Standard measurement of interharmonics in a power supply system while evaluating obnoxiousness of a flicker

Flicker is caused by the fluctuation of voltage that supplies the source of light. Such a fluctuations are accompanied by the existence of interharmonics. This paper summarizes the measurement of interharmonics accordant to IEC 61000-4-7 standard. Also included are the results of analysis of flickermeter signal chain for the input signal composed of two interharmonics. The relation between the P_st indicator value and amplitudes and phases of the two interharmonics is determined. Condition for taking into consideration the phase relations while evaluating the P_st indicator value is also given. It is concluded that the evaluation of P_st indicator value is not possible only on the basis of IEC 61000-4-7 standard measurements for harmonics.