181 © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 D. D. Chowdhury, NextGen Network Synchronization, https://doi.org/10.1007/978-3-030-71179-5_10 Chapter 10 Synchronization for Smart Grid Infrastructure 10.1 Introduction Over a century, power system went through tremendous changes to provide reliable and steady source of energy. The power system and for that matter power grid is considered a marvel of reliability yet reliability principle puts a limit to continuous 100% uptime. There are various sources that could cause abnormalities in power grid operations. These abnormalities may stem from internal and external causal factors. To keep the power grid reliable and operation 100% of the time, monitoring of power quantities in real time is essential and this requires both integration of new technologies and robust implementation of ICT (Information Communication Technologies) and grid-wide security mechanism to protect it against attacks. Smart grid initiatives take all these context into account while suggesting a time- synchronized architecture for interconnectivity, operations, and control of power grid. Without time synchronization, it would be diffcult to visualize, analyze, and take preventive actions of any anomalies of power Grid. In a workshop arranged by NIST (National Institute of Standard and Technologies), grid operator identifes most challenges yet essential requirements for real-time monitoring of power quan- tities, these include TWFL, use of synchrophasor technologies, WAMS, event tim- ing, and reconstruction to operation and control of digital substations. All these functions require precision time synchronization. This chapter discusses synchroni- zation needs from historical perspective and explores its importance in the operation of modern “next generation” smart grid. Additionally, the chapter specifes end-to- end time synchronization requirements for power system while discussing various power profles that needed to be implemented for optimal operations of power systems.