The amount of the active power production by the photovoltaic systems depends on the radiation intensity and temperature. In this concept, the optimal use of photovoltaic systems is considered for controlling the voltage and correcting the power factor over day and night. Using this concept, it is possible to use photovoltaic systems in a more optimal way during the day and night. In this method, the photovoltaic systems capacity is not only used during the night to generate reactive power. Although studies have investigated the optimal locating of the distributed generation, DG is referred to as only the source of active power generation. In this paper, a new method for optimal placement of the photovoltaic systems, by considering their inverter nominal capacity to generate reactive power in addition to the active power in order to improve the voltage profile and reduce the system losses of the micro-grid, was employed. Two 33-bus and 6-bus networks were selected for investigating, and after implementing the method as well as applying the genetic algorithm optimization, it was determined that the optimal location of the photovoltaic systems by taking into account the active and reactive power production. Manuscript profile