Coordinated design of multiple controllers for suppressing low frequency oscillation considering signal delay and interaction

This paper presents a multi-controller parameters coordinated design method with the signal delay and interaction considered for power system damping control. Firstly, the branch and bound (BAB) method is used to comprehensively compare the controllability and observability index and the interaction indicator, and then screen control loops with large controllability and observability and small interactions so that parameters of each controller can be designed individually. Secondly, independently design parameters of controllers. The local controllers with no signal delay, can be designed through pole placement method. As for the wide-area controllers with signal delays, the parameters are optimized through the genetic algorithm so that the delay margin calculated by delay-dependent stability criterion is maximum. In addition, the impact of the delay value when designing is considered and the phase restriction of residue compensation is relaxed so that this wide-area controller design method can achieve larger delay margin. Finally, the small interactions among controllers and the larger delay margin are verified by a two-area four-machine system.