The National Electricity Transmission Company Transelectrica SA inaugurated the construction of a new voltage level, namely 400 kV, within the Arefu 220/110 kV substation, which thus ensures the stability and operational safety of the electrical transmission network and the optimal supply of consumers in the Argeș-Vâlcea region. The investment, with a total value of over 83 million lei, includes the construction of the 400 kV substation in state-of-the-art GIS (Gas Insulated Switchgear) technology, which ensures a high level of operational reliability and safety, and the installation of a 400 MVA, 400/220 kV autotransformer.
The 400/220/100 kV Arefu substation plays an essential role in the evacuation of electricity produced in the hydroelectric power plants in the area, especially by the Vidraru Hydroelectric Power Plant, and contributes to supplying consumers in Argeș and Vâlcea counties, while providing the necessary flexibility for the integration of renewable energy sources.
The works were carried out by Association between SIEMENS ENERGY SRL – ELECTROMONTAJ CARPAȚI S.A. – ELECTROMONTAJ S.A. between January 2023 and December 2024, and the major investment project regarding the increase in the operational safety of the Argeș-Vâlcea network area, the construction of the 400 kV Arefu substation and the installation of a 400 MVA, 400/220 kV autotransformer had as its main objective the strengthening of the operational safety of the network by connecting the Argeș – Vâlcea area to the 400 kV transmission network. Until this investment was made, this area was supplied exclusively by the 400/220/110/20 kV Bradu substation, through a 220 kV line ring. By building the new substation and installing the 400 MVA, 400/220 kV autotransformer, a second connection of this ring was created with the 400 kV transmission grid, which brings a significant increase in the stability and reliability of the energy system.
At the same time, the installation of the new autotransformer ensures better integration of the electrical grids and optimization of power flows, improving the stability of the National Power System.
A major benefit of this investment is the implementation of advanced automation and control systems, which allow continuous monitoring of equipment through specific automatic surveillance, self-testing and self-diagnosis functions, thus ensuring predictive maintenance of the equipment.
By achieving the 400 kV voltage level in the Arefu station, it is possible to increase the capacity to connect to the grid both new electricity production plants and new consumers.
The 220/110 kV voltage levels in the Arefu Electric Transformer Station, put into operation in 1967-1968, were modernized through an investment project completed in 2023.
CNTEE Transelectrica SA focuses its efforts on strategic investments for the re-engineering and modernization of the Electric Transmission Network (RET). According to the Development Plan of the Electric Transmission Network for the period 2024 – 2033, approved by the National Energy Regulatory Authority, with a total value of 9.4 billion lei, the projects intended for the re-engineering and modernization of electrical installations planned for the next 10 years by the National Electricity Transmission Company Transelectrica SA have the largest share of the value of the Development Plan, equivalent to approximately 2.9 billion lei.