Dry Air Insulated Smart RMU (SF6 Free) Smart Ring Main Unit
Standards: IEC 62271-100:2008, IEC 62271-102:2018, IEC 62271-103:2011, IEC 62271-200:2011, IEC 62271-1:2017
The dry air insulated smart RMU (SF6 Free) is an environmentally responsible alternative to SF6-insulated switchgear, developed in response to global sustainability demands. Since 2015, HCRT has invested in the research and development of this advanced solution. By utilizing dry air as the insulation medium, this RMU eliminates the use of SF6 gas, significantly reducing environmental impact while maintaining high performance and safety.
All live components are fully enclosed within a sealed gas tank, protecting internal insulation from dust and moisture and ensuring reliable operation in harsh environments. The tank includes a visible disconnector window, providing enhanced operator safety.
| Load Break Switch (Cabinet C) | Circuit Breaker (Cabinet V) | Disconnector/Earthing Switch | ||
| Rated voltage (kV) | 12 | 12 | 12 | |
| Rated current (A) | 630 | 630 | 630 | |
| Rated frequency (Hz) | 50 | 50 | 50 | |
| Arc extinction | Vacuum | Vacuum | ||
| Power-frequency withstand voltage (kV) | Phase to Phase | 42 | 42 | 42 |
| Phase to Ground | 48 | 48 | 48 | |
| Lightning impulse withstand voltage (kV) | Phase to Phase | 75 | 75 | 75 |
| Phase to Ground | 85 | 85 | 85 | |
| Rated short-circuit breaking current (kA) | 20 | |||
| Breaking times of rated short-circuit breaking current | 30 | |||
| Rated short-circuit closing current/peak withstand (kA) | 50 | 50 | 50 | |
| Rated short-time withstand current (kA) | 20 | 20 | 20 | |
| Rated short-circuit duration (s) | 4 | 4 | 4 | |
| Rated cable charging breaking current (A) | 10 | |||
| Arc duration (s) | 1 | 1 | 1 | |
| Partial discharge (pC) | ≤5 | ≤5 | ||
| Mechanical life (times) | 10,000 | 10,000 | 3,000 | |
Note: Contact HCRT if a different condition is required. We offer customized solutions as well.