| Brand | ROCKWILL |
| Model NO. | Fully Sealed SF6 Indoor Ring Main Unit for Distribution Substation -11kV or 24kV |
| Rated voltage | 24kV |
| Series | RMR |
The Rockwill 11kV/24kV fully sealed SF6 RMU is specifically designed for secondary distribution networks, making it an ideal choice for distribution stations, box-type substations, and industrial facilities. Its fully sealed stainless steel gas tank completely encloses all live high-voltage parts, protecting them from humidity, dust, and pollution to ensure long-term, maintenance-free operation.
The RMU operates on a closed-ring power supply: the main feeder forms a loop, and each distribution branch draws power from both the left and right sides. If one main line fails, the other side continues to supply power, effectively achieving dual-source reliability with single-source configuration.
Dual-Source Reliability: Based on a closed-ring power supply principle, when the primary source fails, the secondary source feeds immediately. This achieves dual-source reliability with a single-source configuration, significantly improving supply continuity.
Visible Safety: Equipped with a visible break, operators can visually confirm the switch contact position, eliminating the risk of operational errors.
Compact & Space-Saving: Its small footprint and lightweight design save over 30% of floor space compared to traditional switchgear, ideal for space-constrained indoor distribution rooms.
Flexible Configuration: Supports flexible expansion with C-module (switch-disconnector), F-module (switch-fuse combination), and V-module (vacuum circuit-breaker), meeting diverse distribution needs for incoming, outgoing, and bus-tie applications.
Three-Position Mechanism: Integrated closing, opening, and earthing positions with mechanical interlocking prevent operational errors.
| Ring 11kV/24kV | C-module | F-module | V-module | ||||
| Switch disconnector | Earthing switch | Switch-fuse disconnector | Downstream earthing switch | Vacuum circuit-breaker | Earthing switch/ disconnector | ||
| Rated voltage | kV | 12/17.5/24 | 12/17.5/24 | 12/17.5/24 | 12/17.5/24 | 12/17.5/24 | 12/17.5/24 |
| Rated frequency | Hz | 50/50/50 | |||||
| Power frequency withstand voltage | kV | 28/38/50 | |||||
| Lightning impulse withstand voitage | kV | 75/95/125 | |||||
| Rated normai current | A | 630/630/630 | 200/200/200 | 630/630/630 | |||
| Breaking capacities: | |||||||
| -active load | A | 630 | 200 | 630 | |||
| -closed loop | A | 650 | 200 | 650 | |||
| -offload cable charging | A | 140/140/140 | |||||
| -offload transformer | A | 20 | |||||
| -earth-fault | A | 205/160/160 | N/A | 205/160/160 | |||
| -earth-fault cable charging | A | 117/91/91 | N/A | 117/91/91 | |||
| -short-circuit breaking current | kA | N/A | N/A | 20/16/16 | |||
| Marking capacity | kA | 50/40/40 | |||||
| Short tirne current 3s | kA | 20/16/16 | 20/16/16 | 20/16/16 | 20/16/16 | 20/16/16 | 20/16/16 |
1) Depending on the current rating of the fuse-link
2) Limited by high voltage fuse-links
3) Maximum rating for bushings Interface C (400 series bolted)
4) GOST version is available with 42kV power frequency to withstand voltage
5) For rated frequency 60Hz de-rating for current parameter needs to be applied
Ambient Temperature: -25℃ to +40℃
Altitude: ≤ 1000m
Relative Humidity: ≤ 95% (at 25℃)
Seismic Resistance: Up to 8 degrees
Pollution Level: Class III
Installation Site: Indoor, well-ventilated, free from corrosive gases and flammable/explosive substances
With simple structure, compact size, and cost-effectiveness, the RMU is widely used in distribution stations, box-type substations, residential complexes, high-rise buildings, and industrial facilities. It divides load current, interrupts short-circuit current, controls transformer no-load current, and manages charging current for overhead and cable lines.
We offer an industry-leading 10-year warranty from the date of commissioning. During the warranty period, we provide free repair or replacement for any defects in design, materials, or manufacturing.
Damage caused by improper operation, unauthorized modification, or force majeure is not covered. After the warranty expires, we continue to provide lifetime technical support and spare parts supply.
Standard RMU is designed for altitude ≤1000m and relative humidity ≤95% (at 25℃). For higher altitudes or extreme humidity, we offer customized designs with adjusted insulation levels and anti-condensation measures. Please advise your site conditions.
The RMU is fully sealed with a stainless steel gas tank, designed for maintenance-free operation over its service life. The SF6 gas is sealed for life (typically 30 years) with a leakage rate of less than 0.1% per year, complying with IEC 62271-200.
Yes. Our RMU supports flexible expansion with C, F, and V modules in any combination. Common configurations include C+C, C+F, C+V, and C+C+V, depending on your single-line diagram and protection requirements.
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