Economic Loading of a Transformer System

Loading of transformers must be guided by both economic and thermal limitations. For economic limitations, the costs of installation and operation must be evaluated for each type of transformer. Thermal limitations should be in accordance with the present ASA Loading Guide.¹ Transformers subject to both normal and emergency operating conditions should have thermal limitations established for both conditions. Transformer loading must be within the thermal limitations of connected equipment. Voltage regulation requirements may limit the loading of distribution transformers.