Silviu Vornicu
@tuiasi.ro
Universitatea Tehnică „Gheorghe Asachi” din Iași
RESEARCH INTERESTS
Electromagnetic field
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Eduard Lunca, Silviu Vornicu, and Alexandru Salceanu
IEEE
In its first part, the paper describes a 3-axis virtual gaussmeter for measuring and characterizing low level magnetic fields in the frequency range from 10 Hz to 2 kHz, mainly generated by overhead power lines and underground power cables. It consists of a 3-axis detachable probe, a data acquisition unit and LabVIEW software running on a portable computer, which features a graphical user interface with multiple functionality and advanced data visualization. In addition to RMS value, waveform and frequency-spectra measurements, the MAG-3D gaussmeter allows for magnetic field monitoring including Max and Min Hold functions, as well as automatically plotting lateral and longitudinal profiles of the resultant magnetic field (total magnetic flux density) according to the standard procedures used in human exposure studies. In the second part of the paper, lateral profiles measured for a 220-kV double circuit overhead power line are compared to similar results obtained by analytical calculation with a previously developed software tool, PowerMAG. Overall, a very good agreement between results can be observed.
Eduard Lunca, Silviu Vornicu, and Alexandru Sălceanu
MDPI AG
There is a special concern for measuring and simulating low-frequency magnetic fields generated by underground power cables, particularly in human exposure studies. In the present study, an accurate 2D finite element model for computing magnetic fields generated by three-phase underground power cables with solid bonding is proposed. The model is developed in ANSYS Maxwell 2D low-frequency electromagnetic field simulation software for a typical 12/20 kV (medium-voltage) three-phase underground power cable in both trefoil and flat formations, but it can be adapted to any cable system. Model validation is achieved by analytical computations conducted with a software tool based on the Biot–Savart law and the superposition principle. RMS magnetic flux density profiles calculated at various heights above the ground with these two methods correlate very well. This is also true for induced shield currents. The application of the finite element model to multiple three-phase power cables laid together is also considered.
Marius Branzila, Stefan-Andrei CîŞlariu, Silviu Vornicu, and Carmen Brinzila
IEEE
When we discuss the quick development of technology, the weather station has become an asset for those who want to enjoy a tool that can provide accurate data about temperature, pressure, and various weather data, but also an essential element in the successful operation and development of various economic branches. In this work, we have presented how to take information from the environment and use it to create predictions. Using a modular concept, we can easily connect several controllers without making significant changes to the original system, which is a great advantage over other products on the market.
Eduard Lunca, Silviu Vornicu, and Alexandru Salceanu
IMEKO
Silviu Vornicu, Eduard Lunca, Bogdan Constantin Neagu, and Florin Constantin Baiceanu
IEEE
The study investigates the distribution of the extremely low-frequency magnetic field around multiple highvoltage overhead power lines in parallel configuration. It is conducted using a computation approach based on the finite element method for an arrangement of five 110-kV doublecircuit lines located in a suburban area of the Iasi city, Romania. Results obtained by numerical simulation are then compared to appropriate regulations regarding human exposure to magnetic fields. The cumulative effect of the magnetic fields from multiple overhead power lines is also discussed.
Eduard Lunca, Silviu Vornicu, Ionel Pavel, and Mihai Andrusca
IEEE
Eduard Lunca, Bogdan Constantin Neagu, and Silviu Vornicu
Springer International Publishing
Alexandru Salceanu, Silviu Vornicu, Eduard Lunca, and Marcel Istrate
IEEE
The paper is mainly dedicated to determining the influence of bundle conductors configurations on the electric and magnetic field levels determined at the standard height of 1 m above the ground. The technical-economic advantages are concisely presented, but also the inherent disadvantages of implementing such solutions. One of the main advantages is theoretically analyzed: the reduction of the risk of initiating corona discharges, as a result of the decrease of the potential gradient from the conductor surface, implicitly meaning the increase of the electric field strength near the ground. The theoretical approaches were reinforced by simulations performed with the help of ANSYS and EMFACDC software. It was considered the real case of a 400 kV network through which phase currents of 1050 A are transported, in three distinct variants: single conductor, double bundle and triple bundle. Electric field increases were found by 37% in the case of triple bundles, taking as reference a single conductor per phase. If the same total current is considered, the chosen bundle configurations have no influence on the generated magnetic field.
Alexandru Salceanu, Silviu Vornicu, Dragos Florin Bordeianu, and Constantin Dan Neagu
IEEE
In the first part of our paper is presented in some details the issue of corona discharges produced in the immediate vicinity of the overhead high voltage power lines. The deterministic connection between the potential gradient at the surface of the active conductors and the initiation of corona discharges is theoretically approached. The decrease of electric field strength in the very surrounding area of the active conductors reduces the risk of corona discharges, but at the cost of increasing the electric field strength at the standard height (from the perspective of human exposure) of 1 m from the ground. We have considered a perfectly balanced 400 kV double-circuit three-phase overhead line, using suspension towers SN 400231, transmitting 1580 A (rms value) per phase in 4 distinct variants: a single conductor, respectively bundles of 2, 3 or 4 (parallel) subconductors. For each bundle, we have considered two representative types of spacer-dampers:side of 3 and 5 dm, respectively. For each case and sub-case, simulations have been performed using ANSYS and EMFACDC software, drawing the lateral profile of the electric field strength at three representative heights: 1 m from the ground, the height of the conductors (9 m) and the symmetrical height (above the conductors, 17 m from the soil). Useful conclusions have been drawn, both to reduce the risk of initiating corona discharges and to protect residential areas from electric field strength generated by the bundle-type configurations of over 220 kV overhead power lines.
Eduard Lunca, Silviu Vornicu, and Catalin Damian
IEEE
In this paper, a PC-based temperature and humidity recorder with USB connectivity is presented. It is developed around a well-known 8-bit PIC18F4550 microcontroller from Microchip Technologies and features intuitive application software developed in the LabVIEW graphical programming environment. The recorder has a temperature range of 0°C to 60°C, a humidity range of 10% RH to 95% RH and a maximum display rate of 1 s. The instrument is compatible with Windows 7/Vista/XP and connects to the PC via a simple USB cable. The device is mainly intended for indoor environmental monitoring.
Silviu Ursache, Eduard Lunca, and Silviu Vornicu
IEEE
In this paper, a DC digital gaussmeter for measuring magnetic fields up to $\\pm 1000 G( \\pm 100$ mT) is presented. It consists of two interchangeable transverse magnetic field probes based on Hall-effect sensor integrated circuits (ICs), a data acquisition module developed around a 8-bit PIC18F4550 microcontroller, a standard 2x16 character LCD display and a 5 V power supply module operating from 6 AA batteries. The instrument features USB connectivity and LabVIEW software for PC remote control. The gaussmeter is suitable for a full range of DC magnetic field measurements, and can be used for both research and teaching activities.
Silviu Vornicu, Eduard Lunca, and Alexandru Salceanu
IEEE
In this study, a simple 2D finite element model is proposed for computing the RMS magnetic flux density generated by overhead high-voltage power lines. The model is implemented in ANSYS Maxwell 2D electromagnetic simulation software, for the particular case of a 110 kV double-circuit overhead power line. The results obtained with this model are then compared to those obtained by analytical computation software, revealing a very good agreement. The proposed 2D ANSYS Maxwell model is mainly intended to check the compliance with the magnetic field exposure limits established by safety regulations, but other applications are also possible.
Ovidiu Bejenaru, Catalin Lazarescu, Silviu Vornicu, and Valeriu David
IEEE
EMC is a permanent challenge for many items associated with radio communications. Inside this large frame work, human exposure issue should be always considered. For that, it is worth of knowing the impact on the short and on the long term of electromagnetic field irradiation over biological tissues of human body. The present paper is a study over the estimation of specific absorption rate (SAR) on a developed 3D model of the human body in case of exposure to electromagnetic fields generated by mobile communications in some areas (indoor and outdoor) with specific instrumentation (Spectran HF-60105 V4 spectrum analyzer with HyperLOG 60100 antenna). The SAR values was determined by simulation using the CST MW Studio® software and the values were compared with limits values for SAR imposed by ICNIRP (1998) restriction limits and European Directive 2004/40/CE standards, adopted also in Romania by HG number 1136 from 30 august 2006. Additionally, the RSAR, while dealing with simultaneous exposure to different frequency fields should be considered.
Silviu Vornicu, Eduard Lunca, and Alexru Salceanu
IEEE
Exposure to low frequency magnetic fields has been a subject of health concern and scientific debate over the past decades. This issue stimulated the interest towards the development of methods and software tools for computing magnetic fields generated by various power-frequency systems. Underground power cables are widely used in urban areas, but they have not been investigated as much as other sources. In this study, the low frequency magnetic fields generated by a typical 12/20 kV underground power line will be assessed by both analytical computation, using a software tool developed in LabVIEW, and numerical simulation, with a 2D electromagnetic modelling software. The obtained results will be comparatively analyzed and checked against relevant exposure limits.
E Lunca, S Vornicu, A Salceanu, and O Bejenaru
IOP Publishing
In this article, a simple 2D finite element model is proposed for computing the RMS electric field strength generated by overhead power lines. The model it is implemented in FEMM 4.2, a high quality, open source finite element software for solving low frequency electromagnetic problems, for the particular case of a 110 kV single-circuit overhead power line. The results obtained with this model there are analyzed and then compared to those obtained by analytical calculations, revealing a very good agreement. The proposed FEMM 4.2 model it is primarily intended to assess the compliance with the electric field exposure limits established by health regulations, but other applications are also possible.