Estimation of frequency and phasor using enhanced nonlinear least error squares method for synchrophasor application

摘要

Nonlinear least error squares (LES) method reported in the literature, has been used for frequency estimation of power signal having harmonic contents. However, anticipation of achieving high accuracy and increased range of frequency estimate with existing solution technique leads to computational burden on FPGA processor. In this paper, a novel algorithm is proposed to enhance the accuracy of nonlinear LES technique without imposing any computational burden for the requirement of synchrophasor application. This is accomplished by finding the minimum value of squared Euclidian norm of error vector obtained by nonlinear LES method only at the selected frequency intervals. The behavior of algorithm with respect to window length of signal is analyzed through simulation. Also the proposed algorithm is employed for measurement of phasors. The performance of the proposed algorithm is verified and demonstrated for the different tests mentioned in synchrophasor standard IEEE C37.118.1 and its amendment IEEE C37.118.1a-2014. The enhanced nonlinear LES is implemented on NI cRIO 9082 using Xilinx Spartan-6 LX150 FPGA platform for real-time measurement.