Frequency control is one of the most important control problems in interconnected power system design and operation, and is becoming more significant today due to the increasing size, changing structure, emerging microgrids, renewable energy sources (RESs), environmental constraints, and new uncertainties. Several control loops are operating to maintain the system frequency at its set-point. Each one has its particular specification and relies on a given amount of power reserve that is kept available to cope with power deviations. The majority of supply-demand balancing is achieved by controlling the output of dispatch-able generating units. The frequency control in a modern power system should perform complex multi-objective regulation optimization problems characterized by a high degree of diversification in management policies, and widely distribution in demand and supply sources. Wide-area measurement system, distributed generation (DG), microgrids, and controllable loads (demand response) provides new challenges and opportunities to handle the frequency control in new power grids. This Lecture presents a thorough understanding of the frequency control fundamentals in modern power systems as well as in the Microgrids with distributed DGs/RESs. Some new challenges, probable solutions, and new synthesis perspectives will be addressed. The lecture mainly summarizes the relevant research and academic experiences of the speaker in Iran, Australia and Japan over the last two decades.
