Fast estimation of dynamic variations in voltage and current phasor for power system application

Abstract

Bus voltage and current phasors in a power system network undergo dynamic variations under system disturbances and faults. With the advent of synchrophasors, it is possible to measure these phasors within a cycle. However, fast prediction of rate of change of these phasors and acceleration of changes will find direct applications in system protection and stability prediction. This work has proposed the use of a subspace based technique based on second order Taylor series approximated Total Least Square Estimation of Signal Parameters via Rotational Invariance Techniques (TLS-ESPRIT) to estimate fundamental phasors, which also give the derivative and double derivative of the phasors in complex domain. The accuracy of the estimated first and second order derivative terms of the amplitude and the phase is tested by computing the amplitude and phase at an accelerated time step of 0.01 sec using the derivative and double derivative obtained in the current cycle in the presence of noise. The validity of the proposed method is further tested for voltage and current signals obtained from New England 39 bus system.