Quadratically Convergent Optimal Power Flow

A newly developed sparse implementation of an optimization method using exact second derivatives is applied to the optimal power flow problem. Four utility systems are studied using a variety of objective functions, including fuel costs, active and reactive losses, and new shunt capacitors. Systems solved range from 350 buses to 2000 buses. Comparisons are made with an older algorithm which uses an Augmented Lagrangian to demonstrate the advantages of run time and robustness of the new method. The algorithm and accompanying software represent a technological breakthrough, since they are suitable for solving systems on the order of 2000 buses and demonstrate solution speeds of 5 minutes on large mainframe computers. The method is particularly well suited to infeasible, or even divergent starting points. An option to add shunt capacitors in the event of hopeless infeasibility guarantees an optimal solution for many difficult to solve systems. An automatic scaling feature is added to correct numerical ill-conditioning resulting from series compensation or poor R/X ratios.