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Zagreb, Croatia

Vujevic S.,University of Split | Balaz Z.,Croatian Motorways Ltd | Modric T.,University of Split | Sarajcev P.,University of Split
International Review of Electrical Engineering | Year: 2012

This paper presents a hybrid numerical model for computation of the phase-to-ground fault current distribution between soil and neutral conductors of grounding system. Hybrid model is combination of electromagnetic model and transmission line model. In numerical realization, the finite element technique is used. Using electromagnetic model, conductive coupling between all buried non-insulated conductive parts of grounding system is taken into account. Using transmission line model, inductive coupling between phase conductors and ground wires of parallel overhead power lines is used. Similar transmission line approach is used for parallel power cable lines and cable line grounding wires. In computer programs developed for ground fault current distribution, the conductive coupling between all buried non-insulated conductive parts of grounding system can be taken into account or neglected. From the numerous numerical examples, it can be deduced that one can introduce a significant error by neglecting the conductive coupling. In presented numerical example, error caused by neglecting the conductive coupling between all buried non-insulated conductive parts of grounding system can be observed in rms values and phase angles of currents and potentials. © 2012 Praise Worthy Prize S.r.l. - All rights reserved.

Vujevic S.,University of Split | Balaz Z.,Croatian Motorways Ltd | Lovric D.,University of Split
Proceedings of the Joint 3rd International Workshop on Nonlinear Dynamics and Synchronization, INDS'11 and 16th International Symposium on Theoretical Electrical Engineering, ISTET'11 | Year: 2011

Grounding systems of various shapes can be approximated by a cylindrical metal plate. Highly accurate expression for the metal plate ground impedance is needed in numerical analysis of various electromagnetic problems. Such expression is developed using an analytical formula for the potential distribution of equipotential metal plate in homogeneous unbounded medium. The Galerkin - Bubnov weighted residual methods is employed to expand this analytical expression valid in homogeneous unbounded medium to an expression valid in homogeneous earth. © 2011 IEEE.

Jasarevic I.,University of Zagreb | Prelogovic E.,University of Zagreb | Krhen H.,Plinacro Ltd. | Miller B.,Trames | And 2 more authors.
Rock Engineering in Difficult Ground Conditions - Soft Rocks and Karst - Proceedings of the Regional Symposium of the International Society for Rock Mechanics, EUROCK 2009 | Year: 2010

The wider area of the town of Dubrovnik is characterized by the constant and well pronounced tectonic activity. This is confirmed by a relatively high concentration of strong earthquakes, especially in the vicinity of Dubrovnik. The following structures are present in this area: underground public car park in Dubrovnik and a ten-storey hotel in Orašac. The EC-8 requires analysis of the influence of local soil and rock conditions on seismic activity, and this through introduction of soil and rock categories A, B and C. In case of facilities under study, the basic problem was to design and realize relatively high protective anchored reinforced-concrete structures ranging from 10 to 30 metres in height. © 2010 Taylor & Francis Group, London.

Vujevic S.,University of Split | Lovric D.,University of Split | Balaz Z.,Croatian Motorways Ltd | Gaurina S.,University of Split
International Review on Modelling and Simulations | Year: 2013

In this paper a model of a two-winding transformer based on the finite element technique is proposed. The model employs a T-equivalent circuit of the transformer. Local systems of equations are derived both for the case of a single-phase transformer and for the case of the three-phase transformer. Three most often used transformer connections are observed in the case of the three-phase transformer. These models of a two-winding single-phase or three-phase transformers will be used in an electromagnetic model for analysis of ground fault current distribution based on the finite element technique. © 2013 Praise Worthy Prize S.r.l. - All rights reserved.

Mandzuka S.,University of Zagreb | Zura M.,University of Ljubljana | Horvat B.,Japanese Ministry of Economy, Trade, and Industry | Bicanic D.,Croatian Motorways Ltd | Mitsakis E.,Center for Research and Technology Hellas
Promet - Traffic - Traffico | Year: 2013

The paper analyzes the current guidelines of the European Union on deployment of Intelligent Transport System, as well as their importance for the development of the Croatian transportation system. The crucial problems of modern transport and traffic are indicated as: congestions and congestion costs, harmful emissions in road transport, fatalities, etc. The current state of Intelligent Transport System development in Croatia is presented based on the transport infrastructure, modern road telematic industry, and other supporting activities (including scientific research, educational activities, standardization system, etc.). The final part of the paper deals with the need and potentials for the development of South East European regional ITS architecture.

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