Today, power grid frequency control regains research interest due to the coming challenges of increasing renewable energy penetration, changing structure and emerging new distributed generators (DGs), storage systems, controllable loads and power electronics technologies. Recent advances in control, communication and computing technologies accelerate this process. The frequency control in a modern power grid 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 systems, integration of DGs/Microgrids, controllable loads (demand response) and performing virtual inertia provide new concerns and opportunities to handle the frequency control in new power grids. This speech addresses an updated review on most important frequency control challenges, modern relevant control possibilities, important achievements, and new research directions.