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Content available Calculation of electric shock current caused by touch and step voltage in grounding grids including climatic conditions
Sikora Roman, Markiewicz Przemysław, Korzeniewska Ewa, Nikitina Alyona
Przegląd Elektrotechniczny
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2024
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R. 100, nr 4
217--220
EN
Appropriately designed grounding should provide such a distribution of electrical potential on the ground surface to ensure the values of electric shock currents are at an acceptable level. The potential distribution depends on the design and size of the grounding system and the resistivity of the soil. The value of the electric shock current depends on the distribution of electrical potential on the ground surface determining the values of step and touch voltages and the impedance of the human body. The impedance value of the human body is affected by factors such as the condition of the epidermis, and the path of shock, but also environmental factors such as humidity and temperature. The article presents the results of calculations of human body impedance and electric shock current for different environmental conditions and different design variants of the grounding system, determining the values of step and touch voltages.
PL
Odpowiednio zaprojektowane uziemienie powinno zapewniać taki rozkład potencjału elektrycznego na powierzchni gruntu, aby zapewnić wartości prądów rażeniowych na akceptowalnym poziomie. Rozkład potencjału zależy od konstrukcji i rozmiaru systemu uziemienia oraz rezystywności gruntu. Wartość prądu rażeniowego zależy od rozkładu potencjału elektrycznego na powierzchni ziemi, określającego wartości napięć krokowych i dotykowych oraz impedancji ludzkiego ciała. Na wartość impedancji ciała człowieka mają wpływ takie czynniki jak stan naskórka, droga rażenia, ale także czynniki środowiskowe takie jak wilgotność i temperatura. W artykule przedstawiono wyniki obliczeń impedancji ciała człowieka i prądu rażenia dla różnych warunków środowiskowych i dla różnych wariantów projektowych systemu uziemienia, determinującego wartości napięć krokowych i dotykowych.
2
Content available remote Using interpolation method to estimation step and touch voltage in grounding system
Sikora Roman, Markiewicz Przemysław, Mączka Mariusz, Pawłowski Stanisław, Plewako Jolanta
Przegląd Elektrotechniczny
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2023
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R. 99, nr 2
263--266
EN
The article presents a methodology for calculating the step voltage on the ground surface above the grounding grid of an MV/LV substation. The calculations are performed by using the interpolation method based on the knowledge of the electric potential distribution. The electric potential distribution was determined for the grounding grid model using the finite element method in ANSYS program. The interpolating relationship of two variables allows the calculation of step voltage for any location of human feet.
PL
W referacie przedstawiono metodykę obliczenia napięcia korkowego na powierzchni gruntu nad uziomem stacji SN/nN. Obliczenia są wykonywane za pomocą interpolacji w oparciu o znajomość rozkładu potencjału elektrycznego. Rozkład potencjału elektrycznego został wyznaczony dla modelu uziomu z wykorzystaniem metody elementów skończonych w programie ANSYS. Wyznaczona zależność interpolująca dwóch zmiennych pozwala na odliczenie napięcia krokowego dla dowolnej lokalizacji stóp człowieka.
3
Content available An accurate model of LED luminaire using measurement results for estimation of electrical parameters based on the multivariable regression method
Sikora Roman, Markiewicz Przemysław, Rózga Paweł
Metrology and Measurement Systems
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2022
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Vol. 29, nr 2
251--269
EN
Light sources and luminaires made in the LED technology are nowadays widely used in industry and at home. The use of these devices affects the operation of the power grid and energy efficiency. To estimate this impact, it is important to know the electrical parameters of light sources and luminaires, especially with the possibility of dimming. The article presents the results of measurements of electrical parameters as well as luminous flux of dimmable LED luminaires as a function of dimming and RMS supply voltage. On the basis of the performed measurements, a model of LED luminaire was developed for prediction of electrical parameters at set dimming values and RMS values of the supply voltage. The developed model of LED luminaire has 2 inputs and 26 outputs. This model is made based on 26 single models of electrical parameters, whose input signals are supply and control voltages. The linear regression method was used to develop the models. An example of the application of the developed model for the prediction of electrical parameters simulating the operation of an LED luminaire in an environment most similar to real working conditions is also presented.
4
Content available Active power losses and energy efficiency analysis of HPS lamps with electromagnetic control gear and electronic ballast under the sinusoidal and nonsinusoidal condition
Sikora Roman, Markiewicz Przemysław, Rózga Paweł
Bulletin of the Polish Academy of Sciences. Technical Sciences
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2021
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Vol. 69, nr 3
art. no. e137194
EN
Outdoor lighting is an important element in creating an evening and nocturnal image of urban spaces. Properly designed and constructed lighting installations provide residents with comfort and security. One way to improve the energy efficiency of road lighting installation is to replace the electromagnetic control gear (ECG) with electronic ballasts (EB). The main purpose of this article is to provide an in-depth comparative analysis of the energy efficiency and performance of HPS lamps with ECG and EB. It will compare their performance under sinusoidal and nonsinusoidal voltage supply conditions for the four most commonly used HPS lamps of 70 W, 100 W, 150 W, and 250 W. The number of luminaires supplied from one circuit was determined based on the value of permissible active power losses. With the use of the DIALux program, projects of road lighting installation were developed. On this basis, energy performance indicators, electricity consumption, electricity costs, and CO 2 emissions were calculated for one-phase and three-phase installations. The obtained results indicate that an HPS lamp with EB is better than an HPS lamp with ECG in terms of energy quality, energy savings, and environmental impact. The results of this analysis are expected to assist in the choice of HPS lighting technology.
5
Content available Reduction of the step voltages of MV/LV substation grounding system based on shaping electric field
Sikora Roman, Markiewicz Przemysław
Archives of Electrical Engineering
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2021
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Vol. 70, nr 3
601--613
EN
The article presents the analysis results of the effectiveness limitation of the step voltage by forming an electric field on the ground surface. For shaping the electric field, a method consisting of screens placed around the point of the earth current flow was used. The analysis was performed using an example of an MV/LV substation grounding system. This research was conducted applying a mathematical model of the grounding system and screens by means of the finite element method. The influence of metal, insulating screens and surface material on the step/touch voltage values for the considered grounding system was estimated. Most of the methods described can be applied in practice. In the opinion of the authors, the method of using screens made of insulating and conductive materials has not been sufficiently described in the literature. Moreover, in the available literature there is no in-depth analysis of the described electric field shaping methods.
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