How to Connect Underground Cables to NOJA Power OSM Reclosers

While the NOJA Power OSM Recloser system is most commonly applied to the electricity overhead distribution network, there are many applications for connecting underground cables to the same asset. This poses the question, “Why would an engineer use an overhead protection asset for underground cables?”

The OSM Recloser integrates primary high voltage switchgear with the protection and control system needed to protect electricity distribution networks. Since the entire system is built and tested at the factory, design engineers can save significant capital investment by relying on this system, rather than discrete or custom assets.

With a peak interrupting capacity of 16 kA and all the standard underground protection features such as Overcurrent, Earth Fault and mitigation methods for capacitive cable charging currents, the NOJA Power OSM Recloser can be applied to many underground network applications.

In this article, we cover a few ways that NOJA Power OSM Reclosers can be connected to underground cables.

Overhead to Underground Conversion

NOJA Power’s OSM Recloser system is often used as the pole top point of conversion to underground connections. While the 38 kV product (as pictured above) requires a cable conversion accessory, the 15 kV and 27 kV NOJA Power OSM Recloser terminals are compatible with both overhead bushings and DIN C type terminals. This allows users to terminate underground cables directly onto the recloser, as shown below.

The Ground Mount Kiosk

NOJA Power developed the Ground Mount Kiosk (GMK) for integration of switchgear for solar renewables and private infrastructure connections. This arrangement places a NOJA Power OSM Recloser in a powder coated stainless steel kiosk, with additional busbars and clearance to allow connection of additional sensors and third party metering equipment.

For more comprehensive overview of the GMK and protecting underground equipment, visit www.nojapower.com.au/product/gmk

Custom Kiosks

With the DIN C standard bushings being available on all OSM Recloser models, many electrical design houses have opted to implement their own kiosk arrangements compliant with local regulations.

While these are often less cost effective than the standard NOJA Power GMK, they offer even further flexibility to meet local design requirements. A few project examples are shown below, exploring the versatility of this protection asset.

Conclusion

Many underground cable connections can be protected using NOJA Power’s OSM Recloser System.

“Because we have DIN C epoxy resin bushing profiles it makes our tanks very flexible for overhead to underground transition points, underground cable termination directly onto our bushings maintaining a fully insulated bushing arrangement and ground mount kiosk type applications again maintaining a fully insulated system inside the kiosks,” says NOJA Power Group Managing Director Neil O'Sullivan.

“For the 15kV and 27kV rated OSM tanks the DIN C profile is standard for our 328kV tanks, the DIN C is an option that needs to be ordered at time of manufacture.”

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