The performance of distance protection relay on series compensated line under fault conditions

This paper presents the behaviour of the distance protection relays on a series compensated transmission line under fault conditions. Series compensation presents distance protection elements with unorthodox line impedance and as a result the relays may operate incorrectly. Sub-harmonic oscillations and non-linearity of the line impedance are some of the challenges introduced by series compensation of transmission lines. The study is carried out in a Digsilent power factory environment and results pertaining to the response of the distance relay on a 400 kV series compensated line under fault conditions are presented.