This article discusses the characteristics, challenges, and security issues related to smart grids. It also explores the standards and protocols used in smart grids. The article covers the IoT in smart grids, challenges faced by smart grids, and security and privacy issues related to smart grids. It also provides an overview of the mostly used protocols related to smart grids that can be classified according to their usage in different areas such as demand response, substation automation, metering, electric vehicles, distributed generation, enterprise and the control center and the wide area monitoring.