The construction of a 220kV transmission line started on August 25 in the northern province of Bac Giang, to serve the supply of electricity from Son La Hydroelectric Power Plant to the national grid.

The 5.3km line is expected to complete on August 30.

Contractors have used a hot-air balloon to lay the cable across the river.

The method helped shorten the construction time and save the cost for site clearance in the project areas.

Previously, hot-air balloons were also used in several other transmission projects in the northern mountainous region, where the lines ran through dangerous terrains. They included the 200kV line from Nho Que hydro-electric power plant in Ha Giang province to the Cao Bang 200kV station, and the 500kV line from Son La to Hiep Hoa.-VNA