Optimal reactive power control of distribution feeders with distributed energy resources: Interaction analysis and validation

In the voltage regulation problem of MV distribution systems with Distributed Generation (DG), the regulator of the On Load Tap Changer (OLTC) equipped with Line Drop Compensator (LDC) interferes with the DG voltage regulator. This interaction can significantly changes the voltage profile along the feeders. With the aim to propose a solution to this problem, the present paper firstly models this interaction and subsequently defines a sufficient condition which sets an upper bound on the reactance of the LDC. According to the defined condition it is possible to define two separate areas of MV distribution system. The first area collects the nodes controlled by the LDC and the second one the nodes controlled by the DG. In this way the OLTC with LDC and the DG voltage regulator both improve the voltage profile without generating mutual interactions. The study is developed with reference to the DG voltage regulator designed according to an optimization procedure named Optimal Set Point Design (OSPD), previously proposed by the same authors. The validity of the presented analysis is finally validated by numerical simulations.