Our research team with Powertech Labs, Canada, has been developing an integrated software system for large-scale power grid online security and risk assessment with model validation capabilities using real-time node/breaker models and PMU measurements, which has been successfully deployed in the Grid Control Center at one of the largest provincial power systems in China. This software serves as a platform performing high-fidelity simulations for grid planning and operation, using multiple channels of real-time PMU measurements and node/breaker models. It lays a solid foundation for developing further advanced applications to enhance situational awareness.