**Ramunas Deltuva \* and Robertas Lukoˇ ¯ cius**

Faculty of Electrical and Electronics Engineering, Kaunas University of Technology, LT-51367 Kaunas, Lithuania; robertas.lukocius@ktu.lt

**\*** Correspondence: ramunas.deltuva@gmail.com; Tel.: +370-612-98623

Received: 24 March 2020; Accepted: 1 May 2020; Published: 8 May 2020

**Abstract:** A high-voltage AC double-circuit 400 kV overhead power transmission line runs from the city of Elk (Poland) to the city of Alytus (Lithuania). This international 400 kV power transmission line is potentially one of the strongest magnetic field-generating sources in the area. This 400 kV voltage double-circuit overhead transmission line and its surroundings were analyzed using the mathematical analytical methods of superposition and reflections. This research paper includes the calculation of the numerical values of the magnetic field and its distribution. The research showed that the values of the magnetic field strength near the international 400 kV power transmission line exceed the threshold values permitted by relevant standards. This overhead power line is connected to the general (50 Hz) power system and generates a highly intense magnetic field. It is suggested that experimental trials should be undertaken in order to determine the maximum values of the magnetic field strength. For the purpose of mitigating these values, it is suggested that the height of the support bars should be increased or that any individual and commercial activities near the object under investigation should be restricted.

**Keywords:** magnetic field strength; magnetic flux density; magnetic potential; current density; power transmission line
