Analysis Of Field Phase Angle Data Of PMU At Both Ends Of Transmission Line And Research On Detection Method

Phasor measurement unit(PMU),which could provide high-frequency phasors including the amplitude and phase angle synchronized with Global Positioning System(GPS)/BeiDou Navigation Satellite System(BDS)signal,plays a vital role in dynamic monitoring of power systems.However,bad data often exists in PMU measured data,which makes the data difficult to be applied.Therefore,in view of the problems existing in the measured PMU data of both ends of the line,it is of great engineering significance to analyze the problem data and propose detection methods.(1)Aiming at the phenomenon of continuous jump of phase angle difference in field data,a method of identifying and eliminating bad PMU phase angle difference data based on hyperplane clustering is proposed.Firstly.the hyperplane clustering method is established to cluster the phase angle difference data.Secondly,the virtual reactance parameters calculated by the average voltage are compared with the offline reactance parameters of the control center to realize the selection of data types.Furthermore,the performance of the proposed method and the effectiveness of the method are verified by simulation.Finally,based on the measured data of PMU,the engineering practicability of this method is proved.(2)The influence of the frequency deviation of crystal oscillator(FDCO)on PMU measurement is analyzed and deduced in the steady state of the system,after the GPS/BDS signal is lost.Through the study of the deviation of phase angle difference in the field data,it is judged that the deviation of phase angle difference is related to the time synchronization which depends on the frequency of crystal oscillator after the GPS signal is lost.Then,firstly,the measurement formula of PMU data in steady state is derived.Secondly,the influence characteristics of PMU data are analyzed in detail,and the change characteristics are given.Finally,the simulation data verify the effectiveness of the analysis.(3)The influence of crystal oscillator frequency deviation on PMU measurement under the condition of system oscillation is analyzed and deduced.after the loss of GPS/BDS signal.Firstly,the measurement formula of PMU data under power system oscillation is derived.Secondly,the influence characteristics of PMU data are analyzed in detail,and the change characteristics are given.Furthermore,the effectiveness of the analysis is verified by simulation data under various oscillation conditions.Finally,the explaination of the constant deviation in voltage phase angle difference(VPAD)data of field data is given.(4)Aiming at the problem of phase angle difference caused by frequency deviation of crystal oscillator when GPS/BDS signal is lost,a detection and estimation method for frequency deviation of crystal oscillator based on correlation coefficient and Hough line detection is proposed.Firstly,the characteristics of phase angle difference data under normal condition and the condition that GPS/BDS signal is lost and frequency deviation of crystal oscillator exists are analyzed.Secondly,according to the characteristics of phase angle difference when frequency deviation of crystal oscillator exists,a detection method for frequency deviation of crystal oscillator is proposed based on Hough line detection.Finally,based on the simulation data and the simulation measured data,the applicability of the detection method in various cases is verified.