New method of line selection for single phase grouding fault based on aggrandized transient current signal

Transient signals can be taken usage for fault line selection when there is single phase grounded fault in the ungrounded neutral network. One method based on aggrandized transient fault current signal is presented in this paper. With one special designed resonance circuit parallel installed with the power line,the difference of fixed frequency components in the transient fault current between before and after the resonance circuit is enlarged,which can increase the sensitivity of selection criterions and simplify the process of frequency choosing when take use of transient signals for line selection. The stability of line selection for different types of network is proved by simulating test.