IEEE Draft Standard for Measurement and Limits of Voltage Fluctuations and Associated Light Flicker on AC Power Systems

Background information on supply voltage fluctuations caused by fluctuations in power demands of installations is provided by this standard. The manifestation of these supply voltage fluctuations as lamp flicker is presented in this standard. A flicker measurement method using a meter that is described in IEC 61000-4-15 is presented in this standard. The short-term (Pst) and long-term (Plt) indices used for the quantification of lamp flicker are defined in this standard. For different system voltages, planning levels for flicker that the utilities need their system to be limited to in order to reduce customer complaints are defined in this standard. The procedure for determining emission limits for individual installations at the point of common coupling (PCC) so that the planning levels can be achieved in practice is defined in this standard. Then, an assessment procedure for evaluating flicker compliance against emission limits is described. Methodologies to analyze background flicker to identify the flicker contribution of individual sources are also presented in this standard. Rapid voltage changes (RVCs) that are caused by various system events such as switching of capacitor banks, energization of power transformers, and starting of induction motors are also addressed by this standard. Methods to estimate flicker or RVCs at the PCC for various types of fluctuating installations are provided by this document. Example terms and language that can be the basis for defining relative responsibilities and assessment methods for installations that may cause flicker and RVCs are included in the document.