Abstract
This paper proposes a robust approach to accurately estimate parameters for compensated lines in the presence of low-frequency oscillation (LFO) that arises in measurements during a fault close to the series capacitor. The estimation uses measurements available from phasor measurement units (PMUs) and considers both cases of transposed and untransposed lines. The robustness toward measurement errors or departures from the fundamental frequency model due to LFO present in PMU signals is introduced by exploiting the least trimmed square (LTS) estimator. The least trimmed squares is a highly robust estimator that treats the bad effects of outliers. Mutual line parameters between the phases are calculated as well. Simulations were performed with the included sensor errors, and the results show the superiority of the LTS-based estimation compared to the classical estimation using the weighted least squares. The performance of the proposed approach was also assessed with a real-time digital simulator.