Fault Current Distribution and Current Division Factor of Grounding Grid in Complex Power System Network

Based on the combination of the phase-coordinate model of transformer and the traditional phase-coordinate method,a calculation method of fault current distribution and current division factor of grounding grid is put forward when ground short circuit takes place within substation,which is connected with numbers of transmission lines(including overhead lines and underground cables),and the corresponding calculation software FCDFGS is developed.With comparison of the results of software calculation and field measurement,the validity of the calculation model and correctness of the measurement method are verified,and the factors which have effect on current division factor of grounding grid are analyzed.The results show that current division factor of grounding grid presents saturation effect,and the parameters within the first 10 to 15 towers neighboring the substation are the most remarkably effective.Finally,technical measures to reduce grounding grid fault current are also brought forward.