What is a typical percent power factor for a new or in-service medium-voltage oil-filled power transformer?

The typical percent power factor for a new or in-service medium-voltage oil-filled power transformer is around 0.5%. This value is reflective of the transformer's insulation system and the dielectric losses that occur in the transformer during operation. A power factor of 0.5% indicates that the transformer is operating efficiently, with minimal losses compared to the actual power being transformed.

This percent power factor is an important measure because it helps in assessing the operational health of the transformer, the efficiency of energy transmission, and the performance of the transformer under load conditions. A lower power factor percentage generally implies a better efficiency, as it indicates minimal reactive power losses in the system.