State-variable control of shunt FACTS devices using phasor measurements

Abstract

This paper addresses the problem of state-variable stabilizing control of power system using shunt FACTS devices. This stabilizing control is activated in the transient state of a power system and is supplementary with respect to the main steady-state control of a FACTS device. Stabilizing control laws have been derived for a non-linear multi-machine system model using direct Lyapunov method with the aim to maximize the rate of energy dissipation during power swings and therefore maximization of damping. The proposed control strategy is executed by a non-linear multi-loop controller with rotor angles and speed deviations of synchronous generators used as the input signals. The input signals, obtained from a phasor measurement system, are necessary only from a small area around the controlled shunt FACTS device. Validity of the proposed state-variable control has been confirmed by computer simulation for a small multi-machine test system.