Impacts of Cyber System on Microgrid Operational Reliability A microgrid is a typical cyberphysical system. The coordinated control of each unit in a microgrid mainly relies on the cyber system. Once performance degradation of the cyber system happens, such as outages or transmission delay, the stable operation of the microgrid will likely be affected. In this paper, an analytical method is presented to quantify the impacts on the microgrid operation reliability from cyber system element failures and transmission interference. First, the link model and the information transmission model of the cyber system are established to describe the cyber routing path and the information transmission service quality, respectively. Then, the Sequential Monte Carlo method is employed to simulate the operation of the microgrid. Finally, the impacts of the element failure and the transmission interference of the cyber system on microgrid operational reliability is quantitatively analyzed. Additionally, sensitivity analysis is carried out, focusing on the impacts of the cyber network topology, element failure rate and different types of information transmission quality indexes including delays, routing error and information transmission error. The results of the numerical examples demonstrate the effectiveness of the proposed model and method.

Control of CommunicationsDependent Cascading Failures in Power Grids The most severe failures in power grids are often characterized as cascading failures where an initial event triggers consequent failures all along the grid often leading to blackouts. Upon identifying a failure and its cascade potential, timely control actions should be performed by the grid operators to mitigate the effect of the cascade. These actions have to be delivered to one or more control devices, creating a dependency between the power grid and its control network. This paper examines the dependency of the operation of the power grid on the control network. Different from literature studies on failure control, our dependency model captures the impact of networking parameters. We formulate an algorithmic model that describes the impact of this dependency on cascade control. Based on this model, we propose an efficient cascade control algorithm using load shedding with consideration of delays in the communication network for power grids. Finally, we evaluate the impact of the powercommunication network dependency with uncontrolled grids, idealsimple control grids and our proposed control scheme. The results demonstrate that the proposed algorithm can significantly reduce the failure of power lines while sustaining larger power demand for users.