Sensitivity-based external equivalent for reliability assessment of subtransmission & distribution systems

Abstract

It is well known that topology changes in a power system strongly influences the results of reliability assessment studies. Besides, it is obvious that the topology of an external system also affect the reliability of the internal system through changes on the power flows within the rest of the system, and hence, through changes on the tie lines. In order to properly model the interconnection between the internal network and the rest of the system, an adaptive external equivalent model, obtained from the sensitivity matrix between tie-linepower flows and injectedpowers, is proposed for reliability assessment studies. The proposed technique has been applied to the IEEERTS, and test results show that the proposed methodology is suitable both for planning studies and for 24-hour-ahead reliability assessment studies.