Microsoft Word - wseas_skare_paper.rtf

Abstract: DC auxiliary systems are usually relied upon as the last source of reliable electric power at an installation of power plants and substations. Because DC auxiliary systems and battery power sources differ from AC systems, it is important that DC system protection designer is aware of their special considerations. In Standard IEC 61660-1 is given mathematical model for dynamics analysis in DC auxiliary systems of power plants and substations. In this paper, the authors performed short-circuit currents calculation in real DC auxiliary system of TPP Rijeka using mathematical mode defined in standard IEC 61660-1. Calculation results were verified on site during DC circuit breakers selectivity testing.