Int. J. Power and Energy Conversion, Vol. 3, Nos. 1/2, 2012 127 Copyright © 2012 Inderscience Enterprises Ltd. Weakest bus identification for optimal location for FACTS systems in multi-machine power network Mohamed K. Jalboub*, H.S. Rajamani, J.C. Readle, Read A. Abd-Alhameed and Abdelbaset M. Ihbal School of Engineering, Design and Technology, Bradford University, Bradford, BD7 1DP, UK E-mail: M.K.JALBOUB@Bradford.ac.uk E-mail: H.S.RAJAMANI@Bradford.ac.uk E-mail: J.C.READLE@Bradford.ac.uk E-mail: R.A.A.ABD@Bradford.ac.uk E-mail: A.M.I.IHBAL@Bradford.ac.uk *Corresponding author Abstract: As a result of the electronic revolution in power electronics technology, a number of control devices under the term flexible AC transmission system (FACTS) have been proposed and implemented and this has led to improvements in efficient energy transfer, reduced looses and maximised use of existing infrastructure. FACTS controllers have been designed using high power electronic system components, in particular the voltage source converter (VSC) that permits quick response to control inputs. In this paper, a model is proposed for a multi-level, 48-pulse VSC for a FACTS system. The proposed model is studied in terms of both reactive power compensation and harmonic distortion. The model and control algorithms are simulated in MATLAB (Simulink). In order to identify the best location (the weakest bus) of the FACTS controller, a study is conducted on 14-bus IEEE reliability test system using some static voltages stability indices found in the literature. The results are presented and discussed. Keywords: two-level VSC; flexible AC transmission system; FACTS; harmonic distribution; reactive compensation; stability indices; weak bus; power and energy efficiency; Matlab (Simulink). Reference to this paper should be made as follows: Jalboub, M.K., Rajamani, H.S., Readle, J.C., Abd-Alhameed, R.A. and Ihbal, A.M. (2012) ‘Weakest bus identification for optimal location for FACTS systems in multi-machine power network’, Int. J. Power and Energy Conversion, Vol. 3, Nos. 1/2, pp.127–142. Biographical notes: Mohamed K. Jalboub received his BSc in Electrical Engineering from Garyounis University, Beneghazi, Libya, in 1987, and received his MSc in Electric Engineering from Belgrade University, Belgrade, Yugoslavia, in 1997. He is currently reading for his PhD in School of Engineering, Design and Technology, Bradford University, UK. His special fields of interest include flexible AC transmission system (FACTS), power system stability and renewable energy.