Successful energization of the first 500kV - 900MVA transformer manufactured in Vietnam on the national power grid

The national-level science and technology product - the 500kV-3x300MVA transformer designed and manufactured by Dong Anh Electrical Equipment Corporation (EEMC) was successfully energized at 11:23 PM on December 14^th 2025, at 500kV Hoa Binh Substation (Hoa Binh Ward, Phu Tho Province). This is also the 500kV Hoa Binh Substation Capacity Upgrade Project invested by the National Power Transmission Corporation.

The 500kV-3x300MVA transformer is a product of a national-level science and technology project assigned by the Ministry of Science and Technology to EEMC. After being evaluated as an excellent product by the State-level Acceptance Council and approved for operation by Vietnam Electricity (EVN), EEMC deployed transportation and installation at the AT2 position of 500kV Hoa Binh Substation. Under the direction of EVNNPT and coordination of related units, the transformer unit completed installation, testing, and calibration on December 8^th 2025.

The 500kV Hoa Binh Substation Capacity Upgrade Project is a special-grade, Group B energy project, with investment scale: replacing 2 existing 500/220/35kV-450MVA transformers with 2 new 500/220/35kV-900MVA transformers, increasing the total station capacity from 900MVA to 1,800MVA. Phase 1 replaces AT2 transformer from 450MVA to 900MVA; Phase 2 will replace AT1 transformer from 450MVA to 900MVA, expected to be completed in the coming phase.

In the context of the 450MVA transformers at 500kV Hoa Binh  Substation operating at overload at many times, the station's capacity upgrade will contribute to ensuring operational safety as well as enhancing power transmission capacity from large and small hydropower sources in the Northwest region, ensuring stable power supply for Phu Tho province, Hanoi Capital and northern provinces, especially in the context of increasing load demand. This is an urgent project playing an important role in ensuring national energy security.

According to the Power Transmission Project Management Board (under EVNNPT), the project construction process faced many challenges due to construction in cramped conditions; equipment at 500kV Hoa Binh Substation being energized; hydropower plants in the area being mobilized at maximum capacity to optimize costs, making power outage registration difficult. Under the close direction of EVNNPT and support from dispatch levels, Power Transmission Company 1, and Hoa Binh Power Transmission Team, AT2 transformer of 500kV Hoa Binh Substation was successfully upgraded in capacity.

For Dong Anh Electrical Equipment Corporation, this is an important step marking the first time a domestic enterprise has mastered the design and successful manufacture of a 500kV transformer with the largest capacity on Vietnam's transmission grid. At the same time, it helps EEMC train a team of design engineers, technology engineers, managers and skilled technical workers to master the technological equipment line for manufacturing 500kV transformers. This success is also a premise for EEMC to continue striving to research and develop new products, contributing to localizing major electrical equipment on Vietnam's power grid.

EVN.COM.VN