Damping inter-area oscillation in power system by using global control signals based on PSS devices

Abstract

In this paper presents a online technique to determine the most effective signals for damping inter-area oscillation in power systems. For implementing the proposed method in real time envirinement, various inter-area scenarios are analyzed from which the best global control signals are proposed as input to controllers. It is shown that the local control signals (LCS) which are commonly used to PSSs for damping local oscillations are not able to damp the inter-area oscillations. It is proposed that for an unstable inter-area scenario the global control signal (GCS) provided based on the concept of center of inertia (COI) of oscillating areas is able to damp inter-area oscillation. The proposed GCS can be categorized into two states as 1-global area signals and 2- global inter-area signals. Also, it is shown that depending on the pattern of the oscillating areas the proper combination of both types of global signals could be able for damping inter-area oscillations. The simulation studies on IEEE 39-bus test system show the effectiveness of the proposed signals for damping inter-area oscillations.