Vacuum Circuit Breaker Ring Main Unit

The Vacuum Circuit Breaker Ring Main Unit (RMU) is a compact, metal-enclosed medium-voltage switchgear system engineered for 12kV to 24kV secondary power distribution networks. Combining vacuum circuit breaker (VCB) technology with load break switches, it provides reliable circuit protection, sectionalizing, and switching in a sealed stainless steel tank. Designed for indoor and outdoor compact substation installations, it ensures continuous power supply while minimizing spatial footprint and maintenance requirements. 

Sealed Stainless Steel Enclosure: Primary switching components are hermetically sealed in a laser-welded 304 stainless steel tank filled with dry air or SF6 gas, ensuring complete immunity to external environmental moisture, dust, and coastal salinity.

Maintenance-Free Vacuum Interrupter: Utilizes axial magnetic field vacuum interrupters rated for 10,000 full-load mechanical operations, eliminating contact wear and dielectric degradation during arc extinction.

Modular Extensibility: Standardized side-extensible busbar interfaces allow rapid configuration changes on-site without gas handling or specialized vacuum sealing tools.

Interlock Safety Mechanism: Mechanical five-anti interlocking logic prevents misoperation between the circuit breaker, earth switch, and cable compartment door, complying with IEC 62271-200 standards.

Secondary Distribution Substations: Compact urban substations requiring minimal footprint and high operational reliability.

Renewable Energy Integration: Collector substations and pad-mounted setups in solar photovoltaic (PV) and wind power generation plants.

Industrial Facilities: Medium-voltage incoming and outgoing feeder protection for manufacturing plants, data centers, and mining operations.

Commercial Infrastructure: High-rise buildings, airports, and railway tunnel power distribution rings.

Protection & Control Units: Integration of self-powered numerical protection relays (e.g., Schneider Sepam, ABB, or Siemens Siprotec series) matching specific utility coordination curves.

Motorized Actuation: Remote-controllable motorized spring-charge mechanisms equipped with RTU interfaces for SCADA and smart grid automation integration.

Cable Compartment Layout: Tailored riser, surge arrester, and CT/VT configurations to accommodate single-core or three-core XLPE cables with standard inner cone or outer cone bushings (EN 50181 Type C).

Enclosure Finishes: C3/C4 anti-corrosion powder coating specifications for harsh industrial or marine environments.

Precision Sheet Metal Fabrication: Enclosures are processed via Trumpf CNC laser cutting and AMADA bending centers, maintaining dimensional tolerances within +/- 0.1 mm to ensure gasket compression integrity.

Robot-Assisted Welding: Automated TIG/MIG robotic welding cells execute continuous seams on stainless steel tanks, followed by 100% helium leak detection testing with a sensitivity threshold of 1 x 10^-7 Pa*m3/s.

Routine Factory Testing (FAT): Every unit undergoes partial discharge measurement (< 10 pC at 1.2 U0), power frequency withstand voltage testing at 28kV/1 min, and micro-ohm resistance verification of main circuits prior to dispatch.

Type Test Reports: Fully tested by KEMA or equivalent STL-member independent laboratories according to IEC 62271-200, IEC 62271-100, and IEC 62271-102.

Quality Management: Manufactured under ISO 9001, ISO 14001, and ISO 45001 certified production systems.

Documentation Package: Each shipment includes individual factory test certificates, electrical schematic CAD drawings, routine test logs, and installation/operation manuals in English.

Export-Grade Packaging: Secured on heavy-duty fumigated wooden pallets, wrapped in multi-layer VCI (Vapor Corrosion Inhibitor) anti-moisture film, and enclosed in robust plywood crates suitable for containerized ocean freight or air cargo.

Standard Lead Time: 4 to 6 weeks for standard configurations; custom engineering submittals and complex relay integration require 8 to 10 weeks.

Shipping Terms: FOB, CIF, or DDP terms available with shock and tilt indicators attached to external crating to monitor transit handling.