Compared with conventional transformers, the rectiformer is special in connection mode, which is multi-tap and not equipped with the differential protection. In this paper, the differential protection algorithm for Mu...Compared with conventional transformers, the rectiformer is special in connection mode, which is multi-tap and not equipped with the differential protection. In this paper, the differential protection algorithm for Multi-tap special transformer was derived. The regulating methods for the rectiformer were studied first, and then the rectiformer model of one electrolytic aluminium plant was built by PSCAD/EMTDC, characteristics of the rectiformer bank were also analyzed. The algorithm was derived on the basis of the per-unit system, and the processing methods of the regulating transformer’s tap position information were proposed. Finally, a contrast of differential protection algorithm between the multi-tap special transformer and the conventional transformer was made.展开更多
本文基于多窗谱分析—奇异值分解(MTM-SVD)方法对长江中下游降水和热带太平洋海表面温度(SST)进行不同时间尺度信号的分离和时空重构,研究了年际时间尺度上与厄尔尼诺—南方涛动(ENSO)相关的热带太平洋SST强迫对长江中下游降水的影响及...本文基于多窗谱分析—奇异值分解(MTM-SVD)方法对长江中下游降水和热带太平洋海表面温度(SST)进行不同时间尺度信号的分离和时空重构,研究了年际时间尺度上与厄尔尼诺—南方涛动(ENSO)相关的热带太平洋SST强迫对长江中下游降水的影响及可能机制。结果表明,长江中下游地区降水和热带太平洋SST存在着准两年(2.4年)和准四年(3.7年)的协同变化周期,且这两个年际主导模态分别与El Niño的中太平洋(CP)型和东太平洋(EP)型有关。与两类El Niño事件相关的SST强迫会引发不同的东亚大气环流异常响应,均有利于长江中下游地区降水偏多。在准两年周期上,CP El Niño成熟期会引发东亚—太平洋型大气遥相关;在准四年周期上,EP El Niño成熟期会产生经向偶极型分布的东亚大气活动中心。此外,两类El Niño事件成熟期均会激发西北太平洋异常反气旋环流。上述大气环流系统变化共同增强了从南海向长江中下游地区的水汽输送,造成该地区在两类El Niño成熟期间降水偏多。对2002年中国降水事件的个例分析表明,准两年和准四年周期变率对同期长江中下游地区降水变化的相对贡献存在差异。准四年周期变率有利于2002年春季长江中下游降水的偏多,而准两年周期变率起到减少的作用;2002年秋季的情况与之相反。本研究结果有助于深化对热带太平洋多时间尺度SST强迫影响长江中下游降水年际变化机制的认识,并提高长江中下游地区降水预测的准确性。展开更多
文摘Compared with conventional transformers, the rectiformer is special in connection mode, which is multi-tap and not equipped with the differential protection. In this paper, the differential protection algorithm for Multi-tap special transformer was derived. The regulating methods for the rectiformer were studied first, and then the rectiformer model of one electrolytic aluminium plant was built by PSCAD/EMTDC, characteristics of the rectiformer bank were also analyzed. The algorithm was derived on the basis of the per-unit system, and the processing methods of the regulating transformer’s tap position information were proposed. Finally, a contrast of differential protection algorithm between the multi-tap special transformer and the conventional transformer was made.
文摘本文基于多窗谱分析—奇异值分解(MTM-SVD)方法对长江中下游降水和热带太平洋海表面温度(SST)进行不同时间尺度信号的分离和时空重构,研究了年际时间尺度上与厄尔尼诺—南方涛动(ENSO)相关的热带太平洋SST强迫对长江中下游降水的影响及可能机制。结果表明,长江中下游地区降水和热带太平洋SST存在着准两年(2.4年)和准四年(3.7年)的协同变化周期,且这两个年际主导模态分别与El Niño的中太平洋(CP)型和东太平洋(EP)型有关。与两类El Niño事件相关的SST强迫会引发不同的东亚大气环流异常响应,均有利于长江中下游地区降水偏多。在准两年周期上,CP El Niño成熟期会引发东亚—太平洋型大气遥相关;在准四年周期上,EP El Niño成熟期会产生经向偶极型分布的东亚大气活动中心。此外,两类El Niño事件成熟期均会激发西北太平洋异常反气旋环流。上述大气环流系统变化共同增强了从南海向长江中下游地区的水汽输送,造成该地区在两类El Niño成熟期间降水偏多。对2002年中国降水事件的个例分析表明,准两年和准四年周期变率对同期长江中下游地区降水变化的相对贡献存在差异。准四年周期变率有利于2002年春季长江中下游降水的偏多,而准两年周期变率起到减少的作用;2002年秋季的情况与之相反。本研究结果有助于深化对热带太平洋多时间尺度SST强迫影响长江中下游降水年际变化机制的认识,并提高长江中下游地区降水预测的准确性。
