Analysis of unsymmetrical fault using symmetrical component for improvement of overcurrent protection scheme

The distribution power system maintains its steady state mainly because of the correct and quick remedial action taken by the protective relaying equipment. Transient currents due to fault and switching events are common in power system. The operation of protective relay for transient due to switching condition is undesirable. The method of symmetrical components provides a technology for understanding and analyzing power system operation during unbalanced conditions and it also prevents undesirable operation due to switching. In this paper the concept of symmetrical components is used for improvement of distribution system over current protection.