With the rapid growth of electric vehicles (EV) connected to the distribution network, in general to low voltage network, the development of a simulation tool becomes necessary in order to determine the EV penetration level, to assess impacts of EV integration on the distribution network and opportunities contributed by EV. In this paper, a simulation tool based on the probabilistic three phase Load Flow (PLF) program has been developed by using Monte Carlo techniques. By using this tool, technical and economic impacts of EV integration on the distribution network are assessed. Studies of the potential opportunities of ancillary services provided by EV are also carried out. Low voltage rural and urban networks are used for these studies.