The influences of distributed electrical energy sources based on renewable energy resources over the power transmission and distribution systems are varied. The possible effects are more pronounced in the case of electricity generated using solar and wind resources, given the specificity and intermittency of the power produced from these resources. Photovoltaic systems (PVS) are one of the most promising renewable energy solutions. In case of the grid connected photovoltaic systems, these could provide many benefits to the network utilities. This paper intends to present the effects of PVS upon the power quality (PQ) parameters carried out in case of a radial distribution network within Bihor County Power System (BCPS), by analyzing the results of the measurements performed upon the electrical parameters from the point of common coupling (CCP) where these PVS are injecting the produced power. Measured values are compared with the limitations set in the international standards and the technical code of distribution networks, respectively the connecting conditions stipulated regarding these sources.