Do you think that the MMC-HVDC model download from the website lacks the blocking function, that is, it cannot represent the blocking state of the SM and the converter? I’ve run a MMC-HVDC system based on this model and set a pole-to-ground fault on the dc side at t=3s. The converter is set to be blocked at t=3.005s. I find that two of the arm currents drop to zero instantly when the converter is blocked, as shown in Fig. 1. The results may contradict the already found results published in papers. In my opinion, the arm current wouldn’t drop to zero instantly when the converter is blocked because the process of the arm current freewheeling by the arm inductor still needs time.