Dynamic coordinated control of governor-converter for variable speed pumped storage unit based on real-time optimization

• Mathematical model of variable speed pumped storage unit is established. • Coordinated optimal controllers under generating and pumping modes are deduced. • Coordinated optimal operation mechanism under two modes are revealed. • Dynamic coordinated transient characteristics under two modes are illuminated. The regulation and control of the traditional fixed speed pumped storage unit (FSPSU) can only be realized by the governor, while the regulation and control of the variable speed pumped storage unit (VSPSU) can be realized by the coordination and cooperation of the governor and the converter, which improves the flexibility and efficiency of regulation of VSPSU. However, the complexity of the coordination between the two also increases the difficulty of system operation control. This paper studies on dynamic coordinated control of governor-converter for VSPSU based on real-time optimization. Coordinated optimal controllers for VSPSU under both generating and pumping modes are derived, with two feasible governor-converter dynamic coordinated control modes for each mode being designed based on real-time optimization. The dynamic coordinated operation mechanisms and transient characteristics under different modes are revealed. The results show that real-time tracking of optimal speed or optimal guide vane opening (GVO) is guaranteed during transient processes of VSPSU based on real-time optimization, better aligning with optimal operational requirements. Under generating mode, the dynamic coordinated control strategy is recommended where rapid active power regulation is achieved through converter based on power priority control strategy, while real-time optimization and precise tracking of speed are implemented via frequency regulation mode of governor based on dynamic variations of output power and working head. Under pumping mode, the dynamic coordinated control strategy is recommended where rapid active power regulation is achieved through converter based on power priority control strategy, while real-time optimization and precise tracking of GVO are implemented via GVO regulation mode of governor based on dynamic variations of input power and working head.