Current paper deals with three main issues, regarding the operation of the electric power systems in the presence of distributed generation. The first issue regards the assessment of the main continuity of supply parameters, such as frequency of interruptions, duration of interruption, power not served and energy no served. This issues are the base guidelines for the network system operators' decision of building new distributed generation capacities which might be able to mitigate the electric network loss of operation. The second issue addressed was the consume variability of the various low-voltage consumers. This particularity, in conjunction with the sheer number of consumers leads to the creation of serious unbalance for the daily curve. This means that if the network system operator cannot contain the load variability, it must buy energy from intraday energy market, with a price decisively higher than the one of the reserved capacity. This issue leads to a two-fold necessity: implementing a better know-how system in order to better contain the customers load fluctuation and the necessity of distributed generation implementation, in order to help load shedding. The third issue regards general technical aspects with respect to the electrical distribution systems operation in the presence of distributed generation.