Design of a self-tuning power system stabilizer for multi-machine power system

It is well-known that the existing power system stabilizers (PSS) cannot properly deal with composite mode oscillations of machines. Because it is difficult to design the PSS which can be effective for both local and inter-area modes. In this paper, a self-tuning power system stabilizer using speed and active power input signals without a lead-lag network is proposed for damping multi-modal oscillations in a power system. The dominant frequency is identified by introducing a lowpass filter and a highpass filter. Based on the value of the dominant frequency, the optimal gains for both speed and active power signals are obtained. The proposed PSS is implemented on a digital computer. Fourth order Chebyshev filters have been used. The proposed PSS has been tested on multi-machine systems for various disturbances and found to provide good damping under any disturbance with arbitrary initial condition