Experimental Study of the Summation of Flicker Caused by Wind Turbines

Abstract

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.

Voltage Flicker Detection Based on Probability Resampling

“…Step 5 is used to make online statistics of the value sent by the previous steps, and according to the cumulative probability, Equation 5is applied to calculate the short-term flicker value and, further, the long-term flicker is obtained. p st = 0.031 4p 0.1 + 0.052 5p 1 + 0.065 7p 3 + 0.28p 10 + 0.08p 50 (5) where p 0.1 , p 1 , p 3 , p 10 , and p 50 denote S(t) of Cumulative Distribution Function (CPF) exceeding 0.1%, 1%, 3%, 10%, and 50%, respectively.…”

“…Fluctuating load affects the power supply quality of the power system and threatens the reliable operation of other equipment in the power grid. With the rapid development of high-speed railways and increasing utilization of clean energy, electrified railways with large fluctuations in traction load and clean energy network have become essential parts of the power grid [1][2][3][4][5]. Voltage flicker is a subjective perception of the fluctuations in lamp illuminance caused by voltage fluctuations.…”

Assessment of Flicker Emission in a Grid Connected Wind Farms

“…Due to voltage fluctuations, the flickering is induced in the load flow. In a grid connected wind farm, flicker emission happens because of the fluctuations in power due to the variations in wind speed, wind shear, and tower shadow effects [2][3][4][5]. It depends on mean wind speed, short circuit capacity, and grid impedance angle [6][7][8][9][10][11].…”

Enhancement of the Flickermeter for Grid-Connected Wind Turbines

“…However, the CRIEPI does not provided a method to evaluate the voltage flicker caused by wind turbines. Although the works in Gherasim [15], Redondo [16,17], and Manas [18] implemented the flickermeter based on the IEC standard for wind turbines, the ∆V 10 standard has not been considered. Thus, in this work, we added the ∆V 10 method into the IEC 61400-21-1 standard to propose an enhanced version of the two-mode IEC voltage flicker measurement for wind turbines, which is suitable for countries using the IEC standard or the ∆V 10 standard.…”