This is a project registered by EVN and EVNNPT to welcome the 12th National Party Congress.

The 500kV Son La – Lai Chau transmission line project was started in December 2013, with a total investment of VND 4,000 billion, with a total length of 158.5 km (2 circuits) from the 500kV Son La transformer station to the 500kV distribution yard of Lai Chau Hydropower Plant; expanding and installing equipment for 2 500kV bays at the 500kV Son La transformer station.

The 500kV Son La – Lai Chau transmission line includes 311 tower locations passing through the districts of Muong La, Thuan Chau (Son La); Tuan Giao, Muong Cha, Muong Lay (Dien Bien); Nam Nhun district (Lai Chau). The 500kV expansion section is located within the premises of the 500kV Son La transformer station, in Pi Toong commune, Muong La district (Son La).

The project is invested by EVNNPT, the Northern Power Project Management Board (NPMB) represents the investor in managing the project. The units participating in the construction include: Power Construction Joint Stock Company 1, Power Construction One Member Limited Liability Company 2, Power Construction One Member Limited Liability Company 4, Vietnam Power Construction Joint Stock Corporation, Song Da 11 Joint Stock Company, Song Da 11 - Thang Long Joint Stock Company, Power Installation and Construction Joint Stock Company, Construction Installation Joint Stock Company. Power Transmission Company 1 supervises the construction and takes over the management and operation when the project is completed.

The Son La - Lai Chau 500kV Transmission Line Project and the expansion of the Son La 500kV station were invested in construction to connect and transmit the capacity of Lai Chau Hydropower Plant (1,200MW) and small and medium hydropower plants in the Northwest region to the National Power System, contributing to ensuring the ability to supply electricity from hydropower plants in the Northwest region to loads in the North.