Morphological Lifting Scheme for Current Transformer Saturation Detection and Compensation
Morphological Lifting Scheme for Current Transformer Saturation Detection and Compensation
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DOI：
10.1109/tcsi.2008.924112
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发表时间：
2008-11-01
影响因子：
5.1
通讯作者：
Wu, Q. H.
中科院分区：
文献类型：
--
作者：
Lu, Z.;Smith, J. S.;Wu, Q. H.
电流互感器（CT）饱和会导致保护继电器误动，甚至阻止跳闸。当铁心残余磁通加上故障引起的磁通变化时，电流互感器被迫进入深饱和，二次电流波形严重失真。本文提出了一种形态提升方案来提取信号波形中包含的特征。使用该方案可以准确地实现CT饱和检测，并找到饱和开始和结束的拐点。本文还提出了一种基于检测结果的补偿算法来重建健康的二次电流。最后在一个电力系统实例上对所提出的形态提升方案和补偿算法进行了验证。仿真结果清楚地表明，该方法能够成功地检测和补偿残余磁通饱和CT的畸变二次电流。
Current transformer (CT) saturation can cause protective relay mal-operation or even prevent tripping. The wave shape of the secondary current is severely distorted as the CT is forced into deep saturation when the residual flux in the core adds to the flux change caused by faults. In this paper, a morphological lifting scheme is proposed to extract features contained in the waveform of the signal. The detection of the CT saturation is accurately achieved and the points of the inflection, where the saturation begins and ends, are found with the scheme used. This paper also presents a compensation algorithm, based upon the detection results, to reconstruct healthy secondary currents. The proposed morphological lifting scheme and compensation algorithm are demonstrated on a sample power system. The simulation results clearly indicate that they can successfully detect and compensate the distorted secondary current of a saturated CT with residual flux.