Study On Disturbance Identification And Propagation Based On Synchrophasor Measurements

With the development of grid interconnection,the disturbance propagation is more and more able to be presented as electromechanical wave propagation process.The propagation velocity of wave process is much less than that of information transmission.This provides a novel viewpoint to analysis the disturbance propagation process and creates condition for the disturbance propagation suppression.In the dissertation,the advantages of synchronous phase measurement that dynamic tracking ability are used,based on the modeling and disturbance identification of electromechanical wave,the disturbance propagation process and influence of the power system are predicted.It lays data base for the development of targeted control strategy.The main work and innovations are listed as follows:Electromechanical wave frame structure model suitable for disturbance transfer analysis is put forward.The influence of the line parameter and grid structure on the disturbance propagation is analyzed.The frame structure is used to analyze the disturbance dynamic process is established.The unbalanced power and generator angle are set as the state parameters of the transfer function.The influence of the line reactance on the inertia distribution is taken into account.The distribution method of inertia in the frame structure is proposed.This model can accurately analyze the electromechanical wave propagation process in power system.It lays a theoretical foundation for analyzing and predicting the disturbance propagation.The disturbance identification method based on the synchrophasor measurements is proposed.The power distribution characteristics of the generator bus after the disturbance occurs is analyzed.And the disturbance identification method with the generator as boundary is proposed.The localization function based on the current change is defined.Without affecting the disturbance location accuracy.the amount of calculation in the location process is reduced.In addition,the unbalanced current nonzero node quantity and distribution in unobservable region is analyzed.Then.the disturbance location method under the unobservable circumstance is proposed.The proposed disturbance identification method can provide disturbance information for prediction of disturbance propagation and Implementation of control strategy.The analysis method of disturbance energy size is proposed based on free energy theory.The Gibbs function in thermodynamics is used to analyze the disturbance energy assessment process.The expression form of free energy is defined.Further,the energy distribution characteristics of various types of disturbances in the power system are analyzed.The energy variation in the process from the initial state to the equilibrium state is deduced and analyzed.The concept of free energy is introduced into the power system.The free energy function of the power system quantifies the strength of the energy shocks generated by various disturbances to the power system,and provides more perfect disturbance information for the establishment of targeted control.The prediction method of disturbance energy attenuation is proposed.The influencing factors of disturbance energy change process and propagation path are deduced and analyzed.The disturbance energy function of generator bus is defined.The influences of factors such as line reactance,disturbance frequency,propagation speed and generator inertia on the disturbance energy change process are analyzed.The disturbance energy attenuation degree coefficient is proposed.The proposed method provides a theoretical basis for the analysis of the disturbance energy attenuation process and the development of targeted control measures.