Distribution system advancing is very important for many Researchers and power engineers. Fast load flow techniques are highly desired as conventional techniques are consuming very long time. Power flow in the distribution system is one of the most critical point in the grid for analysis study. The integration of variety of renewable energy for the sake of sustainability from consumers and utility to the existing grid requires extra modification to obtain the stability and cost-saving for consumer and utility. This paper presents a review of distribution network load flow analysis after the renewable energy resources penetrated the grid. It also reviews the main old techniques that are with us until today and some of their introduced modification.