The effects of the proportion factor of TCSC on SSR and SSO

The proportion factor of TCSC has an effect on damping SSR for AC system and SSO for AC-DC hybrid system when it is in series in a compensated line. High proportion factor of TCSC can increase the equivalent resistance of the system at a certain compensation ratio, which ensures the system has the adequate positive equivalent resistance to avoid the threat of SSR and SSO. After comparison of damping curves in different proportion factors by using the test signal method, it can be proved that high proportion factor has better damping characteristic to eliminate both SSR and SSO. In addition the compensation method of fixed capacitor in series with TCSC is better than only the fixed capacitor compensated. Numerical tests show that the conclusion proposed in this paper is effective and feasible.