基于暂态仿真的主变涌流对线路零序过流保护的影响研究

摘要

通过阐述变压器零序电流产生机理,指出变压器各相铁芯饱和差异是产生零序分量的根本原因.基于EMTDC/PSCAD平台系统分析了剩磁、合闸角和变压器中性点接地方式对励磁涌流零序电流基波分量最大值的影响,分析结果表明当达到实际最大剩磁时通过调整合闸角可以获得最大零序电流基波分量.仿真分析还发现线路零序过流加速段保护在较大的励磁涌流零序电流下有误动风险,建议通过提高零序过流加速段定值或增加二次谐波制动原理来提高保护的可靠性.%Through the description of the generating mechanism of the zero sequence current transformer, this paper points out that the different core saturation of each phase of transformer is the fundamental causes of the zero sequence components. Based on EMTDC/PSCAD, the effect of residual magnetism, closing angle and the neutral grounding mode of transformer on the maximum of fundamental component of magnetizing inrush zero sequence component is analyzed. Results show that when the residual magnetism is maximum, adjusting the closing angle can obtain the maximum of zero sequence current fundamental component. In addition, it is found by simulation that there is disoperation risk in the line zero sequence overcurrent accelerating protection caused by the larger inrush current zero sequence component. Improving the reliability of protection by increasing the zero sequence current acceleration setting value or twice harmonic restraint principle is suggested.