The full scale test house was equipped with the lightning protection system and connected to the 15 kV/400 V transformer station. The simulated stroke current was injected into the installation with a current surge generator. Distribution of current in the lightning protection system and connected power supply installation is presented. Measurements were done for several configurations of the LPS, and for current amplitudes ranging from 1 to 10 kA. The results indicated variation with both the amplitude and the shape of the waveforms. The resistance was measured for several groundings individually and for entire grounding system with respect to the surge generator location. Measured waveforms showed frequency-dependent behavior of the circuit. Therefore, in order to improve current simulation accuracy the grounding system impedance should be considered rather than pure resistance. The vertical ground rods of the test house have capacitive impedances, while the long underground cable connected to the grounding system of the transformer has inductive impedance.

The railway transport system is a key factor supporting industrialization in all aspects of human activity. However, in order not to lose its importance, it must meet the challenge of modern civilization. The safety, reliability, and efficiency of railway transport, to a large degree, depend on using highly integrated electronics, which are very sensitive to various disturbances generated in the electric traction system and train or coming from the environment. One of the sources of electromagnetic disturbances are high-voltage (HV) power lines running close to the railway infrastructure. The purpose was to assess the electromagnetic impact of overhead HV transmission lines on buried signaling cables of the railway traffic control system crossbreeding with them. The levels of voltage induced in the cable under steady state and the earth fault in the HV line at various soil resistivity were estimated. A software tool based on a hybrid numerical method that combines circuit theory and electromagnetic field theory was used for computations. It was found that very high voltages may be induced in the signaling cables during earth faults in the HV lines, which may lead to serious interference or damage to the equipment. The results provide useful knowledge for implementing modern railway traffic control systems and protection measures.

The aim of the paper is to compare different multilayer soil models in computer estimation of grounding system resistance as an alternative conception to typical uniform and two-layer soil models. Experimental tests of a simple grounding system are described. Preliminary measurements were conducted at the new open-air laboratory belonging to the Rzeszow University of Technology (RUT), Poland. Finally, measurements of soil resistivity by use of different methods, and at the same time, the ground resistance measurements of simple grounding system were performed. Using the experimental data, a different multilayer soil models were proposed and the grounding resistances of the same grounding system were computed. In case of impact excitations characteristic for lightning currents the potential distributions around the analyzed grounding system are shown for the selected multilayer soil, and then, the obtained simulation results are compared with the case of the corresponding uniform soil.

The paper presents results of the lightning protection system (LPS) tests for a small residential structure with the connected home appliances and electronics conducted in 2013 at the new test site in Poland using the mobile surge current generator. The primary objective was the same as in the previous studies, that is, to examine the current waveshapes in different parts of the circuit and the division of the injected surge current between the grounding system of the LPS and remote ground. The current waveshapes in the vertical ground electrodes differed from the injected current waveshapes and from the current waveshapes in other parts of the test system. Computer simulation using ATP-EMTP carried out in order to verify the measurements. Vertical and horizontal ground electrodes are modeled for specified parameter resulting from the geometrical configuration of the system and the measured soil conductivity. Computed results show a good agreement with the experimental data. A significant influence of frequency dependent components of the system impedances on current waveshapes has been noticed.

Investigations were conducted aimed on examination of frequency characteristics of middle to low voltage distribution transformer used to supply residential buildings. Two methods were used for the investigations. First, the impedances (absolute values and angles) of transformer middle and low voltage windings were measured and registered using precision LCR meter for frequency range from 20 Hz to 10 MHz. These impedance characteristics were also examined using voltage surge generator and digital oscilloscope. Registered voltage and current waveforms were denoised and transformed to frequency domain. Apart from investigation of distribution transformer the frequency characteristic of input impedances of typical household electrical appliances were examined using the LCR meter. The conducted measurements are significant part of investigations concerning the lightning and overvoltage protection of residential buildings, which are conducted at the test site belonging to Rzeszow University of Technology.