A Supervisory Hierarchical Fuzzy logic controller for power system stabilizer

The paper presents a novel design of Supervisory Hierarchical Fuzzy Controller (SHFC) for power system stabilizer to damp the low frequency power system oscillations. The control objective is to enhance the stability and to improve the dynamic response of the Single Machine Infinite Bus (SMIB) system operating in different operating conditions. The Power System Stabilizer (PSS) have the capability of producing appropriate stabilizing signals against a wide range of operating conditions and disturbances. For this purpose, a design of novel supervisory hierarchical fuzzy controller for PSS is proposed. Its control structure consists of an intelligent upper level supervisory fuzzy controller and a lower level direct fuzzy controller. The performances of the proposed method under different operating conditions are tested. It is found that the dynamic performance of proposed method shows improved results over the conventional PSS and direct fuzzy logic controller based PSS in different operating conditions and disturbances.