Robust Power System Stabilizer Design Using Eigenstructure Assignment

This paper presents a design of a power system damping controller using partial right eigenstructure assignment. The eigenstructure assignment technique selects a set of closed-loop eigenvalues along with their right or left eigenvectors. The selection of eigenvectors offers extra flexibility which is exploited in this paper by designing a robust damping controller which provides the required damping under multiple operating conditions. A multi-input controller is used to increase the degrees of freedom available for the design. Remote measurements available from synchronised phasor measurements are also considered. The problem is formulated as a multi-objective nonlinear optimization problem and solved using the nonlinear simplex function in MATLAB. The proposed technique is used to design a robust power system stabilizer for the interconnected New England New York simplified power system model. Four contingencies are selected as additional operating conditions. The designed controller is validated using a nonlinear simulation.

I. Introduction

Electromechanical oscillations are inherent dynamic characteristics of an electrical power system and poor damping of these oscillations is a stability problem which is often encountered in large interconnected power systems. Moreover, poor damping can limit the power transfer capability of tie lines connecting geographically separated areas. Damping controllers such as power system stabilizers (PSSs) are the most common and economical devices that improve damping of electromechanical oscillations. PSSs are feedback controllers which are installed at generators to modulate the voltage reference of automatic voltage regulators. These controllers use locally available signals as their control inputs.