The primary purpose of a state estimator is to provide a reliable power system model and operating conditions in real time. The real time model and operating conditions are utilized in a variety of other applications, such as: • Load Forecasting; • Optimization; • VAR Control; • Available Transfer capability; • Security Assessment; • Congestion management; • Dynamic Line Rating; • Transient Stability; • EM Transients; • Day Ahead; • Power Balance; • Spot Pricing; • Transmission Pricing; • Ancillary Services, etc. It is critical that the state estimator provides a reliable real time model for all these applications. More