Closure to Discussion on “Two-Step Spectral Clustering Controlled Islanding Algorithm”

The method proposed in the procedure of the first step of the spectral clustering controlled islanding (SCCI) is actually equivalent to the application of slow coherency. The slow coherency method is very useful for ofiline analysis. However, the following two questions must be answered before slow coherency can be applied to identify suitable generator groups: 1) have the generators lost synchronism, or will they, i.e., is the separation of generator groups necessary? 2) How many generator groups should be formed? This means that there are distinct drawbacks when applying slow coherency online; however, the method can still be adapted to this purpose to a certain extent [1]. We think a better way is using an online algorithm to replace the slow coherency method [2], [3]. The drawbacks and limitations of the first step of the SCCI have been discussed in Section III-A.