Research On Optimal Tuning Of Power System Stabilizer To Improve Power System Oscillation

With the growth of interconnected power system, problems related to low frequency oscillation have been widely reported, including major incidents. Interactions between the generators of different areas and their regulators require a global optimization of their performances. The small signal stability improvement, in particular the damping of oscillations, has become, therefore, a priority.As the most cost effective damping controller, power system stabilizer (PSS) has been widely used to suppress the low frequency oscillation and enhance the system dynamic stability. The problem of power system stabilizer parameter tuning is a complex exercise due to the presence of several poorly damped oscillations modes. Among many PSS tuning methods, the problems of ensuring a good performance over a wide range of operating conditions, and the optimal PSS location are sometimes not considered.The main objective of this paper is to ensure a maximum damping of the inter-area modes as well as of the local modes by optimal parameters tuning and placement of power system stabilizer (PSS) using particle swarm optimization (PSO) and participation factor method. In this approach, Matlab and DIgSILENT are employed and linked together in a specific automatic data exchange procedure. The test system and the controllers are modeled in DIgSILENT where the generators participation factors are computed, and a hybrid PSO algorithm is implemented in Matlab. For evaluating the particles performance throughout the searching process, an eigenvalue-based multi-objective function using relative and absolute stability parameters which are obtained from the system eigenvalue analysis is used. The proposed method allows an optimal tuning of PSS with the best placement. The performance of this optimization method has been evaluated on the four machines two area power system, via linear modal eigenvalue analysis, and non-linear time domain simulations.