All three use SF6 switching technology but at different levels of insulation integration. The XGN15-12 is a box-type switchgear with an SF6 load switch tank inside a metal enclosure — only the switch itself is gas-insulated, while busbars and other components are air-insulated. The HXGN15-12 is a dedicated RMU with SF6 insulated switching compartments but still has partially air-insulated busbar sections. The GHRM is a fully gas-insulated switchgear (GIS) where ALL live parts — busbars, load switch, earthing switch, and connections — are enclosed within a single SF6-filled stainless steel tank. This makes the GHRM: (1) immune to all environmental contaminants (dust, humidity, salt, chemicals), (2) IP67 submersible, (3) much more compact (up to 60% smaller), (4) modularly expandable via plug-in gas-busbar connections, and (5) IAC AFL arc-resistant. It's the premium choice for the most demanding environments.

Modular expandability means each GHRM unit is a self-contained gas-insulated module (e.g., incoming feeder, outgoing feeder, metering unit, bus-riser, fuse combination unit) that can be connected to other modules using plug-in gas-tight busbar connectors. This allows you to: (1) start with a basic configuration and add more feeders later as load grows, (2) mix and match different module types to create custom assemblies, and (3) add or replace modules on-site without de-gassing the entire assembly — each module maintains its own sealed gas environment. The plug-in connections are gas-tight and require no special tools or gas handling. This is a significant advantage over fixed-design RMUs where the configuration cannot be changed after manufacture without returning to the factory.

The stainless steel SF6 gas tank of the GHRM is rated IP67, which means it is dust-tight and can withstand temporary immersion in water up to 1 meter deep for up to 30 minutes without water ingress or damage. This is achieved through precision welding of the stainless steel tank and hermetic sealing of all penetrations. This makes the GHRM suitable for installation in underground vaults, basement substations, coastal areas, and other locations prone to flooding or high humidity. Note that the IP67 rating applies to the gas tank itself — the external cabinet/enclosure has IP3X–IP4X protection. For prolonged submersion or deep underwater applications, special configurations may be required. Always verify specific installation requirements with our engineering team.

IAC (Internal Arc Classification) AFL means the switchgear has been type-tested to safely contain and manage internal arc faults. "A" means the arc fault is contained on the accessible front side (operator side), "F" means the unit has passed the test with all covers and doors in place, and "L" means the cable compartment side is also protected. The GHRM is rated IAC AFL up to 20kA for 1 second. This is critically important for operator safety: in the rare event of an internal arc fault (caused by equipment failure, improper maintenance, or foreign objects), the arc energy and hot gases are safely directed away from the operator through pressure relief channels, preventing catastrophic panel rupture and operator injury. Utilities and industrial customers increasingly require IAC classification as a standard safety requirement for personnel-accessible switchgear.

The GHRM operates at a relatively low SF6 gas pressure of 0.15–0.4 bar (absolute), which is only slightly above atmospheric pressure. This low-pressure design reduces stress on tank seals and minimizes leakage potential compared to higher-pressure GIS systems. The insulating performance of SF6 at these pressures is more than sufficient for 12kV and 24kV applications. Because the tank is sealed for life with ≤0.1% annual leakage, the pressure remains within specification for decades without any maintenance. Standard units include a visual gas density indicator that can be inspected during routine walk-throughs. For automated installations, optional gas density monitors with alarm contacts are available to provide remote monitoring of gas pressure via SCADA or building management systems.

The GHRM is designed for distribution automation (DA) and smart grid integration with several optional features: (1) Motor-operated mechanisms — enable remote control of load switches and earthing switches via SCADA systems, supporting DNP3, IEC 61850, Modbus, or other communication protocols. (2) Fault Passage Indicators (FPI) — detect and indicate fault current passage on each feeder, enabling faster fault location and automatic network reconfiguration. (3) Partial Discharge (PD) monitoring — sensors that continuously monitor for partial discharge activity within the GIS, providing early warning of insulation degradation. (4) Integrated protection and control relays — digital relays with metering, protection, and communication capabilities. These automation features allow the GHRM to be integrated into modern DA systems for automatic fault isolation, service restoration, load switching, and real-time network monitoring — essential for smart city and digital grid deployments.