The calculation of single-phase impedance current on heavily loaded long circuit of double end power

Aiming at the heavily loaded long circuit of double end power, the paper provided the computing technology of single phase ground short-circuit current when the influences of load were took into consideration. Through the embodiment, analyzed is the error of impedance current with two different conditions: neglecting load influences and including load influences. The results show that there are small errors, this is basically allowed in general engineering applications. But there are bigger error on the grounding phase impedance current positive sequence. It will influence seriously the setting of relay protection equipment and safe automatic equipments.