Dependence of Voltage Fluctuation Severity on Clipped Sinewave Distortion of Voltage

The article presents the novel findings on the dependence of voltage fluctuation severity on voltage distortion caused by power electronic loads. The results indicate the need to modify the recommended limitation of the IEC flickermeter bandwidth to cut-off frequency at least 450 Hz by the IEC standard, to consider the possible obnoxious voltage fluctuation caused by power electronic devices. The real voltage distortion of the “clipped sine” or “sharpened sine” type, resulting from nonlinear currents, the flow of which is forced by power electronic devices, was considered in the research. The basics of indicator P
_st
/P
_lt
measurement by IEC flickermeter are discussed, and the influence of sinusoidal supply voltage distortion on the indicator P
_st
measurement was investigated. The analytical model of IEC flickermeter signal chain was proposed to explain the influence of supply voltage distortion on the indicator P
_st
measurement. This model was verified by comparing the results of numerical simulations and laboratory measurements.