Document Type : Research Paper


1 Electrical Engineering Dept., University of Technology-Iraq, Alsina’a street,10066 Baghdad, Iraq.

2 Electromechanical Engineering Dept., University of Technology-Iraq, Alsina’a street,10066 Baghdad, Iraq.


Losses in the transmission line have a significant and growing impact on power systems around the world. Line losses overheat power lines, therefore electrical power systems require powerful processors and intelligent management methods. Flexible AC Transmission System (FACTS) device UPFC is one of the most important devices due to its ability to reduce total line losses that cause an increase in the transmission line capacity of the power system. In this paper, we used Particle Swarm Optimization (PSO) to determine the optimal location for the installation of UPFC device to minimize losses in the transmission line in the Iraqi international grid (ING) 400kV using a proportional-integral (PI) based UPFC controller. The potential solutions of PSO are called particles. All the particles selected in this controller depend on their parameter only, which keeps feasible solutions in their memory. The algorithm is coded in MATLAB and it is incorporated with the conventional Newton Raphson’s load flow analysis. The result shows that the proposed optimization method applied for two UPFC compensator parameters in the power system contributed to minimizing the active and reactive power losses under normal operating conditions using a modified version of the PSO algorithm.


  • Determine the best location of the unified power flow controller (UPFC) for utilizing in 400KV Iraqi national grid (ING).  
  • Novel comparative analysis between classical proportional integral (PI) controller and an optimal controller such as particle swarm optimization (PSO).
  • Propose an effective method for transmission line active and reactive losses minimization.
  • Investigate the load flow analysis of the power system using Newton Raphson’s method.


[1] J. Sahlin, Line Loss Prediction Model Design at Svenska kraftnät, 2016.
[2] E. Acha, et al. FACTS Modeling and Simulation in Power Networks,John Wiley and Sons LTD, England, 2004.
[3] N. G. Hingorani and L. Gyugyi, Understanding FACTS Concepts and Technology of Flexible AC Transmission Systems, IEEE Press, New York, 2000.
[4] F. M. Albatsh, S. Ahmad, S. Mekhilef, I. Alhamrouni, and M. F. A. Hamid, Power flow control using fuzzy based UPFC under different operating conditions, Journal Electrical of Systems, 13, 2, 2017, 398–414.
[5] A. Touhami, Enhancement of Active and Reactive Power Flow Control over the Transmission Line using UPFC, International Journal of Computer Science, communication & information Technology, 6, 2018,1–8.
[6] G. A. Salman, M. H. Ali, and A. N. Abdullah, Implementation Optimal Location and Sizing of UPFC on Iraqi Power System Grid (132 kV) Using Genetic Algorithm, International Journal of Power Electronics and Drive Systems, 9,5, 2018,1607-1615.
[7] S. Hocine and L. Djamel, Optimal number and location of UPFC devices to enhance voltage profile and minimizing losses in electrical power systems, International Journal of Electrical and Computer Engineering (IJECE), 9, 5,2019,3981–3992.
[8] K. K. Kuthadi, M. S. Babu, and N. Tella, Optimal Location and Parameter Settings of FACT’ s Devices for Enhancing Power System Stability and Minimization of Power Losses, Inte. Jou. of Engineering Science and Technology (IJEST), 4, 06, 2012, 2699–2707.
[9] S. V Patil and P. K. Mahajan, A Review on Implementation of UPFC for improvement of active power flow capability in power system using IEEE 14 bus system International Research Journal of Engineering and Technology (IRJET), 4, 4, 2017 542–547.
[10] L. Gyugyi, Unified power-flow control concept for flexible AC transmission systems, IEE Proceedings C Generation, Transmission and Distribution, 139, 4, 1992.
[11]  Laszlo Gyugyi, Advanced Solutions in Power Systems: HVDC, FACTS, and Artificial Intelligence, Chapter 10, 2016.
[12] R. Sadikovic, Power flow control with UPFC, 1–20, 2015.
[13] L. P. YIN Jijun, CHEN Gang, XU Haiqing, LI Qun, LIU Jiankun, Unified Power Flow Controller Technology and Application, Academic Press ,2017.
[14] C. R. Fuerte-Esquivel, E. Acha, and H. Ambriz-Pérez, A comprehensive newton-raphson UPFC model for the quadratic power flow solution of practical power networks, IEEE Transactions on Power Systems, 15, 1, 2000 ,102–109.
[15] A. Moamen, M. Abdel, R. Ahmed, Optimal Power Flow with Facts Devices, PhD Thesis, Department of Electrical Engineering Indian Institute of Technologe, Roorkee, 2004.
[16] M. Zahid et al., New approach for optimal location and parameter setting of upfc for enhancing power systems stability under contingency analysis, Energies, 10, 11, 2017.
[17] Y. Shi and R. Eberhart, A Modified particle swarm optimizer, Proceedings of the IEEE Conference on Evolutionary Computation, ICEC, 1998, 69–73.
[18] M. Clerc, Particle Swarm Optimization. ISTE Ltd, USA, 2006.