An Evaluation of Extending an Existing Substation Automation System using IEC 61850

Substation Automation Systems are commonly used to control, protect and monitor substations in a power system. Many existing substation automation systems use proprietary protocols, which are no longer supported. Therefore, expensive and complex solutions are often required when automation equipment fails or reaches the end of life (15/20 years), or a substation extension is required. Older proprietary-based protocols in substation automation systems are being updated and replaced by introducing the IEC 61850 standard series.IEC 61850 brings significant changes to how Intelligent Electronic Devices used for protection are to be tested. The introduction of non-traditional relay signals resulted in the need for new tools and processes regarding commissioning, testing and maintenance.This paper provides an overview of existing proprietary protocols and outlines the IEC 61850 standard. The challenges in testing IEC 61850 protection equipment are investigated. Finally, a power utility approach for extending existing legacy substation automation systems is demonstrated in a lab-based trial. The comparison illustrated the many benefits of installing and extending substations using IEC 61850 rather than reengineering the proprietary systems.