摘要:变压器利用电磁感应原理把一种电压的交流电能转变为频率相同的另一种电压的交流电能，在电力系统中，需要用变压器将电压升级进行远距离传输，以降低线路损耗，当电能到达用户区后，再采用不同等级的变压器将电能降压使用。因此，变压器的正常运行对保持系统的稳定性与安全有着特殊的意义。本课题利用MATLAB/SIMULINK软件，设计一个变压器差动保护仿真系统，通过仿真来验证差动保护正确性和合理性。实施纵差动保护要解决好以下几个问题：如何正确识别励磁涌流和短路电流；解决好躲开区外短路故障时差动回路中的不平衡电流和保护灵敏度间的矛盾；外部短路故障切除电压恢复的暂态过程中，保证差动保护不误动作；电流互感器饱和不应影响纵差动保护正确动作等问题。

关键词 纵差动保护；SIMULINK；仿真；躲开故障

Abstract:Transformer using the principle of electromagnetic induction to a voltage alternating current can change another voltage of the same frequency of the AC power, in the power system, need to use the transformer voltage upgrade for long-distance transmission, in order to reduce the loss of line, when the energy reaches the user area, then the different level of transformer power step-down use, therefore, the normal operation of the transformer has a special meaning for maintaining stability and security system. This topic using MATLAB/SIMULINK software, the design of a transformer differential protection simulation system, the simulation to verify the correctness and rationality of the differential protection. The implementation of differential protection to solve the following problems: how to correctly identify the inrush current and short circuit current; solve from external short-circuit fault time difference between loop of the unbalanced current and the transient protection sensitivity; external fault with voltage recovery, assurance of differential protection misoperation; current transformer saturation should not affect the correct operation of differential protection.

Keywords  Longitudinal differential protection   Simulink   Simulation  Avoid fault