In this case study, the utility responded to the customer’s flicker complaint after an installation of a tankless water heater and took measurements to verify the severity of the problem. With the measurements made, it was possible to use modeling software to simulate the effect of upsizing the transformer from 25 kVA to 50 kVA.
The model predicted that the flicker should be reduced by 40%, which would more than satisfy the minimum power quality requirements. The utility proceeded to replace the 25 kVA distribution transformer with a 50 kVA model along with a follow-up recording.
The measurements validated the modeling predictions, and the customer stated that even though the flicker was still noticeable it was much less severe and tolerable. In the future utility planning and customer guidelines must take into account the possibility of a tankless electric water heater and its very high power requirement...
This white paper includes: