Harmonic Distortion can be Elusive Cause of Power Problems

摘要

If your plant is experiencing inexplicable nuisance tripping, inconsistent power quality or extensive power interruptions, harmonic, distortion may be the culprit. Water treatment plants and pumping stations supported by variable-frequency drives (VFDs) may be unwittingly threatened with power system problems including interruptions, ihterference, downtime, and even disruption of instrumentation and other sensitive equipment due to an elusive culprit called harmonic distortion, an undetected condition which has been said to cost billions of dollars in annual losses due to downtime, equipment failures and malfunctioning systems. Although harmonic distortion is hard to see and measure, it is no mere gremlin. It is a very real problem that often accompanies the installation of equipment with motors controlled by VFDs. VFDs are an integral part of today's water and wastewater power systems because they save energy, provide added control and reduce mechanical and electrical stress during starting and stopping of loads. However, unless certain precautions are taken, VFDs can also induce harmful harmonic distortion.