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The paper presents the possibility of using ERP business software for the purpose of analyzing steady states of electric drives. A centrifugal pump is used as an example of active load. After reviewing previous research and presenting the basic principles of using the ERP model, the analysis of the operation of the centrifugal pump and the processing of the results of the propulsion measurements were approached. Two flow control options are considered and both methods are compared regarding energy consumption. After that, the method of calculating energy saving using the ERP model is shown. The calculation results provide data on different costs depending on the type of flow control. Since an induction motor with a frequency converter is provided for flow control by changing the speed, the final step is rough profitability estimate of the investment in frequency converter, which was also done directly in the ERP model. [ABSTRACT FROM AUTHOR]

During transients that occur in an electric network, large currents can flow and large electromagnetic torques can be developed in electric generators. Accurate calculation of currents and magnetic fields during transients is an important element in the optimal design of generators and network parts, as well as mechanical parts of machines and other torque transmission parts. This paper describes the modeling of a sudden three-phase short-circuit on a synchronous generator using the finite element method (FEM) and the dynamic model. The model for simulations that use the FEM was built in the MagNet software package, and the dynamic model is embedded in the MATLAB/Simulink software package. The dynamic simulation model of a part of a network with two identical generators, represented by equivalent parameters, was developed. The results obtained after the simulation of a sudden three-phase fault in the generators by both methods are presented, including three-phase voltages, three-phase currents, machine speeds, excitation voltages, and mechanical power. In particular, the short-circuit current in the phase with the highest peak value was analyzed to determine the accuracy of the equivalent parameters used in the dynamic model. Finally, the results of these two calculation methods are compared, and recommendations are presented for the application of different modeling methods. [ABSTRACT FROM AUTHOR]

The System Integrity Protection Scheme (SIPS) is a specialized protection scheme which differs to a great extent from the common protection, especially in its main intention. It is designed for integrity protection, failure prevention and mitigation of disturbance consequences in the whole power system (PS) or modern distribution system (MDS) with a significant power of distributed generation (DG). The input parameters for establishing SIPS in PS are synchronized phasor measurements obtained from the Phasor Measurement Units (PMUs), as a globally acknowledged Smart Grid technology. The realization requires that SIPS is added to the existing Wide Area Monitoring, Protection and Control (WAMPAC), based on synchronized measurements. This paper proposes an algorithm that anticipates optimal PMU placement and then uses angular stability protection based on traditional IEDs supported by synchronized measurements. By using such approach, the system avoids possible blackouts due to the combined operation of the traditional protection and WAMPAC. The proposed SIPS system is tested on specific area in the Croatian transmission system integrating hydro power and wind energy converting power plants. Due to the increased power of renewable energy sources (RES), the proposed algorithm is applicable to modern distribution systems. [ABSTRACT FROM AUTHOR]

The requirements for the quality of protection on metal structures in terms of durability, reliability and efficiency require from the manufacturer to define certain procedures and verification of anticorrosion protection activities. Today, the criteria used to evaluate the success of the protection and the general quality of the structure are the criteria listed in the EN 1090 standard and in the compatible standards related to the realization and protection of metal structures. The article briefly describes the basis of the requirements of the standard, the eligibility criteria for the protection of structures and it also gives a practical example of the verification process through preparation, implementation and control. [ABSTRACT FROM AUTHOR]

The paper presents results of a research made by teachers of undergraduate electrical engineering students in determining the significance of using didactic tools in order to increase the students` motivation to participate actively in the teaching process. Converters used in this research are designed and modelled by students themselves for laboratory power-electronics exercises. It is shown that using didactic tools improves understanding of complex subjects when the students have the opportunity to link practical exercises with the theoretical explanations given in lectures. [ABSTRACT FROM AUTHOR]

Thermoelectric modules are used for heating or cooling if an electric current flows through them. If one side of such a module is heated and the other side is cooled, the outputs show a potential difference that creates the current flow through an enclosed circuit. The paper describes briefly the physical basis of the operation of semiconductor thermoelectric modules and their application for generating electricity as thermoelectric generators. The experimental measurements were made with different available modules of thermoelectric generators. The analysis of obtained results has provided the conclusions about the possibility of their application as sources of electricity. Although the efficiency of thermoelectric modules is still quite low, the latest research reveals the possibility of the use of materials that make modules more efficient. Considering the fact that they do not contain moving parts, they are characterized by reliable, long-lasting work and simple operation and maintenance. [ABSTRACT FROM AUTHOR]

This paper analyses how the type of winding affects the current distribution and power losses in armature winding. Using finite element method, four different types of winding used in large asynchronous motors are analyzed: form-wound concentric, with and without transposition, and form-wound barrel, with and without transposition, for the stationary state. In two cases, the calculation shows clear differences between maximum currents in strands, a shift in their phases, and a resulting increase of AC resistance. In two other cases, minor deviations, smaller phase shift and smaller increase of AC resistance, are detected. It indicates that in certain types of armature winding of large motors the strands transposition leads to significant positive effects in terms of motor power, while in other cases it leads to unnecessary complications making the manufacture of large asynchronous machines more difficult, with relatively small positive effect on the motor power losses. [ABSTRACT FROM AUTHOR]

Copyright of Technical Journal / Tehnički Glasnik is the property of Polytechnic of Varazdin and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Technical Journal / Tehnički Glasnik is the property of Polytechnic of Varazdin and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Disruptions in the global market are influencing value and supply chains reminding businesses and industries that variability and diversity of supply chains may be essential for surviving and sustainability. Operations management of any business has to address these challenges in order to avoid any serious interruptions in supply of materials in production industries by seeking substitute inputs. At the same time, the technological development offers new materials with similar quality properties, making thereby the substitute material search more difficult in terms of selecting appropriate materials with a level of quality which is similar enough. Another aspect in shifting can be found in more social-related reasons addressing changes in the value chains like traceability, low carbonization, and a more customer-oriented approach, because of moving towards green digital business. In this sense the intention of this work was to propose an algorithm for customizing the process of identifying appropriate materials in production by relying on existing algorithms i.e., the Ashby mapping, big data, applying algorithms of data analysis based on exclusion criteria embracing transformation paradigms, for enabling customization of the material selection process. The proposed algorithm was applied on two case examples, demonstrating that diversity of materials plays an important role in addressing customization requests from customers. Consequently, understanding and implementing a customer-centric approach in various phases of the product life cycle contributes to a better response by businesses faced with issuing customized offerings. [ABSTRACT FROM AUTHOR]

Interest in sports predictions as well as the public availability of large amounts of structured and unstructured data are increasing every day. As sporting events are not completely independent events, but characterized by the influence of the human factor, the adequate selection of the analysis process is very important. In this paper, seven different classification machine learning algorithms are used and validated with two validation methods: Train&Test and cross-validation. Validation methods were analyzed and critically reviewed. The obtained results are analyzed and compared. Analyzing the results of the used machine learning algorithms, the best average prediction results were obtained by using the nearest neighbors algorithm and the worst prediction results were obtained by using decision trees. The cross-validation method obtained better results than the Train&Test validation method. The prediction results of the Train&Test validation method by using disjoint datasets and up-to-date data were also compared. Better results were obtained by using up-to-date data. In addition, directions for future research are also explained. [ABSTRACT FROM AUTHOR]

This paper proposes an approach to schedule and allocate regulating reserve in systems with a large share of generation from wind power plants (WPPs). The method for scheduling regulating power is based on the correction of day-ahead schedules planned by the known variations of the load- and wind-power from the previous hour. The correction term incorporates the tendency of changes for previous hours. In this way, more of the regulating power can be reserved during sudden changes in the intensity of the wind. Hence, available existing operational data are required, instead of historical data. The method for allocation of regulating power to regulating units is based on minimization of the transmission losses with optional correction according to economic criteria. The qualitative analysis of the relevant economic features is introduced, as well as the possibilities for applying advanced information and communications technology. The methods discussed were tested for the standard test network RTS 96 and for the Croatian transmission network. Test results showed considerable reduction of the unnecessary positive and negative regulating reserve with increased safety compared to the classic method. Furthermore, optimal allocation of regulating reserve reduced transmission losses for all the cases discussed. Reductions were more significant when the layouts of WPPs and regulating capacities were more geographically dispersed. [ABSTRACT FROM AUTHOR]