35kV Gas Insulated Metal Enclosed Switchgear (35kV GIS/C-GIS) is a fully enclosed, fully insulated, compact all-in-one power distribution device that seals all primary components such as circuit breakers, disconnectors, busbars, and transformers within a metal enclosure filled with SF₆ (or environmentally friendly mixed gas). It is a mainstream solution for 35kV distribution networks, featuring high reliability, miniaturization, and maintenance-free operation.
1. Product Positioning and Application Scope
Voltage Level: Rated voltage 40.5kV (for 35kV system), three-phase AC 50Hz, suitable for single busbar / single busbar section systems.
Core Functions: Power reception, distribution, control, protection, and monitoring, supporting frequent operations and rapid fault clearance.
Typical Scenarios:
Urban core areas, underground substations, high-rise building distribution rooms (limited space)
High-altitude, humid, salt spray, pollution, coastal areas
Wind power / photovoltaic gathering stations, rail transit, industrial and mining enterprises, data centers
Renovation of old substations, emergency power supply, rapid expansion projects

II. Core Technical Parameters (General Configuration)
Rated Voltage: 40.5 kV
Rated Current: 1250A/1600A/2000A/2500A
Rated Short-Circuit Breaking Current: 25kA/31.5kA/40kA
Heat Stability Current (4 seconds): 25kA/31.5kA/40kA
Magnetic Stability Current: 63kA/80kA/100kA
Insulating Gas: SF₆ (0.02–0.05 MPa) / Environmental-friendly Mixed Gas
Protection Grade: Air Box IP67, Cabinet IP54
Mechanical Life: Circuit Breaker ≥ 10,000 times, Isolating Switch ≥ 20,000 times
Environmental Temperature: -40℃ to +55℃
Altitude: ≤ 4000m (Customized for High Altitudes)

III. Structure and Composition (Modular Design)
1. Core Gas Chamber (Sealed Body)
It adopts a stainless steel/aluminum alloy welded gas box, filled with SF₆ gas for insulation, and includes:
Breaker: Vacuum arc extinguishing (mainstream) or SF₆ arc extinguishing, equipped with spring / permanent magnet mechanism
Three-position Isolating Switch: Isolation / Grounding / Closing integrated, simplifying the structure
Busbars, current / voltage transformers, lightning arresters, cable terminals
Each gas chamber is independently sealed, with complete pressure monitoring and explosion-proof devices.
2. Functional Modules (Standard Bays)
Infeed cabinet, Outfeed cabinet, PT / Lightning Arrester cabinet, Metering cabinet, Busbar Linkage cabinet, Isolating cabinet
The cabinet width can be reduced to 600–800mm, reducing the floor space by 50%–70% compared to traditional air-insulated cabinets (KYN61).
3. Secondary and Intelligent Cabin
Integrated with protection and control, measurement and control, online monitoring (partial discharge, SF₆ density, temperature), communication (IEC 61850), five-prevention interlock, dew prevention control.
IV. Core Performance and Advantages
Extremely miniaturized, with minimal floor space
Fully sealed gas insulation, eliminating air clearance, single cabinet volume is only 1/3 of traditional cabinets, significantly reducing construction and space costs.
Comprehensive environmental adaptability, high reliability
Gas box IP67, not affected by condensation, dirt, salt fog, high altitude, with a fault rate far lower than air-insulated cabinets, maintenance-free period ≥ 10 years.
Perfect safety interlock
Built-in mandatory five-prevention + gas chamber pressure interlock + grounding interlock, preventing misoperation, ensuring extremely high safety for personnel and equipment.
Factory prefabrication, rapid commissioning
Completed assembly, inflation, and testing in the factory; on-site only requires foundation connection and cable connection, installation period ≤ 7 days.
Intelligent and green
Support remote monitoring, fault diagnosis, unmanned operation; low loss, low noise, suitable for smart grids and the dual-carbon goals.