## 3 Results
### Measurements of the EMF Strength around Energy Infrastructure  
In the case of existing energy infrastructure, the simplest solution is often to carry out measurements that show the actual \(E\) and \(B\) values in a given area. Measurements of actual \(B\) values are presented on the example of a 15 kV/0.4 transformer-distribution station located in the basement and on the ground floor of a residential building in the north of Poland. In order to determine the distribution of the MF in the vicinity of the mentioned transformer station, \(B\) measurements were carried out, based on which the values of \(H\) were estimated. The obtained results are presented in Figure 1. Further investigations focused on the determination of the maximum values of \(H\) in the building under consideration as well as in the apartment next to the transformer station. The extremum denoted value of was 5.3 A/m and 0.4 A/m, respectively. For the purposes of further analysis, exposure to the highest recorded \(H\) value was assumed, i.e., 15 A/m (close to the grounding wire of the power transformer). An example of \(E\) measurements is a study conducted on a building plot in northern Poland. An overhead 110 kV line of the following parameters runs over this plot: three AFL-6 240 mm\({}^{2}\) working cables (L1-L3) and a shield line (LR) with an OPGW 43/22 mm\({}^{2}\)/555 optical fiber with a cross-section of 96 mm\({}^{2}\). Knowing the parameters of the poles located in the immediate vicinity of the plot (Type P+5, Series S24, and Type ON120+5, Series S24), the minimum height of the wires above the ground was determined, taking into account the cable sag (see Figure 2). During measurements at a height of 2 m above the ground in the middle of the span, the results were obtained as shown in Figure 3. The coordinates on the x-axis match the data from Figure 2. The maximum value of \(E\) is 0.83 kV/m. It should be also mentioned  
Figure 1: Experimentally measured values of the magnetic field intensity \(H\) in [A/m] at the 15/0.4 kV/kV transformer station. The red circles in the side view indicate the measurement points. Figure 2: Distribution of cables (working cables L1, L2 and L3 and a grounding wire LR) in the 110 kV line in the middle of the span between the poles. The distances in the drawing (in meters) are given from the base of the power pole. that in a specific position under two line wires placed one above the other, \(E\) reaches a value of 0.66 kV/m due to the screening properties of EFs emitted by the wires. Below is a brief description of other objects examined and the highest measured electric (\(E_{max}\)) and magnetic (\(H_{max}\)) field intensity values, which are listed in Table 1:  
* A multi-family building with balconies near 110 kV overhead line: Measurements of the vertical component of \(E\) were taken under a high-voltage line at a height of 2 m above the ground on a straight line connecting the power pole with the corner of the building, near the pole and on the balcony on the fourth floor. The \(E\) values at a height of 2 m above the ground do not exceed 0.5 kV/m. Higher field intensities were measured at a distance of 2 m from the balcony grate, i.e., 1.8 kV/m, and above the balcony balustrade, 1 kV/m;
* An office space with inappropriate equipotential bonding: The highest \(B\) values were found in the room near the computer monitor screen (0.58 uT). At a distance of 0.1 m from the monitor surface, the value of \(B\) is reduced to 0.3 uT. Higher \(B\) values were noted in rooms through which the gas connection made of steel pipe passed. The probable cause of the observed phenomenon was the lack of an insulating insert on the gas connection or incorrectly made equalization connections in the building. The MFs measured directly on the pipe surface outside the building reached \(B\approx 5\) uT, which is the result of the main frequency current flow;
* A room above the MV/LV indoor station: Measurements were performed on the floor surface above the room where the 15/0.4 kV transformer was installed.