Secure And Reliable Communication Infrastructures Towards The Smart Grid

LU, XIANG. Secure and Reliable Communication Infrastructures towards the Smart Grid.(Under the direction of Professor Jianfeng Ma and Professor Wenye Wang.)The smart grid is an emerging technology representing a brand-new paradigm of power management. It incorporates power infrastructures with information technologies to enable ubiquitous interconnections of power devices towards two-way flows of electric-ity and information. With the bidirectional information and energy flows, a variety of management, automation applications are envisioned to offer the smart grid significant advantages over the current power system in terms of efficiency, flexibility, intelligence, resilience, and sustainability. However, the exciting prospect of the future energy manage-ment paradigm imposes many technical challenges on the communication infrastructure of the smart grid. Especially, as a typical cyber-physical system, the quality of communica-tion services directly determines the power quality supplied to customers, the movement of the electricity price, the operations of power devices, even the maintenance of entire system states, which is subject to many factors such as the heterogeneity of information technologies, the diversity of communication requirements, the vulnerability to malicious attacks. and the failures of communication devices.We intend to acquire a comprehensive understanding of the communication infras-tructure in the smart grid regarding the system performance, security and reliability, which will help us utilize information services more effectively and efficiently in response to diversified requirements of intelligent energy managements. To this end, we firstly identify the primary feature of communication traffics in the smart grid, that is, all infor-mation flows are composed of mission-critical messages with rigorous, yet different timing requirements. Surrounding this issue, we take a smart grid demonstration project, the Future Renewable Electric Energy Delivery and Management (FREEDM) systems, as an example to employ an empirical study to investigate four fundamental aspects of power system communications, namely, the communication requirements, the performance of the communication infrastructure, the performance affects of security functions, and the system resilience to the device failure. The study on the first three perspectives attempts to acquire hands-on system implementation experiences and find appropriate protocols and schemes for specified intelligent, automation applications, whereas the study on the last perspective aims to evaluate impacts of failures on the network structure and system reliability.Specifically, we make the following contributions towards a secure and reliable com- munication infrastructure in the smart grid. Firstly, we have designed and implemented a real-setting communication prototype to interconnect power devices using the state-of-the-art wired and wireless communication technologies. Secondly, we acquired first-hand performance results and valuable insights regarding the applicability of the predominant communication protocol for smart grid applications. Thirdly, we have investigated per-formance affects of prestigious security functions on time-critical control messages, and highlighted the guidelines and principles in design of novel security schemes. Last, we have demonstrated potential iterative cascading failures between the coupled, yet interdepen-dent communication and power networks of the smart grid, and qualitatively suggested strategies to mitigate the catastrophic system behaviors. The work in this dissertation presents hands-on experiences and basic performance understanding of the communica-tion infrastructure in the smart grid, which will benefit us to enhance the intelligent management of the power system.