International Conference on Engineering Research and Education School of Applied sciences & Technology, SUST, Sylhet Submitted: xx Month, xxxx │ Revised: xx Month, xxxx │ Accepted: xx Month, xxxx pp. 1 Power Factor Improvement of IEEE 14 Bus Network and Voltage Sag Mitigation of a Power System by Using DSTATCOM Md Abdur Rahman 1* , Ashikur Rahman 2 , Monowar Wadud Hridoy 3 and Md. Shamsul Arifin 4 1,3,4 Chittagong University of Engineering and Technology, Chattogram, Bangladesh 2 Khulna University of Engineering and Technology, Khulna, Bangladesh • Email: kakoncuet9@gmail.com, ashikeee720@gmail.com, mwhridoycuet59@gmail.com, shamsul@cuet.ac.bd *Corresponding author [Md Abdur Rahman] Keywords: • DSTATCOM; • Voltage sag; • Power factor; • SVC; • PI controller. Abstract: This article represents the design of a Distributed Static Compensator (DSTATCOM) for the mitigation of voltage sag in an unbalanced electrical network and improvement of power factor in the electrical system, which is the IEEE 14 bus network. The DSTATCOM is used instead of a Static Var Compensator (SVC). The normal test system is analyzed to alleviate the voltage sag. For reactive power compensation, IEEE 14 bus system is analyzed to improve the power quality using DSTATCOM. The DSTATCOM injects a reactive current into the system for correcting the voltage sag, also compensates the reactive power of the IEEE 14 bus system that increases the power factor of the system. In this research, the 6-pulse DSTATCOM configuration with Insulated Gate Bipolar Transistor (IGBT) has been designed. Proportional-Integral (PI) based controller is used to generate the gate pulse. Simulation results reflect that, the DSTATCOM mitigates voltage sag and improves the power factor. 1. Introduction Maintaining good power quality and robust power flow are the two most common challenges for engineers working in the power sector. The most common types of power quality issues incorporate voltage sag, harmonics, swell, etc. Voltage sag is characterized as a short decrease in magnitude of voltage for a certain time. As per the IEEE characterized standard (IEEE Std. 1159, 1995), this is the decreasing of rms voltage from 0.1 p.u. to 0.9 p. u. (per unit), for a length of half-cycle to one minute [1]. About 80% of the problems in power quality (PQ) are related to voltage sag [2]. Voltage Sag remains just 0.1 second, which may cause huge costs associated with equipment restarting, lower quality items, production losses, etc. It also reduces the satisfaction of end-user [3]. There are certain reasons for happening voltage sag which includes faults due to short circuits, abrupt load changes, starting of large induction motor and transformer energization, etc. [4-7]. Different strategies have been applied to mitigate or reduce voltage sags. The conventional techniques are by installing uninterruptible power supplies (UPS), utilizing capacitor banks, and by introducing parallel feeders. However, due to significant expenses of new feeders and UPS, uncontrollable reactive power compensation, the problems in PQ are not solved