Smart Ring Main Unit

The ring main unit (RMU) is the core switching equipment for ring network power distribution in medium-voltage distribution networks. The rated voltage is typically 10kV (12kV) and 35kV. Multiple cabinet units connect in a ring configuration through busbars. This forms a closed loop. Under normal operation, the loop runs with one open point. When a fault occurs on any section, switches at both ends of the faulty section open quickly. The other side continues supplying power. This achieves fault isolation and rapid power restoration. This ring configuration greatly improves power supply reliability in urban distribution networks, industrial parks, and commercial complexes. This is the fundamental difference between ring main units and traditional terminal switchgear. Anhui Tiankang's smart ring main unit covers three major technologies: SF6 gas insulated, solid insulated, and dry air environmentally friendly insulated. These adapt to urban switching stations, outdoor ring network cabinets, renewable energy step-up stations, and subway tunnels.

The core component of the ring main unit is the three-position load switch (closed/open/grounded). This handles ring current carrying, sectioning, and maintenance safety grounding. Outgoing circuits typically use load switch + high-voltage current-limiting fuse combinations. These protect distribution transformers. For heavy loads or applications needing to interrupt short-circuit currents (like PV grid connection), vacuum circuit breakers are used.

Smart ring main unit products have standard unit combinations. These include incoming units (ring-in/ring-out with three-position switch), feeder units (transformer outgoing with fuse protection), PT metering units (voltage monitoring and metering), and DTU intelligent terminal units (distribution automation). The enclosure is fully insulated and fully sealed. Interlocking mechanisms meet "five-prevention" safety operating requirements.

For insulation technology, SF6 gas insulated ring main units are the most widely used type in urban distribution networks. High-voltage components are sealed in stainless steel gas tanks filled with sulfur hexafluoride. These are fully sealed and maintenance-free. The compact size makes them suitable for outdoor ring network cabinets. Solid insulated ring main units (XGN series) use epoxy resin casting to encapsulate all live parts. They do not rely on greenhouse gas SF6. They are fully insulated and fully shielded. This makes them particularly suitable for humid, high-altitude, salt spray, and dusty chemical plant areas.

Dry air environmentally friendly gas cabinets use nitrogen or dry air instead of SF6. These meet carbon neutrality project requirements. All three technologies offer indoor and outdoor stainless steel enclosure (IP67 weatherproof and corrosion-proof) installation options. All products strictly follow GB 3906 and IEC 62271-200 standards. They have passed complete type tests (power frequency withstand, lightning impulse, internal arc fault, etc.). We support primary and secondary fusion solutions (distribution automation DTU integration). Export shipments include CE certification and IEC standard test reports.