How to recognize and reduce power system harmonics and noise    

November 8, 2023

Although devices using power electronics can produce distortion in electrical distribution systems, it’s up to the engineer to apply effective solutions to mitigate them.

It’s important to understand what creates harmonics and how an uninterruptible power supply (UPS) design mitigates these harmful harmonics in the power system. Attendees will understand how to mitigate damaging harmonics with effective UPS design.

Every rectifier, regardless of the technology or power electronics used, will produce harmonics. Therefore, an input filter is required to reduce the harmonics. Small filters on the input and output of the UPS can also be used to create a virtual neutral allowing common-mode harmonics to pass through to the inverter. The harmonics are then canceled by the output of the inverter.

Learning objectives

• Understand current and voltage harmonics in electrical systems, and their negative effects on the facility electrical system.
• Know how electronic power equipment, such as a variable frequency drive, creates harmonics.
• Understand characteristic and noncharacteristic harmonics.
• Understand IEEE 519 guidelines for the reduction of electrical harmonics.
• Learn techniques for mitigating harmonics with recommended applications.