power electronic equipment equivalent model is Expressed as: Wherein, the For the device main loop transfer function, In order to control the response function of the system, Is a nonlinear characteristic function; as the weight coefficient of the corresponding feature function, Is the total number of nonlinear characteristic functions; is an order index of the nonlinear feature function, Is a laplace operator.
6. A method for calculating short-circuit parameters taking into account the influence of power electronic equipment according to claim 5, wherein said short-circuit parameter calculation framework Expressed as: Wherein, the Is the fundamental short-circuit impedance of the system, A dynamic correction term for taking into account the power electronics effects; For dynamic compensation coefficients based on the state of the system, Is the equivalent impedance of the power electronics device, For the device weight coefficient(s), Is the total number of power electronic devices in the system; The power electronics are numbered and indexed.
7. A short-circuit parameter calculation method considering power electronic equipment influence as set forth in claim 6, characterized in that said multi-objective optimization function Expressed as: Wherein, the For each of the optimization sub-objective functions, For the corresponding weight coefficient(s), In order to regularize the term(s), In order to optimize the vector of the parameters, For the number of sub-objective functions, Indexing the sub-objective functions.

Description

Short-circuit parameter calculation method considering influence of power electronic equipment Technical Field The invention relates to the technical field of relay protection of power systems, in particular to a short-circuit parameter calculation method considering influence of power electronic equipment. Background With the widespread use of power electronics in power systems, traditional short-circuit parameter calculation methods face new challenges. The existing calculation method is mainly based on kirchhoff's law and a circuit superposition principle, and nonlinear characteristics and dynamic response characteristics of power electronic equipment cannot be fully considered. This results in a large deviation of the short-circuit parameter calculation result from the actual value in a system containing a large number of power electronics. In addition, the existing method is difficult to accurately describe the quick dynamic response process of the power electronic equipment at the moment of failure, and the accuracy of short-circuit protection is affected. Disclosure of Invention The present invention has been made in view of the above-described problems occurring in the prior art. Therefore, the invention provides a short-circuit parameter calculation method considering the influence of power electronic equipment, which solves the problems that the existing short-circuit parameter calculation method is large in deviation between a calculation result and an actual value and difficult to accurately reflect a transient process of a fault due to insufficient consideration of nonlinear characteristics and quick dynamic response characteristics of the power electronic equipment. In order to solve the technical problems, the invention provides the following technical scheme: in a first aspect, the present invention provides a method for calculating a short-circuit parameter in consideration of an influence of power electronic equipment, including: acquiring multidimensional operation data of the power system; Based on the preprocessed multidimensional operation data, fusing a system state vector model and a power electronic equipment equivalent model to obtain a layering system calculation model; Based on the layering system calculation model, executing system initialization, and determining an initial state to obtain an initialized system calculation model; Based on the initialized system calculation model, constructing a short-circuit parameter calculation frame, and executing preliminary solution of short-circuit parameters to obtain a preliminary short-circuit parameter result; based on the preliminary short-circuit parameter result, the model parameters are adjusted in real time through a dynamic compensation and multi-objective optimization mechanism to obtain an optimal parameter set; based on the optimal parameter set, solving the short-circuit parameters by adopting an iterative algorithm, judging whether the calculation result is converged by combining multi-dimensional error evaluation, and outputting the final short-circuit parameters according to the convergence judgment result. The optimal scheme of the short-circuit parameter calculation method considering the influence of the power electronic equipment comprises that the preprocessed multidimensional operation data comprises standardized processing of the multidimensional operation data, and outliers and high-frequency noise are eliminated by combining median filtering and wavelet transformation. The invention relates to a method for calculating short-circuit parameters considering the influence of power electronic equipment, which comprises the following steps: based on the preprocessed multidimensional operation data, combining a power system topological structure and power electronic equipment parameters to construct a layered model framework, wherein the layered model framework comprises an electrical characteristic layer, a control characteristic layer and a fault characteristic layer; based on the hierarchical modular structure design, a system state vector model is established by integrating node voltage, branch current, power and equipment control parameters; Based on the real-time running state and control parameters contained in the system state vector model, combining the main loop characteristics and a control response mechanism to construct an equivalent model of the power electronic equipment; Integrating the system state vector model and the power electronic equipment equivalent model into a layering model framework to obtain a layering system calculation model. The invention relates to a method for calculating short-circuit parameters considering the influence of power electronic equipment, which comprises the following steps: Based on the preprocessed multidimensional operation data and the layering system calculation model, an initial voltage vector, a system impedance matrix and power electronic equipment control parameter