Transmission Line Loadability Increase through Series Compensation

This paper deals with the loadability of seriescompensated lines. Aim of the paper is to provide loadability curves calculated considering various technical limits, namely the thermal limit, the voltage drop limit, the Joule losses limit, and the steady-state stability limit. These curves are evaluated with respect to single circuit 400-kV overhead transmission lines (OHLs) equipped with standard triple-core aluminium conductor steel-reinforced (ACSR) conductor bundles of 3×585 mm2 cross section. The paper describes the optimization procedure used to maximize the active power transported at the receiving-end of the line. The optimal level of series compensation is obtained as a result of the optimization problem constrained by all the technical limits listed above. The last part of the paper is devoted to an extensive numerical application that has the aim of demonstrating the feasibility and applicability of the proposed approach. This study highlights the loadability increase that can be obtained through series capacitors, and might support the decision-making for the investments required by series compensation.