电力变压器的励磁涌流和匝间故障识别新方法

在引入瞬时功率Pq分解的基础上，提出了一种依据变压器两侧三相差瞬时有功功率和瞬时无功功率中直流分量比值的变化关系来识别变压器励磁涌流和匝间短路故障的新方法．该方法既具有传统变压器电流差动保护简便易行的优势，同时又从平均有功与平均无功相对变化关系出发，进一步揭示了变压器励磁涌流与匝间短路故障本质上的不同．EMTP仿真实验结果表明：该方法简单可靠，识别效果显．

A new algorithm for the discrimination between inrush and inner-turn faults of power transformer

This paper proposes a new algorithm based on the theory of instantaneous reactive power for transformer protection. This algorithm is mainly based on the relationship of DC component between the instantaneous active power and the instantaneous reactive power. There are not only the advantages of simpleness and convenience that conventional current ?based differential protection has, but also the advantages, due to considering the relationship between active power and reactive power, of revealing the differences between inrush currents and internal fault currents more deeply in nature. A new way of thought for seeking more appropriate schemes of transformer protection is provided in this paper. The results of Electromagnetic Transient Program (EMTP) simulation show that a valid discrimination between internal fault currents and inrush currents in transformers can be made by this algorithm, which is simple and reliable.