State feedback control of power system oscillations

Abstract

Damping of electromechanical oscillations in power systems is one of the major concerns in the operation of power system since many years. The oscillations may be local to a single generator or generator plant (local oscillations), or they may involve a number of generators widely separated geographically (inter-area oscillations). These oscillations causes improper of the power system incorporating losses. Local oscillations often occur when a fast exciter is used on the generator, and to stabilize these oscillations, Power System Stabilizers (PSS) were
developed. Inter-area oscillations may appear as the systems loading is increased across the weak
transmission links in the system which characterize these oscillations. If not controlled, these oscillations may lead to total or partial power interruption. Electricité de France developed two state feedback controllers aiming to effectively damp electromechanical oscillations present in
power systems. These are Desensitized Four Loop Regulator (DFLR) and Extended Desensitized Four Loop Regulator (EDFLR). The DFLR is designed to damp local lectromechanical
oscillations while the EDFLR aims at damping both local and inter-area oscillations. The dynamics of the DFLR and EDLFR are needed to be studies in order to model them. These
models are to be incorporated with the generator models to get a power system model with state feedback control. On simulating the system in Simulink with the controllers we will get the power system model with state feedback control and we can observe how these controllers are helpful in damping the oscillations.