\(\bullet\) This system has 3-phase (3\(\phi\)) fault at the midpoint of each line, as shown in the figure given below.
\(\bullet\) It is considered as a one of the most popular test cases in the relays coordination problems. It is the first selected system used in the first puplished paper  in the literature.
\(\bullet\) The plug-setting (\(PS\)) is considered discrete in uniform steps of 0.5 A, while the time-multiplier setting (\(TMS\)) is considered continuous. The coordination time interval (\(CTI\)) is equal to 0.2 s. The researcher can change these settings to get fair comparsion with other conducted studies in the literature.
\(\bullet\) In this test case, the transient selectivity constraints are considered too. All the CT ratios (\(CTR\)), the listed P/B relay pairs, the 3\(\phi\) fault at the middle of each line, the generator and line data and the variable bounds of the relays settings are given below (click on them for bigger size):
II. Single-Line Diagram:
\(\bullet\) This single-line diagram was drawn by Ali R. Alroomi in Dec. 2013 and all the necessary data were coded in MATLAB m-files.
IV. References (Some selected papers that use this system):
 A. Urdaneta, R. Nadira, and L. Perez Jimenez, "Optimal Coordination of Directional Overcurrent Relays in Interconnected Power Systems," IEEE Transactions on Power Delivery, vol. 3, no. 3, pp. 903–911, Jul. 1988.
 M. M. Mansour, S. Mekhamer, and N.-S. El-Kharbawe, "A Modified Particle Swarm Optimizer for the Coordination of Directional Overcurrent Relays," IEEE Transactions on Power Delivery, vol. 22, no. 3, pp. 1400–1410, Jul. 2007..
 H.H. Zeineldin, "Optimal Coordination of Microprocessor Based Directional Overcurrent Relays," in 2008 Canadian Conference on Electrical and Computer Engineering (CCECE 2008), pp. 289-294, May 2008.
 T. Amraee, "Coordination of Directional Overcurrent Relays Using Seeker Algorithm," IEEE Transactions on Power Delivery, vol. 27, no. 3, pp. 1415–1422, Jul. 2012.
 M. El-Mesallamy, W. El-Khattam, A. Hassan, and H. Talaat, "Coordination of Directional Overcurrent Relays Using Artificial Bee Colony," in 22nd International Conference and Exhibition on Electricity Distribution (CIRED 2013), pp. 1-4, Jun. 2013.
 S. Ralhan, and S. Ray, "Directional Overcurrent Relays Coordination Using Linear Programming Intervals: A Comparative Analysis," in 2013 Annual IEEE India Conference (INDICON), pp. 1-6, Dec. 2013.
 F. A. Albasri, A. R. Alroomi, and J. H. Talaq, "Optimal Coordination of Directional Overcurrent Relays Using Biogeography-Based Optimization Algorithms," IEEE Transactions on Power Delivery, vol. 30, no. 4, pp. 903–911, 2015.
 V.A. Papaspiliotopoulos, G.N. Korres, and N.G. Maratos, "A Novel Quadratically Constrained Quadratic Programming Method for Optimal Coordination of Directional Overcurrent Relays ," To be published in IEEE Transactions on Power Delivery, 2015.