计及故障持续时间的换流变压器阀侧单相接地故障分析

换流变压器阀侧单相接地故障发生时刻具有随机性,其相对于换流阀通断时刻的位置不同,会导致不同的暂态过程。首先提出了类换相失败的概念,以换相失败和类换相失败为切入点,在将故障发生时刻分段的基础上,考虑了瞬时性故障时,故障持续时间对于换流器暂态过程的影响。理论分析和仿真验证表明,换流变压器阀侧高压桥发生故障时,会立即造成类换相失败的发生,而低压桥瞬时性故障时,可能不对外体现故障特征。

Analysis on Single phase Grounding Fault at Converter Transformer Valve Side Considering Fault Duration

The occurrence of single phase grounding fault at HVDC converter transformer valve side is stochastic The relative position to the converter valve leads to different transient process On basis of fault time division, the conception of commutation like failure (CF) is proposed, and the transient process of instantaneous fault is analyzed from the point of CF view considering the fault duration. Both the theoretical and simulation analysis show that, when the fault occurs at high voltage bridge, it leads to CF immediately, when the fault occurs at low voltage bridge, it may show no fault feature to the protection devices.