Table of Contents Introduction: The Communication Backbone of the Smart Grid Era Overall Architecture of Smart Substation Communication Systems: Protocols and Standards  2.1 Comparison of the Three-Layer Architecture  2.2 Communication Media and Redundancy Design 2.3 Comparison Between Traditional and Smart Substation Architectures Key Communication Links and Data Flows: Real-Time Performance and Big-Data Analytics  3.1 Data Flow Path 3.2 Performance Improvements Power Commun