Giving power quality the Mythbusters treatment

Discover the truth behind common misconceptions in power quality management

In A Few Good Men, Jack Nicholson's character Colonel Jessep famously informed Tom Cruise's Lieutenant Kaffee that he couldn't "handle the truth." Jessep walked right into Kaffee's trap, leading to his fall from grace.

Not understanding the truth about power quality issues could have similar consequences for even the most informed engineers. There are misconceptions out there that can trap you, leading to costly errors and inefficiencies. You’re probably familiar with some of them, but we’ve found that there are common power quality ones that continue to persist, making it even more important to distinguish between fact and fiction. As experts in the field, the Power Electronics team has a deep understanding of the challenges businesses encounter when dealing with power quality issues, especially when it comes to the misinformation that refuses to fade away.

If you've seen Mythbusters, you'll know it's all about exploring common myths and deciding if there's any truth to them. We've given five of the most common power quality myths the same treatment below, for the a full deep-dive of all of the power quality myths we encounter, check out our Breaking the frequency white paper.

Myth #1: Assuming that power factor correction solves all power quality issues

While power factor correction is crucial for improving system efficiency, it doesn't address the complexities of modern electrical systems. Traditional linear loads have been replaced by non-linear ones like LED lighting and Variable Speed Drives (VSDs), introducing significant harmonics into the system.

Focusing solely on correcting power factor overlooks the challenges posed by harmonics in today's context.

Myth #2: Assuming that power quality issues only occur externally

The truth here is that engineers need to acknowledge the significant role internal factors within the facility play in contributing to these problems. While disturbances from the external power supply can occur, they're exceptionally rare. There's also the belief that correcting power quality issues should focus solely on the point of supply. This overlooks the impact of internal equipment and operations on power quality.

Ultimately, power quality problems often stem from the load itself, leading to issues like Radio-Frequency Interference (RFI) or distortion. However, it's not just the presence of loads but also their usage patterns that significantly impact power quality.

Myth #3: Assuming power quality is a one-time design consideration

It's not. Power quality is not a fixed aspect of electrical system design but rather a dynamic phenomenon subject to change over time due to factors like equipment aging and system modifications. Engineers must recognise the importance of continuous monitoring and periodic assessments to maintain optimal power quality standards. Ongoing monitoring plays a crucial role in identifying potential issues early, allowing proactive intervention to mitigate risks and prevent damage to critical electrical infrastructure.

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Myth #4: Assuming power quality is only about the power triangle

The reality is that engineers need to recognise that power quality extends beyond the triangle. Overlooking factors like electromagnetic compatibility (EMC) and radio-frequency interference (RFI) can pose significant risks to sensitive electronic equipment and communication systems. While voltage and current measurements provide valuable insights, subtler aspects of power quality may go unnoticed.

Myth #5: Assuming that a centralised power quality system will solve everything

This is an oversimplified approach, as it overlooks the need for load analysis to strategically place corrective devices. Often, the greatest benefits are achieved by deploying equipment near the source of disturbance, rather than relying solely on centralised solutions like traditional capacitor-based Power Factor Correction (PFC) systems. While these systems were historically sufficient for managing reactive power concerns, modern technologies require a more nuanced approach.

Discover more power quality truths

What we've covered here is only a small percentage of the misconceptions and myths surrounding power quality. There are many more out there, and to help you gain a clear understanding of them, we've identified eight of them, and have examined each one in detail in our white paper, Breaking the frequency: Exposing eight common myths in power quality.

Download the white paper and set yourself on a path toward a more knowledgeable and effective strategy for power quality management. You CAN handle the truth!