gas-insulated switchgear (GIS)

       The main differences between gas-insulated switchgear (GIS) and ring main units (RMU) are as follows:1. Insulation medium: GIS uses sulfur hexafluoride (SF6) gas as the insulation medium, while RMUs mainly rely on air or solid insulation (such epoxy resin)125. 2. Structure and protection level: GIS usually adopts a fully enclosed structure with a higher protection level (such as IP6), which can effectively prevent external environmental influences; RMUs mostly adopt a semi-enclosed structure with openings at the top and bottom for easy heat dissipation and maintenance, the protection level is relatively lower267. 3. Cost and maintenance: GIS has a higher cost, with a unit price of about 50,00 to 150,000 yuan, and requires regular testing of SF6 concentration, with an annual inspection cost of about 2,00 to 5,000 yuan; RMUs have a lower cost, about 20,000 to 80,000 per unit, simple maintenance, and an annual inspection cost of about 500 to 1,500 yuan2. 4. Application scenarios: is suitable for highly polluted, high-humidity, or space-constrained environments, such as city centers, industrial zones, or underground distribution rooms, and is particularly suitable places with high power requirements like airports and subways; RMUs are suitable for environments with better conditions and strict cost control, such as residential areas and shopping malls128.5. Performance and reliability: GIS has advantages such as small volume, high voltage resistance, and dust and moisture resistance, with strong arc extinguishing capability and a short- breaking current of up to 25kA-31.5kA; RMUs have a simple structure and stable operation, but are easily affected by the environment require regular cleaning2. In summary, the choice between GIS and RMU should be weighed based on the specific application scenario, budget, and environmental conditions. With increasing environmental protection requirements, SF6-alternative gas-insulated switchgear is gradually becoming popular, but the cost is still higher than traditional RMUs .