An improved newton method for radial distribution system load analysis

Abstract EN

This paper presents a modified Newton method of load flow analysis for radial distribution systems.

It is derived with the Jacobian matrix is in UDUT 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.

The method has advantages over Newton’ s method in terms of speed of solution (no.

of iterations), and reliability of convergence by inserting a minimization technique (Cubic Interpolation Technique).

The algorithm exhibits a control of the convergence.

As such the method converges for cases when conventional Newton’ s method and some other popular methods diverge.

Two large distribution systems of 490 nodes and 722 nodes with different r/x ratio in line impedance are used to examine the performance of the method.

These tests have shown that the proposed method is as robust and efficient as the forward/back sweep method.

The proposed method can be extended to the solution of three phase unbalanced representation.