Parametric analysis of DC fault transients in two terminals MMC-HVDC underground transmission link

Abstract

In an underground HVDC transmission link, dc line faults lead to transient overcurrent and overvoltage. These transients are detrimental for cable as well as converter station equipment including IGBTs. Considering the complexity in analytical study of such transient phenomenon, EMT program (PSCAD) is used to analyze the fault transients. The arm reactor and submodule capacitors directly affect the magnitude of transients. Therefore, magnitude of transient as a function of the arm reactor and submodule capacitor size is presented in detail in this paper. Results of this study can provide insight for researchers and engineers involved in protection system design and insulation coordination of MMC-HVDC grids.