Research On Quantitative Indicators Of Frequency Dynamic Temporal And Spatial Distribution Characteristics In Large-scale Power Grids

The nationwide grid scale is becoming continuously larger owing to the regional characteristics of interconnected power systems.When large disturbances occur in interconnected power systems,the power flow will change,which will cause the frequency fluctuation.Nowadays,frequency stability has become the most important issue in power system analysis.For large-scale power grids,the research on the spatial and temporal distribution characteristics of frequency dynamic has been emphasized and valued,in recent years,a series of results have been achieved,but the traditional research methods are based on the time domain simulation model.The analysis method of frequency data by PMU to study the spatial and temporal characteristics of frequency dynamic has not been widely used,in view of the fact that acquisition of massive data can understand more valuable information in detail and reflect the actual operation state of the power grids,this thesis mainly conducts quantitative study of the spatial and temporal distribution characteristics of frequency dynamic by analysising data and puts forward two quantitative indicators.This thesis firstly explaines the relevant concepts and analysis methods of frequency dynamic and the spatial and temporal characteristics,then presents several quantitative indicators reflecting the spatial and temporal distribution characteristics of frequency dynamic.Finally,two commonly used measures in traditional methods are selected to quantify and analyze the bus frequency of the spatial and temporal distribution characteristics of frequency dynamic at the generator terminals after disturbance in New England 10-machine and 39-node test system.This thesis presents an index reflecting the characteristics of the spatial and temporal distribution characteristics of frequency dynamic.The least mean square time delay estimation method is used to calculate the response time of the bus frequency at each generator terminal after disturbances occur.This method does not need to know the parameters of the input signal,it is a step-by-step process of "adapting to understanding" and estimating the desired statistical characteristics,it can clearly show that the frequency changes at different locations have timedelay characteristics after large disturbances occur in the power system.When power disturbances occur in the power systems,the energy carried by the rotor can not be instantaneously spread throughout the whole network because of the inertia and density of each position,so the frequency will present a dynamic change process in space.This thesis combines pearson linear correlation in statistics with the M-P theorem in the theory of random matrix spectrum analysis,calculates and compares the maximum eigenvalue of M-P theorem with the maximum eigenvalue of the spatial observation correlation matrix of the bus frequency at each generator terminal after disturbance,Finally,the index of measuring the spatial and temporal characteristics of frequency dynamic is defined.It can reflect the correlation between the dynamic frequency data and the type of disturbance,the location of disturbance and season.