Synchronous Generator Parameter Identification Based On PMU Small Disturbance Data

With the completion of construction in the interconnection projects between the large power grids in China,the real-time dynamic monitoring of the large-area grid operation had become a problem that must be considered to ensure the safe and stable operation of the grid.The emergence of Global Positioning System(GPS)and the rapid development of the computer communication technology provide great convenience and guarantee for real-time monitoring of the operation status of the whole power grid.PMU has provided a key measurement procedure for the safe and stable operation of the power system.That is to say,the real-time monitoring of the generator power angle and the bus voltage phasor in the wide area of the power system,in order to observe the real operating state of the entire power grid.PMU also provides an accurate parameter basis for safety monitoring and rational dispatching of generator sets in power systems,normal and abnormal state monitoring of power grids,and dynamic process control.This thesis focuses on the topic of synchronous generator identification.Firstly,the basic voltage equation and the fundamental flux equation of the synchronous generator are introduced.Based on them,the several practical models of synchronous generators in practical engineering applications are listed in this thesis.In view of the high accuracy of the sixth-order model of the synchronous generator,it is decided to use the sixth-order practical model as the identification model of the synchronous generator in the parameter identification.The model is identifiable before the identification so as to verify whether the model can be well effectively identified.Then the frequently-used numerical analysis method for solving the higher-order differential equations of the generator is introduced.The improved Euler method to solve the differential equation with fourth-order accuracy is selected in this paper.And the reference basis for judging the parameter identification results in the process of optimizing the parameters is given.Finally,the basic principle of synchronous parameter identification and the basic flow of parameter identification are briefly described.With MATLAB as the tool the simulation platform was built.The excitation voltage disturbance was simulated by Simulink to simulate the behavior of synchronous generator under various disturbances.The synchronous parameter identification scheme based on improved genetic algorithm was used to identify the simulation results.The identification scheme was feasible based on the parameter identification results.And under the built simulation platform,the traditional parameter identification scheme and the parameter identification scheme based on improved genetic algorithm are used to identify the parameters.Then the results of the two parameter identification schemes are analyzed,and the similarities and differences of different schemes are obtained.The PMU data and its processing are briefly introduced.The parameter identification scheme based on the improved genetic algorithm is analyzed by measured data to analyze its feasibility,stability and the accuracy.The similarities and differences between the traditional parameter identification scheme and the improved genetic algorithm scheme which based on parameter identification are compared in the measured examples.Then the calculation results of two schemes are compared and analyzed.The objective function of the parameter identification which based on the improved genetic algorithm is smaller.The conclusion of an experiment that the behavior of the synchronous generator is closer to the actual operating is gotten at last.