Differences and similarities between ANSI and IEC cultures for MV assemblies — The Brazilian experience

The Brazilian Petroleum and Chemical Industry had basically used MV power assemblies based on ANSI/NEMA for many years. But, in the last three decades, due to the Brazilian Standard Association orientation, the users and manufacturers have been changing their philosophies to the IEC culture. As it has been an everyday increasing of the opportunity and also the need of medium voltage electrical power distribution in Petrochemical facilities, there is the opportunity to adopt MV switchgear or controlgear design based on ANSI or IEC standards, according to each plant specifications. Although the use and design of MV assemblies are based on the electric power system needs and characteristics, they are also a compromise with the current scenario and experience of a specific petrochemical facility. Since both ANSI and IEC universes have a strong experience, knowledge and huge safety concerns in electrical equipment design and application, the final choice is an interesting decision. It is important to keep in mind that the use of MV assemblies have to face technical and safety key issues as they are connected to an industrial power system, and both ANSI and IEC deal with such requirements very carefully: each one in its own way. This paper deals with impacting topics related to MV switchgear and controlgear like: · ANSI and IEC requirements; · Rated values and characteristics; · Ancillary and power equipment application; · Safety; · Ergonomics.