Adaptive coordinated frequency regulation framework and dynamic performance enhancement mechanisms for variable-speed pumped storage units with high-performance frequency support

To enhance the frequency support capability of full-size converter variable-speed pumped storage units (FSCVSPSUs) under islanded and weak-grid conditions, this study proposes a coordinated control strategy integrating an adaptive virtual synchronous generator (VSG) with frequency compensation. In this strategy, an RBF neural network is employed to realize adaptive regulation of virtual inertia, while an adaptive damping adjustment mechanism based on frequency deviation is incorporated to improve dynamic stability under frequency disturbances. In addition, a fast frequency compensation mechanism is introduced to accelerate power response during large disturbances. Leveraging the proposed control framework, a systematic analysis is conducted on the frequency regulation performance (FRP) of the unit under diverse load levels, hydraulic heads, and initial power operating conditions. This study's results corroborate the applicability of the proposed strategy significantly enhances both frequency support capability and dynamic recovery performance of FSCVSPSUs. Moreover, variations in hydraulic head and initial power exert only a minor influence on frequency response and power recovery processes, indicating a favorable decoupling between FRP and operating conditions. These findings confirm the superior frequency regulation potential of FSCVSPSUs within emerging power systems characterized by low inertia and high renewable penetration.