Research On Dynamic Load Modeling And Parameter Identification Of Power Electronic Power System

Power system load modeling is a key technology widely studied in the fields of power system analysis,planning,control,and operation and monitoring.The ability to accurately reflect the external characteristics of the load is very important for power system simulation and safe and stable operation.In the past,after a lot of research on power load modeling at home and abroad,there have been very rich load model structures,and there are also classic models that have been put into use on a large scale.However,in recent years,the scale of use of renewable energy power generation,high-voltage direct current transmission and electrified loads has continued to expand,and the power system is undergoing extensive and profound changes,and it shows multi-time scale dynamic characteristics.System stability and security problems caused by unknown mechanisms have emerged one after another at home and abroad,which has posed a serious threat to the operation of the system.The current load models can not describe the load external characteristics well to some extent.Facing the arduous challenge under the new situation of power electronic power system,this paper focuses on the study of the dynamic load of the power electronic power system under the mesoscale disturbance.Equivalent mechanism model.The main research contents of the thesis are as follows:1.Establish a correct mathematical model of power electronic dynamic load.Considering the power electronic device and its control system,the whole is used as a power electronic interface into the traditional dynamic load model,and the equivalent mechanism model of the power electronic dynamic load is obtained.After a lot of analysis to determine the topological structure of the model,solve the problem of strong coupling and nonlinearity of the equation,and eliminate the intermediate variables while ignoring certain losses,and integrate the voltage and frequency as the input,and the active and reactive power as the output.The dynamic model in the form of transfer function is built on the simulation platform and the physical model corresponding to the topology is built,and the disturbance settings are performed three times respectively.The dynamic response of the two outputs is compared,and the correctness of the established dynamic model is verified.2.Perform sensitivity analysis on the established model parameters.After considering the load power electronics,the established model parameters also increase,which not only brings inconvenience to parameter identification,but also increases the complexity in terms of practicability.Based on this,the trajectory sensitivity theory and the control variable method are used to analyze each parameter in the model in turn,and the parameters to be identified are determined according to the results and actual conditions,which greatly reduces the complexity of the model and lays a foundation for the next step of research.basis.3.Identify key parameters based on particle swarm algorithm.First obtain the data through experiments and preprocess the data,calculate the parameters with low sensitivity using classical values,then use the particle swarm algorithm to identify the parameters with higher sensitivity,and fit the experimental curve to the identification curve.The results show that the two The high degree of fit of the author once again proves the validity of the model established in this paper,and at the same time has a certain practicality.