Power flow formulation based on a mixed-linear and nonlinear system of equations

Power flow solutions are the key in many power system studies. In this paper, the power flow problem is formulated within rectangular coordinates. Using a voltage-dependent load model and linear approximation techniques, the problem is formulated as a system of mixed linear and nonlinear equations. An efficient matrix decomposition is then applied to facilitate establishing the Jacobian matrix in the linear subproblems of Newton's method. The accuracy of the proposed method is compared to the original nonlinear formulation and relative errors less than 0.1% are achieved. The average computation time of the proposed method is about 30% less than the conventional method.