A robust method for transmission line sequence parameter estimation using synchronized phasor measurements

• Published in: Electric power systems research Vol. 223; p. 109616
• Main Authors: Goklani, Hemantkumar, Gajjar, Gopal, Soman, S.A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2023
• Subjects: Line parameter estimation; Percentage unbalance; Phasor measurement units (PMUs); Line parameter estimation; Phasor measurement units (PMUs); Percentage unbalance
• ISSN: 0378-7796; 1873-2046
• DOI: 10.1016/j.epsr.2023.109616

We present a positive and zero sequence line parameter estimation method, that is robust to systematic errors in the instrument transformers, especially when they are within the specified tolerance as per standards. Using Monte Carlo simulations, it is shown that the proposed approach is robust and accurate for all operating conditions, specifically for short length and lightly loaded transmission lines. We also validate the proposed approach on 400 kV and 765 kV transmission lines using actual field phasor measurement unit (PMU) data. Further, estimation of zero sequence line parameter values is somewhat tricky because not enough unbalance exists during the normal operation of the power grid. Therefore, we quantify the minimum percentage unbalance needed in currents to determine zero sequence line parameter values within 1% tolerance. We also present the line length and line loading effects in estimating zero sequence line parameter values using simulations. Simulation and field PMU data results on 765 kV and 400 kV lines of different lengths and loading levels show that the proposed method estimates accurate positive and zero sequence line parameter values. •A robust method of positive and zero sequence line parameter estimation that works for a wide range of operating conditions is proposed.•Estimation of zero sequence line parameters is tricky because not enough unbalance exists during the normal operation of the power grid.•Therefore, the minimum percentage unbalance needed in currents for the determination of zero sequence line impedance values within 1% error is quantified empirically.