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.

Many recent studies have dealt with the future of the power distribution system, and there are different technologies which will facilitate the development towards the smart power distribution grid vision. Plug-in electric vehicles (PEV) and distributed generation (DG) technologies will become integral part of this vision. PEVs are specific because they can act both as a load and as a source of energy in a concept known as Vehicle-toGrid (V2G). This paper analyses the impact of these technologies on an example of a real medium-voltage distribution network operating in Bosnia and Herzegovina. The impact of each technology and in combination with another technology is analyzed. It is shown that the impact of PEVs may be negative in terms of the increase in the peak load and power losses as well as transformer overloading for scenarios of a high-penetration level and uncontrolled charging. However, controlled charging and regulated implementation of V2G can be beneficial in certain terms. The Photovoltaic (PV) technology can reduce the power losses, but will violate voltage-limitations in periods of high solar insolation, especially for a high-penetration level. By controlling the new emerging technologies, many of the negative impacts can be reduced and even turned into positive effects.