With analyzing the principle, the defect of IEC flickermeter is introduced, when it is used to detect the flicker caused by interharmonics. By investigating the root-mean-square (rms) of the waveform with interharmonics, the relationship between interharmonics which would lead to the fluctuation of effective value of equal voltage is decided. Then an improved method for IEC flickermeter has been proposed based on frequency domain analysis. With the reconstitution of the waveform, the proposed method broadens the detectable range of IEC flickermeter, and improves the accuracy in detecting the flicker signal of high order interharmonics. By analyzing the flickers caused by a single interharmonic, as well as the modulated wave, this paper has proved that the proposed method is effective. Then the interharmonic-fiicker curves based on the proposed method are derived.%分析了IEC闪变仪的工作原理,指出了其检测由间谐波引起的闪变时的不足.通过对间谐波引起的电压有效值波动的分析,得到了引起同等电压有效值波动的间谐波之间的关系,并以频谱分析为基础,提出了一种对IEC闪变仪的改进方法.通过将闪变信号进行重构,大大扩展了IEC闪变仪的可检测范围,并提高了对含有高次间谐波的闪变信号的检测精度.通过对单个间谐波和调幅波引起的闪变问题的分析,证明了该方法的有效性,计算了单个间谐波和调幅波的闪变限制曲线.
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