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A compact and wideband ultra‐high‐frequency antenna is developed in this work. Based on the Minkowski fractal geometry of the lateral boundaries of monopole and the upper boundary of ground plane, miniaturization is realized. Meanwhile, by optimizing the dimension of the semi‐elliptical part of monopole and the triangular notch of ground plane, the impedance bandwidth is enhanced. To confirm the performance of antenna, a series of experiments are conducted. The size and ratio bandwidth of antenna are compared with existing broadband ones. The proposed antenna with size of 0.3 λL × 0.25 λL covers the frequency ranging from 700 MHz to more than 3 GHz and possesses an average gain of 4.08 dBi.

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The proportion of renewable energy is increasing rapidly to develop low-carbon power systems and the intermittence nature of renewable energy harms the security operation of power systems. The participation of interruptible loads is an effective means to handle the intermittence of renewable energy. However, the capacity value of interruptible loads has not been fully recognized, which results in limited involvement of interruptible loads in power system operations. Hence, it is urgent to analyze the capacity value of interruptible loads. In this paper, a capacity value calculation method of interruptible loads is proposed. A joint optimal operation model of interruptible loads and multiple power sources including thermal power units, hydropower units, and wind turbines is established to realize the application paradigm of power system operations with interruptible loads. Case analysis based on the operation data of the power system in a particular area verifies that the proposed method can effectively recognize the capacity value of interruptible loads and reduce the installed capacity of thermal power units. It thereby lays the theoretical foundation for analyzing the role of interruptible loads in the low-carbon transition of the electric energy industry.

With the wide integration of various distributed communication and control techniques, the cyber-physical microgrids face critical challenges raised by the emerging cyberattacks. This paper proposes a three-stage defensive framework for distributed microgrids against denial of service (DoS) and false data injection (FDI) attacks, including resilient control， communication network reconfiguration, and switching of local control. The resilient control in the first stage is capable of tackling simultaneous DoS and FDI attacks when the connectivity of communication network could be maintained under cyberattacks. The communication network reconfiguration method in the second stage and the subsequent switching of local control in the third stage based on the software-defined network (SDN) layer aim to cope with the network partitions caused by cyberattacks. The proposed defensive framework could effectively mitigate the impacts of a wide range of simultaneous DoS and FDI attacks in microgrids without requiring the specific assumptions of attacks and prompt detections, which would not incorporate additional cyberattack risks. Extensive case studies using a 13-bus microgrid system are conducted to validate the effectiveness of the proposed three-stage defensive framework against the simultaneous DoS and FDI attacks.

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