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.

Modelling of harmonics in large medium voltage (MV) distribution networks has so far been a challenge due to the presence of a large number of harmonic sources contributing to total harmonic voltages. This study proposes a deterministic methodology of modelling harmonics in large real MV distribution networks using aggregate harmonic source models parameterised based on measurements and results from the literature. In this research, background harmonic voltages from the sub-transmission system are parameterised based on measurements in the analysed network. Aggregate harmonic current emission of different customer categories in low-voltage (LV) networks (households and small commercial customers) parameterised based on several measurements in LV networks was dominated by residential or office customer type configurations. The harmonic current emission of industrial customers is parameterised based on the results from published literature. Two methods for modelling harmonic sources are used and compared: (i) modelling according to the IEC 61000-3-6 summation law and recommended summation exponents and (ii) modelling using complex phasors. The results of the models show a good match with the measurements from power quality monitors installed in the analysed MV network. Based on these results, the method according to the IEC 61000-3-6 is recommended for large MV distribution networks.