Renewable sources of energy (RES), especially photovoltaic (PV) micro-sources, are very popular in many countries. This way of clean power production is applied on a wide scale in Poland as well. The Polish legal regulations and tariffs specify that every prosumer in a low-voltage network may feed this network with a power not higher than the maximum declared consumed power. In power networks with RES, the voltage level changes significantly along the power line and depends on the actually generated as well as consumed power by particular prosumers. There are cases that prosumers connected to this line cannot produce and inject the full permissible power from PV sources due to the level of a voltage higher than the technically acceptable value. In consequence, it leads to the lack of profitability of investments in installations with PV sources. In this paper, voltage variations in a real rural low-voltage network with PV micro-sources are described. The possible two general solutions of voltage levels improvement are discussed—increase in the cross-sectional area of the bare conductors in the existing overhead line as well as the replacement of the overhead line with a cable line. The recommended solution for the analyzed network, giving the best reduction of voltage variations and acceptable cost, is underlined. Such a recommendation can also be utilized in other rural networks.
Assessment of biomass potential for power production: a GIS based method
