MOSCOW, June 9, 2026 —— Rockwill Electric today announced that its medium-voltage line automatic voltage regulator (AVR) has successfully completed over three years of field operation and validation by customers in Russia. The equipment maintained stable operation and remains in excellent condition under harsh environments reaching -45°C. This marks a substantial technical breakthrough for Rockwill in the field of power transmission and distribution equipment for ultra-cold regions.
According to feedback from a Russian power grid company, since their commissioning in 2022, Rockwill's line automatic voltage regulators have been in continuous operation across multiple substations and lines in Siberia and the Far East for more than three years, enduring several winters where minimum temperatures dropped below -50°C. "The regulator's tap changer operations, voltage regulation accuracy, and control systems showed no signs of low-temperature stalling, insulation failure, or seal aging and leakage. All operating parameters remained normal, far exceeding our expectations for extreme-cold equipment," commented the customer's head of operations and maintenance.
On-site Operation Photos of Rockwill RVR Series Voltage Regulators in Extreme Cold Conditions
To overcome the extreme challenge of -45°C, Rockwill implemented systematic technical improvements in equipment materials, low-temperature resistant sealing, and specialized regulator structures:
Upgrade of Low-Temperature Resistant Materials: Eliminating risks of cold brittleness.
Advanced Low-Temperature Sealing System: Ensuring long-term sealing reliability under extreme cold.
Optimization of Specialized Regulator Switch Technology.
The Technical Director of Rockwill stated: "The 'excellent condition' reported by our Russian customers after more than three years of field operation is the best validation of our technical team's scientific research spirit and practical capabilities. Moving forward, we will continue to deepen our technical innovations to provide global users with even more reliable equipment."
As the global energy transition accelerates and carbon neutrality goals gain momentum, medium-voltage distribution equipment is rapidly evolving towards SF₆-free, eco-friendly, compact, and intelligent solutions. Traditional SF₆ gas faces increasingly stringent environmental regulations due to its high Global Warming Potential (GWP), while conventional air-insulated equipment is limited by lower insulation margins and large footprints. In this context, Rockwill officially introduces its new-generation 24kV Dry Air Ring Main Unit (Pure Air / Dry Air Insulated RMU). Featuring a significantly smaller footprint, lower working pressure, and a completely green insulating medium, it provides a highly competitive SF₆-free solution for the industry.
Core Product Features
The Rockwill 24kV Dry Air Ring Main Unit uses pure dry air as the sole insulating medium, achieving true zero-carbon footprint. Its key design parameters and advantages are as follows:
Insulating Medium: 100% dry pure air, GWP=0. Contains no fluorinated gases or gas mixtures, entirely eliminating environmental risks and handling costs associated with SF₆.
Working Pressure: 0.2 MPa, lower than typical industry levels, reducing demands on sealing system design and long-term maintenance.
Ultra-Compact Dimensions:
Single Module Width: C/F functional unit cabinet width is only 325 mm, enabling flexible configurations.
Three-Unit Compact Design Dimensions: Height: 1330 mm × Width: 975 mm × Depth: 780 mm.
The overall footprint is significantly smaller compared to similar SF₆-free products, making it ideal for space-constrained installations (e.g., underground substations, urban renewal projects, compact switchrooms).
High Performance: Rated voltage 24kV, rated current 630A, rated short-time withstand current 20kA/3s, mechanical endurance ≥10,000 operations, protection rating up to IP67 (gas compartment) and IP54 (cabinet).
Smart Integration: Supports integrated primary-secondary intelligent monitoring and control, enabling real-time condition monitoring, rapid operation, and precise protection.
Comparative Analysis with ABB SafeRing/SafePlus Air
As a fellow SF₆-free dry air-insulated solution, the new Rockwill unit demonstrates clear advantages in installation footprint and working pressure:
Technical Parameter Comparison: Rockwill 24kV Dry Air RMU vs ABB SafeRing/SafePlus Air 24kV
Parameter
Rockwill 24kV Dry Air RMU
ABB SafeRing/SafePlus Air 24kV
Insulating Medium
Dry Pure Air
Dry Air
Rated Voltage
24 kV
24 kV
Rated Current (Busbar)
630 A
630 A
Working Pressure
0.2 MPa
0.25 MPa
Dimensions (H×W×D) for Typical 3-Unit Configuration
1330 mm × 975 mm × 780 mm
1400 mm × 975 mm × 797 mm
Single Module Width (Functional Unit)
325 mm
325 mm (for 12/24 kV functional units)
Environmental Profile
GWP=0, No fluorinated gases
GWP=0
Key Features Compact design, lower working pressure, fully sealed gas compartment, smart monitoring & control Same footprint, interfaces, and operation as previous SF₆ models
Key Advantage Insights
More Compact Size: Rockwill's design is 70mm lower in height and 17mm less in depth, offering a smaller overall volume while maintaining the same width. This saves valuable space in substations.
Lower Operating Pressure: The 0.2 MPa working pressure, compared to 0.25 MPa, reduces structural demands on the gas compartment, potentially enhancing long-term sealing reliability and lowering manufacturing complexity.
Equivalent Environmental Performance: Both utilize dry air insulation with a GWP of 0, fully complying with stringent environmental regulations like the EU F-gas Regulation.
Summary of Technical Advantages
Green & Sustainable, Entirely Fluorine-Free: Uses pure air insulation, eliminating SF₆ or other F-gases across the entire lifecycle—from production and operation to decommissioning—thus solving challenges related to greenhouse gas regulation and handling.
Space-Saving Design for Constrained Sites: Leverages optimized electric field design and solid composite insulation to ensure insulation performance while minimizing phase-to-phase and phase-to-ground clearances. Its industry-leading compact footprint is especially suitable for urban core areas, underground substations, and industrial park upgrades.
High Reliability, Maintenance-Friendly Design: Fully sealed, welded stainless-steel gas compartment with long-life sealing ensures internal dryness and stability, preventing faults like condensation. The integrated operating mechanism and smart units support condition monitoring, enabling predictive maintenance.
Easy Installation & Strong Compatibility: Features a standard modular design with interfaces compatible with mainstream products, supporting rapid deployment and non-stop power supply switching for efficient distribution network upgrades.
Typical Application Scenarios
Urban Distribution Network Upgrades: Underground substations, capacity expansion in old residential areas.
Industrial Parks & Data Centers: Locations with high power supply reliability requirements and limited space.
Renewable Energy Plants: Ring main units for PV or wind farm grid connection points.
International Grid Projects: Particularly suited for regions with strict environmental regulations and space constraints.
Conclusion
The launch of the Rockwill 24kV Dry Air Ring Main Unit marks a significant step forward in the compactness and practical engineering of SF₆-free ring main units. While maintaining high performance and reliability, it offers superior space utilization and lifecycle cost benefits through its smaller size and lower operating pressure. As global demands for environmental sustainability and efficiency continue to rise, this product will provide robust support for the safe, green, and efficient operation of distribution networks.