The digital substation also called the complete smart grid is the fourth and last step toward the automation solution. In this step, the digitalization starts from the primary level with the replacement of convention CT instruments with optical and flexible CTs and VT instruments with Capacitive Voltage Electronic Transformer. This provides the solution for reduced material cost, increased reliability and operation of primary assets, and retiring skill force. The hardcore copper wiring is replaced by a transmission bus that is IEC-61850 compliant, which increase the Interoperability of devices and workforce safety the advantages we get from digital substations are