Vulnerability Analysis and Protective Measures for the Design of a Secure, Resilient and Cost-Effective Smart Grid System

Important features of smart grids are identified as efficient transmission of electricity and monitoring data, speedier recovery from disrupted power supplies, decreased operation and management costs, improved security, etc. All these can be made possible by a well-planned advanced communication system for the grid. However, most of the existing research not only fail to provide a clear understanding of the intra-and-inter dependencies of joint power-communication systems, necessary for a reliable and resilient operation of the grid, but also debates on the best suited design for the communication network. This dissertation introduces a simple, yet accurate multi-valued-logic based model of interdependency called the Modified Implicative Interdependency Model (MIIM) which can depict the interactions between the components of these power-communication systems and using this model an existing problem in the grid concerning cascading failure of entities is solved. Communication system for smart grid is responsible for securely sending both power transmission control data and environmental monitoring data to Control Centers. In this dissertation, a hybrid communication network, comprising of both wired and wireless communication is proposed together with a secure routing protocol to mitigate different types of cyber-attacks. Also, to prevent false data injections and owing to some limitations in MIIM, a further improvement is made to develop the Multi-State Implicative Interdependency Model which considers the data dependency of communication entities. In this dissertation, the issue of communication cost incurred due to ill-designed topology is also addressed, and an optimal-cost communication topology is planned for modern smart grids. It is also identified that communication cost analysis cannot be done without considering the optimal placement of Phasor Measurement Unit (PMU). Consequently, the optimal PMU placement problem is studied simultaneously with the minimum cost network design problem, and an attempt to minimize the overall cost is made in this dissertation. All the designs and network algorithms proposed here, are tested on substation location data of Arizona.