基于附加相位判别的自适应二次谐波励磁涌流制动方案研究

在详细推导单相励磁涌流的傅里叶级数表达式基础上,分析出涌流波形中各次谐波之间满足一定的相位关系,即单相涌流中基波相位与2次谐波相位差为0°或180°,由此提出了一种基于附加相位判别的自适应2次谐波励磁涌流制动方案。该方案充分利用涌流波形中的幅值相位信息,改善了某些涌流不明显情况下传统2次谐波制动原理的不足,同时空投变压器内部故障时也不会误闭锁差动保护。各种情况下的仿真与动模数据的测试结果表明:自适应附加相位制动方案的差动保护比传统2次谐波判据性能优良,且有较好的实际工程应用价值。

An Adaptive Second Harmonic Restrained Method Using Phase Angle and Amplitude for Inrush Detection

The analysis of frequency spectrum for single transformer inrush indicates that the phase difference between fundamental wave and second harmonic phasor is equal 0o or 180o.An adaptive second harmonic amplitude and phase restraint scheme is put forward to avoid malfunction under inrush conditions. The amplitude and phase information in the inrush waveform is fully used in scheme. The simulation results indicated that the scheme is better than the traditional second harmonic restrain method. It will not malfunction when a transformer is energized, and it will issue a trip signal quickly when transformer with internal fault is energized.