Research Of Power System Electromagnetic Transient And Electromechanical Transient Hybrid Simulation Based On PSCAD

With the rapid development of power industry, the scale of power system is ex-panding. While the access of HVDC and FACTs also makes the system operation and control more complex. These put forward higher requirements for power system simula-tion technology.HVDC and FACTS and other power electronic devices, which respond rapidly to fault process, need to be simulated by electromagnetic transient simulation to study the rapidly changing phenomena during its transient process. Due to the large computation amount, its simulation scale is often limited. If electromagnetic transient simulation for large-scale simulation analysis is adopted, the system of large-scale should be equivalent and simplified, and this would reduce the simulation accuracy. Electromechanical transi-ent simulation is mostly based on the quasi-steady-state model. It is difficult to simulate fast transient characteristics of HVDC and other power electronic devices. Meanwhile, it has some limitations in studying the rapid impact of local network fault of pure AC sys-tem. The electromagnetic-electromechanical transient hybrid simulation combines the advantages of both electromagnetic transient simulation and electromechanical transient simulation, adopting electromechanical transient simulation to simulate large-scale con-ventional power system. For the key areas, it adopts electromagnetic transient simulation. This technology can better coordinate simulation scale, precision and speed, and provides a new method for the research of the stability and dynamic characteristics of large scale power system.The electromagnetic-electromechanical transient hybrid simulation algorithm pre-sented in this paper embeds the electromechanical transient simulation program into the main program of commercial electromagnetic transient simulation software PSCAD/ EMTDC. The electromagnetic side subsystem is constructed by the component library of PSCAD, and simulated by EMTDC in detail. The external AC system is simulated by electromechanical transient simulation program. Data exchange is implemented through the interface bus, thus the digital simulation of the entire network is realized. In the sim-ulation of electromagnetic side subsystem, electromechanical side is replaced by Thevenin equivalent circuit; in the program calculation of electromechanical side, the electromagnetic side is replaced by equivalent power source. Through the comparison between the simulation results of the proposed hybrid simulation and pure electromag-netic model, the correctness of hybrid simulation method based on PSCAD is verified.