Distributed generation voltage control issues and solutions

This paper discusses the problems encountered with distribution feeder circuits, both inside and outside the substation, when distributed generation is connected. The rate of installation of distributed generation, mostly in the form of wind and solar power, is increasing. The dynamic nature of distributed generation, being largely dependent on weather conditions (i.e., sun and wind), results in a variable output from the distributed generation sources. This paper discusses problems encountered when applying line drop compensation at the substation´s load tap changing transformer to compensate for voltage drops across feeder circuits serving load. The paper explains what occurs on the feeder circuit when distributed generation output suddenly decreases or completely deenergizes. The paper discusses voltage problems that can occur when the feeder regulators or load tap changing transformers are in both forward power and reverse power modes. This paper assumes DG power output at unity power factor and not transporting VArs into the distribution system.