基于综合形态算法的变压器励磁涌流识别方法

Identification Method of Transformer Magnetizing Inrush Current Based on Comprehensive Morphological Algorithm

针对励磁涌流对变压器差动保护的影响,提出了一种基于综合形态算法的励磁涌流识别方法。首先,利用改进形态梯度算子对采集的信号进行处理,然后利用加权形态滤波算子对梯度信号进行滤波。然后,基于内部故障电流和励磁涌流基波相似性的显著差异构造判据对二者进行区分。判据1用来快速识别大多数内部故障,判据2应对电流互感器饱和及空合于内部轻微匝间故障等特殊情况。两识别判据通过协同逻辑,实现涌流情况下的保护闭锁与内部故障情况下的快速动作。最后,通过PSCAD/EMTDC仿真对所提算法进行了验证分析。

Aiming at the influence of magnetizing inrush current on transformer differential protection,a method of magnetizing inrush current identification based on comprehensive mathematical morphology is proposed.First,the improved morphological gradient operator is used to process the sampled signal,and then the weighted morphological filtering operator is used to filter the gradient signal.Based on the significant difference in fundamental wave similarity of internal fault current and magnetizing inrush current,two criteria are constructed to distinguish them.The first criterion is used to quickly identify most internal faults,and the second criterion deals with special cases such as current transformer saturation and no-load closing with a slight internal turn-to-turn fault.The two identification criteria can realize protection blocking in the case of inrush current and fast operation in the case of internal faults through collaborative logic.Finally,the proposed algorithm is verified and analyzed through PSCAD/EMTDC simulation.