Project Description

Artesian Water is adding a Water Treatment Plant to a location that currently includes a sizable amount of PV Solar panels as well as a very high percentage of its motor loads being controlled by VFDs. Combined with the inclusion of a diesel generator for standby power, these two conditions presented design challenges. In order to protect electrical utility workers, PV Solar inverters only create power when the utility waverform is present. They would not function properly with the generator and might even harm it. To avoid this, a distribution panel was added to connect the Solar inverters to the utility side of the generator’s automatic transfer switch (ATS). VFDs are considered non-linear loads and if they are used on more than 20% of a facility’s loads may cause harmonic distortion. In this facility VFDs constituted more than three times this level. The harmonics generated could affect the site’s neighbors and the neaby PV Solar inverters. Duffield added an active harmonic filter to the design to cancel out the harmonics.