A new methodology for the analysis and optimal setting of directional polarisation methods for overcurrent elements in line protection applications

Abstract

Abstract Directional protection of transmission lines is an important feature in situations where short‐circuit direction must be correctly detected. The proper operation of this protection is highly dependent on phasor comparison techniques called polarisation methods. In practice, there are not clearly defined procedures to analyse and set polarisation methods. Hence, these methods are not normally studied in detail, so their effectiveness is often uncertain. For this reason, this work proposes a novel methodology for analysing the performance of polarisation methods, which includes criteria for the selection of the most appropriate methods and their settings according to each application. Particular phasor diagrams and angular statistics are used for the analysis, while a mathematical optimization problem is defined to determine the best settings of these methods. Based on the benefits that can be obtained, the methodology is intended to be considered as an effective strategy to ensure proper use of polarization methods. The methodology is applied in a portion of the Ecuadorian Transmission System which shows the possibility of studying the performance of polarisation methods. The selection and optimal setting criteria of these methods are also analysed providing opportunities to improve the initial performance of the protection system.