2002 Transmission and Distribution Latin America Conference 18-22 March 2002 Sao Paulo, Brazil

This letter presents a simulation-based case study that indicates the need for accurate dynamic modeling of protection systems. In many cases, a static analysis based on current and voltage phasors may be sufficient to assess the performance of protection systems. There are several circumstances under which such a simplified study does not provide the depth of analysis necessary to obtain accurate results, however. This letter presents a study of the influence of transformer magnetizing inrush current on the performance of different types of distance protection relays. Three types of distance relays have been investigated: Micromho, THR, and REL 100. The studies have been performed in order to demonstrate the difference in responses to the same event when detailed dynamic models of protection relays are utilized.