Abstract
Previous voltage stability studies have shown that typical OLTC controls can cause oscillatory behaviors as wel as reverse controls in tap changing operations due to interactions among multiple OLTC controls. These phenomena are undesirable from the viewpoint of both economy and security of power system operations.
In this paper, to avoid the above undesirable phenomena as well as to realize suboptimal voltage profile agains voltage instability, we proposes a new control method to coordinate numerous OLTC controls existing in transmissim and distribution networks. The method is based on the autonomous decentralized control scheme. A fundamenta theory and some techniaues for this control scheme are proposed.