Public enterprise Elektroprivreda BiH

Sarajevo, Bosnia and Herzegovina

Public enterprise Elektroprivreda BiH

Sarajevo, Bosnia and Herzegovina
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Salihbegovic I.,Public Enterprise Elektroprivreda BiH | Steinhart H.,Aalen University of Applied Sciences
2011 23rd International Symposium on Information, Communication and Automation Technologies, ICAT 2011 | Year: 2011

Magnetic circuit design of wound rotor low-voltage three-phase synchronous generator for autonomous operation is presented in this paper. The Maxwell software based on two-dimensional finite element method (2D FEM) is used to study the performance of the synchronous generator in specified static operating regime. Two machines with different configurations are analyzed. These machines are characterized by the same stator and rotor external dimensions and used materials. Moreover, stators of all machines are exactly the same while the rotor magnetic circuit structures and excitation windings are different. Calculated characteristics and their comparisons are presented and discussed. Some characteristics of prototype, which is currently under construction, are given. © 2011 IEEE.


Bajric R.,Public enterprise Elektroprivreda BiH | Zuber N.,University of Novi Sad | Isic S.,Dzemal Bijedic University of Mostar
Applied Mechanics and Materials | Year: 2013

This paper provides a review of the literature, progress and changes over the years on fault detection of gears using vibration signal processing techniques. Analysis of vibration signals generated by gear in mesh has shown its usefulness in industrial gearbox condition monitoring. Vibration measurement provides a very efficient way of monitoring the dynamic conditions of a machine such as gearbox. Various vibration analysis methods have been proposed and applied to gear fault detection. Most of the traditional signal analysis techniques are based on the stationary assumption. Such techniques can only provide analyses in terms of the statistical average in the time or frequency domain, but can not reveal the local features in both time and frequency domains simultaneously. Frequency/quefrency analysis, time/statistical analysis, time-frequency analysis and cyclostationarity analysis are reviewed in regard for stationary and non-stationary operations. The use of vibration signal processing detection techniques is classified and discussed. The capability of each technique, fundamental principles, advantages and disadvantages and practical application for gear faults detection have been examined by literature review. © (2013) Trans Tech Publications, Switzerland.


Bijedic A.,Public enterprise Elektroprivreda BiH | Salkic H.,University of Tuzla
International Review of Electrical Engineering | Year: 2014

The paper presents the analysis of the results of research implemented on a solar plant in trial period, maximum power of 10 kW, performed in order to assess the impact of a solar plant on distribution network and the quality of electrical energy. The electrical energy quality parameters values are collected in the common coupling point and compared to criteria set in EN 50160 standard. The analysis is made for the case before and after connecting a solar plant, both with minimum and maximum consumption. Also, the same analysis is performed for the case of 50% of installed capacity of solar plant production. The calculation is performed in Power CAD software package. © 2014 Praise Worthy Prize S.r.l. - All rights reserved.


Dimitrijevic Z.,Public enterprise Elektroprivreda BiH | Tatic K.,University of Sarajevo | Knezevic A.,Center for Economic | Salihbegovic I.,Public enterprise Elektroprivreda BiH
Energy Policy | Year: 2011

Bosnia and Herzegovina (BH) is a country in transition but is determined to pursue accession to the European Union (EU). One requirement for joining the EU is compliance with the EU environmental acquis, although BH is currently lacking adequate experience and the required research. Therefore, it is advisable to quantify the costs and benefits of meeting the EU environmental acquis to the fullest possible extent, even though comparing costs and benefits may not be the only relevant criterion for decision making. Because the EU's ExternE methodology for estimating the external costs of air quality has been used in numerous studies aimed at formulating environmental, transport and energy policies, BH has consulted this methodology to help make decisions about restricting emissions from major combustion sources. Therefore, with the help of the EcoSenseWeb software, which fully complies with the ExternE methodology, this study was developed to examine the current situation resulting from electricity generation at a fossil fuel power plant and the units that are to be built in BH and to review the SO2 emission limit for new thermal plants in BH. © 2011 Elsevier Ltd.


Dimitrijevic Z.,Public Enterprise Elektroprivreda BiH | Tatic K.,University of Sarajevo
Energy Policy | Year: 2012

After the recent war (1992-1995) the country BH includes the two entities, the Federation of Bosnia and Herzegovina (FBiH) and the Republic Srpska (RS). Given these two entities the country is politically divided. The country is in transition and determined on accession to the European Union (EU). Coal-fired plants exist in both entities, two in FBiH and two in RS. Significant investment is needed to ensure that existing coal-fired units comply with EU Directive on large combustion plant by 2017. BH (like some EU countries) has chance to negotiate the position of country with the EU with possible outcome to receive delay in fulfilling requirements for some coal-fired plants or even some exceptions. Also, there is a lack of reliable and harmonised energy data in BH-over all data collection on air pollutant emissions is not yet established. So, some data collection is done for the needs of this paper and by using the specific external cost, annual emissions of pollutants and cost-benefit analyses the most acceptable scenarios for investments in desulphurisation and denitrification on the existing coal-fired units in BH on the economic and environmental base, not political, is presented in the paper. © 2012 Elsevier Ltd.


Beater wheel mills are designed to prepare a coal powder air fuel mixture for combustion in furnace chambers of coal-freed power plants by coal drying, pulverizing, classifying and transport. Their multipurpose function usually results in operation instability accompanied by unacceptable vibration. This usually is a signifcant problem due to unplanned shutdowns. Beater wheel mill maintenance program requires special attention due to operation under non-stationary conditions. The purpose of this paper was to identify pulverizing process parameter that affect the beater wheel mill vibration level and severity at the same time by using statistical principles under a wide range of operating conditions. This paper intends to establish the foundations to investigate correlation of pulverizing process parameter with beater wheel mill vibration in order to setup a better predictive maintenance program. To achieve this goal, the beater wheel mill vibration under different combinations of selected pulverizing process parameters are analyzed using statistical tools. Experiments were carried out under different conditions for two identical but separated beater wheel mills. The infuence of pulverizing process parameter, such as electrical current of the driving motor, mill capacity, boiler production, coal types on mill vibration are investigated to identify the potential malfunction of beater wheel mills and their associated components for predictive maintenance purposes. The results have demonstrated that the selected pulverizing process parameters do not have signifcant infuence on beater wheel mill vibration severity. Unlike most coal mills where pulverizing process parameters must take into account, here with beater wheel impact mills it is not the case and condition monitoring of these mills could be conducted offline or online using standard vibration condition monitoring methods.


Zuber N.,University of Novi Sad | Bajric R.,Public enterprise Elektroprivreda BIH | Sostakov R.,University of Novi Sad
Eksploatacja i Niezawodnosc | Year: 2014

The paper addresses the implementation of feature based artificial neural networks and vibration analysis for the purpose of automated gearbox faults identification. Experimental work has been conducted on a specially designed test rig and the obtained results are validated on a belt conveyor gearbox from a mine strip bucket wheel excavator SRs 1300. Frequency and time domain vibration features are used as inputs to fault classifiers. A complete set of proposed vibration features are used as inputs for self-organized feature maps and based on the results a reduced set of vibration features are used as inputs for supervised artificial neural networks. Two typical gear failures were tested: worn gears and missing teeth. The achieved results show that proposed set of vibration features enables reliable identification of developing faults in power transmission systems with toothed gears.


Zuber N.,University of Novi Sad | Cvetkovic D.,University of Niš | Bajric R.,Public enterprise Elektroprivreda BIH
Applied Mechanics and Materials | Year: 2013

Paper addresses the implementation of feature based artificial neural networks and selforganized feature maps with the vibration analysis for the purpose of automated faults identification in rotating machinery. Unlike most of the research in this field, where a single type of fault has been treated, the research conducted in this paper deals with rotating machines with multiple faults. Combination of different roller elements bearing faults and different gearbox faults is analyzed. Experimental work has been conducted on a specially designed test rig. Frequency and time domain vibration features are used as inputs to fault classifiers. A complete set of proposed vibration features are used as inputs for self-organized feature maps and based on the results they are used as inputs for supervised artificial neural networks. The achieved results show that proposed set of vibration features enables reliable identification of developing bearing and gear faults in geared power transmission systems. © (2013) Trans Tech Publications, Switzerland.

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