The addition of the external temperature sensor gives the HealthSense the ability to measure both the top and bottom oil temperatures, along with the ambient temperature. And with the transformer's specific top-to-hotspot thermal gradient (at full load), this allows for the determination of the load % at each sample point. This provides a realistic representation of the load at any point measurements were taken.
The load model developed using the HealthSense can be projected forward to forecast daily load variations in the future giving an improved forecast for the life of the transformer (See DP Forecast).
 BS IEC 60076-7:2018. Power Transformers. Part 7: Loading Guide for Mineral-Oil-Immersed Power Transformers. 2018.