Differential Transformation of Nonlinear Power Flow Equations.

Differential transformation (DT) method has shown to be promising for power system simulation in our recent works. This letter applies the DT method to nonlinear power flow equations and proves that the nonlinear power flow equations are converted to formally linear equations after DT. This letter further extends the constant power load assumption in the classical power flow formulation to the more general and practical ZIP load assumption and proves that the linear equation after DT still holds for ZIP load model with slight modifications on the coefficient matrices. These results demonstrate great potential of the DT method in solving power system nonlinear problems.