Research On Self-tuning Algorithm Of PSS

With the development of the large-scale power system, low-frequency oscillation is becoming a serious threat to the power system security. Power system stabilizers (PSS) have been proved the most effective method to damp the low-frequency oscillation. The parameters of power system stabilizers are calculated off-line. In particular, as the power system becomes larger and more complicated, the parameters of PSS become more difficult to adapt the changes of power system conditions.This paper presents a new self-tuning control strategy on PSS to overcome drawbacks. The self-tuning PSS has been designed as a damp control system contains an identifier and a controller. This control system can adapt to the changing operation conditons and different oscillation modes. As a result, the self-tuning PSS provides better damping to the oscillation of the system than the conventional PSS. The self-tuning algorithm includes two parts:the algorithm of online oscillation modes identification based on Prony analysis, and the algorithm of PSS parameters tuning. Low-frequency oscillations identification method is presented after comparing the merits and demerits of two methods, FFT method and Prony method. PSS parameters tuning methods also be reseached based on different frequency and the parameters tuning program is writen. Finally The simulation result of the real power grid validates the effectivity of the presented method.