This part of IEC61378 provides information to users about specific topics related to industrial and HVDC converter transformers with design, construction, testing and operating conditions differing from conventional transformers used in power systems. In addition, it is the aim of the present part of IEC61378 to provide manufacturers with the technical background that forms the basis for the principles used within IEC61378‑1 and IEC61378‑2 . It is intended that this part of IEC61378 is used to supplement and not replace or supersede the application guide for power transformers, IEC60076‑8 , since many of the general principles contained within it are equally applicable to converter transformers.