Dynamic phasor-driven digital distance relays protection

Abstract

This paper describes an in-depth signal processing analysis of the second-order Taylor-Kalman-Fourier (T2KF) filter as input signal to a phase comparator in digital distance relay. Tripping condition corresponds a successful phase comparison between operating signal and polarization signal (the angle among signals is inside angular limits, typically ± 90∘), this is equivalent to the fact that the measured impedance is less than the relay setting. The analysis is performed by regarding a phase comparison stage fed by phasors provided with the T2KF. In this paper, the proposed filter improves the relays steady-state and transient responses, in comparison with the well-known Fourier and Cosine filter, since the T2KF filter avoids fluctuations that may lead to overreach and underreach problems. The results are carried out in order to assess the proposed application.