Single phase ground fault occurs, the the CYCL asymmetric current source installed in the substation (or on the line close to the distribution transformer substation near) asymmetric current source movement, the fault line with the special characteristics of the pulse current signal. 2. Flop and flash indicating single phase to ground fault, short circuit and ground fault indicator (Short and Grounded Fault Indicator) THFI-II installed on a fault line fault indicator to the the asymmetric current source generated signal is detected. This can determine the point where single-phase ground fault outlet, branch and section. Fault indicator can also be indicated by determining the short-circuit current short-circuit fault, this can determine the point where the short-circuit fault outlet, branch and section. The fault indicator installed in the substation outlet at fault signal to the substation RTU, earth fault line through the optical fiber, the photoelectric conversion.