A comparative study on LQR and H∞ control for damping oscillations in power system network considering different operating points

This paper presents the comparative study on damping of oscillations in interconnected power system network considering multiple operating points using Linear Quadratic Regulator (LQR) and H_∞ control techniques. The LQR control strategy is designed in such a way that the required states are to be known and H_∞ control strategy is designed by using linear matrix inequality(LMI) approach. The control techniques are implemented for base case operating point and multiple operating points such as line outage, load change. Both controller performances are tested on the New England 39-bus 10-machine system in time domain and frequency domain by using MATLAB/Simulink environment. From the results it is observed that H_∞ control design has shown promising results over the LQR design for different operating points. However, the LQR control design gives good results over the H_∞ control design if the weights are increased to very high values.