Eight-Module GIS Switchgear E-House

Adjacent modules are aligned on their mating faces and held by splice plates: each plate straddles the two frames and is drawn up on paired bolts with flat washers and nuts, repeated at intervals up the height of the seam. Outside, an aluminium capping strip closes the seam and takes the sealing; inside, the seam is trimmed by the lining panels. This turns the over-dimension haulage and single heavy lift of a one-piece building into eight separate vehicle loads and eight conventional lifts — each module's envelope is controlled for transport in its own right, and site work is alignment, tightening and sealing. Joint accuracy is held by trial assembly at the works, with dimensional and structural inspection completed before despatch.

The interior is detailed around the GIS layout the customer provides: mounting base positions and levels follow the support frames, operating aisles are held on the control face, working room for gas handling is held on the compartment side, and roof provisions follow the lifting points. The GIS itself is supplied by the customer or integrated within the agreed scope; its voltage class, rated current, gas pressure and switching duty are governed by the equipment maker's technical agreement. ETENZ is responsible for the mounting bases, in-cabin interfaces, wall and floor penetrations and the reserved terminal boxes for secondary cabling. This enclosure serves a 220 kV class installation — that is the voltage class it serves, not an electrical rating of the enclosure itself.

Climate control is configured per module rather than per building: each module is sized to its own heat load and carries a wall-mounted industrial air-conditioning unit, with a rain hood above it, a sealed wall penetration, and the condensate line run down the outside. Adjacent modules do not share an air path, so one unit out of service does not affect the rest. Cooling capacity is confirmed against the heat load; environmental design targets are configurable, typically −40 to +55 °C operating temperature and derated operation up to 4000 m altitude. Air conditioning, lighting and maintenance sockets are fed from the module's own auxiliary distribution box — and ETENZ designs and manufactures those distribution and control boxes in house.

SF6 is denser than air, so a leak settles and collects near the floor where high-level extraction cannot reach it. Extract fans and discharge openings are therefore set low, close to floor level, taking low-lying air straight out of the enclosure, while intakes are set high to establish a top-down airflow. The fans are mounted outside on the wall in weather housings with removable service panels, and the openings carry protective mesh and filters so ventilation volume is met alongside the IP54/55 ingress target. Fan start and stop can be interlocked with in-cabin gas monitoring, with the monitoring devices and interlock interfaces either supplied within scope or reserved. Air volume and interlock logic are confirmed against the project's gas-compartment volume and the applicable code.

The enclosure carries an outward-opening escape door fitted with a push bar: from inside, one hand opens it without a key, so nobody has to find a key or work a lock in an emergency. An exit sign and fire emergency lighting sit above the door and switch in automatically on loss of mains. The door and frame are sealed and insulated, and a removable louvre in the lower panel joins the ventilation path. Fire detection, alarm, release and interlock interfaces are reserved out of the enclosure during fabrication; the suppression package can be supplied and installed by ETENZ within scope, or nominated and free-issued by the customer. No enclosure-level fire-resistance or burglary-resistance class is claimed.