Urban, suburban and rural medium voltage overhead distribution feeders, sectionalizing protection for long distribution lines, solar farm outgoing overhead circuits, distribution network renovation and expansion projects. It isolates transient and permane
ROCKWILL Air insulated Ring Main Unit (RMU) is factory-assembled, metal-enclosed modular switchgear for medium voltage distribution systems. It uses atmospheric air as the insulating medium, equipped with load break switches and optional fuse combination units for transformer protection. The modular design allows flexible combination of ring-in, ring-out and transformer protection bays. The product complies with IEC 62271-1:2017, IEC 62271-103:2019 and IEC 62271-200:2021. Relevant documents include Type Test Certificate No. TT-2025-04131, Witness Test Report No. WT-2025-09066, Routine Factory Test Report No. FT-2025 series, Raw Material Mill Certificates, all issued by CNAS accredited independent high voltage test laboratory and available for tender submission, utility review and project site acceptance. Manual or motorized operating mechanisms can be selected, and optional fault indicators and communication modules support distribution automation. Tropicalised anti-corrosion treatment is available for high humidity, heavy rain and coastal salt mist environments.
low carbon switchgear, green switchgear ,environmentally friendly switchgear, SF6 free ring main unit, SF6-free medium voltage switchgear
24kV SF6 free RMU ,12kV SF6 free RMU ,36kV SF6 free RMU ,40.5kV SF6 free RMU
SF6 Alternative RMU ,zero GWP switchgear, zero GWP RMU, pure air insulated RMU,24kV SF6 free RMU
This ring main unit adopts atmospheric air as the insulating medium between live parts and earth, no SF₆ gas is required, which simplifies gas management and reduces greenhouse gas related risks.
SM66 type RMU is designed for nominal 36kV power system with rated maximum voltage of 40.5kV.
This RMU adopts atmospheric air as insulation medium, SF₆ gas free, avoiding gas leakage and greenhouse gas concerns.
It supports flexible modular combination including ring-in bay, ring-out bay and transformer protection bay. It can be equipped with load break switch only or load break switch plus fuse combination unit.
Manual operation mechanism is standard, and motorized actuator is optional for remote control and distribution automation.
Fault passage indicators, temperature sensors and communication modules are optional for fault location, status monitoring and SCADA integration.
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