The Power industry was in demand of a universal global communication standard to enable interoperability and integration between different manufacturers and types of IED, for substation Automation. International Electro-technical Commission (IEC) has developed a global communication standard IEC 61850 to facilitate substation automation. This paper discusses the protocol structure of IEC61850 and researches on the GOOSE messages for interlocking, Ethernet topologies with IEC62850 and SCL. It also elaborates the challenges of migration to IEC61850. Migration to IEC61850 for old substations is a complex and time consuming process, effort has been given to outline a step by step process to introduce IEC61850 into a substation.