* Corresponding author: Murat Mustafa Savrun, Adana Science and Technology University, Department of Electrical-Electronics Engineering, 01250 Adana, Turkey, E-mail: msavrun@adanabtu.edu.tr 1 Adana Science and Technology University, Electrical-Electronics Engineering 01250 Adana, Turkey 2 Çukurova University, Electrical-Electronics Engineering 01330 Adana, Turkey 3 Adana Science and Technology University, Automotive Engineering 01250 Adana, Turkey 4 Ankara Yıldırım Beyazıt University, Energy Systems Engineering 06760 Ankara, Turkey Copyright © JES 2018 on-line : journal/esrgroups.org/jes Murat Mustafa Savrun 1,* , Adnan Tan 2 , Tahsin Köroğlu 3 , Mehmet Uğras Cuma 1 , Kamil Çağatay Bayındır 4 , Mehmet Tümay 1 J. Electrical Systems 14-1 (2018): 174-187 Regular paper                                                                ! !" !                 #  #     $ #   " %  $    $    !            &     ’  $      " (       $    !  " )  *+ , #               - " .$               !" Keywords: Voltage Sag; Voltage Swell; Disturbance Generator. Article history: Received 4 January 2018, Accepted 6 February 2018 1. Introduction Voltage sags are considered one of the most encountered power quality problems in power systems. Voltage sag is a momentary decrease in the rms voltage between 0.1pu and 0.9 pu (10%–90% of the nominal voltage) at the power frequency of duration from 0.5 cycles to a few seconds. They may be caused by natural events (lightning or freezing), switching operations of power electronic equipment, nonlinear characteristics of loads and fault currents. The voltage swell is a power quality problem but it is not encountered as frequently as the voltage sag. Voltage swell is a momentary increase to between 1.1pu and 1.8 pu in the rms ac voltage (110% of the nominal voltage) at the power frequency of duration from 0.5 cycles to a few seconds. They may be triggered on the unfaulted phase by occurred faults on the other phases. Voltage sags and swells may damage a large number of voltage-sensitive loads, cause a shutdown of a process and cause high economic hardship [1-4]. In order to mitigate the effects of voltage sags and swells on the voltage sensitive users, sag compensating devices such as DVR, UPS, static series compensator (SSC) etc. are inserted to the power systems. It is important to test the performance of these compensating devices under various voltage sag and swell conditions. The performance analysis of the devices must be carried out for diverse sag/swell duration, depth and point of initiation. A