scope:

This standard provides background information on supply voltage fluctuations caused by variations 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 61000-4-15.⁶ This standard defines the short-term (P_st) and long-term (P_lt) 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.

Purpose

This document identifies and defines requirements to system operators, owners, and engineers who are responsible for interconnecting installations that cause voltage fluctuations. It provides information on various flicker and RVC indices that are used to characterize the voltage fluctuations and explain the principles and methodology that can be used to determine requirements for connecting fluctuating installations to both radial and network systems. This document provides methods for determining appropriate flicker planning levels and emission limits for installations with fluctuating power flows. The need for the standard is to provide the industry with flicker and RVC limits and analysis methods that can be consistently applied across the industry. This will allow consistent planning of facilities and designing of solutions to deal with voltage fluctuations issues.

⁶Information on references can be found in Clause 2.