This research seeks to apply interior point optimization methods to network modeling and state estimation problems involving unmeasured external network states. In addition, it will improve the efficiency of interior point methods for power systems problems. The basic approach will minimize the injected power mismatch at buses on the boundary of the local network. Alternate strategies for choosing the barrier parameter of the interior point algorithm will be investigated to improve efficiency. The outcome of this work will be a set of robust, rational approaches to large scale network modeling as well as an expanded set of powerful state estimation tools ready for practical implementation.