Improved and extended DG capability in voltage regulation by reactive and active power

Distributed Generation (DG) units are fluctuating power sources that may cause a fluctuating voltage at the point of common coupling (PCC) with the grid. Their connection to distribution networks makes the voltage regulation important since the voltage fluctuations can generate flickers problems. Wind Generation is considered as example of DG. The power electronic converters that connect wind turbines to the grid can contribute to voltage regulation. Reactive power compensation is mostly adopted. Moreover since distribution networks are much more resistive than transmission ones, the conventional technique of voltage regulation by reactive power compensation shows its limits. Therefore new techniques are needed. In this contribution the active power curtailment is investigated and a new controller for voltage control by reactive power compensation is proposed. This controller concerns a new technique in the voltage control loop which improves the dynamical response of the voltage control. It is given by a combination of a feed-back and a feed-forward action.