Reasearch On The Effect Of PMU Data Quality On Power System Dynamic Monitoring And Line Parameter Identification

The measurement data of PMU is synchronous and high speed uploaded,which provides the conditions for the dynamic security monitoring of power system.In recent years,PMU has a rapid development in the global scope.The domestic and foreign scholars have conducted extensive research on the power system dynamic monitoring and line parameter identification based on PMU.With the improvement of related monitoring and application algorithms,the PMU phasor measurement accuracy has become the key to the related monitoring and application accuracy.In this paper,the influence of PMU phasor measurement accuracy on the power system dynamic measurement and line parameter identification is studied.In this thesis,the cause of phasor measurement errors under static and dynamic condition of PMU is analyzed.It is revealed that the spectrum leakage will be caused by the frequency offset of the input signal under the static condition and the average effect of DFT will occur under the dynamic condition,resulting in measurement errors.As to the problem of monitoring the sub-synchronous harmonic,based on PMU data,and its accuracy,the recorded field data is analyzed to find harmonic characteristics.Then compare the analysis result of the recorded wave data with phase data,and verify the corresponding relationship between the phase oscillation frequency and the harmonic frequency.The influence of the phasor and frequency uncertainty on reducing accuracy is analyzed,and the relationship between amplitude of phase error,phase angle error,frequency error and harmonic reduction accuracy is pointed out.Directing to the problem of inaccurate identification of line parameters,the influence of of amplitude and phase error of PMU voltage and current phase on the transmission line parameter identification accuracy is analyzed.The identification accuracy of resistance is mainly affected by the voltage amplitude;the identification accuracy of reactance is mainly affected by the voltage angle.The relationship between the identification accuracy and the error is linear.By analyzing the decoupling relationship of the influence of errors on the identicication accuracy,it is pointed out that the relative error of the resistance and reactance is equal to the algebraic sum of each part.