Medium Voltage SF6 Fully Insulated Sealed Electrical Ring Main Unit Compact Switchgear

This Medium Voltage SF6 Fully Insulated Sealed Electrical Ring Main Unit Compact Switchgear is Lugao's flagship product. Featuring a fully sealed, maintenance-free design, it can provide power distribution for 12kV, 24kV, and 36kV power grids worldwide. This ring main unit also complies with international certifications such as CE, ISO, and IEC. As a professional electrical switchgear supplier, Lugao's SF6-insulated switchgear completely isolates all high-voltage components from the external environment. Its metal-enclosed structure ensures safe operation under the most demanding conditions, from underground substations to coastal facilities.

Main technical parameters

Typical Scheme Diagram：

Product details:

What makes this ring main unit unique?

1. True Full Insulation Design

Unlike traditional air-insulated switchgear, Lugao's Medium Voltage SF6 Fully Insulated Sealed Electrical Ring Main Unit Compact Switchgear are manufactured using laser-welded technology in a fully sealed stainless steel tank. All live components—including load switches, vacuum circuit breakers, grounding switches, and main busbars—are completely sealed with SF6 gas. This gas-insulated switchgear boasts a high protection rating, fully resistant to harsh environments such as moisture and condensation, dust, and airborne pollutants.

2. Compact Design, Small and Exquisite Size: This compact switchgear significantly reduces floor space. Its modular design allows for various configuration options while maintaining a small footprint, making it suitable for underground power distribution networks, compact substations, and space-constrained industrial facilities.

3. Maintenance-Free Operation: This fully sealed switchgear eliminates the need for routine maintenance of high-voltage components. Therefore, this SF6-insulated switchgear requires no gas replenishment during its 30-year design life.

Available Configurations

This Medium Voltage SF6 Fully Insulated Sealed Electrical Ring Main Unit Compact Switchgear accommodates a range of functional modules to address diverse application requirements, allowing flexible configuration based on specific customer needs:

1.  C Module – Load Switch Unit

   Features a three-position load switch (make-break-earth)  

   Designed for transformer protection and cable switching operations  

   Break position is visible via an integrated observation window  

2. F Module – LBS-Fuse Combination Unit

   Integrates a load switch with fuse-based protection  

   Provides three-phase tripping functionality through a trigger pin mechanism  

3. V Module – Vacuum Circuit Breaker Unit  

   Employs a vacuum circuit breaker for the protection of cables and transformers  

   Suitable for applications requiring frequent switching operations  

   Supports an optional integrated protection relay  

4. D Module – Direct Cable Connection  

   Provides a straightforward cable connection without any switching apparatus  

   Intended for non-switched feeders or busbar riser applications  

5. M Module – Metering Unit  

   Equipped with voltage and current transformers for measurement purposes  

Includes test terminals and interfaces for mounting instrumentation

Frequently Asked Questions (FAQ)

Question 1: What is a ring main unit?

Answer 1: This Medium Voltage SF6 Fully Insulated Sealed Electrical Ring Main Unit Compact Switchgear is a compact gas-insulated switchgear suitable for 12kV, 24kV, and 36kV power distribution. The ring main unit uses a fully sealed stainless steel tank containing SF6 gas, which insulates all high-voltage components, including load switches and vacuum circuit breakers.

Question 2:What configurations are available for this ring main unit?

Answer 2: This compact switchgear offers modular configurations:

Module C: Load switch unit for cable and transformer switching

Module F: Load switch-fuse combination for transformer protection

Module V: Vacuum circuit breaker for frequent operation

Module D: Direct cable connection for non-switching feeders

Module M: Metering unit with voltage and current transformers

Question 3:Can this ring main unit be expanded in the future?

Answer 3: Yes,Additional ring main unit modules can be connected using gas-insulated busbar connectors.

Question 4:What safety features are included?

Answer 4:Mechanical interlocks,Internal arc classification,Pressure release,Grounding switch.

Question 5:What is the delivery time?

Answer 5:Standard configurations are in stock; customized models take approximately 20 days.For urgent needs, please consult