Summary

Most of the reported decoupled flow methods are derived from the Newton method by neglecting the coupling subjacobians The paper presents a novel decoupled load flow method that does not ignore the coupling subjacobians. The effects of the coupling subjacobians are carefully taken into account by properly modifying the mismatch vectors and coefficient matrices of the proposed decoupled load flow equations. In the absence of PV busbars and for the same R/X ratio of all branches, the performance of the proposed decoupled load flow method may be considered as good as that of the Newton method. The performance of the proposed method was investigated on the IEEE 14-, 30- and 118-busbar systems, in addition to a simple two-busbar system, for various values of the branch resistance R and the R/X ratio. Iterations required by the proposed method to solve the load flow problems were compared with those found in the Newton and conventional fast decoupled load flow methods