Distributed optimal power flow (OPF) of large-scale multi-area interconnected power systems is a challenging problem. This letter proposes a distributed OPF approach based on the modified decomposition-coordination interior point method (DCIPM). The proposed method eliminates the zero rows of the coupling matrix and partially factorizes the augmented Newton matrix on the foundation of DCIPM

which speeds up the computation. Eliminating zero rows significantly reduces the size of the coupling matrix

and the partial decomposition of the augmented Newton matrix exploits the sparsity of the coupling matrix. The proposed distributed OPF approach is more convergent and efficient than the traditional distributed optimization methods and faster than the centralized MATPOWER

as verified in different systems

the largest of which contains 70

000 buses.