###### Abstract  
In control systems of power grids, conveying observations to controllers and obtaining control outputs depend greatly on communication and computation resources. Particularly for large-scale systems, the costs of computation and communication (cyber costs) should not be neglected. This paper proposes a self-triggered frequency control system for a power grid to reduce communication costs. An equation for obtaining the triggering time is derived, and an approximation method is proposed to reduce the computation cost of triggering time. In addition, the communication cost of frequency triggering is measured quantitatively and proportionally. The defined cost function considers both physical cost (electricity transmission cost) and communication cost (control signal transmission cost). The upper bound of cost is estimated. According to the estimated upper bound of cost, parameters of the controller are investigated by using the proposed optimization algorithm to guarantee the high performance of the system. Finally, the proposed self-triggered power system is simulated to verify its efficiency and effectiveness. f 1 20  
Since more and more systems have become increasingly networked, wireless, and spatially distributed, event-based systems are proposed to adopt a model of calls for resources only if necessary, and to utilize communication bandwidth, computation capability, and energy budget efficiently [9; 10; 11; 12]. The proposed control-based model allowed each control task to trigger itself to achieve the optimization of computing resources and control performance. The execution time of next instance was scheduled by the executing instance. As a function of the utilization factor and control performance, the next instance execution point was dynamically obtained in time [13; 14; 15; 16; 17]. The dynamic selection of an appropriate threshold was investigated for basic send-on-delta (SoD) sampling strategies. The error reduction principle was formulated and proved to reduce the signal tracking-error in an available transmission rate [18; 19]. A new event-based control strategy was proposed and applied to differential wheeled robots. Compared with the classical discrete-time strategy, the proposed event-based control strategy not only reached the same accuracy, but also obtained a higher efficiency in communication resource usage [20; 21; 22; 23]. In power system frequency regulation research, [PERSON] [24] used linear matrix inequalities (LMI) with parameters tuned by particle swarm optimization (PSO). [PERSON] [25] analyzed the dynamic participation of doubly-fed induction generators and coordinated control for frequency regulation of an interconnected two-area power system in a restructured competitive electricity market. [PERSON] [26] presented a study on frequency regulation in an isolated hybrid distributed generation (DG) system with the robust H-infinite loop shaping controller. Although much frequency regulation research has been done in order to achieve better physical performances, cyber costs also need to be taken into account. Considering both physical performance and the cyber cost of power system, event-driven schemes are usually used. [PERSON] [27] proposed a methodology for real-time prediction that required event-driven load shedding (ELS) against severe contingency events. [PERSON] [28] presented a novel emergency damping control (EDC) to suppress inter-area oscillations occurring as anticipated low-probability cases in power system operations. The proposed EDC combined an event-driven scheme and a response-based control strategy. [PERSON] [29] elaborated a new approach based on parallel-differential evolution (P-DE) to efficiently and globally optimize ELS against voltage collapse. However, continuously monitoring plants using event-driven schemes takes many cyber resources. In contrast with the EDC approach, STC does not generally require dedicated hardware to continuously monitor the plant state and check the defined stability conditions [30; 31; 32; 33].