Including voltage dips mitigation in cost-benefit analysis of storages

Energy storage systems are valuable components of the future Smart Distribution Systems, thanks to their ability to increase the flexibility of the overall system and to provide a wide range of services. Unfortunately, their costs are still high and their profitable implementation has to be carefully justified. Voltage dips are the most common power quality disturbance in distribution networks. Their mitigation can be obtained by reinforcing the networks, i.e. by substituting overhead lines, with high fault rates, with buried cables, or, more easily, by installing custom power devices, as Dynamic Voltage Restorers (DVR) able to supply the needed energy to the protected customers during the dip. Among other services, energy storage systems can perform the same task of DVRs against the voltage dips and this benefit can contribute to make cost-effective their investment. The paper proposes an approach to estimate the benefit derived by the use of storages as DVR for reducing the expected number of voltage dips suffered by the customers. The obtained revenue can be added to the total benefit ascribable to the storage.