Kamil Filik

Current Impulses in the Lightning Protection System of a Test House in Poland

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.

Calibration of electric field antennae operating in the ELF-MF frequency range at the lightning research station in Rzeszow

The purpose of this paper is to find calibration coefficients for antennae operating at the Lightning Research Station in Rzeszow. Two types of antennae used for acquisition of lightning electric field were examined. The first sensor was the ELF electric field mill registering slow electric field variations originated in the thunderstorm cloud. The second antenna was designed to recording relatively fast ELF-MF components of lightning as return stroke, continuing current and preliminary breakdown. In order to create uniform distribution of electric field during the calibration a dedicated setup was made in the high voltage laboratory. Different generators were used to create adequate field waveforms. Due to significant difference in amplification and bandwidth for each sensor. Devices were calibrated together with 10 meter cables dedicated for wiring signal from antenna to the A/D converter. Estimated calibration coefficients were 47.5 mV/kV and -334 mV/kV for the slow and fast electric field sensor, respectively. Small variation of those coefficients was observed when the signal transmission line was terminated by the characteristic impedance. Cable length does not affect the measured signals in this configuration.

Lightning current distribution in a laboratory model of lightning protection system

The paper presents the results of preliminary laboratory tests of impulse current distribution in a model of the lightning protection system (LPS). The wooden frame house was prepared in a scale 1:5. It was based on the full size object subjected to lightning currents during open air experiments at the test side in Huta Poręby near Rzeszów. It was equipped with the model of the lightning protection system connected to the supplying electrical installation. The surge current injected to the tested system in the laboratory was produced with use of the lightning transient generator. Measurements were done for three varied shapes of the injected impulse current. The obtained results indicated the frequency dependent behaviour of the tested system. The current distribution in the proposed laboratory model of LPS is similar to those achieved during the tests on the real scale objects in recent years. Streszczenie. W artykule przedstawiono wyniki badań laboratoryjnych rozpływu prądów piorunowych w modelu urządzenia piorunochronnego. W skali 1:5 przygotowano drewniany szkielet budynku mieszkalnego, odwzorowujący obiekt używany do poligonowych badań rozpływu prądów udarowych w jego instalacjach piorunochronnej oraz elektrycznej, prowadzonych w Hucie Poręby niedaleko Rzeszowa. Zaproponowany model odzwierciedla istniejącą na poligonie instalację odgromową wraz z przyłączoną do niej niezasiloną typową elektryczną instalacją w postaci wewnętrznej sieci elektrycznej nn wraz z osprzętem, dochodzącej do złącza kablowego ziemnej linii kablowej nn, stacji transformatorowej i linii napowietrznej SN. Pomiarów dokonano dla trzech różnych kształtów wstrzykiwanego prądu udarowego. Uzyskane rozpływy prądów impulsowych są zbliżone do tych, obserwowanych podczas poligonowych badań pełnowymiarowych systemów przez ostatnie lata. Badany model wykazuje zależny od częstotliwości charakter. (Rozpływ prądów udarowych w modelu laboratoryjnym urządzenia piorunochronnego).

Experimental investigation of the effectiveness of lightning protection system

The preliminary laboratory experiments were carried out of impulse current distribution in a laboratory model of the lightning protection system. The tested system is a model in a scale of 1:5 based on the full size test house equipped with the lightning protection system and connected to a supplying electrical installation used for an open air experiments conducted for the few years. The simulated lightning current was injected into the laboratory model of installation with a surge current generator. Distribution of current in the tested system is presented. Measurements were done for varied shapes and peak levels of the injected current. The results indicated an influence of frequency depended parameters of the laboratory model on both the peak level and the shape of the current waveforms, recorded in measuring points. The results obtained during the laboratory and the open air experiments are comparable.

Surge current distribution in the lightning protection system of a test house equppied in electrical and electronic appliances

Open air experiments were conducted of surge current distribution in the lightning protection system, supplying cable and electrical installation of a test house equipped in household appliances. Surge currents were injected from the generator into the installation. Current distributions in elements of tested system were measured with multi-channel electro-optical system. To verify the experimental results the simulations of surge current in the test house modeled in ATP-EMTP were conducted. The results indicated a significant influence of frequency dependent parameters of the test house elements on both the amplitude and the shape of current waveforms.