The effect of Distributed Generation on distribution system reliability

Concerns on environmental and economical issues drive the increasing developments that support small scale generators to be connected close to distribution networks, i.e. distributed generation (DG). However, the connection of DG would affect the distribution system structure and operation greatly. Since these DG sources are normally placed close to consumption centers and are added mostly at the distribution level, the effect of DG on distribution system reliability becomes a growing concern to the customers and electric utilities. This paper analyses the reliability improvement effect of DG on distribution system by comparing the system reliability indices before and after connection of DG. As is known, distribution system consists of hundreds of thousands of components. The acquisition of all component parameters is impossible. Therefore, in this paper, an interval algorithm is introduced to deal with the uncertainty of component data to calculate the interval reliability indices. At last, through comparison of the interval reliability indices when DG connected in different locations on distribution feeder, this paper also analyses the effect of connecting location on distribution system reliability.