In simplest terms, harmonics can be defined as distortions to a voltage or current waveform. These distortions occur when non-linear, or non-sinusoidal, loads draw from a sinusoidal voltage source. In other words, harmonics can be generated whenever the smooth symmetrical sine wave of your AC power source is converted to squarish pulses by any of the plant components below, to name just a few of the most common harmonic sources.
- VFDs, Variable Frequency Drives
- VAR Compensators
- Pulse Rectifiers
- Electric Arc Furnaces
- DC Converters
- Switch-mode Power Supplies
- AC and DC Electric Motor Drives
Rockwell Automation provides an excellent source for detailed information on the causes, effects, and corrective measures which can be taken to mitigate harmonics when they occur in their white paper Power System Harmonics for anyone who wants to dive into the math and Fourier theory.
But the numbers which have really drawn attention are the increased total loads caused by the proliferation of non-linear harmonic load generating devices in modern 21st-century industrial plants. Harmonics are a steady state phenomenon which repeats with every 60Hz cycle and shouldn't be confused with other types of transients such as voltage sags, spikes, or dips. Harmonics increase the total load for the typical plant. The ever-increasing loads, most notably from expanding VFD applications, have resulted in stricter limits set in place by utilities who have to supply the expanding demand as well as what the Rockwell Automation report describes as more "stringent recommendations in IEEE Std. 519."
For plant owners that increased harmonic load not only results in increased power costs but when unresolved can take a toll on electrical components as well. Consulting-Specifying Engineer highlights the plant components at risk including:
- Conductors which may overheat and experience energy loss caused by higher frequency currents forced to travel through a smaller cross-section area near the surface of the conductor
- Transformers experience eddy currents and losses caused by higher frequency currents circulating at the core
- Motors may be run audibly noisier and are at risk for premature failure caused by mechanical oscillations induced by harmonic currents at the shaft
- Other VFDs and electronic switch-mode power supplies are subject to failure caused by increasing voltage waveforms.
It's obvious that reducing harmonics is crucial for plant efficiency and there are a number of system accessories which can be deployed such as in-line chokes installed on individual motors and inductive line reactors. For those willing to make significant capital expenditures harmonic trap filters and broadband filters have been the traditional options. But now there is a much better solution available for mitigating harmonics in the age of Industrial 4.0.
Introducing the Yaskawa U1000 Industrial MATRIX Drive
The Yaskawa America U-1000 industrial matrix drive offers the best solution to reducing harmonics without having to spend on additional system accessories, not to mention time and labor for installing those numerous accessories on electrical components dispersed throughout the plant. The U-1000 is the award-winning ultra-low harmonic drive with a worldwide reputation for harmonic suppression and regenerative energy savings in a compact space. It's the only drive available which provides an all-in-one solution to reducing harmonics.
The U-1000 offers versatile low input distortion over a wide load and speed range and it's built to last with an MTBF (mean time between failures) rating of 28 years. It has a 0-400 Hz output frequency range and is tough enough to handle 150% overloads for up to 60 seconds. The continuous autotuning features keep performance at its peak by compensating for motor temperature changes. In periods of excessive demand, the U-1000's quick functioning voltage and current limiters maintain optimized continuous performance. The drive uses DriveWizard computer software and Application Sets for easy configuration and features multilanguage LCD display to accommodate bilingual workforces. Most importantly of all the Yaskawa U-1000 facilitates IEEE 519 Compliance for harmonics reduction.
About Mader Electric
At Mader Electric we've been keeping businesses up and running since 1903. Now we've made it our mission to help enterprises make the challenging transition to the age of Industrial 4.0 with our expertise in the latest cutting-edge technology, and the Yaskawa U-1000 Industrial Matrix Drive is just one example. We provide the full range of high-tech electrical services including SCADA and plant automation, fabrication, electrical, and pump and motor services so don't hesitate to contact us for all of your industrial electrical needs.