A Survey on Cyber-Physical Security of Active Distribution Networks in Smart Grids

Distribution systems are evolving from traditional passive networks into, what is known as, Active Distribution Networks (ADNs). Unlike traditional distribution networks, ADNs are characterized by bi-directional power flow, the high penetration of DERs, storage capabilities and sophisticated control strategies. Multiple layers of communications, sensing and computation are being integrated into ADNs for monitoring, control and protection of a variety of components and critical operations. This enhanced dependency on information and communication technologies, however, increases the exposure of ADNs to cyber-attacks. Several papers have been published in recent years with a focus on cyber-physical security (CPS) of smart grids. However, the published survey papers primarily emphasize the transmission level of smart grid threats and challenges, with little focus on the ADNs. Given the rapid deployment of ADNs and the increasing cyber threats against power grids and critical infrastructures, we are motivated, in this article, to present a review and survey focused, instead, on the latest research advancements in the area of CPS for ADNs. This paper represents the first survey of timely research in the area of CPS of ADNs with a focus on ADN critical operations and components. The cyber-physical aspects of each critical operation/component are analyzed. In addition, the challenges and requirements of associated communication protocols and standards are presented. Cybersecurity of ADN devices and sensors including Phasor Measurement Units (PMUs), smart meters, advanced metering infrastructure and protection relays are discussed in detail. Moreover, a thorough study of ADNs application drivers and enablers including microgrids, Electric Vehicles (EVs), Internet-of-Things (IoT) and smart homes is conducted. Potential and existing solutions by industry are highlighted. Finally, survey outcomes and directions for future work are presented to highlight emerging avenues of research.