Simplified reliability evaluation formulae for overhead medium voltage distribution networks

For the reliability evaluation of overhead medium voltage distribution networks, the required data of traditional methods are too big to be collected and inputted. Moreover, some data of a distribution power grid, especially the planning distribution networks, cannot be completely provided. As a result, it is necessary to put forward simplified reliability evaluation formulae. In this paper, the simplified evaluation formulae of system average interruption duration and frequency indexes for failure outage and scheduled interruption are deduced respectively, considering the influences of not only the main lines, distribution transformers and switches of a single type, but also big lateral lines and various types of switches, thus making the formulae more practical. Moreover, according to the interruption times based on the line length or the line segment number, two sets of evaluation formulae of scheduled interruption are deduced. The reliability evaluation of IEEE RBTS-Bus2 is performed by using the deduced formulae, and the results of better precision are obtained with little increased input data.