Damping enhancement by robust tuning of SVC controllers in the presence of load parameters uncertainty

The paper explores the influence of power system loads on static VAr compensator (SVC) damping effectiveness. Equipped with properly tuned additional stabilizers, SVCs have been successfully used for improving the damping of electromechanical oscillations in power systems. The damping improvement is usually achieved through indirect voltage influence through voltage dependent loads. Tuning of an additional compensator stabiliser (ACS) traditionally assumes that loads are statically voltage dependent. However, load parameters are generally uncertain and loads often exhibit same dynamic response. This uncertain dynamic behaviour of loads can introduce an additional phase shift between voltage and load response and such can detune the ACS. Examples of detuning effects of dynamic loads as well as robust tuning of ACS are presented and discussed.