Abstarct: Traditional distribution networks are radial in nature, supplied at one end through a main source. These networks generally have a simple protection system usually implemented using fuses, re-closers, and over-current relays. One of the significant events that have occurred in recent years in the power industry is the presence of distributed generation sources in power grids. With the installation of DG into distribution networks, the rate and direction's of the active and reactive power flow through the lines and the radial mode is change. As a result, the overall behavior of distributed systems is change as well. So the coordination between network protective equipment before installation of DG, is no longer valid. The impact of DG on the coordination of protective elements depends on the size, capacity, types and installation place of this resource. Hence it is necessary to study the interaction between the feeder and distributed generation units. The purpose of this thesis is study of the problems that caused by the installation of distributed generation sources on radial distribution networks protections, and in order to solve these problems, we have evaluated the various approaches that have been proposed in recent years, such as: Exchange and re-set protection devices, adaptive protection, agent-baxsed protection,fault current limiting, and ... . It is notable that each of these methods has been subdirectories that has specific strategies and algorithms in specific terms and conditions and by employing the new algorithm and a new approach combines the existing methods can be achieved in order to design a protective system. Finally, an adaptive protection method has been studied that using multilxayer Perceptrons (MLPs) neural networks and has the best application independent of the number, size and location of DGs. This method implemented on a network of 25-bus an industrial city in the province of Qazvin and has been evaluated.With this method, by receiving the current contribution of each source, faulty area and faulty line are identify and relay commands for separation and related operation to the breakers.