What Are Harmonics and Why Should You Care?

As businesses grow and incorporate more advanced technology, maintaining power quality becomes critical. One key issue that’s often overlooked is harmonics—an electrical disturbance that can have serious implications for both your operations and your bottom line. Understanding harmonics, how they affect your power system, and what you can do to manage them is essential for ensuring the efficiency, reliability, and safety of your business’s electrical infrastructure.

Understanding Harmonics: What Are They?

Harmonics are a type of electrical disturbance, but unlike short-lived disturbances, such as voltage sags or surges, harmonics are persistent. They are continuously present as long as the devices generating them are operational. Harmonics are created by non-linear loads, which include electrical equipment that does not consume power in a linear way.

Some of the most common types of equipment that generate harmonics include:

• Variable speed drives: Often used to control motor speeds in industrial settings.
• LED drivers: Found in lighting systems.
• Uninterruptible power supplies (UPS): Used to provide backup power.
• Inverters: Used in solar energy systems and other applications.

Unlike typical electrical disturbances that may last for only a fraction of a second, harmonics are a constant form of “electrical pollution.” Eric Solot, managing director of Alpha Power Solutions, likens them to sewage contaminating a river. If you only have one source of pollution, the impact may not be severe, but when many sources contribute to the problem, it becomes harmful. This analogy effectively illustrates the cumulative damage harmonics can cause within an electrical system.

The Impact of Harmonics on Your Business

Harmonics may seem like a technical issue, but their effects are far-reaching and can lead to significant operational and financial consequences. Businesses of all sizes should be aware of the following risks:

1. Equipment Damage and Premature Failure

When harmonics are present in an electrical system, they cause overheating in cables, transformers, and other equipment. This overheating reduces the lifespan of critical components, leading to frequent maintenance needs or even premature equipment failure. Overheating can also affect the performance of sensitive electronic devices, increasing the risk of costly repairs and unplanned downtime.

In extreme cases, harmonics can cause the tripping of circuit breakers and protection devices even though these systems have not reached their designed current limits. This can create confusion and inefficiencies as businesses struggle to identify the root cause of the problem.

2. Increased Energy Consumption and Costs

One of the most direct effects of harmonics is decreased energy efficiency. When your power system is polluted with harmonics, more energy is required to perform the same tasks. This not only increases your operational costs but also places unnecessary strain on the electrical grid.

Harmonics also lead to higher demand charges from utility companies, as they make your system appear to be drawing more power than it actually is. These inflated energy bills can go unnoticed if businesses aren’t monitoring their power quality, leading to significant overspending over time.

3. Downtime and Production Losses

Equipment failure due to harmonics can lead to unexpected shutdowns, disrupting your production schedules. For businesses that rely on continuous operations, this can translate into lost revenue and missed deadlines. Even a short disruption during peak production hours can have a ripple effect, slowing down the entire production chain.

In some cases, businesses may even need to implement their own form of load shedding, where they turn off certain machines to keep others running, as a way to prevent system overloads caused by harmonics. This can severely impact productivity and overall output.

How to Identify Harmonics in Your System

The first step in addressing harmonics is to conduct a comprehensive harmonic audit of your electrical system. During this audit, you will identify which devices are contributing the most to harmonic pollution. As mentioned earlier, not all devices generate harmonics, so the goal is to pinpoint the major culprits.

Here’s how businesses can approach identifying and managing harmonics:

• Audit your system: A thorough audit will help identify the sources of harmonics and measure their levels throughout your electrical distribution system.
• Prioritise key contributors: Applying the 80/20 rule, focus on the 20% of devices that are contributing to 80% of the harmonics. Addressing these will have the most significant impact on improving power quality.

It’s essential to note that some level of harmonics is acceptable. There are industry standards that define safe levels of harmonic distortion, so businesses don’t need to eliminate harmonics completely—just reduce them to safe levels.

Solutions for Mitigating Harmonics: Passive and Active Filters

Once you’ve identified the sources of harmonics in your system, the next step is to implement solutions that reduce their impact. There are two primary methods for mitigating harmonics: passive filters and active filters.

Passive Filters

Passive filters are installed at the source of harmonic generation, such as directly at a variable speed drive or UPS system. These filters prevent the harmonics from leaving the device and spreading to the rest of your electrical system. In Solot’s sewage analogy, passive filters act like septic tanks installed near each toilet, treating the waste before it enters the river.

Passive filters are generally the most cost-effective solution for managing harmonics, especially when dealing with isolated devices that are the main contributors to the problem.

Active Filters

Active filters work by generating harmonics that are the exact opposite of those present in your system. These opposing harmonics effectively cancel out the harmful ones, improving overall power quality. In the sewage analogy, active filters are like a large treatment facility that purifies the entire river.

While active filters can be highly effective, they are also more expensive than passive filters. They are typically used in complex systems where multiple devices are generating harmonics, making it difficult to address the problem at the source.

Hidden Costs: Fines and Overcharges as a result of excessive harmonic levels being generated by a site

Another reason to pay attention to harmonics is the costs associated with poor power quality due to excessive harmonic levels. In many countries, utility companies impose fines on businesses that generate harmonic levels which exceed the limits set by the power quality standards applicable in those countries. However, in some regions, including South Africa, these penalties are not yet enforced.

Maintaining Your Power System: The Importance of Regular Monitoring

Once harmonics are addressed, businesses must ensure that their harmonic filtration equipment continues to function properly. Maintenance is key to ensuring long-term savings and avoiding downtime.

Many companies now offer remote monitoring services that allow technicians to assess the performance of power quality equipment in real-time. These systems can send alerts when maintenance is needed or when an issue arises, allowing businesses to address problems before they lead to downtime or system failures.

Address Harmonics Before They Harm Your Business

Harmonics may seem like a technical concern, but the impact on your business is very real. From increased energy costs to equipment failure and downtime, harmonics can cause significant operational and financial damage if left unaddressed.

Fortunately, with the right strategies—such as conducting a harmonic audit, installing passive and/or active filters, and maintaining these filters—businesses can significantly reduce the risks associated with harmonics. These actions not only improve power quality but also lead to long-term cost savings and operational efficiency.

By taking a proactive approach to managing harmonics, businesses can protect their infrastructure, avoid unnecessary fines and overcharges, and ensure their operations run smoothly. To learn more about how harmonics could be affecting your business and what you can do to mitigate their impact, read our detailed blog post for further insights and solutions.