CT saturation calculations - are they applicable in the modern world? - part IV: CT sizing as per IEC standards and the benefits of non conventional instrument transformers

The previous parts of this series of papers was dedicated to current transformers (CTs) designed and tested according to ANSI standards. The determination and specification of CTs for applications based on North American practices was also discussed. This part presents many of the same themes as the previous parts including test results, but from the viewpoint of the International Electrotechnical Commission (IEC) standards and practices outside of North America. Although Ohm´s law and Maxwell´s equations are the same everywhere, how CTs are specified and the responsibility of the different actors can be very different. It is important for engineers to be aware of these differences when executing applications in different parts of the world.