XGN15-12 SF6 Ring Main Unit (RMU) Technical Description The XGN15-12 SF6 Ring Main Unit (RMU) is a compact, gas-insulated switchgear solution designed for medium-voltage (MV) distribution networks, typically rated at 12 kV. It integrates advanced SF6 gas insulation technology to ensure high reliability, safety, and minimal maintenance in demanding electrical distribution applications. Design and Construction The RMU features a modular, metal-enclosed design with SF6 gas as the primary insulating and arc-quenching medium. The gas-tight enclosure ensures environmental protection, preventing moisture and dust ingress while maintaining stable dielectric performance. The unit is constructed with robust stainless steel or aluminum alloy panels, offering corrosion resistance and mechanical durability. Key Components 1. SF6 Gas Insulation: The sealed gas chamber houses all live parts, including circuit breakers, switches, and busbars, ensuring compact dimensions and enhanced safety. SF6’s superior dielectric strength allows for reduced phase-to-phase and phase-to-ground clearances. 2. Load Break Switches (LBS): Equipped with spring-operated mechanisms for reliable load switching and isolation. Some models include fault-make, load-break (FMLB) capability for emergency operations. 3. Vacuum Circuit Breaker (VCB): Optional integrated VCB provides overcurrent and short-circuit protection with fast interruption and long electrical life. 4. Busbar System: Modular design supports ring or radial configurations, enabling flexible network expansion. 5. Protection & Monitoring: Includes mechanical/electric interlocks, pressure gauges for SF6 monitoring, and optional remote control via SCADA systems. Technical Features - Rated Voltage: 12 kV - Rated Current: Up to 630 A (load break switches) / 1250 A (busbar) - Short-Circuit Withstand: Typically 20 kA (1s or 3s) - SF6 Gas Pressure: 0.04–0.05 MPa (absolute) at 20°C, with low leakage rate (<1% per year). - Operating Mechanisms: Manual, motorized, or solenoid-driven options. Applications - Urban Distribution: Ideal for space-constrained substations due to compact footprint. - Renewable Energy: Supports grid integration of solar/wind farms. - Industrial Parks: Ensures reliable power distribution with minimal maintenance. Advantages - Safety: SF6 insulation eliminates fire risks and reduces arc hazards. - Low Maintenance: Sealed design minimizes inspection needs. - Environmental Resilience: Operates reliably in harsh conditions (-30°C to +40°C). Standards Compliance The XGN15-12 complies with IEC 62271, GB/T 11022, and other international standards for MV switchgear. In summary, the XGN15-12 SF6 RMU combines advanced insulation technology, modularity, and robust protection features to deliver efficient and dependable medium-voltage power distribution.