From truck-mounted units to a twin-module E-House at a 500 kV substation: ETENZ de-icing enclosures

A second fixed DC de-icing system is being added at China Southern Power Grid's (CSG) 500 kV Liping substation in Guizhou, and its control E-House is now in place on site. Built from two modules joined side by side, the E-House measures 11.4 × 5.6 × 3.5 m overall, making it the largest by volume of the de-icing enclosures and E-Houses ETENZ has manufactured for NR Electric. Since 2023, the series has grown to more than 20 units, serving State Grid and CSG de-icing projects across seven provinces and regions.

Why the Liping E-House comes in two modules

At 5.6 m, the complete E-House is wider than normal transport allows. It was therefore built in the factory as two modules, shipped to Liping separately and joined side by side at the station, where they open into one continuous room. Interior integration followed NR Electric's panel layout, and the air conditioners mounted outside on the end wall, along with the fire protection system inside, were delivered with the E-House. For project details, see the Liping DC de-icing control E-House case study.

Enclosure types for power line de-icing systems

A DC de-icing system rectifies AC power from the substation into direct current and applies it to the ice-coated line, where the current heats the conductor itself until the ice melts. The system's rectifier valve groups, protection and control panels and cooling equipment can be housed in factory-built enclosures and shipped to the substation as complete units. ETENZ has built the following types for NR Electric:

• Truck-mounted mobile de-icing units: enclosures 4.3 m or 6 m long, about the width of a standard shipping container, carried on a truck and moved between substations as de-icing work requires.
• Fixed-station containers and control E-Houses: the primary equipment is housed in a container 13–14 m long, and the protection and control panels in a control E-House about 7 m long, with the two sited at the same station. For some stations, ETENZ also mounted and wired the panels inside the control E-House.
• Filter and valve enclosures: the de-icing system's filters and valve groups are housed in two separate enclosures, 8.8 m and 6.5 m long respectively.
• Overhead ground wire de-icing enclosures: 7 m long, built for systems that de-ice a line's overhead ground wires.

Sizes vary widely, but every design starts from NR Electric's equipment layout. A truck-mounted unit has to keep its length, width and height within vehicle transport limits. At fixed stations, the arrangement of the panels and primary equipment sets the enclosure length. The Liping control E-House, 5.6 m wide, travels as two modules that are joined at the station.

Fitting the de-icing system at the factory

Enclosures usually go first to NR Electric's factory, where the de-icing equipment is fitted into them, and then ship to the substation as complete units. Air conditioning, fire protection, cable entries and lifting points are laid out to suit the equipment arrangement while the enclosure is being built. At the substation, what remains is lifting each unit into position and making the external connections.

In this series, ETENZ manufactures the enclosures and, project by project, adds air conditioning, fire protection and interior integration. Containers and control E-Houses for truck-mounted and fixed de-icing systems can be custom-built around the equipment layout and transport conditions.