This paper proposes an effective control mechanism including decentralized event-triggered conditions with a coincident control signal updating strategy, which dramatically reduces massive amount of data transmission and remarkably saves network bandwidth. Meanwhile, an asymmetric Lyapunov–Krasovskii functional (LKF) with relaxed conditions is proposed to investigate the robust performance of load frequency control (LFC) in power system. The development is capable of dealing with the frequency fluctuation of power system by utilizing LKF stability theory and stochastic analysis techniques under non-ideal communication network, such as unexpected loads, network delays and random deception attacks. Furthermore, the well-designed examples are presented to assess the effectiveness of this control strategy with quantitative analyses on: (i) implementation of control designing; (ii) comparison of communication efficiency using different trigger mechanisms; and (iii) evaluation of H∞ performance under different attack probabilities and delay upper bounds.