The information and network communication securities are the key ingredients for the stability and reliability in Smart grid system. Focusing on the network security aspect, we explore and outline some of the important requirements identified by the NIST framework and roadmap for Smart Grid interoperability standard. The thesis briefly explains the structure of standards including BACnet, DNP3 and IEC61850. We illustrate use cases and present power substation automation as an example with emphasis on the the security requirement of IEC 62351 and NIST IR 7628. The goal is to provide first-time readers an entry point to the core of guidelines and requirements more easily.