Controller Design and Performance Improvement for Neutral-Point Voltage Regulation Converter of Hybrid Grounding System

To improve the security and reliability of distribution networks when addressing single-phase ground faults, this paper presents an improved voltage control strategy for hybrid grounding system, taking into account harmonic disturbances. Firstly, the study begins by introducing the active voltage arc-extinguishing principle, the topology and coordinated control of hybrid grounding system. And then, an improved control strategy for the neutral-point voltage regulation converter is further proposed. The methodology incorporates inner-loop PI control for current and outer-loop multi-PR control for voltage regulation. Parallel resonance controllers are introduced to suppress harmonics, with the addition of a lead correction stage to enhance the steady-state and dynamic performance of the control system, effectively achieving fault point arc extinguishing. Finally, simulation results verify the rationality and effectiveness of the improved control strategy and its practical application.