Estimation and Sizing of Frequency Reserves from Flexible Demand Units

The installed capacity of renewable energy sources is increasing at a high rate, and even larger extent is predicted in the future. Conventional generators which have been providing stability and reliability to power system are being replaced by renewable energy sources. Consequently, problems in terms of power system stability are arising and are reflected in frequency deviation. Therefore, additional reserves are needed and as one of the possible solutions is electric boilers or water heaters modelled as flexible load. This work presents the analysis of the dynamic response of generating units and flexible loads in load frequency control subjected to intermittent renewable energy sources generation. Moreover, estimation of frequency reserve requirements based on overall system performance and capabilities of new regulation resources in future power systems dominated by renewable energy sources is done.