和应涌流条下变压差动保护动作特性分析可研性说明书.docVIP

（ 摘 要 随着越来越多的超高压远距离输电线路在我国的建成和运行，大容量变压器的应用也日益增多。电力变压器在电力系统输电和配电各个环节中广泛使用，因此也就对变压器保护的可靠性和速断性提出了更高的要求。差动保护是变压器的主保护，变压器在空载合闸或外部故障切除后恢复供电时，差动回路会流入励磁涌流，若差动保护不能识别并躲过此电流，就会发生误动。因此，励磁涌流的识别一直也是国内外继电保护工作者的研究热点。 励磁涌流一直是影响变压器差动保护正确动作的原因之一，本文从励磁涌流的机理以及特征出发，研究了励磁涌流对变压器差动保护的影响。 论文最后以两单相变压器并联运行为例，利用励磁涌流偏向时间轴一侧的特点，解释了和应涌流的产生机理及其变化特点，指出和应涌流产生的本质原因是由于合闸变压器励磁涌流流过系统电阻使得其它变压器工作母线电压偏移，导致铁心饱和造成的。文中初步分析了各种因素对和应涌流的影响，讨论了和应涌流对变压器保护的危害，并在此基础上提出了相应的防范措施。 关键词：励磁涌流，变压器，和应涌流，MATLAB仿真 Abstract As EHV power network is developing rapidly, large capacity power transformers are used widely in the transmission system and distribution system. Therefore, high performance and high reliability of power transformer protection are required urgently. At present, the main protection of internal faults of the power transformer is the differential protection. When the unloaded power transformer is switched on the power system or in the process that a fault, outside the protected zone, is cleared, the magnetizing inrush current will ususlly produced. The differential protection relays will maloperate. So it is still a research focus for relaying researchers in the world. Inrush current has been one of the reason which infects the correct operation of the transformer differential protection, then we research how the inrush current influence the transformer differential protection based on mechanism of inrush current , the effects of current compensation. Based on the analysis of sympathetic inrush in operating transformers, the principle and characteristics of sympathetic inrush are explained . It is shown that the inrush current caused by the energized transformer running across the system resistance results in the deviation of voltage in the common node which lead to the saturation of the core of the transformer is the main reason for the sympathetic inrush on the adjacent transformer. Then the influence on transformer protection caused by s