Authors'' reply

A limitation of the model order selection criterion as proposed in the above correspondence is pointed out. It is shown that the results obtained from the criterion are not generally unique and acceptable.     

Criterion for inductive compensation location to enhance systemsteady state stability

Huge reactive power surplus at light load operation may force system generators to operate in the under excited mode which reduces system stability margin. In this paper analytical expressions for generator reactive power sensitivities with respect to reactive compensation are derived. A criterion based upon these sensitivities with respect to reactive compensation are derived. A criterion based upon these sensitivities for choosing reactive compensation locations to improve system steady state stability is proposed. The effectiveness of this proposed criterion is demonstrated through application to the Saudi Consolidated Electric Company (SCECO)-Central Power system     

Comment on "On selecting a low-order model using the dominant mode concept"

In the above-mentioned paper [1], the authors presented a criterion for selecting the order of a low-order system to approximate a high-order model. Their criterion is very similar to what has been presented before in [2] and [3]. The authors claimed that the extension to handle systems with complex eigenvalues [3] is incorrect. Also, they used examples to show the superiority of their criterion. In this comment, it will be demonstrated that their claims are not absolutely correct.     

On the selection of the dominant poles of a system to be retained in a low-order model

A criterion is presented for selecting the order of the reduced-order model of a given high-order system. The eigenvalues of the system are not restricted to be real only.