Gas Insulated Switchgear Application in Urban Rail Transit

Gas Insulated Switchgear (GIS) ensures the stability and safety of power grid operation through its high-quality manufacturing processes. The long-term system integrity and technical excellence of this equipment rely heavily on the expertise and quality provided by the gas insulated switchgear manufacturer. Today, infrastructure demanding high supply reliability and safety, such as urban rail transit systems, increasingly utilize this type of switchgear. So, why is gas insulated switchgear so widely adopted in urban rail transit?

I. Epoxy Resin Encapsulation: Ensuring Prime Insulation and Safety

Urban rail transit lines often traverse areas with harsh environmental conditions, including those subject to condensation, salt spray, or severe pollution, imposing strict safety requirements on the power distribution equipment.

The majority of gas insulated switchgear units employ epoxy resin casting to cover live components, which are then sealed within a grounded metallic enclosure. This design provides the cabinet with exceptional explosion-proof and insulation capabilities, effectively resisting external environmental degradation and ensuring the purity and stability of the internal insulation medium. This process is vital for key components: the GIS bushing ensures effective gas sealing and external conductor connection; internal support and isolation are provided by the epoxy insulator; and integrated current measurement is achieved through the epoxy resin current transformer.

II. Power Switch: Explosion Protection and Enhanced Reliability

A key reason for the high-frequency application of GIS in urban rail transit operations is that its power switch is equipped with a professional explosion-proof device (such as pressure relief channels and diaphragms). In the event of an internal fault, this device can rapidly release pressure, maximizing the safety of personnel and equipment.

This not only helps improve the control and operational capacity of the power distribution network but also effectively prevents the switch body from suffering contamination and corrosion. Furthermore, the specifications of the power switch bushings can be upgraded or modified to flexibly suit the demands of explosion-proof environments.

III. Low Maintenance: Fully Sealed Structure

The GIS unit utilizes a fully sealed gas compartment structure, where internal parameters like pressure and humidity are fixed at the factory and completely isolated from the external environment. These vital parameters are continuously monitored by devices such as the SF6 gas pressure gauge to ensure the integrity of the sealed system.

Consequently, the equipment requires no frequent on-site inspection or maintenance. For urban rail transit systems, which face heavy operational demands and extremely short maintenance windows, this feature is a critical advantage for enhancing power supply reliability and reducing operational costs.

IV. Compact Size: Hermetic Sealing and Trend Toward Miniaturization

Gas insulated switchgear is generally recognized for its compact size and excellent hermetic sealing. Thanks to the superior insulating properties of the gas medium, GIS is significantly smaller than traditional air-insulated switchgear. Modern trends of MV switchgear design lean toward miniaturization and intelligentization, providing high adaptability to the various environments along urban rail transit routes.

By enhancing the rated voltage withstand capability of the insulation layers, GIS ensures the safe and stable operation of the power system while maximizing space saving in underground substations or equipment rooms.

Summary

In conclusion, the adoption of gas insulated switchgear, with its fully sealed and compact structure, perfectly meets the core demands of urban rail transit power systems for “high reliability, high safety, and low maintenance.” From excellent insulation performance in harsh environments (epoxy resin) to rapid response capabilities during faults (explosion-proof design), GIS ensures the stability of the electrical system. A proven medium voltage switchgear manufacturer is essential to integrating these technologies effectively into the network. As technology evolves, the functionality and scope of GIS continue to expand, firmly establishing its vital role in the transportation power distribution sector.