Abstract Voltage unbalance and voltage variations are common issues in low voltage distribution networks caused by unbalanced connection of single-phase loads and electric vehicles (EVs) among phases. Part of the real low voltage grid in Bosnia and Herzegovina, in the vicinity of the town of Tešanj, was analysed. The impact on single-phase consumer and single-phase EVs penetration was analysed. The grid was modelled using DIgSILENT PowerFactory software. Three cases of the distribution of consumers by phases were analysed. Each of the three cases is expanded with four scenarios depending on the penetration of EV into the grid. Results showed that none of the twelve scenarios remained within the permissible limits of −10% voltage variation limit of EN 50160 for phase A. Seven of the twelve scenarios exceeded voltage unbalance limits +2% according to EN 50160.

Abstract This paper investigates the strategic placement of capacitor banks in the distribution network of Gračanica, with a specific focus on the medium-voltage feeder Grades. The primary objective is to optimize voltage profiles, minimize power losses, and enhance the overall performance of the distribution network. The significance of this research lies in its thorough examination of optimal capacitor placement within the medium-voltage (MV) branch of distribution networks, specifically considering the intricate interplay between capacitor banks and MV branch components, underlining the necessity for informed decisions in the context of distributed generators (DG) integration to enhance overall network performance. The study further investigates the impact of integrating DGs on these objectives on capacitor placement in the MV feeder. Employing the DIgSILENT PowerFactory software tool for modelling the MV feeder and utilizing a genetic algorithm for capacitor placement optimization, the study underscores the robustness of this approach in handling various conditions and seeking optimal solutions. Simulation results demonstrate that strategically placing capacitor banks and integrating DGs can significantly improve the voltage profile and reduce power losses within the distribution system. The findings of this research support 2MVA of concentrated DGs at the middle of the line as the most efficient and most economically beneficial situation on the medium-voltage feeder Grades study case and contribute valuable insights, serving as a reference for future studies on optimal capacitor placement.

Distributed generation (DG) especially energy acquired from renewable energy sources (RES) plays a significant role in modern power sector due to high carbon emissions around the globe. Its emerging potential is feasible by implementing microgrids as they are beneficial for networks in terms of increasing flexibility and stability, providing frequency and voltage support, power factor compensation etc. This makes the investment into microgrid incorporating RESs attractive, while at the same time reducing overall investment in the grid. Higher cost and stochastic nature of intermittent RES are complications for the implementation and operation of such solutions. This paper will analyse economic feasibility of hybrid power system (HPS) implementation consisting of a wind generator (WG), a photovoltaic system (PVS), gas combined heat and power plant (CHP) and storage batteries. Each of the elements is optimized according to power demand and RES’s potential. Technical analysis of the grid integration, parallel operation of the system and the grid is analysed with an example of a real medium-voltage distribution network operating in Bosnia and Herzegovina by using quasi-dynamic load flow simulation of one-week time-period. Finally, different operating mechanisms and strategies will be proposed, following the minimal power form the grid premise to satisfy maximum usability of RES’s potential. It is shown that implementing such HPS would be beneficial in terms of both economy and, ecology, as well as in reducing energy losses. Besides, it will reduce power supplying costs and energy losses, as well as and secure better exploitation and utilization of natural renewable energy sources. These technologies positively affect power network by decreasing the risk of network-components overloading, better exploiting the power-generation facilities based on renewable resources and positively impacting voltage profiles. Similar places, situated on remote locations, may use this analysis as an example to follow, to reduce their costs of electricity, acquire more reliable and sustainable power supply, and embrace green future.

Abstract In the dynamic field of power systems, integrating distributed generation (DG) sources like solar photovoltaic (PV) plants is crucial for enhancing reliability and fostering sustainability. However, this integration poses voltage profile management challenges in electrical grids. This study investigates voltage profile optimization in Bosnia and Herzegovina’s Gračanica network, focusing on a medium voltage feeder with 68 buses. Using DIgSILENT PowerFactory software, six scenarios with different configurations of solar plants are analyzed for their impact on voltage profiles and power losses. Results show that while DG integration offers benefits, incorrect sizing or placement can increase power losses. Optimal DG benefits are linked to specific sizes and locations. This research emphasizes the need for balancing PV generation with load demands and provides insights for optimal PV plant size and output to minimize negative impacts. These findings aid energy planners and policymakers in implementing distributed solar PV in medium voltage networks.

Abstract Voltage unbalance is common issue encountered in low voltage distribution networks, caused by uneven allocation of single-phase customers among phases. This paper analyses part of real low voltage distribution network in Bosnia and Herzegovina. The impact of single-phase customers and single-phase connected micro photovoltaic power plants (MPPP-s) were analysed. To reduce unbalance and improve voltage profiles, Phase Balance Optimization toolbox in DIgSILENT PowerFactory software was performed in six scenarios with different distribution of customers and different percentage of penetration of MPPS-s. The aim was to find method with least number of changes in customer and photovoltaic phase connection that fits within defined limits of voltage variations and voltage unbalance of European standard for power quality (EN 50160). Conclusion is that MPPP-s cause voltage increases in the network, as well as an increase in voltage unbalance, but these effects can be mitigated by proper distribution of customer loads and MPPS-s among phases.

While distributed generators (DGs) can reduce carbon dioxide emissions, they can also cause disturbances and lead to power quality (PQ) issues, with harmonic voltages being an important parameter to consider. In this paper, the impact of 14 connected photovoltaics (PVs) and a small hydropower plant (sHPP) on harmonic voltage distortions in a real medium voltage (MV) and low voltage (LV) distribution network in Bosnia and Herzegovina was analyzed. Simulation tools carried out by DigSILENT PowerFactory offer a wide range of advantages that give system operators the ability to have insight into PQ behavior in the presence of intermittent renewable energy sources (RES). Due to the inverter-based electricity generation, PV power plants inject harmonics into the LV network. The impact is relatively small and does not violate the limits from the European PQ standard EN 50160 due to the relatively small power of the modelled existing PVs. However, integrating additional PVs could lead to a violation of limits. Therefore, where a large power of PV power plants is installed, if it is possible to integrate sHPP, they will contribute to the reduction of generated harmonics without the need to reduce the power of PV. The contribution of this paper is that it compares the impact of different power generation technologies on harmonic voltages using data from a real network rather than a test network.

Abstract Phase unbalance is a common issue encountered in LV electricity distribution networks, caused by uneven allocation of single-phase loads among phases. This paper analyses a part of a real LV distribution network, situated in Bosnia and Herzegovina. The impact of single-phase customers and single-phase charging of electric vehicles was analysed. To reduce unbalance and improve the voltage profiles, Phase Balance Optimization in DIgSILENT PowerFactory software was performed in six scenarios with different customer and electric vehicle unbalance. The goal was to find a method with the least number of changes in the customer and electric vehicle phase connection that fits within defined limits of voltage variations and voltage unbalance of a European norm for power quality (EN 50160). Results showed that all analysed scenarios were improved, with reference to voltage variation and voltage unbalance values, and were found acceptable by the limits from standard EN 50160.

Abstract In the past couple of years, the integration of electrical vehicles (EV) in the power system has been capturing the attention of many researchers, which has led to this being a frequently analysed topic in scientific papers and seminars. Some of the main parameters related to power quality that are observed, while integrating EVs, are voltage variations and voltage unbalance. The low-voltage rural network, of a small settlement located on the outskirts of Zavidovici, has been modelled for the purpose of this paper. Several cases were considered. As the first base case, an analysis was performed when there were no connected vehicles in the network, then the case with 20% penetration, 35% penetration, and 80% vehicle penetration. Practical analysis was done in DIgSILENT Power Factory software. It has been concluded that electrical vehicles cause a voltage drop in the network, while at the same time causing an increase in voltage unbalances.

Majority of new technologies in electrical engineering nowadays belong to the field of smart grids. Smart grids master programs are being implemented in the Western Balkans countries through the EU funded project ELEMEND. Within smart grids curriculum, practice-oriented teaching is crucial to teach students practical skills needed on the job market. This paper presents the practice-oriented approach of the team from the Public Electric Utility Elektroprivreda of Bosnia and Herzegovina d.d. - Sarajevo, being taught at the International Burch University within three courses from the Smart Grids in Electrical Distribution Systems master program. Apart from the basic theoretical knowledge, students are given projects with real-life problems and real data. Students are being trained to do projects using two commercial software tools. Projects are often on some of the challenging topics of smart grids and the final results of the project are therefore often published in international and national journals and conferences. Also, excursions and site visits to real-life visits of some of the smart grid technologies are organized, as well as internships for some of the students. Therefore, students are at the end trained and qualified for smart grid related jobs on the job market.

Modelling of flicker in large real distribution networks has been a challenge until now, due to huge number of flicker sources contributing to total flicker levels in the network. In this paper, voltage flicker is modelled for a large real medium voltage (MV) distribution network. The total flicker is calculated from background flicker resulting from high voltage network and from flicker emission of a large number of sources in the analysed MV network. The flicker emission was modelled by statistical distributions of emission levels. Results of the simulation were compared to flicker measurements from several power quality monitors, installed in the feeders of the analysed MV network. The results show a significant similarity between the model and the measurements. Conclusion of this work is that the voltage flicker can be modelled with sufficient accuracy, even in large real MV networks.

Electric vehicles (EVs) retain the focus of the public attention because of the constant development and promotion of their technology and global warming awareness. Their integration is expected to experience an exponential rise along with new challenges for the existing networks. Simultaneous and unregulated charging of a large fleet of EVs increasingly burdens the power system and negatively affects the power quality parameters, especially during the daily peak-period. The paper analyses the power quality analysis of a low-voltage distribution network in Bosnia and Herzegovina. Different EV types are investigated, such as Mitsubishi i-MiEV, Renault ZOE, Volkswagen e-Golf, and Tesla X, to determine their impact on harmonic voltages impact for three EV penetration levels: 10%, 20% and 50%. Wallbox charging mode is also investigated. The results are evaluated compliably with the European power-quality standard EN 50160. Results show that none of the analyzed EV penetration scenarios violate the permissible harmonic voltage limits, except for the 50% EV penetration scenario with wallbox charging.

Abstract The aim of this paper is to analyse the stand-alone operation of the microgrid located in Umoljani, Bosnia and Herzegovina. The analysis was performed for two scenarios; one representing a summer day and the other a winter day. The analysed network was modelled using the DIgSilent PowerFactory. The Photovoltaic (PV) system, Wind Generator (WG) and battery sizing were performed using the HOMER software tool. The load data for the location was obtained from JP Elektroprivreda Bosne i Hercegovine. The analysis showed that the network was able to operate in stand-alone mode. Voltage levels were under the voltage limit defined by EN 50160. Line loading was decreased compared to loading in grid-connected mode. As given by the obtained results for the two scenarios, the consumer demand could be satisfied without the inclusion of WG. However, different input data (wind speed data measured on the location) could change the sizing of the production facilities as the results of the optimization calculations in HOMER, which needs to be considered in microgrid configuration.

A microgrid concept for the thermal and electrical energy supply of a Sport-Recreation Center Ajdinovići (S.R.C.A.) has been proposed in this paper. A self-contained and intelligent power distribution grid has been developed for this case, taking into account the location, locally available renewable energy sources and the very purpose of this center. Comparative analyses between independent power supply through the proposed hybrid power system and the supply over the transmission and distribution network were performed. Technical and economical optimization of an energy system with distributed power generation was done by applying HOMER and DIgSILENT PowerFactory professional software tools. As a result, hybrid power system is more cost-effective than the conventional supply by the power distribution network, microgrid meets the technical criteria based on the analysis of power flows and the stability of the network has been achieved. Establishment of energy independence for the existing S.R.C.A. besides economic factor will show several benefits regarding better use of locally available resources, reduction of CO2 emissions and energy efficiency increment as well as an employment opportunity to the local people, thus contributing to the sustainability of the region.