A voltage regulation system for distributed generation

Voltage regulation at the point of common coupling (PCC) can increase the penetration level of distributed generation (DG) into the distribution network. This paper deals with a voltage regulation algorithm for a grid-connected DG, based on active and reactive power control. A review of different DG reactive power control solutions is made. When the reactive power control is not sufficient to keep the voltage on the appropriate range, an action on the active power must be considered. Two DG operating modes are identified and two switching methods between those modes are compared in respect with DG dynamics. The operating modes switching may induce some oscillations that can be eliminated using an appropriate control algorithm.