基于非周期分量的变压器差动保护研究

Study on Transformer Differential Protection Based on Non-periodic Variable

采用全波周期N点采样积分运算,精确估计指数函数型衰减直流信号的时间常数和幅值。研究结果表明:线路两侧的非周期分量在区内故障时表现为故障电流,区外故障时为穿越性电流,经过计算、比较,可准确判断区内、区外故障。基于非周期分量给出了变压器差动保护的动作判据,仿真结果表明该原理保护不受励磁涌流、故障类型、故障位置和故障过渡电阻的影响。

This paper uses full wave cycle N sampling integral operation method to accurately estimate ume constant aHu ,u.- plitude of exponential function typed decaying direct current signal. Study results indicate that non-periodic variables on both sides of the line behave as fault current when happening internal fault while may be as through-current when happening ex- ternal fault. In addition, by calculation and comparison, it is able to correctly iudge internal and external faults. On the ba- sis of non-periodic variable, it proposes action criteria for transformer differentia protection and the simulation result indi- cates that this principle may not be affected by excitation surge current, fault types, fault position and faulted transition re- sistance.