Considering that nowadays has occurred to a widely application of distributed generation in distribution systems, it is necessary to investigation of problems and issues that may arise the distribution system. In this paper the main issue is to investigate the effect of random load behavior of distribution system on enhancement of system loadability in presence of DG units. The results show that random load behavior how and how much will affect on improved system loadability. To do these investigations, at first the optimized place for installing DG has been specified in certain load condition using Genetic Algorithm, and its effect on loadability is investigated. Then network loads has taken randomly and the results are obtained and investigated for this case too. Moreover, in certain load condition, effect of number of DG and type of generation capability of real and reactive power (due to the fact that some types of DG can only generate and inject real power) has been studied and best one is specified.
