说明：  This is the PSCAD project file for the modeling and control of high-voltage direct current (HVDC) transmission line. Control algorithms are simulated in the file. Power electronic devices are modeled in detail. This file is very useful for beginner to learn the topology, design, control, and operations of HVDC transmission systems. This file can also be copied and pasted to an existing file to serve as a building block of the user s existing system.