The grey band is the region of acceptable or useful voltage magnitude that is 10% of the nominal voltage. Each line represents one transformer. The grey lines are the voltage profiles of transformers whose voltage was constantly below the nominal range throughout 2023. The orange lines represent the transformers that delivered a nominal voltage during some parts of the day and for which the voltage dropped below the nominal range during peak load. Finally, the blue lines represent transformers whose voltage was constantly within the nominal range throughout 2023. Within the same district, different transformers delivered different voltage qualities to customers, and these inequalities were consistent at different times of the day. Therefore, they were not affected by time-of-day changes in load.
