To investigate the active power regulation performance of the double-fed variable-speed pumped-storage unit, this study analyzed the control principles of the unit, established a subsystem model including the hydraulic model, and set up a simulation test platform for the control system of the double-fed variable-speed pumped-storage unit. The simulation study was conducted to investigate the rapid response characteristics of the active power of the unit. The results show that doubly fed variable speed pumped storage units have fast active power regulation capabilities, especially in the early stage of active power regulation. The goal of fast active power regulation is achieved by quickly converting the unit’s rotational speed kinetic energy and active power. This characteristic is not possessed by conventional fixed speed units and has significant advantages in fast power regulation application scenarios such as primary frequency regulation.