GIS (Gas Insulated Switchgear) is a high-voltage switchgear that uses SF₆ gas as the insulating medium. It seals components such as circuit breakers, disconnectors, earthing switches, transformers, lightning arresters, and busbars within a grounded metal casing, achieving compact and reliable power control and protection.
I. Definition and Composition
Structure: A fully enclosed metal casing filled with SF₆ gas replaces traditional air insulation. Key components include circuit breakers, disconnectors, earthing switches, busbars, instrument transformers, and lightning arresters.
Insulation Medium: SF₆ gas offers excellent insulation and arc-extinguishing capabilities, significantly reducing equipment size.
II. Core Features
1. Compact and Efficient
Small Size: The three-phase, common-chassis structure (e.g., a bay width of only 0.8 meters) reduces floor space by over 70% compared to traditional equipment, making it suitable for space-constrained environments such as cities and hydro power stations.
Lightweight: The aluminum alloy casing reduces weight (approximately 3.5 tons for a standard bay), lowering floor load requirements and supporting multi-story installations.
2. High Performance and Reliability
Arc Extinguishing Technology: The circuit breaker utilizes "thermal expansion + blow-through" self-extinguishing technology, offering a breaking current of up to 40kA, an electrical life of ≥22 cycles, and a mechanical life of over 10,000 cycles.
Low Loss: The casing minimizes eddy current losses, and the spring mechanism operates with an operating noise level of ≤55dB (meets urban nighttime standards).
Sealing: The annual SF₆ leakage rate is ≤0.1%, and the modular design reduces sealing points, requiring minimal maintenance.
3. Intelligence and Adaptability
-Supports online monitoring (gas density, mechanical properties, and partial discharge), making it compatible with digital substations. Passed -50°C~55°C high and low temperature and magnitude 9 earthquake tests, suitable for harsh environments such as plateaus, dirt, and severe cold
GIS switchgear has become the mainstream choice for high-voltage power distribution due to its high degree of integration, safety, reliability and strong adaptability, and is particularly suitable for scenarios with limited space and harsh environments.
