MT 31 - TC 22/SC 22F/MT 31

IEC 62751-2:2014 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.

Specifies end-to-end dimensions for given nominal sizes and pressure ratings of buttweld, two-way, global-type, straigth pattern control valves for nominal sizes DN 15 through DN 450. Aids users in their piping design by providing normalized dimensions of buttweld end control valves.

IEC 62751-1:2014 sets out the general principles for calculating the power losses in the converter valves of a voltage sourced converter (VSC) for high-voltage direct current (HVDC) applications, independent of the converter topology. Several clauses in the standard can also be used for calculating the power losses in the dynamic braking valves (where used) and as guidance for calculating the power losses of the valves for a STATCOM installation.