A System for Dispersed Generator Participation in Voltage Control and Primary Frequency Control of the grid

When the amount of power that is generated by dispersed power sources becomes a significant part of the total generated power, the control of grid voltage and frequency may become a problem, because ever less centralized power plants for voltage and frequency control remain. Therefore, a method is proposed to let dispersed power sources participate in voltage control and primary frequency control. The method is specifically meant for dispersed sources that are connected to the power system via a power electronic interface, such as photovoltaic systems, variable speed wind turbines and fuel cells. The method takes advantage of the possibilities to control the active and reactive current of the power electronic interface independently, within limits imposed by the prime mover and the converter rating. Theory, simulations and experimental results obtained with a scaled model are presented. Both simulations and experimental results show qualitatively that dispersed generators can help to stabilize voltage and frequency