International Journal of Electrical and Computer Engineering (IJECE) Vol. 10, No. 4, August 2020, pp. 3898~3910 ISSN: 2088-8708, DOI: 10.11591/ijece.v10i4.pp3898-3910  3898 Journal homepage: http://ijece.iaescore.com/index.php/IJECE A probabilistic multi-objective approach for FACTS devices allocation with different levels of wind penetration under uncertainties and load correlation M. EL-Azab 1 , W. A. Omran 2 , S. F. Mekhamer 3 , H. E. A. Talaat 4 1 Electrical Engineering Department, Ain Shams University, Egypt 2,3,4 Electrical Engineering Department, Future University, Egypt Article Info ABSTRACT Article history: Received Apr 3, 2019 Revised Jan 16, 2020 Accepted Feb 26, 2020 This study presents a probabilistic multi-objective optimization approach to obtain the optimal locations and sizes of static var compensator (SVC) and thyristor-controlled series capacitor (TCSC) in a power transmission network with large level of wind generation. In this study, the uncertainties of the wind power generation and correlated load demand are considered. The uncertainties are modeled in this work using the points estimation method (PEM). The optimization problem is solved using the multi-objective particle swarm optimization (MOPSO) algorithm to find the best position and rating of the flexible AC transmission system (FACTS) devices. The objective of the problem is to maximize the system loadability while minimizing the power losses and FACTS devices installation cost. Additionally, a technique based on fuzzy decision-making approach is employed to extract one of the Pareto optimal solutions as the best compromise one. The proposed approach is applied on the modified IEEE 30-bus system. The numerical results evince the effectiveness of the proposed approach and shows the economic benefits that can be achieved when considering the FACTS controller. Keywords: FACTS MOPSO Multi-objective optimization Probabilistic load flow Two points estimation method Wind energy Copyright © 2020 Institute of Advanced Engineering and Science. All rights reserved. Corresponding Author: M. EL-Azab, Electrical Engineering Department, Ain Shams University, Cairo-Egypt. Email: mahrous@osman.net 1. INTRODUCTION In recent years, the current growth in demand for electricity and rising population of the world are forcing electric utilities to take benefit of renewable energy sources (RESs) in the generation mix. In recent years, the interest in RESs is more and more increasing, mainly because of the rising concern to environmental issues and of the decreasing investment cost for such systems, also thanks to very favorable national policies of financial support. One of the greatest widely used renewable energy source is the wind, where the global installed capacity of wind energy systems has reached 591GW in 2018 [1]. Moreover, the fluctuations in the wind power causes vulnerabilities to the power system and prompts technical challenges on the network operation [2]. The application of F'ACTS controllers, which are based on power electronic switches, in power systems has been increasing [3]. These controllers supply reactive power compensation, which can increase the maximum transfer capability of electrical network, and therefore, can be utilized to enhancement the different performance parameters of the electric network in dynamic state and steady state [4]. The efficiency of the FACTS devices in improving the network performance mostly depend on their size and location. In the scientific publications, defining the ideal locations and compensation degree of FACTS