Frequency control in microgrid based on inertial response of wind turbine and curtailment of photovoltaic generation

It is of great importance to mitigate frequency fluctuation in power systems with high penetration of renewable energy sources such as wind turbines and photovoltaics. Especially, in isolated microgrids like island power systems, frequency regulation becomes more significant because the system frequency easily changes by relatively small moment of inertia. To cover the small system inertia, it is effective that renewable energy sources contribute to the stabilizing control, namely frequency response. Wind turbine has a rotating mass with stored kinetic energy so that it is possible to increase its output by using the energy as a concept of inertial response control. Also, power curtailment is available in the case of both wind turbines and photovoltaics. Hence, this paper describes a cooperative frequency control method based on combination of the inertial response and the active power curtailment control. By comparing with delta control, which has been implemented by a number of system operators in European countries, the effectiveness of the cooperation between inertial response and curtailment was examined.