RELRAD-an analytical approach for distribution system reliability assessment

The use of reliability analysis within the framework of distribution system planning is addressed. A specific model for reliability calculations in radially operated distribution systems is presented. Due to increased outage costs in terms of specific costs of nondelivered power and energy (NDP and NDE), an increased part of system operating costs is related to reliability aspects. Customer´s outage costs, based on the willingness-to-pay principle, are given the same principal treatment as power system electrical losses. This approach is becoming generally accepted by the power companies in Norway. The reliability model is based on an analytical approach, connecting component failures to load point outages. The description is based on statistical distributions