At present , differential protection is often used as the main protection for traction transformers . however , the existing of certain factors , such as magnetizing inrush , over - excitation , ct saturation and mismatching of ct ratio , will result in that it is hard to distinguish state current and fault current , and differential protection misoperation or maloperation , then secure operation of electric railways system will be threatened 目前，牵引变压器通常采用差动保护作为主保护，但是在某些因数的影响下差动保护并不能准确的区分牵引变压器内部故障或非内部故障，如故障电流与变压器处于励磁涌流、过励磁， ct饱和及ct变比不匹配等情况下的状态电流就很难准确的区分，可能造成保护误动或拒动，从而危及整个铁道电气化系统的安全运行。
The soldiers transporting the water had encountered this kind of situation before , but never to the extent of holding up traffic . it was different this time . drivers caught in the traffic jam cursed and some impatient ones tried to scare the stubborn old cow away with fire , but she remained undaunted 运水的士兵过去也曾遇过牲口拦路索水的情形，但是从来都不会因此而造成塞车，但这次却不同，后面被塞住的司机诅咒着谩骂着，性急的司机试图点火驱赶，但是老牛倔强如故，丝毫不为所动。
Because passing through the special craft processing and the processing of escaping taste , both may seal many years not to agglomerate , fluidity as before , and solves the sweet taste of glucose , the using factor of production has been possible to reach 100 % , for producing factories to relieve multitudinous puzzle completely 而加益粉由于经过特殊工艺加工及脱味处理，既可封存多年不结块，流动性如故，又解决了葡萄糖的甜味，生产利用率可达100 ，完全为生产厂家解除了众多方面的困扰。
Also , sometimes things look different after we have observed them for a while . the bad person turns out to be just a victim herself - a victim of bad circumstances perhaps , like the old washerwoman in the story . maybe she was very poor and she just stole the two veils because she was desperate and had no other way to help herself 同时有时候我们深入去观察时，将会对事物有不同的看法，有时我们会发现一个坏人，也许只是受环境所逼的难民，就如故事中的那位老洗衣妇，或许她因为贫苦无依，在不得已的情况之下才偷取那两块面纱，赖以度日。
