Evaluation of the customer value of component redundancy in electrical distribution systems

A new regulatory model for the Swedish electrical distribution system operators has been proposed, and is now being implemented. The model is referred to as the network performance assessment model (NPAM). The NPAM is based on fictive reference networks. These emanate from a radial network that is reinforced with redundant components if it increases the customer value more than required investment cost for higher system reliability. The NPAM involves a paradigm shift for the Swedish DSO from a system based on compensation for costs to one based on performance. Evidently, it is of great importance to both the regulator and the different DSOs to evaluate how well the NPAM calculates the performance i.e. the customer values. The aim for this paper is to take a first step in this process; by putting light on how these redundant reference networks are created and used for the NPAM. In order to do this a comparative study has been made for a small test system where two different approaches are used for identifying the resulting redundant reference network for a system. The NPAM approach uses a Monte Carlo simulation technique, and the comparative approach uses an analytical based reliability assessment tool RADPOW, developed at KTH.