在线检测实现了对运行设备特征量数据的实时监测，并对数据进行分析处理，从而预测设备运行状况。但是，电力系统发生故障时产生的谐波和衰减分量的影响会大大增加监测数据的误差。为了解决全波傅氏算法在处理含衰减直流分量信号时产生较大误差的弊端，提出一种改进算法。首先，通过增加两个采样点计算得到周期分量外的特征参数。然后，进行两次傅立叶变换，求取基波和谐波幅值和相位，通过图形化编程语言LabVIEW仿真，证明此方法具有较高的精度，较快的计算速度，优于传统算法，特别是对基波分量效果更为突出。利用LabVIEW做上位机更利于工程实践中功能的扩展。%Online testing not only realizes the real-time characteristic data, but also analyzes the data and forecasts operation status. But, in the power system, influence of harmonic and attenuation component will greatly increase error. In order to solve the greater error caused by decaying DC component in full-wave Fourier algorithm, an improved algorithm is proposed. First, characteristic parameters are calculated in addition to periodic component by adding two sampling points. Then, we use Fourier transform twice so that we can get the amplitudes and phases of fundamental and harmonic. Through a simulation by LabVIEW, it is proved that this method has higher accuracy, faster calculation speed and is superior to the traditional algorithm, especially to the fundamental component. Using LabVIEW is conducive to extended function.
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