A traditional electrical power system is characterized by centralized power generation. However, with the current restructuring of the electricity system and the growing interest in sustainable development, the implementation of new distributed generation units is increasing. Despite the extensive technical, economic and environmental benefits that distributed generation units provide, offering a lower production cost, higher energy quality for the consumer and allowing the postponement of investments in distribution expansion, distributed generation units can add more complexity to a network s protection system. This occurs because the protection systems are designed considering a unidirectional current power flow and one of the main problems arising from the insertion of new distributed generation units is the alteration of the short-circuit current levels. Thus, with the insertion of new distributed generation units, it is necessary to restructure the protection system in order to guarantee that the protection system operates according to the complexity of a network with DG. In this context, this work aims to introduce the concepts of distributed generation, analyze the influence of a distributed generation unit on the three-phase short-circuit analysis of a distribution network system and present the main protection devices operating in a protection scheme. To analyze the influence of the connection of a distributed generation on the short-circuit levels of the network, several simulations were carried out in a system developed and simulated using Matlab/Simulink software. Finally, a proposal for a protection scheme at the DG connection point for the developed system is presented.