What Is IEEE 519 and How Can You Reduce Harmonic Distortion?
Variable frequency drives (VFDs) provide significant benefits for motor control and energy efficiency, but they can also introduce harmonic distortion into an electrical system.
Excessive harmonics can contribute to nuisance breaker trips, transformer overheating, control system disturbances, flickering lights, and premature wear on electrical components.
In this video, ES&E and Hammond Power Solutions (HPS) discuss IEEE 519, the impact of harmonics, and solutions available to improve power quality in VFD applications.
What Is IEEE 519?
IEEE 519 establishes recommended limits for harmonic distortion within an electrical system.
An important part of IEEE 519 is the Point of Common Coupling (PCC)—generally the point where utility power enters a facility and connects with the customer's electrical system.
Managing harmonic distortion at this point helps reduce the impact nonlinear loads can have on the electrical system.
What Causes Harmonic Distortion?
One of the most common sources of harmonics in industrial facilities is the six-pulse VFD.
A VFD converts incoming AC power to DC as part of its operation. This makes it a nonlinear load and creates harmonic distortion. Other devices that convert AC to DC can also generate harmonics, although the appropriate mitigation method can vary by application.
Why Are Harmonics a Concern?
Excessive harmonic distortion can contribute to:
- Nuisance or intermittent breaker trips
- Increased transformer heating
- Erratic control signals
- Flickering lights
- Premature wear on electrical components
- Reduced system reliability
Which HPS Solution Should I Use?
HPS offers several solutions for addressing harmonic distortion and other VFD power-quality challenges.
| Solution | Best For | Primary Purpose |
| Passive Harmonic Filter | Individual VFDs | Reduces harmonics associated with six-pulse drives |
| Active Harmonic Filter | Multiple VFDs or expanding systems | Centralized, scalable harmonic mitigation |
| Line Reactor | VFD protection | Helps with surges and can provide some harmonic reduction |
| Drive Isolation Transformer | Incoming power protection | Helps protect VFDs from power-quality disturbances |
| dV/dt Filter | Longer VFD-to-motor cable runs | Helps reduce reflected wave effects |
| Sine Wave Filter | Very long motor leads | Produces a nearly sinusoidal waveform for the motor |
Passive vs. Active Harmonic Filters
A passive harmonic filter can be a straightforward solution for an individual VFD. When properly sized for the voltage and horsepower of the VFD and motor combination, it targets harmonics commonly associated with six-pulse drives.
An active harmonic filter can compensate for multiple VFDs and can be scaled as additional nonlinear loads are added. It can also monitor harmonic distortion, phase balance, and phase loss while logging electrical data over time.
For Rockwell Automation users, the HPS active harmonic filter includes an Add-On Profile for integration into a Rockwell PLC system.
What About Line Reactors?
Line reactors provide useful VFD protection and can help reduce harmonic distortion in certain applications. However, a line reactor alone should not be considered a complete IEEE 519 harmonic mitigation solution.
Their impact on harmonics can also vary depending on the VFD and whether the drive already includes components such as a DC choke.
Protecting the Output Side of a VFD
Harmonics aren't the only power-quality consideration when using a VFD. Longer distances between a VFD and motor can create reflected wave voltage, which can produce damaging voltage spikes.
For longer motor lead lengths, HPS offers dV/dt filters to help absorb reflected wave energy.
For extremely long distances, a sine wave filter can convert the VFD's PWM output into a nearly sinusoidal waveform before it reaches the motor. This can help reduce stress on motor insulation, reduce audible motor noise, and support very long motor lead applications.
Need Help Selecting the Right Solution?
The right harmonic mitigation or VFD protection solution depends on your electrical system, VFD configuration, motor load, cable length, and application requirements.
ES&E can help you evaluate your application and identify the appropriate Hammond Power Solutions solution for improving power quality and protecting your equipment.