NOJA Power

Technical Article

Published 06/2023

NOJA Power Releases Updated Protection Feature Diagram

A NOJA Power OSM Recloser with RC-10 control

Switchgear engineering firm NOJA Power have released an updated protection and control feature overview for their RC series controllers. The RC series have been controlling NOJA Power OSM Reclosers since the early 2000s, and the latest update captures the full feature set available with the latest versions of RC firmware.

Updated ANSI Protection and Control Summary Diagram for RC Series Controllers
Updated ANSI Protection and Control Summary Diagram for RC Series Controllers

Updated ANSI Protection and Control Summary Diagram for RC Series Controllers © NOJA Power 2023ANSI device numbers are derived from the ANSI C37.2 standard, and allow for schematic representation of protection and control features in the power system. Applied to the RC control as above, it provides an illustrative single page snapshot of all functionality available in the device.

The diagram illustrates the sensor arrangement in the OSM Recloser, with voltage sensing on either side of the vacuum interrupter, coupled with current measurement. These signals are processed and provided to the RC control for protection and automation.

While features such as ANSI 51 Time delayed overcurrent are readily deployed in most NOJA Power OSM Recloser installations, other features are seeing growing deployments when the OSM Recloser system is used for renewable connections. These include ANSI 67 directional overcurrent, 81R Rate of Change of Frequency and ANSI 25 Sync check.

“ At NOJA Power, we pride ourselves on creating the most advanced range of recloser controllers available in the world today while making them as easy as possible to configure, program and use,” says NOJA Power Group Managing Director Neil O'Sullivan.

“It is something we consider in any new functionality development and I am proud of the complex simplicity we create.”

The diagram also highlights key differences between the RC-02/03/10/15 platform and the RC-20 system, where the higher performance CPU and signal processing affords PMU capabilities and monitoring of up to the 63rd harmonic.

For more information, visit or contact your local NOJA Power Distributor.

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