International Journal of Engineering and Information Systems (IJEAIS)   Year: 2020 | Volume: 4 | Issue: 11 | Page No.: 27-33 Damping of Transient Oscillations due to Symmetrical Faults by Insertion of PSS Using GA for Tuning Bahaaldeen Mohammed , Mohammed Altom, Abdalla Naeem Mohammed Elmubarak Adam Abstract: the large disturbances happened in transmission lines due to three phase fault is very dangerous; because this problem may lead to loss of generation units and them synchronism. To solve such problem or reduce it there are various ways to did that, the famous way is to insert the compensation devices such as; TCSC, STATCOM, UPFC, PID, TSSS, AVR and PSS. Here in this paper we used the Power System Stabilizer (PSS) because of high response for damping oscillations and reduce the overall time response for machines to return back to its new position after the three phase fault occurs in transmission lines. Finally after seeing the plots and make comparisons we found that the PSS reduce the overall time response between 20-50%. The difficult that arises from how to get the optimum values of PSS parameters and optimum location of PSS; was solved by using Genetic Algorithm (GA) technique.