Power System protection is a combination of Intelligent Electronic Devices, Digital Relays and other sophisticated equipment. It is an interconnected coordination between the smart devices. This paper gives the improved ideology of Substation Automation, which enables how the analog to digital signals are converted via fiber optics and sends the information to the neighboring devices. There are three major requirements for substation automation: Measurement, communication, Hardware and software. The SA is briefly explained by using one of the level i.e bay level process. Goose process also described in this review paper.