基于互近似熵的电压暂降波形匹配方法

随着越来越多电压暂降敏感设备接入电网,因电压暂降干扰带来的直接及间接经济损失日趋严重,这对供电质量提出了更高要求,准确识别暂降源是治理电压暂降问题中必不可少的步骤。文中分析了各类短路故障引起的电压暂降类型及其经变压器传变后暂降波形的变化情况,并根据理论分析建立各类暂降的标准样本波形。提出了一种基于互近似熵原理的电压暂降源辨识方法,通过计算实测波形与样本波形之间的互近似熵,直接进行相似度匹配,实现故障暂降类别的准确识别,并利用电网实测数据对该方法进行验证。结果表明该方法与实际工程相贴合,具有很强的实用性。

Voltage sag waveform matching method based on cross approximate entropy

As more and more devices sensitive to voltage sag are widely connected to the power grid, the direct and indirect economic losses caused by voltage sag interference become more and more serious, which puts forward higher requirements for power supply quality. Accurate identification of sag sources is an essential step in the treatment of voltage sag.It analyzes the types of voltage sags caused by various short-circuit faults and the changes of voltage sags waveforms after transformer transmission, and establishes the standard sample waveforms of voltage sags according to theoretical analysis. A voltage sag waveform matching method based on mutual approximation entropy principle is proposed. The measured waveforms are compared with the sample waveforms and the similarity matching is carried out directly. Finally, the effect of identifying voltage sag disturbance source is achieved. The simulation results show that the method has high accuracy in identifying the measured voltage sag waveforms in power grid, and the feasibility and effectiveness of the method are verified.