Planning for “high quality” distribution networks

Voltage dips are the most common power quality disturbances. They can often cause serious damages to the end- users, especially to the industrial ones or those involved in services that today are almost entirely based on digital processes. Thus, their mitigation is assuming a key role for both customers and distributors. The first ones look for eliminating any obstacle to the correct operation of their processes, and are often willing to stipulate premium contracts that guarantee a high level of quality to their power supply. The second ones have to solve power quality problems in their networks with restrict available budget, first of all, to achieve the Regulatory targets on quality but also to satisfy the most exigent customers. In previous works, the authors proposed a distribution network planning methodology that adds to the traditional technical constraints also the target of the power quality. In terms of voltage dips, the power quality target to be achieved may be limiting the voltage dips frequency in each node of a given network within a prefixed threshold. In this paper, an improved algorithm able to find the most economical solutions to comply with this constraint has been developed. This improved algorithm considers by the same standards different corrective actions, with the aim at finding the best compromise between investment and benefits. Accordingly with this view, the goal is minimizing the cost that the distributors have to sustain for the protective measures, the cost paid by the customers for the damages caused by the not mitigated disturbances and for the premium quality contracts. The effectiveness of the proposed approach is proved by examples in a test network and in a small one derived from real cases.