Application of compensation method in calculating symmetrical short circuit fault

Based on compensation method, Symmetrical short-circuit fault current formula and nodal voltage formula are deduced in this paper. In the deduction process the time of calculating matrix inversion is eliminated for the node-admittance matrix being not modified when the fault occurs, however triangular matrix method is applied to calculate nodal impedance matrix at the program entrance in the process based on the original network nodal admittance matrix, thus the solution of the electrical network state variables is speed up with preparing data for fault calculation in advance. After further assumptions and simplification, short-circuit current formula is more efficient to estimate the size of short-circuit current, and it is very suitable for real-time online applications. At the same time, current coefficient power contributing which is different from power current distribution coefficient is put forward. A optimal node is found for new power supply to limit short-circuit current by judging the size of current coefficient power contributing.