**1. Introduction**

The institutions involved in electric power transmission in Lithuania and Poland have decided to implement the electricity link "LitPol Link". This link is designed to connect the power systems of the Baltic States to those in Western Europe and also contributes to the development of the general European electricity market as well as boosting the reliability of the power supply. In pursuit of increasing the capacities of electric power transmission, the decision was made to supplement the LitPol Link by installing an extra 400 kV high-voltage AC double-circuit transmission line.

Recently, there has been increasingly widespread concern over the influence of the electromagnetic field (50 Hz) on the health of residents. One of the fundamental challenges is ensuring safe conditions for those living in locations where such an electromagnetic field is present.

The recently adopted Hygiene Standard HN 104:2011 "Human protection against electromagnetic fields caused by overhead power lines" is currently valid in the European Union (EU) and states that the effective values of the magnetic field strength must never exceed exceed 32 A/m or 40 μT (magnetic flux density) in residential environments, or 16 A/m or 20 μT (magnetic flux density) within residential and public service buildings. These values should never be exceeded irrespective of the duration of a person's exposure to an electromagnetic field.

The double-circuit 400 kV power transmission line is one of the most powerful electrical installations in the entire power system; at a frequency of 50 Hz, it generates an intense magnetic field. Therefore, it is necessary to focus on the installation and safe operation of the 400 kV double-circuit

overhead transmission line in order to prevent the magnetic field generated by this power transmission line from exceeding the requirements set by the European Union (EU) Hygiene Standard HN 104:2011.
