基于EMTP的电流互感器饱和特性仿真及分析

电磁暂态程序（EMTP）的基本功能是进行电力系统仿真计算。EMTP程序具有规模大、功能强、模拟真实等优点，目前在国内外高等学校、科研、设计和制造等部门都得到了广泛的应用。电流互感器（CT）采用电磁感应的原理得到与一次侧电流成比例的二次电流，当磁通饱和时励磁电流增大，两侧电流的比例关系发生改变。该文用EMTP仿真计算了电流互感器不同饱和度时二次侧输出电流，结果表明在超出设计的特大电流下二次侧输出电流发生严重畸变。根据离散傅利叶变换，分析了继电保护装置在CT饱和后计算值的特点。

Simulation and Analysis of Saturation Characteristics of CT Based on EMTP

Simulation calculation and analysis in power system is the main function of electromagnetism transient program(EMTP).EMPT is widely applied in colleges,science and design organizations and manufactures,for it has the advantages of powerful function,calculation on a large scale and real results.Using current transformer(CT),people gain secondary side current which is proportional to primary side current.When magnetic flux is saturated,the excitation current is increased and the proportion of the CT is changed.The secondary side currents of CT are calculated in the differential magnetic flux using EMTP,and the results show that the secondary side currents have serious and abnormal changes when the primary side current is much out of designed scope.Using DFT algorithm,the features of calculated values of protection relay is concluded in the case of CT in differential saturation.