换流变零差保护在故障切除恢复性涌流期间的误动风险分析

发布时间：2018-10-22 16:36

【摘要】：在各类差动保护中,零差保护灵敏度高,速动性好,在超高压及特高压变压器保护中占有重要地位。传统认为,涌流对于零差保护而言属于穿越性电流,不会引起其误动,也不需要附加制动判据保障其正常运行。该文通过对换流变恢复性涌流的分析,指出换流变铁心有可能在涌流的作用下产生单向饱和,并产生相应的偏置电流。该电流可能导致灵敏度较高的中性线TA发生偏磁现象,在时长较长,幅值较高的情况下会导致TA测量电流饱和失真,造成零差保护误动。理论分析及仿真验证表明,在故障切除特定工况及特殊合闸角状态下,零差保护存在误动风险,需要额外的制动判据保证零差保护动作的可靠性与选择性。
[Abstract]:Among all kinds of differential protection, the differential protection has high sensitivity and good rapidity, and plays an important role in the protection of UHV and UHV transformers. Traditionally, inrush current is considered to be a traversing current for differential protection, which does not cause misoperation and does not require additional braking criterion to ensure its normal operation. Based on the analysis of rheological restorative inrush flow, it is pointed out that rheological core may produce unidirectional saturation and corresponding bias current under the action of inrush current. This current may lead to the bias magnetic phenomenon in the high sensitivity neutral line TA. When the time is longer and the amplitude is high, it will lead to the saturation distortion of the TA measurement current and the misoperation of the differential protection. The theoretical analysis and simulation results show that the differential protection has the risk of misoperation under the specific condition of fault removal and the special closing angle. The additional braking criterion is needed to ensure the reliability and selectivity of the differential protection operation.
【作者单位】：强电磁工程与新技术国家重点实验室(华中科技大学);三峡大学电气与新能源学院;许继集团有限公司;
【基金】：国家自然科学基金青年科学基金(51607106) 国家电网公司科技项目(JB71-15-041)~~
【分类号】：TM774

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