基于样波分析的变压器励磁涌流判别

二次谐波制动原理的变压器差动保护，在变压器空投或故障切除后恢复复供电时，不能很灵敏的反应上旨变压器发生的某些故障，如轻微匝间故障（3％匝左右），励磁涌流很长时间才衰减，导致差动保护延缓动作。针对上述情况，本文提出一种新的励磁涌流样波分析方法，根据励磁涌流与故障电流的波形特点，采用标准的样波作矢量分析在空投时有效闭锁差动保护，空投内部故障时不降低保护的灵敏度，提高了保护的运作时间。

TRANSFORMER''''S INRUSH CURRENT ANALYSIS BASED SAMPLE-WAVE

Transformer differential protection possibly lead it to act incorrectly, while using 2 nd harmonic restraint at transformer inrush, because transformer is switched in or resumed to supply power after being turned off it, transformer appears faulty, i.e. weakly faulty (short circuit of 3%) in transformer circle, it's inrush current mixing with fault current may last for several seconds, possibly run a risk of unwanted operation from this inrush current. According to this factor, this article brings forward new inrush current's sample wave analytical method, basing on inrush current and faulty current's wave characteristic, using standard wave to finish vector analysis. Operation blocked by 2 nd harmonic component when transformer is switched in and energized. Increase protection relay's acting speed and executive schedule when transformer is switched in and energized with appearing faulty.