一种抑制高压直流输电换相失败的优化控制策略

摘要

为减小直流输电系统发生换相失败及持续换相失败的概率,分析了换流站逆变侧交流母线电压幅值跌落、过零点偏移和直流电流激增对换相失败的影响,提出了一种逆变侧考虑换相电压过零点偏移的关断角整定值动态调整、并在整流侧配有滞后触发控制的优化控制策略.分析了优化控制策略对直流系统运行参数的影响,基于CIGRE标准测试模型,在PSCAD/EMTDC中实现了所提出的控制方法.仿真结果表明,所提的优化控制策略可在一定程度上降低不对称故障和对称故障下传统直流输电系统换相失败的概率,改善系统的故障恢复特性.%To reduce the probability of both commutation failure and continuous commutation failure in HVDC power transmission system, the main reasons causing commutation failure are analyzed, which include the voltage amplitude drop of commutation bus, direct current uprush and commutating voltage zero-cross phase shift.An optimal control strategy in which the extinction angle setting value can be adjusted dynamically considering zero-cross phase shift of commutation bus voltage at the inverter side and delayed trigger is allocated at the rectifier side is proposed.The influence of the optimal control strategy on system operating parameters is also analyzed.Based on the CIGRE benchmark model of HVDC, the proposed control strategy is developed in PSCAD/EMTDC.Simulation results show that the proposed optimal control strategy, to some extent, has the ability to mitigate the commutation failure and continuous commutation failure under single-phase and three-phase grounding fault conditions.Thus, the fault recovery performances of HVDC can be effectively improved.