In view of such present situation that the load is put on a higher voltage level in the short-circuit current simulation calculation of the power system

the network wiring of 2～3 voltage level in the study network is only retained and simplification of the network will certainly cause incomplete zero sequence path. First

the problem after simplifying the zero-sequence path is analyzed. Then

the influence on selection of neutral point reactor of main transformer after simplifying the zero-sequence path is analyzed. The analysis of the calculation example shows that for the nodes where the single-phase grounding short-circuit current is on the verge of exceeding the standard and needs to be accurately calculated

the incomplete zero-sequence path will bring uncertainty factor to the calculation result of single phase grounded short circuit current of the planned network and the selection of grounded small reactance of the neutral point of 500 kV main transformer. Therefore

it is necessary to improve the network wiring of the 1 to 2 voltage levels for the lowerlevel networks of these nodes so to make the calculation results of the bus single-phase grounding short-circuit current more accurate.