基于波形正弦特征和模糊贴近度原理的变压器励磁涌流识别方案研究  

Research on identifying inrush current of transformer based on the sine principle of current waveforms and the fuzzy degree nearness

作　　者：卢雪峰[1] 王增平[1] 徐岩[1] 王慈[1] 

机构地区：[1]华北电力大学电力系统保护与动态安全监控教育部重点实验室,河北保定071003

出　　处：《华北电力大学学报（自然科学版）》2007年第6期23-27,共5页Journal of North China Electric Power University：Natural Science Edition

摘　　要：提出了应用正弦函数的特征和模糊贴近度原理相结合的方法来识别变压器的故障电流和励磁涌流。变压器正常运行、内部短路、外部短路时波形具有正弦波形特征,而励磁涌流波形因包含非周期分量、间断角不具有正弦波形的特征。假设所研究波形均为正弦波形,通过直接寻找可以得到峰值的实际值,通过理论计算可以得到峰值的理论值,然后求实际值和理论值比值的绝对值。利用绝对值的大小区分故障电流和励磁涌流。理论分析和动模实验结果表明:本方法原理简单,易于实现,可以准确识别故障电流和励磁涌流,即使在空载合闸于内部短路故障时保护也能迅速可靠动作,并具有抗CT饱和的能力。This paper proposes a new method of using the sine principle combined with the fuzzy degree of nearness to identify the short circuit current and inrush current of transformers. Under transformer internal and external faults, the three- phase current is mainly sinusoidal. However, the inrush current is featured by no periodic and dead angle, so it is not sinusoidal. This paper assumes that all the waveforms researched are sine waveforms. The actual value of the hump can be found directly. And the theoretical value can be got by calculating. Through the dimension of the absolute value the short circuit current and the inrush current can be distinguished. The results of theoretical analysis and dynamic simulation show that the method mentioned here can identify the short circuit current and the inrush current precisely , and make it rapid and reliable for the protective relay to trip even if switching on under no- load conditions with an internal fault occurring. It also can resist CT saturation.

关 键 词：正弦函数特征 峰值 模糊贴近度 变压器 故障电流 励磁涌流 

分 类 号：TM77[电气工程—电力系统及自动化]