| Puget Sound Energy is a utility company serving Western Washington. They noticed that the voltage had an excessive amount of harmonics and the %THD exceeded the IEEE-519 guidelines.
Puget Sound Energy hired
PowerStudies.com, to model their distribution system from the Greenwater Substation to the Crystal Mountain Ski Resort. The purpose of this study was to determine why the voltage distortion was so high at the location.
The engineers at
PowerStudies.com
found that due to the underground cable capacitance and system transformers, the system was tuned to the 5th harmonic. The ski resort has numerous variable speed drives that produce 5th harmonic currents. These currents along with the system tuned to the 5th harmonic caused the high %THD.
PowerStudies.com worked with the utility to redesign the distribution system and to shift the system resonant point to an even number.
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