During the last decade or so, a tremendous amount of development efforts has been put in the load-flow techniques to produce more efficient and reliable computer solutions. The very large present day net works have to be solved frequently, and there is a great deal of incentive to minimise the amount of calculation and therefore, the cost of calculation. The computer storage requirements of the solution technique are also important. The two primary considerations in the development of an effective engineering computer programme are (1) the formulation of the mathematical description of the problem, and (2) the application of the numerical method for solution. This paper describes the programming details of the Newton Raphson method in cartesian form. The convergence criterian is the power mismatch.