Digital substations of future – Communication Redundancy, Process Bus and Cyber Security

The implementation of Substation Automation systems is transforming over the years from its traditional hardwired approach. Subsequently, there were implementations based on IEC 60870-5-103 protocol. As this protocol was on a serial communication, there were issues concerning the data response time and flexibility of inter-connectivity. The development of the IEC 61850 standard is a great milestone in the development of Substation Automation Systems. The standard is based on networking protocol – TCP/IP. The release of IEC61850 standard for Substation Automation Systems has enabled the utilities break the barriers with the conventional systems and has taken the implementation of Substation Automation Systems to the next level.

IEC 61850 based Substation Automation Systems have been in operation across utilities for many years now. One of the main goals of the IEC 61850 standard is interoperability. It defines interoperability as ability of two or more IEDs from the same vendor, or from different vendors, to exchange information and use that information for correct execution of specified functions. It should be understood that even with standardized data model, services and the substation configuration description language, the IEC 61850 standard still allows a certain degree of freedom to implement the functions, especially for complex distributed functions.

This paper will discuss the two main new developments in IEC 61850 standard - Communication Redundancy, and Process Bus. As when discussing a digital automation system, the aspects of cyber security in implementing such systems cannot be ignored, this paper will also discuss this topic in a digital substation perspective.