Miroslav Prsa

Serbian remote monitoring system for electromagnetic environmental pollution

The increasing number of electromagnetic emitters and need of covering wider territorial areas have caused the spatial density of radiated fields to constantly grow. It initiates alerting of the public opinion and of the governments about so-called electromagnetic pollution phenomena. As support for efforts of municipal and provincial agency for non-ionizing radiation protection, our team has suggested a remote monitoring system for automated and continuous supervision of electromagnetic fields. This system has been recognized by the national Ministry of Sciences and Technological Developments of the Republic of Serbia, which approved and supports its development within the program of technological development of the Republic of Serbia, for the period of 2011–2014.

The concept of the SEMONT monitoring system and its influence on the EM pollution protection

The inevitable increase of artificial electromagnetic (EM) field sources in surroundings has initiated the development of some modern systems for EM pollution observation. This paper presents a concept of the Serbian electromagnetic field monitoring network - SEMONT, which has been designed as an information network for automated, remote and continuous broadband EM monitoring in the environment. The SEMONT network provides the real-time information on the existing levels of the in-situ EM field strength and performs assessment of daily limits of a global exposure of general population, regarding Serbian legislation and ICNIRP recommendations. Having in mind increased risk of possible unhealthy effects of long-term exposure, the Ministry of Education and Science of the Republic of Serbia recognized the importance of the SEMONT system and has supported its development within the framework of the technological development of the Republic of Serbia.

Procedure for incorporation of NBM-550 measurement results into the SEMONT database

One of the consequences of the permanent increase of the electromagnetic (EM) field sources is the emergence of various systems for the remote monitoring of electromagnetic field. These systems are able to perform the continuous monitoring of the EM field in the environment utilizing the wireless sensor network technology. As a support to the authorities, to timely inform the general population on the potentially harmful effects of the long-term exposure to the EM radiation, the development of the Serbian electromagnetic field monitoring network - SEMONT has started. The SEMONT system performs a continuous EM field monitoring and presents the obtained results over its own Internet portal, playing an important role in the field of radiation protection. In order to obtain data on the high-frequency electric field strength over the area of the campus of the University of Novi Sad, the SEMONT system has recently started with initial measurements. This paper considers the SEMONT system database model supporting the measurement results incorporation, obtained by the NBM-550 handheld instruments.

Using Padé Approximation in Takács Hysteresis Model

The application of the modified Takács hysteresis model for numerical modeling of measured hysteresis loops of ferromagnetic material is investigated. In order to better approximate measured hysteresis loops, the Takács model is modified using parameterized Padé approximations of the hyperbolic tangent function. That way, several variants of the modified model are constructed. The experimental data are fitted with the original model, as well as with the modified model, and the quality of conformance between empirical data and the models is assessed. Three numerical criteria are used for comparison: 1) the coefficient of determination; 2) percent error of the residual vector; and 3) percent errors at the five characteristic points on the hysteresis loop. The proposed method shows improvement in cases when hysteresis loops are not reaching saturation, while maintaining accuracy in the saturation. The performance of the modified model is verified by theoretical data.

Determination of electromagnetic field in a three-phase system with three single-core power electric cables 110 KV

Knowing electromagnetic field inside and in the neighborhood of any power electric cable is very important because of the cable influence on its vicinity. This paper shows the determination of a 3-phase cable system electromagnetic field, applying the COMSOL Multiphysics computer program. Two components of electric field strength vector, potential electric field and induced electric field, are calculated separately, as well as the magnetic field vectors. Induced currents are studied in all constructive elements of cable system. The calculation results are done for the concrete 3-phase system, as a combination of 3 single-core cables XHE-49-A, 64/110kV, with the cross-section 1×1000/95mm2, graphically, together with comments.

Impact of steel permeability on ACSR impedance per unit length

Electric characteristics of Aluminum Conductor Steel Reinforced (ACSR) components, aluminum and steel conductivity values, are usually provided by the ACSR manufacturers, but not the steel core permeability. In order to explore how important the steel core permeability is, the paper deals with the impact of this characteristic on ACSR impedance per unit length. For the estimation of this impact, numerous calculations were performed and the results are shown in this paper. The value of relative steel core permeability was varied from 10 to 50000 inside three different standardized ACSR conductors, at eleven different frequencies, up to 2500 Hz (50th harmonic of fundamental frequency). All calculations were carried out numerically, applying COMSOL Multiphysics 3.5a computer program package on simplified two-dimensional model. ACSR resistance per unit length was calculated from heating losses, while the reactance and the inductance per unit length were determined via magnetic energy stored in ACSR magnetic field. Even in the case of great relative permeability value range, the paper shows that the influence of steel core permeability on any ACS conductor is much less than expected, especially at lower frequencies. This fact is the consequence of the big difference in aluminum and steel conductivity values.

Application of current transformer for normal magnetization curve determination

Determination of normal magnetization curve is a well known problem, solved and described in many papers. But none of the normal magnetization curve measurements were performed applying current transformer instead of voltage toroidal transformer sample. Comparing the application of current transformer versus the application of voltage transformer, several different procedures and approaches appeared. All these procedures, together with the appropriate solutions and results were presented in this paper. The results presented in the paper show that current transformer can also be successfully applied for an accurate normal dynamic magnetization curve determination.

The apparatus for the electromagnetic stimulation in stomatology

The aim of this paper was to present the possibilities of the electromagnetic (EM) stimulation in stomatology. According to the results of our experiments the EM stimulation seems to be a useful additional therapy in cases where increased bone repair, soft tissue repair, blood circulation, improved medicament intake and bacteria rejection is needed.