Effects of voltage fluctuation associated to flicker limits on equipments performance

This paper aims to present investigation results related to the effect of voltage fluctuation phenomenon on electrical equipments performance. The voltage variation, which is represented by a simple amplitude-modulated sine wave, is characterized by its frequency and modulation level associated to UIE/IEC flicker severity indexes. This permits the development of an analytical expression to establish a straight relationship between voltage fluctuation and the well-known short-term severity, P_ST. Time domain computer simulations of representative and sensitive loads are then carried out to study their dependence upon flicker limits. The results obtained are useful to support a discussion about the possibility of relaxing the recommended or normative flicker index limits.