scope:

This part of IEC 62751 gives the detailed method to be adoptedfor calculating the power losses in the valves for an HVDC systembased on the ?modular multi-level converter?, where each valve inthe converter consists of a number of self-contained, two-terminalcontrollable voltage sources connected in series. It is applicableboth for the cases where each modular cell uses only a singleturn-off semiconductor device in each switch position, and the casewhere each switch position consists of a number of turn-offsemiconductor devices in series (topology also referred to as?cascaded two-level converter?). The main formulae are given forthe two-level ?half-bridge? configuration but guidance is alsogiven in Annex A as to how to extend the results to certain othertypes of MMC building block configuration.