Performance analysis of power quality impact of Adama-One wind farm in Ethiopia

摘要

Due to the intermittent nature of wind, the power quality of the grid with wind power plants is affected. Hence, in order to assure the power quality of Adama-One wind farm, the continuous performance assessment is recommended using various performance indices. Two aspects of the wind farm performance evaluations are assessed. The first aspect is the evaluation of power and energy production performance indices. From production analysis aspect, the wind farm delivers average power of 18.43 MW to the grid with maximum of 51.09 MW and minimum of 2.08 MW. The energy delivered over one year in 2015/16 G.C has been 157.74 GWH against the design yearly harvest of 162.7 GWH per year. Hence, the Capacity Factor result of annual energy production is found to be 35.3 %. These demonstrate that based on the current status, the wind farm performance is good and within the design range. The second aspect is analysis of harmonic emission from the wind farm as the result of frequency converters and other nonlinear loads. The harmonic current data's are collected at one of the point of common coupling (PCC) which is at 33 KV bus bar systems, where 3 and 5 current injection harmonic filters are installed. Using Matlab software, the steady state harmonic load flow analysis of the wind farm at 33KV bus-bar system is performed. It has been found that the results of mathematically analyzed Total Harmonic Distortion (THD) current and voltage values are almost similar to that of simulated THD output of current and voltage. The wind farm harmonic current emission with maximum calculated value of 5.96 % is found to be within permissible limit set by international standard at selected PCC which is 7%. The maximum calculated THD voltage is also found to be 2.75 % which is less than 5 % set by IEEE STD-519. Hence, power quality of the wind farm can be said to be good and do not have significant negative impact on the power quality of grid system at present. Finally, the grid code standard is proposed.