Design strategy for optimum rating selection in interline DVR

This paper is concerned with design strategy for optimizing the total rating of an interline dynamic voltage restorer (IDVR). DVR has been used in distribution networks for several years as a mean to mitigate voltage sags. In designing a DVR, there is always a trade-off between the size of energy storage system and the rating of DVR. An IDVR, which is two DVRs installed in two feeders with common dc bus, has the capability of active power exchange between two DVRs, and thus the energy storage device is not an issue. Therefore, the design criteria for the selection of rating of an individual DVR are not applicable in IDVR structure. In this paper, the basic equations governing the operation of an IDVR are obtained. The important factors which cause the difference between IDVR and individual DVRs are addressed. A new step by step design procedure is proposed with the objective of optimum selection of rating for an IDVR structure. Illustrative examples are given to show the applicability of the proposed method.