System Grounding Changes

Over the years there has been a multitude of utility voltage schemes throughout the US, and as technology has improved so have the voltage schemes. This improvement in technology occasionally requires the utilities to reconfigure their systems. Unfortunately, this reconfiguration process can have undesirable safety issues if all of the possible negative consequences are not thought out. The guilty scheme in this article is a 15 kV grounded wye which in reality was a solidly grounded 12,470 / 7,200 system.