Investigation of power system harmonics and SSR phenomena related to thyristor controlled series capacitors

Thyristor controlled equipment is one of the major sources of harmonics in power systems impacting power quality. In this paper the thyristor controlled series capacitor (TCSC) installed by power utilities for increase of power transfer capability of transmission lines is investigated in terms of harmonic distortion in the power system. In addition, series compensation may cause subsynchronous oscillations leading to subsynchronous resonance (SSR) phenomena. The investigation of a TCSC control strategy that ensures sufficient SSR damping is presented.