Research On Influence Of PMU Phase Angle Difference Error On Line Parameters Identification And Correctlion

As the eye of power system dynamic monitoring,PMU/WAMS plays an important role in enhancing the resilience,security and self-healing of power system.However,many factors,especially when synchronization device is jammed or satellite signal is spoofed,the synchronization accuracy of applications based on the two-terminal PMU will be reduced,resulting in bias errors in phase difference measurement of PMU data,which seriously affect the line parameters identification or other applications.Therefore,it has great practical significance to study the influence mechanism of PMU phase angle difference errors on line parameters identification and the correction methods with different attacks.(1)The approximate sensitivity expressions are derived,which reveals the influence of phase angle difference errors on the identification of line parameters.Then the effects of different active powers on reactance and resistance are analyzed based on the DC flow equation.And the identifiable condition of line reactance parameters are preliminarily given combined with the simplified equation.(2)The phase angle difference deviation at both line ends may be approximately constant when satellite signal is affected by spoofing attacks,e.g.In this case,a method for correcting the phase difference is proposed,which is independent of the line parameters.The least square method is used to estimate the deviation with the PMU data at both line ends in two different power flow conditions.The results with simulation and measured PMU data verify the effectiveness and the engineering practicalities of the method.(3)The characteristics for phase angle difference deviation at both line ends with different attacks are analyzed according to the receiving process of satellite signal.A method for correcting the phase difference is proposed when the deviation is time-varying,which is independent of the line parameters.The deviation can be estimated using the least square method and the steady-state PMU data at both line ends in different power flow conditions.Then the hypothesis test method and correlation coefficient are used to detect the deviations with different characteristics based on the estimated results at different times,and the phase difference is finally corrected.The validity and reliability of the algorithm are verified by simulation results.