Smart Dry Air Insulated RMU (SF6 Free)

Products
Ring Main Unit (RMU)
Smart Dry Air Insulated RMU (SF6 Free)

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 smart dry air insulated 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.

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Technical Specifications

		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
Power-frequency withstand voltage (kV)	Phase to Ground	48	48	48
Lightning impulse withstand voltage (kV)	Phase to Phase	75	75	75
Lightning impulse withstand voltage (kV)	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

Features

Eco-Friendly Insulation:

Utilizes dry air, eliminating SF6 for a green solution.

Fully Insulated and Sealed:

Provides complete protection against dust and humidity, ensuring reliable operation even under zero gauge pressure.

Enhanced Safety:

Features a three-position isolation switch with a visible disconnection point for safe operation.

Compact and Flexible:

Modular design offers a small footprint and adaptable scheme options.

Safe Arc Suppresion:

Employs a vacuum interrupter instead of a grounding switch for short circuit closing, ensuring safety.

Versatile Connectivity:

Offers multiple options for top and side outlets, high-voltage emergency power supply interfaces, secondary modules, and aviation plug interfaces.

Customizable Solutions:

Designs can be tailored to meet specific customer requirements.

Operating Conditions

Maximum Ambient Temperature: +60℃

Minimum Ambient Temperature: -40℃

Relative Humidity: Daily average ≤95%, monthly average ≤90%

Seismic Grade: 8

Operating Altitude: ≤1000 meters above sea level

Note: Contact HCRT if a different condition is required. We offer customized solutions as well.