Improvement of low frequency oscillation damping by allocation and design of power system stabilizers in the multi-machine power system

•This paper presents an approach to the allocation and designs the PSSs.•The proposed approach has succeeded in determining the dominant generator.•Paper proposed a model for designing PSS regarding oscillation modes of the power.

Some of the earliest power system stability problems included spontaneous power system oscillations at low frequencies. These Low-Frequency-Oscillations (LFOs) are related to the small-signal stability of a power system and are harmful to obtain the maximum power transfer. A contemporary solution to this problem is the addition of Power System Stabilizers (PSSs) to the automatic voltage regulators on the generators in the power system. In this paper, allocation of PSSs in an interconnected power system with inter-area modes has been determined by eigenvalue analysis, and PSSs for the allocated generators have been designed by a frequency response method. Furthermore, for designing PSSs by the frequency method, this paper proposed a new linear power system model which can consider both local and inter-area oscillations of the power network. Designed PSSs based on the proposed model improved damping performance of PSSs which have been designed by the Single-Machine-Infinite-Bus (SMIB) model. The stabilization performance of the designed PSSs (by the proposed approach and linear power system model) on the LFO modes have been verified in two multi-machine power system standard models (IEEE 9-bus and 14-bus).