Development of Phasor Estimation Algorithm for P-Class PMU Suitable in Protection Applications

This paper proposes a phasor estimation algorithm for P-class phasor measurement unit suitable in protection applications using Hilbert transform and convolution of a signal. As the protective relay requires extracted fundamental component of the phasor for its operation, the author’s introduced an algorithm to estimate a robust phasor corresponding to the fundamental component which is close to the actual signal in ${L_{2}}$ -norm. Though IEEE C37.118.1a-2014 standard does not specify the accuracy requirements of phasor under transient condition, the performance of phasor estimator is tested under different dynamic conditions as per IEEE C37.118.1a-2014 standard. The effectiveness of proposed algorithm has also been verified on modified two area power system during fault along with the data generated by the experimental setup in laboratory. The results revealed that the proposed algorithm estimates the phasor accurately irrespective of distortion present in the sinusoidal signals. Furthermore, the proposed estimator inherently filters harmonics, immune to decaying dc components, detects sharp changes in a signal during faults, and effectively works under complex modulated conditions. The above scenario appears frequently in a power system with distributed energy sources. The simplicity, robustness, and generality of the proposed algorithm suits for wide area measurement systems to measure the voltage and current phasors during disturbance in the smart power system networks.