Evaluating voltage fluctuations and flicker using half-cycle RMS values

Evaluating voltage fluctuations and flicker using simulated or recorded data is an important part of the planning process related to power quality. Simulation tools perform calculations using sinusoidal steady-state models and methods and numerous power quality recorders save RMS values on a cycle by cycle basis. Previous work has shown the feasibility of using cycle-by-cycle RMS values as inputs to the standard flickermeter as long as the fluctuation frequency was below 10 Hz. The work in this paper is based on the same concept of using full-cycle RMS values as flickermeter inputs, but the RMS values are updated every half-cycle in accordance with IEC Std 61000-4-30. Using RMS inputs which are updated every half-cycle is shown to offer an increase in performance such that satisfactory results are obtained for fluctuation frequencies up to 22 Hz. This improvement is demonstrated using analytical, simulated, and field measurements results.