NOJA Power

Technical Article

Updated 11/2021

Capacitor Switching with the OSM Recloser

While conventional application of reclosers is for overhead line protection and reliability improvement, the NOJA Power OSM Recloser also holds type test certification for capacitive switching to class C2.

Capacitor switching is more arduous than conventional overhead line interruption. In capacitive circuits, the current leads voltage by 90 degrees. When interrupted, the peak voltage seen by the breaker can be greater than twice the peak system voltage.

NOJA Power OSM Recloser installed as a capacitor switch in the Saharan Desert, Algeria © NOJA Power 2021
NOJA Power OSM Recloser installed as a capacitor switch in the Saharan Desert, Algeria © NOJA Power 2021


To meet this overvoltage insulation requirement, the 38 kV OSM Recloser product with 16 kA interruption capacity is type tested to capacitive switching class C2 for 27 kV switching applications.

NOJA Power OSM Recloser installed in a substation capacitor switching application, Mexico © NOJA Power 2021
NOJA Power OSM Recloser installed in a substation capacitor switching application, Mexico © NOJA Power 2021

“Voltage control of medium voltage networks is becoming more critical as more and more distributed generation is connected to the grid,” says NOJA Power Group Managing Director Neil O’Sullivan.
“Our products are finding more and more application in capacitor switch applications because of our integral voltage measurement capability and an economical packaged complete solution can be provided.”

Using an integrated switchgear solution such as the OSM Recloser for capacitor switching can offer cost savings and additional functionality often unavailable with dedicated designs. Additional features such as Power quality analysis and oscillography captures are some examples added value when using the OSM Recloser in lieu of traditional capacitor switching arrangements.

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