At 11:30 PM on 3 February  2026, the National Power Transmission Corporation (EVNNPT), the Central Power Projects Management Board (CPMB), in coordination with the National Electricity System and Market Operation Company Limited (NSMO) and other relevant units, energized and put into operation the second 500kV shunt reactor at the Son La 500kV Substation, thereby completing the installation of two 500kV shunt reactors at the Substation according to the approved design.

The work forms part of the project on installing 500 kV shunt reactors to optimize compensation capacity once the 500 kV Circuit 3 transmission line is commissioned, within the framework of EVNNPT’s program "Calculation and Optimization of Capacitor and Reactor Capacity on the 500 kV power system". The project aims to address the voltage stabilization problem in the context of the expanding 500kV transmission grid, high transmission output, and complex operating regime along the North-Central-South axis.

Second 500kV shunt reactor at Son La 500kV substation having successfully energized

The project is a special-grade, Group B energy work, invested in by EVNNPT and managed and operated by CPMB. The project scope is implemented at 8 operating 500kV substations on the national power transmission grid, including: Son La 500kV Substation (Son La province); Ha Tinh (Ha Tinh province); Da Nang and Thanh My (Da Nang city); Doc Soi (Quang Ngai province); Pleiku and Pleiku 2 (Gia Lai province); Di Linh (Lam Dong province).

At the Son La 500kV Substation, the project involves the installation of two 500kV – 90MVAr reactors along with synchronized primary and secondary equipment. Previously, one reactor was put into operation on 31 December 2025. The completion of the commissioning of the second shunt reactor plays an important role in the Northwest power grid, where numerous large-capacity hydropower sources operate under regimes that fluctuate significantly with seasonal and hydrological conditions.

The work helps absorb excess reactive power, stabilize voltage on the 500kV grid, limit overvoltage risks during low-load periods, and enhance the reliability of power supply for the national power system, particularly when hydropower output is high to meet production and daily-life demand.

Translator: Hải Yến