The user-defined model of PSCAD/EMTDC and its application in simulation of HVDC transmission line protection

The application of user-defined model in PSCAD/EMTDC provides a solving approach to establish accurate and detailed relay protection models.In this paper,the realization approaches of user-defined model, the operating efficiency of three developing languages and the difference between user-defined model and Module are compared and analyzed. Matlab-based realization mode is recommended as an intermediate one with which new protection algorithms can be studied and evaluated,after an approach is selected,models should be written by Fortran or C language in order to increase the operating efficiency.Memory transfer conflict of user-defined model due to the use of static variable of C language is revealed,and it gives the solution which adopts the common arrays to manage the memory.Based on an actual HVDC transmission traveling wave protection system,a detailed simulation model adopting the user-defined modeling technique is established and simulation result proves the feasibility and validity of the proposed technique.