Mission Critical Safety Functions in IEC-61850 based Substation Automation System - A Reliability Review

The use of Substation Communication Networks (SCN) in power distribution centres of thermal power plants for protection, control and monitoring is increasing as industry's confidence grows in the application of the IEC-61850 based Substation Automation Systems (SAS). IEC61508, which is the standard for functional safety, addresses Electrical/Electronic/Programmable Electronic (E/E/PE) safety based technologies in so far as safety lifecycle as well as reliability and verification of safety related systems are concerned. It follows therefore, that Substation Communication Networks (SCN), as well as associated substation equipment that forms part of the overall safety system should satisfy the requirements of functional safety standard IEC-61508. In this paper, Substation Automation System standard (SAS) IEC-61850, Substation Communication Networks (SCNs) as well as dependability evaluation methods are reviewed and discussed.