The Special Issue includes a collection of papers that present new methods for analyzing, operating, controlling, and protecting future power grids with increasing renewable energy utilization. Specific topics include voltage and var optimization, hardware-in-the-loop testing, the control of wind power systems, distribution system reconfiguration, optimal power flow, load dynamic forecasting, current-limiting reactor operation, risk management for energy markets, resilience maximization, and the control of photovoltaic inverters.