An improved second order method for optimal load flow in electric power systems

The reduced Hessian method, which was inherently a second order method, was applied to optimal load flow problems in electric power systems. This method employed Lagrange multipliers to associate the load flow equations to the objective function. Variable weighting factors were employed in the penalty functions used so that the effects of functional inequality constraints could be incorporated. The original large-size Hessian matrix was converted into a smaller size, but equivalent, matrix which was used to update the operating parameters. A procedure was developed for handling the inequality constraints on control variables in order to retain the excellent second order convergence properties of the reduced Hessian method which by itself, could not recognize the effects of inequality constraints.