Electromagnetic interference, as the latter portion of the name suggests, is a disruption or disturbance created by external and environmental sources, particularly when it comes to radio signals, wireless broadcasts and electrical circuits.

As our use of technology and our reliance on it grow, so does the potential for interference — especially when it comes to systems within our local area. While EM events can cause the occasional service disruption or signal drop, there are more impactful alterations, too.

With renewable energy sources — like wind and solar — interference can actually be detrimental to equipment. Wind turbines, for instance, may suffer damage when faced with EM disturbances. Solar circuits may malfunction or cease operation in the face of strong disruptions, which can be severe for those relying on its energy supply.

How to Prevent Interference

To prevent interference, electromagnetic compatibility or EMC standards must be adhered to. Of course, the concept is nothing new to the energy industry, as regulations and laws are calling for compliance already.

Compliance is less of a problem in relation to wind and geothermal systems. Instead, it's more a challenge for photovoltaic or solar setups. This is because most solar and DC power systems do not meet FCC standards, more specifically Title 47, Section 15, Part B.

FCC Part B expressly limits the maximum EMI or interference that common and household items can emit. Overall, the standard helps cut down on surrounding interference, and it governs most common electronics and devices. That’s why a Wi-Fi or radio signal is hardly affected by something like a coffee machine or a microwave. The appliances and devices are held to a certain standard that hinders the active escape of EMI.

But DC and solar equipment are not held to this same standard, which means they can be released to market even if they exhibit high levels of EMI. As a result, this creates a great deal of noise and interference for surrounding circuits and systems, and solar happens to rely on a lot of DC-powered hardware.

Wind turbines and power plants still have to worry about similar interference, however, as electromagnetic disturbance can cause just as many issues as it does with solar.

Common Ways to Reduce Noise and Interference

There are several ways to reduce interference, even outside of enforcing the FCC standards. Many of them involve protecting the necessary equipment to block out or filter potentially damaging emissions, such as:

• Shielding: Like a warrior’s shield, shielding is designed to block incoming emissions and protect equipment. Most metals can be used for shielding, and their conductivity provides ample protection. It cannot stop noise carried by direct wiring or similar connections, though.

• Cancellation: As a rather simple concept, cancellation involves twisting wire pairs to direct noise away from the main strand. It’s cheap and relatively easy to achieve, so it’s generally the first thing teams will try. The catch is that it doesn’t always work, and even when it does, it doesn’t always have a strong impact on noise reduction.

• Filtering: Filtering involves the use of capacitors for a signal line, or to provide a wire-to-ground opportunity. It works by filtering out noise and interference that is directed away from the main circuit. Because of frequency limits and size requirements of capacitors, filtering can sometimes be way too expensive.

• Suppression: Unlike the other methods, suppression is a relatively new concept. It involves using chokes, cores and beads — often comprising ferrite or iron oxide — to collect noise and convert it into heat, which is then dissipated entirely. It’s a fairly inexpensive method for noise removal and can be used almost anywhere — thanks to a non-conductive property.

With or without preventative solutions in place, it's still important to both test and measure EMC compliance before and after certification.

Active Testing Is Necessary

Ultimately, testing any and all operating systems is important to mitigating potential noise and EMI damage. It’s recommended to establish a pre-compliance testing protocol that measures products and systems before seeking the proper certifications.

Generally, a process will be implemented to measure radiated and conducted emissions, as well as the same immunities. When it comes to renewable energy hardware, active power levels, environmental conditions and surrounding interference will be discerned to find ideal conditions. Developers and energy providers can then work to achieve and maintain those ideal conditions by directly mitigating potential influence using the accrued data.

So, for example, it might be discovered that shielding is necessary to prevent wind turbine interference from surrounding sources. But due to their height, general makeup and composition, it’s not a viable solution for wind turbines. The focus would then shift to finding an alternative that is just as effective. Pre-compliance testing is important here because it will afford enough time to come up with a solution and make the necessary changes to meet regulations.

As a whole, the testing also ensures the resulting systems remain efficient and operational, even in less than ideal conditions.

The content & opinions in this article are the author’s and do not necessarily represent the views of AltEnergyMag

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