Rockwill Medium-Voltage SF6-Free Gas-Insulated Switchgear Series – From RMR to REC and RAR

Within Rockwill's SF6-free product portfolio, the RMR, REC, and RAR series all adopt gas-insulated, hermetically sealed structures that fully enclose high-voltage live parts in stainless steel tanks, ensuring complete sealing and maintenance-free operation. The three series share a similar modular design philosophy, but differ significantly in insulation medium, technical positioning, voltage coverage, and application scenarios.

Core Differences

In terms of insulation medium and environmental characteristics, the RAR series uses dry air, while the REC series uses pure air or nitrogen (N2)—both with a Global Warming Potential (GWP) of zero. The RMR series defaults to SF6 gas, which has a GWP of 23,900, but it can flexibly be retrofitted with nitrogen (N2) or G3 gas for an environmentally upgraded version, reducing GWP to near-zero levels. Typical operating pressures: RAR operates at approximately 200 kPa (absolute pressure); REC operates at only 0.02–0.04 MPa (gauge pressure), which is extremely low; RMR's SF6 fill pressure is around 0.14–0.2 MPa.

Regarding electrical parameters, RAR covers rated voltages from 6 kV to 24 kV, with a rated current of 630 A and a short-time withstand current of 20 kA/3 s. The REC series covers a broader voltage range, from 12 kV to 38.5 kV, with rated currents of 630 A and 1250 A, and a short-time withstand current of 20 kA/4 s (25 kA/4 s optional). The RMR series covers 12 kV, 24 kV, and 36 kV, with a rated current of 630 A at 12/24 kV, and short-time withstand currents ranging from 20 to 25 kA/3 s depending on the voltage level.

In terms of modularity and intelligence, the RAR supports up to 4 module combinations and is compatible with IEC 61850; the REC offers flexible modular expansion and features an integrated smart control and protection unit with built-in FTU/DTU functions; the RMR also supports multiple combinations and flexible expansion, as well as smart distribution automation. Their positioning is as follows: RAR is a fast-deployment, entry-level environmentally friendly solution; REC is a long-life, engineering-grade flagship; and RMR is a versatile, all-condition flexible platform.

RAR Series: Fast-Deployment Dry-Air Eco-Friendly Entry Solution

The RAR series targets the mainstream distribution market, using dry air insulation with zero GWP, fully compliant with IEC standards and the EU F-gas Regulation (EU) 2024/573. The series includes two subtypes: the RAR Ring Air RMU, which supports up to 4 modules and suits most distribution switchgear applications; and the RAR Plus Air, which features a modular metal-enclosed design for easy expansion and adaptation to higher electrical parameters and various protection relays. The RAR retains the same interfaces, dimensions, and operating methods as traditional SF6 versions, requiring no additional training.

Key parameters: rated voltage 24 kV, rated current 630 A, short-time withstand current 20 kA/3 s, protection rating IP67, main circuit absolute pressure 200 kPa, and support for IEC 61850 protocol. The series operates stably at altitudes above 2,500 meters, supports omnidirectional 20 kA/1 s internal arc protection, and features a fully welded gas tank that is immune to external environmental influences, delivering true maintenance-free operation.

REC Series: Mass-Proven Air/Nitrogen-Insulated Flagship

The REC series is a pure air/nitrogen-insulated flagship for medium-voltage distribution, with nearly a decade of global mass production and outstanding advantages in mechanical life, partial discharge control, insulation strength, and weather resistance. Its core technical feature is extremely low insulation gas pressure: approximately 0.02 MPa (gauge) for the 12 kV rating and about 0.04 MPa (gauge) for 24 kV, resulting in lower leakage risk and simpler sealing structures.

The series uses high-purity, low-dew-point synthetic pure air or nitrogen (GWP=0), with total partial discharge below 5 pC. The operating mechanism features zinc-embedded alloy surface treatment, passes salt-spray tests exceeding 168 hours, and achieves a maximum mechanical life of 30,000 operations.

Key parameters: rated voltage 12 kV to 38.5 kV, rated current 630 A/1250 A, short-time withstand current 20 kA/4 s (25 kA/4 s optional), annual leakage rate as low as 0.01%, and tank protection rating IP67.

For the 12 kV rating, the rated power-frequency withstand voltage is 42 kV, and lightning impulse withstand voltage is 75 kV; for 24 kV, power-frequency withstand voltage ranges from 42/65/79 kV depending on the model, and lightning impulse withstand voltage ranges from 75/125/145 kV. The cabinet width is kept within 600 mm, allowing same-size retrofitting in older distribution rooms without wall breaking or civil works. Cabinet-to-cabinet connections use solid-insulated busbar connectors in a "Lego-like" assembly, eliminating on-site vacuuming, gas filling, and leak testing, and reducing single-cabinet commissioning time by over 70%.

The REC is positioned as an "ultra-eco-friendly + ultra-long-life" engineering flagship, particularly suited for applications with stringent environmental requirements, long expected equipment life, and frequent operations.

RMR Series: All-Condition Flexible Gas-Insulated Platform

The RMR series is the broadest product line among the three, with the highest voltage coverage and the most flexible combinations. Its default insulation medium is SF6, and it is composed of hermetically sealed common tanks incorporating load-break switch units, load-break switch–fuse combination units, vacuum circuit-breaker units, and busbar incoming units, fully compliant with IEC 62271-200.

The RMR covers 12 kV, 24 kV, and 36 kV, and supports distribution automation via FTU/DTU and communication devices. For the 24 kV rating, rated current is 630 A, short-time withstand current is 20 kA/3 s, power-frequency withstand voltage is 50 kV, and lightning impulse withstand voltage is 125/150 kV. The circuit breaker has a mechanical life of 10,000 operations, the load-break switch 3,000 operations, the main tank is IP67-rated, and the enclosure is IP55-rated.

In terms of environmental transition, the RMR series offers unique flexibility—besides replacing SF6 with nitrogen (N2), it can also use G3 gas (g3 eco-friendly gas) as a drop-in alternative, directly converting existing SF6 switchgear into environmentally friendly gas-insulated switchgear. This makes the RMR the smoothest, lowest-technical-risk migration path from traditional SF6 to SF6-free solutions, widely applicable to general medium-voltage distribution scenarios and users with environmental transition needs.

International Standards and Certification Systems

Rockwill's RAR/REC/RMR series fully comply with major global standards. The RMR series meets Chinese national standards GB/T 11022-2020, GB/T 3804-2017, GB/T 3906-2020, etc.; the RMR follows IEC 62271-200 and IEC 62271-106; the REC series complies with IEC 62271-1 and IEC 62271-200; and the RAR fully meets IEC standards and the EU F-gas Regulation.

For the North American market, the REC series meets IEC/ANSI standards. For Europe, products follow IEC and EN standard systems, are highly compatible with German VDE standards, and can be customized to DIN/VDE requirements; they can also be designed to French NF C series standards (e.g., NF C 13-100, NF C 13-200) to meet additional safety and quality requirements in French-speaking markets; for the UK, products are compatible with BS EN standards; overall, they comply with the EN standard system and satisfy CE certification technical requirements.

Selection Recommendations

If a project is cost-sensitive and requires rapid compliance with the EU F-gas Regulation, the RAR series is the preferred fast-deployment eco-friendly solution. For projects with strict environmental requirements, expected equipment life exceeding 10 years, and frequent operations, the "ultra-eco-friendly + ultra-long-life" REC series is recommended. For the most common general medium-voltage distribution scenarios—especially when users are still assessing the maturity of SF6-free technology—the RMR series offers a low-risk path: "configure initially with SF6, and later convert in-situ to nitrogen or G3 for eco-friendly operation." It also covers 12 kV, 24 kV, and 36 kV, making it the most flexible combination platform.