A modified Newton method for radial distribution system power flow analysis

A modified Newton method for radial distribution systems is derived in which the Jacobian matrix is in UDU^T form, where U is a constant upper triangular matrix depending solely on system topology and D is a block diagonal matrix. With this formulation, the conventional steps of forming the Jacobian matrix, LU factorization and forward/back substitution are replaced by back/forward sweeps on radial feeders with equivalent impedances. Tests on several large distribution systems ranged from 490 to 1651 in nodes, 0.15 to 5.48 in r/x ratio and 0.0004 Ω to 3.07 Ω in line impedance have shown that the proposed method is as robust and efficient as the back/forward sweep method. The proposed method can be applied to other applications, such as state estimation. The proposed method can also be extended to the solution of systems with loops, dispersed generators and three phase (unbalanced) representation