By Emily Newton

Fluctuations in the local utility power grid can lead to a variety of power quality issues, including voltage surges, outages, and noise. While these challenges may be a minor inconvenience for some facilities, they can cause serious problems for automated technology, which is naturally susceptible to power quality issues. Managing power quality is essential for facilities that want to invest in automation. The right testing and monitoring solutions will be necessary for companies to protect their automation systems.

HOW CAN POWER QUALITY ISSUES IMPACT AUTOMATION?

There are several main types of power-quality issues that can arise from both within equipment and due to grid power fluctuations. These include electrical noise and electrical harmonics.

Electrical noise refers to high-frequency voltage variations. “High-frequency” is always relative to frequencies considered normal for a particular system. Over time, an AC system’s current should appear as a smooth sinusoidal wave. Electrical noise will make this wave ragged and rough.

Electrical harmonics are voltage and current disturbances that are integer multiples of the system’s AC frequency. These harmonics are caused by non-linear loads including:

  • Variable-speed electric motors
  • Rectifiers
  • Computer power supplies
  • Fluorescent lights

Current harmonics tend to be larger than voltage harmonics and often drive voltage harmonics.

Both types of harmonics can induce heat generation, degrading the efficiency, performance, and lifespan of electronics. These harmonics can also cause vibrations and torque pulsations in the output of electric motors, which can stress and shorten the lifespan of the motor’s mechanical components.

In addition to harmonics and noise, both transient or temporary over-voltage and under-voltage can cause issues for sensitive automated electronic systems. Other issues, like voltage dropouts and frequency variations, can cause similar problems for sensitive electronics.

Like harmonics and noise, these problems can cause overheating and reduce the performance of electronic systems. They may also cause system resets.

OTHER TYPES OF DAMAGE CAUSED BY POWER QUALITY ISSUES

Older electromechanical equipment was not as sensitive to changes in voltage or current. Modern electrical automation systems are more sensitive to voltage changes and may have limited tolerances for sudden surges, outages, or noise.

Particularly complex automated systems, like hyper-automation systems, may contain many interlocking parts that can all be vulnerable to power issues. Surges, outages, and other issues may lead to cascading failures in these systems.

In general, power quality issues can lead to a few different issues with sensitive automated systems, including overheating, component or system failure, and a full system reset.

These resets can cause issues with system data and software, potentially corrupting files or deleting important information. In some cases, technicians may need to fully reconfigure the automated system’s underlying software.

The greater the extent of automation within a facility, the more these power quality issues can have an impact. Disruptions in power quality can lead to disruption in automated systems, impacting overall facility performance and reliability.

When systems fail, components can also sustain damage, leading to potentially expensive repairs and maintenance.

MONITORING AND TESTING TO MANAGE POWER QUALITY ISSUES

Once detected and identified, it’s generally possible to solve most power quality issues. However, system users will first need to figure out why an issue occurred before troubleshooting can begin. The troubleshooting process usually involves a few distinct steps: information gathering, measuring and testing, then long-term measurements or audits.

Information gathering is a preliminary step that occurs when an end-user believes power quality issues are damaging an automated system or causing it to behave unusually. The end-user will review existing monitoring solutions for irregularities or fluctuations in variables like machine performance or current.

The end-user may also survey employees and staff or review documentation to identify potential causes of machine issues—like recent maintenance, the removal of important equipment, or changes to the machine’s power supply.

If the end-user determines the machine may be subject to power quality issues, they can begin testing the machine’s power supply for irregularities. Using instruments that measure voltage and current, like a power quality analyzer, the end-user can monitor for fluctuations, variations, outages, and other power quality issues.

Information from these measurements allows the end-user to characterize a system’s power supply and identify potential problems. With this information, they can move on to adopting power supply components that will protect sensitive electronics from these quality issues.

DESIGNING AUTOMATED SOLUTIONS TO MITIGATE POWER QUALITY ISSUES

This information will help the system users determine how they can solve the power quality issue. For example, a replacement power generation system may be a potential solution for grid noise or surges.

Careful consideration of the power generation specifications will be required. The system owner should pay attention to power generation system variables like reliability, size, maintenance needs, and power source.

A business may also need to invest in components that can protect systems from power surges, outages, and other current or voltage variations.

Surge protection devices (SPDs), filters, line conditions, isolation transformers, and uninterruptable power supplies (USPs) are five common devices that businesses use to manage specific power quality issues.

For example, SPDs help mitigate the impact of power surges by either blocking or shorting current (or a combination blocking-and-shorting measure). If a particular automated solution is vulnerable to power surges, these devices can help to damp out sudden current or voltage changes. Key characteristics of SPDs include clamping voltage, response time, and energy rating.

Properly sizing SPDs can sometimes be a challenging task, but the process will almost always be much easier with the right information and pre-planning. The use of multiple SPDs at all levels of a system’s electrical distribution—or “protection at depth”—will also help ensure these devices can effectively protect an automated solution.

Even before power quality issues emerge, best practices can help end-users design automated solutions to be more resilient to power quality issues or to prevent these issues from emerging in the first place.

Information from power quality audits and previous troubleshooting processes can tell an end-user what kind of issues they should expect to manage in a new automated system. With this information, they can pre-emptively employ devices like SPDs, USPs, and filters to improve the reliability and performance of an automated solution.

OPTIMIZING POWER QUALITY FOR SUCCESSFUL AUTOMATED SOLUTIONS

Automation is a powerful tool for improving productivity and streamlining processes in a variety of industries. The sensitive electronics in many automated solutions, however, can be vulnerable to normal utility grid power fluctuations.

Testing, monitoring, and implementing devices that can protect automation electronics will help end-users implement automation without risking downtime or higher maintenance costs due to electrical power quality issues.

By identifying facility power quality challenges and using the appropriate tools, it’s often possible to resolve the most common power issues. 

Emily Newton is a technology and industrial journalist. She is the editor-in-chief of Revolutionized, a publication dedicated to exploring the latest industrial innovations.

MODERN PUMPING TODAY, June 2022
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