A momentary power interruption at home is a minor inconvenience, but a momentary power interruption in a production line can lead to equipment failure. Though today’s automated technology makes better precision and efficiency possible, one drawback is that electronics are susceptible to power quality issues.
Automation in manufacturing has become more commonplace in recent years as technological advances have made installing, using and maintaining such machines more cost effective. Networking technologies, the cloud, software integrations and more have contributed to the increased presence of automation in manufacturing.
Other factors, such as the need to increase efficiency and reduce costs in a competitive landscape, have also contributed to the adoption of automation. The field will continue to evolve and improve as artificial intelligence (AI), machine learning and other advances drive new capabilities and applications.
What Is Automation?
Automation simply refers to equipment and systems that perform tasks or processes automatically. The goal is not to replace humans but to make operations safer and more efficient. There are three main types of manufacturing automation: fixed, programmable and flexible.
Fixed automation, also called hard automation, refers to systems designed to produce a single type of product. Designed, built and programmed for a specific purpose, the equipment is fixed—not easily changed or reconfigured. Because of the upfront costs associated with fixed automation equipment, it is used only for high-volume products. Downtime for fixed automation systems is costly.
Programmable automation is characterized by equipment that can be configured or coded for different processes. Programmable automation equipment can be used for batch production, including small batches of as few as several dozen units or for products that have shorter life cycles. The downtime associated with changing from one product type to another is more predictable but still expensive.
Flexible automation takes the idea of programmable automation a step further by making automated changeovers possible. Flexible automation equipment can adapt to changing production needs and priorities. It can even be controlled remotely—a person does not need to be physically present to handle a changeover.
What Does Power Quality Have to Do With Automation?
Older electromechanical equipment was not as sensitive to changes in voltage. But some automated equipment is sensitive to voltage changes and has a smaller margin of error. Power quality issues can lead to overheating, component and/or equipment failure, automatic resets, data errors or corrupted software.
When equipment experiences disruptions, reliability and peak performance are less attainable. Power quality issues can cause equipment to run inefficiently, malfunction or fail. A power interruption can lead to inaccurate or incomplete data or signals being used in a process with the outcome ranging from low-quality product output to damage to the equipment itself. Even a small disruption can impact an entire system.
There are numerous types of power quality events:
- voltage sags and swells
- voltage interruption
- transients
- unbalance
- harmonics
How to Test & Monitor Power Quality
Once detected and identified, most power quality issues can be resolved. Utilities and equipment manufacturers can often be good resources for recommended solutions. Both are ultimately invested in the success of their customers. Users can take a proactive approach by learning about common symptoms and effects of different power quality events, especially considering that many power quality events happen on the user’s side of the meter. Users should also determine which of their equipment is most sensitive to power disturbances.
Troubleshooting power quality issues
With all power quality monitoring systems in place, users will be able to respond quickly when an issue arises. If a manufacturing line is down because a breaker has tripped for the third time that week, users will have running data to understand when it happened and how long the issue was present. But, to fix the problem, users have to figure out why the three-phase circuit breaker tripped in the first place and break down why it seems to be a random occurrence.
1. Gather Information
The first thing to do when getting to the root of a problem is to gather up all of the information about the plant and problem. Look at the monitoring data, check with those who may know the machinery more intimately to understand what symptoms they have seen and what happened the last time the breaker tripped. There is also a series of questions to ask and keep in mind while looking around the production line:
- Has anything changed recently?
- Did any new machinery get installed (nearby or downstream of the
- electrical service)?
- Has any equipment been removed?
Grabbing an up-to-date drawing is also key to the investigation. Be sure to check it against what is seen on the floor. Any changes are potential areas for concern.
2. Set Up for Measurements
When a user has gathered as much information as possible, it is time to move on to making measurements. Having an instrument that offers a wide range of measurements, like a power quality analyzer, is often the key to success in finding the problem quickly so it can be repaired efficiently.
When working with a power quality analyzer, users want to start by installing the tool before switching the breaker back on, if possible. Once the tool is installed, be sure to double all the connections:
- Are the voltage leads connected to the right phases?
- Are the current probes connected to the right phases?
- Are the probes oriented correctly?
Check the reading on the measurement device—modern analyzers often have a feature that automatically indicates correct connection.
If a user thinks they are going to have to take readings over an extended period of time, keep the analyzer’s power supply in mind. With some modern analyzers, the power can be drawn straight from the measurement circuit, so users do not need to worry about battery life or having to find a wall outlet.
3. Power Up the System & Look for the Problem
Return power to the system by resetting the breaker. At this point, pay close attention to two things: the voltage and the current.
- Is the voltage within the expected tolerance of +/- 10%?
- Is the current being drawn to the expected range?
These two areas of information can offer a quick indication of where the problem might lie. If the voltage is too high or too low, this is why the breaker might trip. If the current draw is higher than expected, it could also trip the breaker.
Next, consider the power being consumed and the power factor—having a power factor below 0.85 is wasteful and can indicate loading problems. This can be relatively easy to fix.
If all of the basics appear normal, check the total harmonic distortion (THD) as this can indicate that some loads are creating problems. The unbalance can be checked by looking at unbalance percentages or at the phasor diagram on the analyzer for voltage and current. Look at the dips and swells documented on the analyzer; has the voltage been outside of limits while measurements have been running?
4. Leave the Data Analyzer
If all of these steps have been completed and the problem has not become clear yet, consider leaving the data analyzer in place so the information can be logged. If the breaker trips for a fourth time, the logger can capture everything that happens before and after the trip. That data can then be downloaded, and a report can be generated to share with experts in order to fully fix the problem.