IEC 62751-2:2014+AMD1:2019+AMD2:2023给出了基于“模块化多电平转换器”的HVDC系统阀门功率损耗计算所采用的详细方法，其中转换器中的每个阀门由多个独立的、双端可控的串联电压源组成。它既适用于每个模块化单元在每个开关位置仅使用单个关断半导体器件的情况，也适用于每个开关位置由多个匝组成的情况- 串联关断半导体器件（拓扑结构也称为“级联两级转换器”）。给出了两级“半桥”配置的主要公式，但也给出了如何将结果扩展到某些其他类型的MMC构建块配置的指导。

IEC 62751-2:2014+AMD1:2019+AMD2:2023 gives the detailed method to be adopted for calculating the power losses in the valves for an HVDC system based on the "modular multi-level converter", where each valve in the converter consists of a number of self-contained, two-terminal controllable voltage sources connected in series. It is applicable both for the cases where each modular cell uses only a single turn-off semiconductor device in each switch position, and the case where each switch position consists of a number of turn-off semiconductor devices in series (topology also referred to as "cascaded two-level converter"). The main formulae are given for the two-level "half-bridge" configuration but guidance is also given as to how to extend the results to certain other types of MMC building block configuration.