基于形态学的特高压直流输电线路雷击干扰识别

研究和识别输电线路雷击干扰的暂态特征对研制基于暂态量的保护及提高其可靠性具有十分重要的意义。数学形态学多尺度形态分解可以将复杂信号分解为具有物理意义的各部分,并且能凸显波形的局部特征。基于此,运用数学形态学对±800 kV特高压直流输电线路的雷击未故障、雷击故障和其他原因接地故障的暂态电流进行多尺度分解,提取高、低频段上的谱能量,并用这2个谱能量的比值构成主判据,实现雷击干扰与故障状态的识别。根据电流首波头的第2尺度和第6尺度分解波形的电流幅值最大值的比,进一步判别是雷击故障还是其他原因接地故障。通过大量的仿真验证了该方法是正确和有效的。

Identification of UHVDC Transmission Line Lightning Disturbance Based on Morphology

Study on the transient characteristics of the electric signal is significant to the development of transient-based protection and its reliability improvement when the overhead transmission lines are disturbed by the direct lightning stroke. The multi-scale decomposition of mathematical morphology can decompose the complex signal into different sections with physical significance, and highlight the local features of the waveform. The mathematical morphology is used to make a multi-scale decomposition of the transient currents resulted from the non-fault lightning stroke, fault lightning stroke and line short circuit of the ±800 kV UHVDC transmission lines. The spectrum energies from the high and low frequency bands are extracted respectively. According the ratio of the maximum amplitudes of the waveforms in the second scale to the sixth scale of the first head of the current, the fault lightning stroke and the line short circuit can be distinguished. Extensive simulations demonstrate that the approach is correct and effective.