Load Frequency Control of Networked Power Systems with Asynchronous Sampled-data Communication and Missing Control Inputs

This paper studies the problem of designing the load frequency control (LFC) scheme for the inter-connected multi-area power systems (MAPSs) with asynchronous sampled-data coomunication and missing control inputs. Due to the effect of asynchronous sampled-data communication and missing control inputs, the MAPS is modeled as sampled-data switched systems. By using the modeling transformation technique, MAPS is further represented as a time-delay switched system with multiple time delays. Combined with average dwell time technique and time-delay systems analysis approach, a series of conditions are obtained for MAPS to maintain grid frequencies and tie line power exchanges with neighborhood areas at scheduled values. Moreover, the relation between the stability and the control inputs missing rate is established and the upper bound of the allowable control inputs missing rate is found. Based on those obtained condition, a useful algorithm is proposed to solve the controller gain for the area control error based sampled-data LFC. The designed LFC scheme not only can guarantee the stability of the MAPS but also can reject the effect of load disturbance. The applicability of the proposed design method is validated by a numerical example with inter-connected three-area power systems.