In the power system, 35kV GIS (Gas-Insulated Switchgear) combined electrical equipment is widely used in substation distribution networks due to its compact structure, strong insulation performance, and adaptability to harsh environments. As the core insulating and arc-extinguishing medium of 35kV GIS, SF6 gas plays a key role in ensuring the stable operation of equipment. However, SF6 is a strong greenhouse gas with a global warming potential (GWP) 23,900 times that of CO₂ and a lifespan of over 3,200 years in the atmosphere. Strict control of SF6 emissions and efficient recovery have become urgent needs for power enterprises to comply with environmental regulations (such as the Montreal Protocol and national GB standards) and achieve green development. This is where the SF6 gas recovery cart for 35kV GIS combined electrical equipment comes into play—it is a dedicated device to solve SF6 gas waste, environmental pollution, and operational safety issues in 35kV GIS maintenance.

1. Core Functions of SF6 Gas Recovery Cart for 35kV GIS

The dedicated SF6 recovery cart is not a universal device; it is optimized for the working parameters and structural characteristics of 35kV GIS, with three core functions that directly address on-site operation and maintenance needs:

• High-efficiency SF6 recovery: 35kV GIS typically has a SF6 gas volume of 50-200kg per unit, and the recovery cart uses a dual-stage compression system to reduce the residual gas pressure in the equipment to ≤50Pa. This achieves a recovery rate of over 99.5%, far higher than the 80% recovery rate of general-purpose carts, minimizing gas waste and emissions.

• Deep purification of SF6: During 35kV GIS operation, SF6 may mix with moisture, air, or decomposition products (such as SO₂, HF) due to seal aging or equipment failure. The recovery cart is equipped with a multi-stage filtration system (molecular sieve, activated carbon, and high-efficiency filter) to reduce the moisture content of recovered SF6 to ≤5ppm and the impurity content to ≤0.1%, ensuring the gas can be reused in 35kV GIS without affecting insulation performance.

• Safe storage and transfer: The cart is configured with a high-pressure seamless steel cylinder (designed pressure ≥15MPa) that meets international safety standards, and is equipped with overpressure protection, temperature monitoring, and explosion-proof valves. It can safely store recovered SF6 on-site and transfer it to a centralized treatment station, avoiding risks such as cylinder leakage during transportation.

2. Why 35kV GIS Requires a Dedicated SF6 Recovery Cart

General-purpose SF6 recovery carts often fail to meet the operational requirements of 35kV GIS, and using dedicated equipment has three irreplaceable advantages:

• Parameter matching: The working pressure of 35kV GIS is usually 0.4-0.6MPa (gauge pressure), which is lower than that of 110kV or 220kV GIS. Dedicated carts are calibrated for this pressure range, avoiding problems such as low recovery efficiency (due to mismatched compression ratios) or equipment damage (due to excessive pressure) when using high-voltage GIS carts.

• Structural adaptability: 35kV GIS has diverse interface types (such as DN20, DN25 flange interfaces) and is often installed in narrow spaces (such as indoor substations). Dedicated recovery carts are designed with a compact body (length ≤2.5m, weight ≤500kg) and a set of interchangeable interface adapters, making it easy to connect to equipment in limited spaces without modifying the GIS structure.

• Operational efficiency: 35kV GIS is widely used in urban distribution networks, and maintenance often requires short power outages (usually ≤4 hours). The dedicated cart has a fast recovery speed (up to 50kg/h for 35kV GIS), which can complete the gas recovery of a single GIS unit within 2-3 hours, ensuring maintenance work is completed on schedule and reducing power outage losses.

3. Selection Criteria for SF6 Gas Recovery Cart for 35kV GIS

When power enterprises purchase a dedicated recovery cart, they should focus on four key indicators to ensure it meets actual needs:

• Recovery efficiency and processing capacity: Prioritize carts with a recovery rate ≥99.5% and a processing capacity of 30-80kg/h—this matches the gas volume of most 35kV GIS units and avoids prolonged operation.

• Intelligence level: Choose carts with PLC control systems and touch screens, which can automatically monitor parameters such as recovery pressure, temperature, and filtration efficiency, and record operation data (such as recovery volume, time). This not only reduces manual operation errors but also facilitates traceability of environmental compliance data.

• Safety certification: Ensure the cart has passed international certifications such as IEC 60480 (SF6 gas handling standard) and domestic GB 19517 (safety requirements for electrical equipment), and check whether the storage cylinder has a national pressure vessel inspection certificate.

• After-sales support: Select manufacturers that provide on-site installation guidance, operator training, and 24-hour maintenance services. Since the filtration system and compression components of the recovery cart need regular replacement, timely after-sales support can avoid equipment downtime affecting 35kV GIS maintenance.

4. The Role of Dedicated Carts in Green Power Development

With the global emphasis on "double carbon" goals, power enterprises are facing increasingly strict SF6 emission restrictions. The SF6 gas recovery cart for 35kV GIS combined electrical equipment not only helps enterprises reduce greenhouse gas emissions and avoid environmental penalties but also reduces the purchase cost of new SF6 gas (recovered gas can be reused after purification, saving 30-50% of gas procurement expenses). In the long run, promoting the use of dedicated recovery carts is an important measure to realize the green operation of 35kV GIS distribution networks and support the low-carbon transformation of the power industry.

In conclusion, the dedicated SF6 gas recovery cart is an indispensable supporting equipment for 35kV GIS maintenance. By focusing on functions such as high-efficiency recovery, deep purification, and safe storage, and combining parameter matching and structural adaptability, it can effectively solve the pain points of SF6 gas management in 35kV GIS, creating dual value for environmental protection and operational efficiency.