Research on Capacity Design Technology for Power Dissipation Devices in Wind Power Transmission via Ultra-Long UHV Flexible DC Systems

This article focuses on the optimization configuration of energy dissipation devices for wind power transmission via ultra-long UHV flexible direct current transmission system in islanded operation scenarios. Large scale wind power transmission via ultra-long UHV flexible DC transmission system faces challenges in transient energy regulation. The energy dissipation devices configured on the sending-end AC side may fail to promptly suppress capacitor overvoltage caused by receiving-end faults due to communication delays. While the energy dissipation devices configured on the receiving-end DC side cannot cope with non-fault pole overcurrent when a single pole exits. Meanwhile, it requires double the rated capacity of dissipation devices for dual configuration which significantly reduce the economic efficiency. This article proposes a capacity optimization calculation method for energy dissipation devices based on dynamic power allocation. By rationally configuring the capacity ratio of AC/DC-side devices while ensuring the total capacity does not exceed the system rated value, transient overvoltage/overcurrent coordinated suppression can be achieved. The effectiveness of this method is confirmed through simulation.