渝鄂背靠背柔直系统交流故障穿越策略研究

Research of AC fault ride-through strategy for Chongqing-Hubei VSC-HVDC back-to-back project

针对柔直系统交流故障可能造成的系统安全与稳定性问题,本文结合渝鄂背靠背柔直系统,考虑实际工程中存在的采样与控制延时,提出了受端交流故障期间的稳流控制策略,包括交流电流限幅控制、直流电压前馈控制、直流电流控制、以及发生严重故障时的换流站暂时性闭锁策略,可有效减小故障与恢复期间交、直流侧的过流与过压,降低器件损坏风险,提高系统的故障穿越能力。基于PSCAD/EMTDC的电磁暂态仿真验证了本文提出的控制策略的有效性。

AC faults of VSC-HVDC bring system security and stability problems.This paper focuses on AC fault at receiving end of Chongqing-Hubei VSC-HVDC.Sample and control delay of the project is considered.An AC fault ride-through strategy is proposed,including AC current amplitude control,DC voltage feedforward control,DC current control and temporary blocking strategy under serious fault.The proposed strategy reduces overcurrent and overvoltage of both AC and DC side,improves fault ride-through ability of the VSC-HVDC system.The risk of device damage is reduced.Simulation results in PSCAD/EMTDC environment demonstrate the effectiveness of the proposed control strategy.