Faced with time delay induced by signal transmission in modern power systems

an improved robust delay-dependent stability criterion is proposed for power systems with multiple time delays and uncertain parameters

where the multiple time delay coupling and uncertain parameters in the actual power system are taken into account. It is noted that the Wirtinger integral inequality used and some slack terms introduced will reduce the conservatism of the result

and these uncertain parameters can be handled by adopting some necessary slack terms and Schur complement. Finally

a typical second-order time-delay system

a single-machine infinite-bus system and the WSCC 3-generator 9-bus are provided to verify the effectiveness of the criterion obtained by using the linear matrix inequality(LMI)control toolbox. And the robust time-delay margin of the power system can be obtained. Simulation results show that the obtained criterion can be applied for robust stability analysis for power systems with multiple time delays and uncertain parameters

and the conservatism could also be greatly reduced. This work is supported by National Natural Science Foundation of China(No. 61673161)

Jiangsu Provincial Natural Science Foundation of China(No. BK20161510)

and Program of Introducing Talents of Discipline to Universities(“111” Program)(No. B14022).