Electricity Today T&D Magazine

As the substation RTU takes on more applications, such as Human-Machine-Interface (HMI), alarm annunciation, math & logic and “relay communication processing”, its need for high availability increases. Anything that takes the RTU out of service – configuration change, firmware update, or component failure – means not only loss of SCADA but also loss of local visibility, loss of non-operational data and, in some applications, loss of local control. Redundancy can address the needs for higher availability. This paper reviews the latest designs for electrical substation RTU redundancy and details required new features, including:

• Current redundancy designs in substation automation
• Limitations of current implementations
• Suggested design philosophies for substation automation redundancy
• Review of desirable redundancy design features: Flexible SCADA interface, including intelligent buffering to prevent Event floods on switchover, selective reporting of Events and acceptance of controls by Standby, and multiple SCADA support
• Ability for the...