Distributed production plays an increasingly important role in reducing losses in the network, reducing electricity prices, achieving environmental and economic benefits, reducing investment in production capacity and postponing the upgrade of the transmission and distribution system. This paper deals with the advantages and disadvantages of the growing number of distributed sources. In the introductory part, a broader view of the issues related to the integration of distributed sources is given, and the standard technical conditions that must be met by each power plant when connecting to the distribution network are described. In the third chapter, the effects of connecting distributed sources to the power grid are discussed. An overview of the connection’s influence on voltage conditions, short-circuit currents, power flows, losses and the quality of electricity is given. In the practical part of the work, the situation in the network was analyzed before and after the connection of distributed sources. The analysis includes the impact of the connection of photovoltaic power plants on voltage conditions and losses of working energy in the network for different degrees of penetration of FN power plants into the network.