Babnik - University of Ljubljana, Faculty of Electrical Engineering Ljubljana, Slovenia
Gasperic - University of Ljubljana, Faculty of Electrical Engineering Ljubljana, Slovenia
Gubina - University of Ljubljana, Faculty of Electrical Engineering Ljubljana, Slovenia
Gubina - University of Ljubljana, Faculty of Electrical Engineering Ljubljana, Slovenia

Summary - An extended fault in a distribution system may cause problems during feeder restoration. Immediately after energizing the feeder, high currents may arise due to a phenomenon called cold load pick-up (CLIPU), causing activation of the overcurrent protection and preventing immediate reconnection of the entire load. The feeder should be sectionalized and the restoration is performed in steps. In the paper, an algorithm for determination of a sequence of restoration actions is presented. The algorithm determines the maximum number of customers that can be reconnected immediately and recommends time delays to restore the remaining sections with regards to the setting of overcurrent protection. The results of a restoration simulation on a part of Slovenian distribution system are presented in the paper.

distribution system, service restoration, step-by-step restoration, cold load pickup