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.