At RT20, Shijia Li presented an incredible webinar on Real-Time Cyber-Physical Simulation of the Electric Power Grid. The evolution of traditional electrical grids towards cyber-physical systems (CPS) depends on the deployment of novel communication infrastructures to facilitate new control functions. This tendency makes the grid more intelligent, but at the same time more vulnerable to cyber threats. The real-time Cyber-Physical System simulation platform provided by OPAL-RT Technologies and Scalable Network Technologies allows users to study the complete system dynamics with or without cyberattacks, and test intrusion detection systems and defense operations in a flexible, scalable, and closed-loop testing environment. As an example, a microgrid control use case is presented to show the impacts of cyber attacks on an IEC 61850 network.