“…Hence, according to the validity measure, the identified optimal number of clusters is equal to seven, which gives the minimum XB index value of (0.0486). From Table 1, the clustering result reveals that generator (6,7,8) and (10,11,12,14) can be combined to become an equivalent one. Generators (3,5) and (9,13) are another cluster and generator 2, 4 and 15 are alone in the other clusters.…”