Journal of Next Generation Technology (JNxtGenTech) Vol. 1, Issue 1, June 2021 8 Mitigation of Sag/Swell in Transmission by using DVR M.V.Suganyadevi 1 , T.Thenmozhi 2 1 Associate Professor, Department of Electrical and Electronics Engineering, Saranathan College of Engineering, Tamilnadu, India-620012. 2 Assistant Professor, Department of Electrical and Electronics Engineering, Sri Sai Ram Institute of Technology,Tamilnadu, India-600044. Email id: mvsuganyadevi@gmail.com 1 ,thenmozhi.ts@gmail.com 2 Article Received: 10 Mar 2021 Article Accepted: 5 Apr 2021 Article Published: 29 Jun 2021 Abstract Power quality issue is considered as major concern in industrial sectors and it will occurs due to variation in voltage, current and frequency. The stability of voltage is collapsed by extensive nonlinear load usage. The necessity of FACTS devices is much more needed. It creates a path to power quality and stabilization. With the advancement of Power electronics it is possible to mitigate power quality issues in distribution network. Voltage sag and swell is considered as major disturbance across load which will lead to intrude voltage across sensitive system.To overcome these things, proposed system employs Dynamic voltage restorer (DVR) in order to improve effectiveness of transmission in KVA. Under differential operating conditioning of load which cause severe disturbance in real and reactive power flow at load line. Further in turn makes variation in power factor too. By designing a simulink model incorporating SMES the compensation technique carried out in it is experimentally verified. Keywords: Sag; Swell; Dynamic Voltage Restorer (DVR); Superconducting Magnetic Energy Storage System (SMES). I. Introduction In recent power quality issue is considered as one of the major problem in transmission and distribution sector. Not only it impact electrical utilities enrolled in transmission section but also it would affect sensitive loads which will collect power from that transmission section. The disturbance in power quality is noted by sudden change in voltage, current and frequency [1]. In certain situation, the power electronic devices are handled. It is widely used in improving power quality and strengthens the system to deliver power consistently towards load. Other than industrial sectors, low voltage consuming individual even suffer from power quality issues.Some localized industries such as iron and steel industries, paper milling industries, chemical industries, etc are very sensitive and it would cause distortion. Household electric appliances like air conditioner, motor and several other sensitive loads affected from this more and more. To ensure lifetime of electrical devices, the quality of power intake to do actions is must. Some consistently occurring voltage disturbances are listed below: voltage sag/swell, voltage spikes, short circuit and open circuit fault, harmonics, etc. increase in poor power supply can cause malfunctioning and stops productivity in industries [2]. Among that above mentioned power quality issues, voltage sag and swell repeatedly occurring in transmission path. The possibility of insulation failure during heavy load is connected with line cause sag in addition with short circuit fault. The decreases in RMS value of line voltage tend to be lesser than nominal voltage is called as voltage sag and it stands up to 1 minute (i.e.0.1 to 0.9pu). In opposition to voltage sag, swell is occurred (i.e.1.1 to 1.9pu). Tuning off huge loads, energising Citation Suganyadevi,M.V., Thenmozhi,T.(2021). Mitigation of Sag/Swell in Transmission by using DVR, Journal of Next Generation Technology, 1(1), 8-14.