Background on light flicker caused by fluctuations in power demands of variable loads is presented in this recommended practice. A flicker measurement method is presented using a meter that is completely described in IEC 61000-4-15. The short-term (Pst) and long-term (Plt) flicker indices used for the analysis of flicker data are defined. Flicker limits for various voltage levels are presented. An assessment procedure for evaluating flicker compliance against emission limits is described. Methodologies to analyze background flicker to identify the flicker contribution of single loads are also presented.
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IEEE Approved Draft Standard for Measurement and Limits of Voltage Fluctuations and Associated Light flicker Analysis of fluctuating Loads on Power Systems
This standard provides background information on supply voltage fluctuations caused by fluctuations in power demands of installations. This standard presents the manifestation of these supply voltage fluctuations as lamp flicker. The standard presents a flicker measurement method using a meter that is described in IEC 61000-4-15. This standard defines the short-term (Pst) and long-term (Plt) indices used for the quantification of lamp flicker. For different system voltages, this standard defines planning levels for flicker that the utilities need their system to be limited to in order to reduce customer complaints. This standard defines 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. Then, an assessment procedure for evaluating flicker compliance against emission limits is described. This standard also presents methodologies to analyze background flicker to identify the flicker contribution of individual sources. This standard also addresses 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. The document provides methods to estimate flicker or RVCs at the PCC for various types of fluctuating installations. The document includes example terms and language that can be the basis for defining relative responsibilities and assessment methods for installations that may cause flicker and RVCs.
IEEE Guide--Adoption of IEC/TR 61000-3-7:2008, Electromagnetic compatibility (EMC)--Limits--Assessment of emission limits for the connection of fluctuating installations to MV, HV and EHV power systems
IEC/TR 61000-3-7:2008 is adopted by this guide. IEC 61000-3-7:2008 provides guidance on the principles that can be used as the basis for determining the requirements for the connection of fluctuating installations to MV, HV, and EHV power systems (LV installations are covered in other IEC documents). The primary objective of this guide is to provide guidance to system operators or owners on engineering practices that will facilitate adequate service quality for all connected customers. This guide provides a methodology to allocate the capacity of the system to absorb voltage fluctuations (i.e., flicker). However, it does not address how to mitigate voltage fluctuations, nor does it address how to increase the capacity of the system to absorb such disturbances. Since the procedures outlined in this guide are necessarily based on certain simplifying assumptions, the approach will not always provide an optimum solution. The recommended approach should be used with flexibility and engineering judgment, when applying the given assessment procedures in full or in part.
IEEE Recommended Practice--Adoption of IEC 61000-4-15:2010, Electromagnetic compatibility (EMC)--Testing and measurement techniques--Flickermeter--Functional and design specifications
IEC 61000-4-15:2010 is adopted by this standard. IEC 61000-4-15:2010 gives a functional and design specification for flicker measuring apparatus intended to indicate the correct flicker perception level for all practical voltage fluctuation waveforms. Information is presented to enable such an instrument to be constructed. A method is given for the evaluation of flicker severity on the basis of the output of flickermeters complying with this standard. The object of IEC 61000-4-15:2010 is to provide basic information for the design and the instrumentation of an analogue or digital flicker measuring apparatus. It does not give tolerance limit values of flicker severity.
IEEE Recommended Practice for Measurement and Limits of Voltage Fluctuations and Associated Light Flicker on AC Power Systems
Adoption of IEC 61000-4-15. Voltage fluctuations on electric power systems sometimes give rise to noticeable illumination changes from lighting equipment. This phenomenon is often referred to as flicker, lamp flicker, and sometimes voltage flicker. This recommended practice provides specifications for measurement of this phenomenon and recommends acceptable levels for 120 V, 60 Hz and 230 V, 50 Hz AC electric power systems. It does not make any flicker emission specifications for certification of individual products manufactured for use on these systems.