简介:thus the sensitivity is high for internal low percentage inter-turn fault without risks of unwanted operation under external fault.,Integration of main and backup protection with duplicate allocation reduces the total number of power transformer protection devices,Lifting differential setting or introducing differential protection with product- quantity restraint will lose sensitivity or even lead to missing operation. With identifying harmonic component and waveform character of differential current asynchronous anti-TA saturation criterion can distinguish between internal fault and TA saturation under external fault.
简介:EInk'smicrocapsulesarefilledwithaclearliquidthatholdsverysmallparticles.Someparticlesareblack.Somearewhite.Alloftheparticleshaveane-lectricalcharge.Tomakeasheetofelectronicpaper,engineersspreadmillionsoftheparticle-filledmicro-capsulesontoapieceofplastic.
简介:在本期的“课例大家评”中,我们刊登了同一课题下的6篇课例供大家点评.2001年第4期,我刊登出了“直线方程的一般形式(第一课时)”课例的征稿启事.截止4月30日,我们收到课例来稿百余篇.这6篇课例就是从这些应征稿件中遴选出来的.为了便于大家点评,我们将6篇课例按学生学习状况的优、中、差分为三组,每组有2篇课例.在撰写点评稿时,您可以对6篇课例进行总评,也可以就学生学习状况相当的两篇课例进行评析,还可以对某一课例做单独的评议.总之,点评的内容应相对集中,以便于编者对稿件进行选择和组构.文稿字数以1000字左右为宜,截稿日期为9月10日.投稿时请在信封左下方注明“课例大家评”字样.欢迎广大数学教师和教研工作者积极参与本次“课例大家评”活动,我们将以较大篇幅集中发表观点新颖、论述深刻、对教学具有较强启发性的优秀来稿.在此,我们还特别对提供“直线方程的一般形式”课例的所有老师表示衷心的感谢.