Effect Of Variable Frequency Drives On Power Systems

Harmonic mitigation is an important consideration for numerous applications. While they are not essential for linear loads, they are certainly required for non-linear loads. A variable frequency drive, which changes the speed of an electric motor by modifying its voltage and frequency, falls in the latter category. In this blog, ADM Engineering Inc., a reputed distributor of harmonic filters and other solutions, explores why VFD causes harmonic mitigation and what its side effects are.

Why Do VFDs cause Harmonic Distortion?

The main reason VFDs cause harmonic distortion lies in why it's considered a major non-linear load in the first place. A VFD converts the incoming AC into DC and back into AC again by changing the frequency. This creates a major distortion in the current waveform. This case is true even if the input voltage is perfectly sinusoidal. Therefore, VFDs cause massive harmonic distortions when they are used.

Impact Of VFDs On A Power System

Overheating Of Motors: The main reason for installing a VFD is to better control the speed of an electric motor. However, the unstable surge of the current caused by harmonic distortions ends up overheating the motor itself. Therefore, it can damage the motor's insulation and reduce the lifespan of important electrical parts.

Malfunction Of Sensitive Devices: Many sensitive devices, such as sensors, meters, and other electronic equipment can also be adversely affected by the harmonic distortion caused by VFDs.

Overload Capacitors: Since harmonic distortion can reduce the power factor of a system, many go for capacitors as a source. Unfortunately, they are not a source of harmonic mitigation, and end up being overloaded due to distortion.

To avoid this harmonic distortion caused by VFDs, it is best to go for active harmonic filters, as they easily combat the dynamic load generated by a VFD. For high-quality harmonic filter options, reach out to us at ADM Engineering Inc. As a leading distributor of harmonic mitigation solutions, our experts guarantee perfect solutions for a variety of applications. Call us now at 1 (877) 236-8337 for expert advice on harmonic mitigation!