Reliability evaluation of distribution system with wind farms based on network-equivalent method

One of the most important issues in the development and utilization of wind-based distribution generation is to quantify the impact of wind power on distribution system reliability. This paper proposes how to deal with wind generators connected to sub-feeders of distribution system in reliability evaluation by means of the network-equivalent approach. The random nature of wind power, which is quite different from the conventional substations generation can not be ignored in reliability assessment. In this paper, wind power uncertainty caused by wind speed is investigated by dividing wind speed into intervals described by the mean output and interval probability. Then load importance is studied by classifying loads into various grades, each with different weight coefficients. It is assumed that wind power supplies to customers on sub-feeders with wind generators within the limits of its random capacity judging by the load grades. The impacts of wind power capacity and different integration locations on distribution networks reliability are also researched. Reliability indices are calculated considering wind generation uncertainty and load importance, revealing the remarkable influence of wind power on distribution system reliability.