Above all in a power plant, but also in any industrial system, the correct sizing of a transformer is one of the most important matters. The operational conditions of a plant depends on the transformer parameters, like: transformation ratio, MVA rating, winding current rating, tap changer range. These parameters could be verified by a number of load flow calculation, but Manunza & Melis Engineering Consulting has developed a different procedure, mainly based on the IEEE standard C57.1161989. This procedure allows for a global vision of the transformer capability in all the operational conditions, obtaining some simple graphs that include the required information.
