A Comperhensive Fuzzy Power System Stabilizer Design with capability of Interaction Elimination

In this paper a method for reducing the interactions among power system stabilizers (PSS) in a multi-machine large scale power system and hence improving the small signal stability is proposed. Dynamic Relative Gain Array (DRGA) matrix is used for identifying input-output pairs that are strongly coupled to decompose a MIMO system to several SISO systems. By using the DRGA, an efficient and simple method for collecting information about how PSSs interact among themselves in different frequencies related to electromechnical modes of the power system is introduced. This information is then employed to design a post processor controller that can eliminate the negative interaction among stabilizers by managing the output signals. In order to increase the flexibility and reduce the sensitivity of the stabilizers toward the system changes, stabilizers and the post processor are designed based on fuzzy logic. The proposed method is evaluated on the two area test system in MATLAB environment. The obtained results show that the post processor, by minimizing the negative interactions among the power system stabilizers, can satisfactorily improve the small signal stability and decrease the sensitivity of these stabilizers regard to variations in operating conditions simultaneously.