Book excerpt: The rapid development and utilization of renewable energy generations (REGs), such as wind power and photovoltaic power, is an important measure for modern power system to achieve carbon neutrality and solve global energy crisis. However, the randomness and volatility of renewable energy generations lead to serious reliability concerns and financial risks to different decision-makers, and the large-scale integration of power electronic brings huge challenges to the planning, operation and control optimization of renewable energy-based systems. Therefore, to achieve the integration of large-scale renewable energy generations, advanced planning, operation and control optimization methods and strategies for modern power systems are required to be developed based on the state-of-the-art power system technologies. The aim of this Research Topic is to report the latest advancements in planning, operation and control optimization of large-scale renewable energy generations in modern power system to solve potential difficulties and challenges.