The purpose of the present paper is to evaluate the sensitivity of modern lighting technologies to different types of RVCs. In order to do that, 27 modern lamps—mainly LED—have been subjected to real RVCs and their response has been assessed. The detection of RVCs on the grid has been performed according to the IEC 61000-4-30 detection method, while the response of the lamps has been measured with a light flickermeter and characterized using the instantaneous flicker perception, as defined in IEC 61000-4-15. The obtained results show a high dispersion in the response of the modern lighting technologies and high values of flicker perception, although with a lower sensitivity than the incandescent lamp. The results led the authors to propose the definition of a new immunity test to be added to the lamp immunity protocol IEC TR-61547-1, to ensure that newly produced lamps cause limited irritation to grid users.

Integration of wind energy into the grid faces a great challenge regarding power quality. The International Electrotechnical Commission (IEC) 61400-21 standard defines the electrical characteristics that need to be assessed in a Wind Turbine (WT), as well as the procedure to measure the disturbances produced by the WT. One of the parameters to be assessed are voltage fluctuations or flicker. To estimate the flicker emission of a Wind Power Plant (WPP), the standard establishes that a quadratic exponent should be used in the summation of the flicker emission of each WT. This exponent was selected based on studies carried out in WPPs with type I and II WTs. Advances in wind turbine technology have reduced their flicker emission, mainly thanks to the implementation of power electronics for the partial or total management of the power injected into the grid. This work is based on measurements from a WPP with 16 type III WTs. The flicker emission of a single WT and of the WPP were calculated. Low flicker emission values at the Point of Common Coupling (PCC) of the WPP were obtained. The flicker estimation at the PCC, based on the measurement from a single WT, was analyzed using different exponents. The results show that a cubic summation performs better than the quadratic one in the estimation of the flicker emission of a WPP with type III WTs.

This paper analyzes the effect of digital differentiation on the measurement of flicker emission from grid-connected wind turbines (WTs). The flicker measurement procedure is defined in the IEC 61400-21 standard, which includes the estimation of a fictitious grid for the measurement of voltage fluctuations exclusively generated by a WT. The study focuses on two aspects of the implementation of the derivative of the line current that affect the estimation of the fictitious grid, namely the bandwidth and the phase response of the digital differentiator. The experiments were performed under two different frameworks, by using simulated simple waveforms and voltage and current recordings from an actual WT. The work cautions about the adverse effect of the phase response of the even-length finite impulse-response differentiators. It also recommends implementing digital differentiators with an accurate bandwidth to derive potential spectral components in the current in the whole bandwidth required by the procedure. This aim can be achieved by increasing either the length of the filter or the sampling rate of the processing. The conclusions should help in accurately implementing the procedure and reducing the deviations found in the flicker emission measurements for grid-connected WTs.