Multi-Time Scale Voltage Regulation Control of Photovoltage Flexible HVDC System Based on AC Energy Storage
Due to the obvious influence of photovoltaic power generation by light intensity and other factors,the power of photovoltaic power generation is unbalanced when connected to the grid with the modular multilevel converter(MMC),which in turn affects the DC voltage stability of the system.In this paper,the issue of multi-time-scale power imbalance in PV access to the flexible HVDC system is studied,and an AC-side energy storage scheme and the additional power feedback loop control strategy are proposed to coordinate the consumption of unbalanced power generated by the system under multiple time scales and transmitter fault scenarios.The simulation results of the 21-level 35 kV grid-connected flexible model show that when the light intensity is abruptly changed to 600 W/m2,the suppression level of the energy storage device to DC voltage fluctuation can reach 11.9%when the additional power feedback loop control strategy is adopted,and the suppression level of DC voltage fluctuation can reach 23.7%when the transmitter fails,which verifies the feasibility of the scheme and the control strategy.
MMCPV grid-connecteddirect voltagemultiple time scalespower imbalanceAC side energy storage
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