POWER SYSTEM OFF-LINE SIMULATION TECHNOLOGY: Power System off-line simulation is a process of establishing mathematical model for power system physical process on digital computer and solving it by mathematical method to carry out simulation research. When building a mathematical model, it is often overlooked some secondary factors, so it is often a simplified model. At present, power system off-line simulation software adopts different simulation methods for different dynamic processes, including electromagnetic transient process simulation, electromechanical transient process simulation and medium-long dynamic process simulation.