Joshua Piccaver takes a look at the areas of industry that require power protection
Health advisors always reiterate that prevention is better than cure. Take care of yourself, and preventable problems are less likely to arise.
Engineers dealing with power-reliant processes should adopt a similar approach to power protection.
A plant’s electrical system works a lot like the body’s cardiovascular system. It’s not something that is often thought about, and it’s easy to forget just how hard the system is constantly working. But, when a problem arises, its effects can be devastating.
Transients, interruptions, harmonics, swells, dips and sags are just some of the power quality problems that can have destructive effects on industrial businesses.
Power quality deviations may originate from problems with the electrical supply, load equipment or from interactions between the two.
While utilities find ways to improve the quality and reliability of the power supply, manufacturers must prevent the incidents that can be devastating for a modern industrial plant.
Hardware damage and system malfunctions are among the top causes of data loss. However, unexpected external events can also cause data loss, such as fire, floods and other power failures that are often beyond a manufacturer’s control.
Data is a powerful business tool, so you want to avoid losing access to this wealth of production, industry and customer insight.
Offsite management options such as cloud storage or cloud backups can present a viable option to counter external events.
Onsite however, backup generators supported by battery-backed uninterruptible power supplies (UPS) are responsible for springing into action if the power is suddenly cut.
As such an event is uncommon, generators must undergo regular load testing to validate the operational performance of the UPS. Load bank testing analyses the UPS and generator under load conditions and is most often carried out during preventative maintenance.
Backup power maintenance will help manage disruptions from the grid, but manufacturers must also make sure their electrical equipment isn’t causing internal problems.
The range and complexity of electrical equipment has increased dramatically in recent years and one of the unwanted consequences of this rise is the creation of harmonic currents, which can cause voltage distortion and quality problems.
Harmonics can have adverse effects on power supply. If the nonlinear loads produce unwanted harmonics, they could cause equipment failure as a result of insulation breakdown, arcing and overheating.
Variable speed drives (VSDs) are just one example of equipment in today’s production facilities that control the speed and torque of motors to better match process requirements.
VSDs can also create harmonic currents that may cause motors to overheat and become noisy, circuit breakers to trip, meters to give false readings, or equipment to fail altogether.
Harmonics caused by equipment like VSDs can be reduced to acceptable levels by using passive filter circuits that consist of inductors, capacitators and resistors. The filter circuit allows the fundamental frequency to pass through while diverting any harmonic frequencies to the resistor bank. Here, the frequencies are dissipated as heat and safely removed from the system.
The events that cause power disruptions are not always preventable. However, plant managers can implement strategies that prevent the consequential disruption. Ensuring a reliable source of backup power and preventing the side effects of unwanted harmonics are just two ways of stopping power problems in their tracks.
Joshua Piccaver is electrical design engineer at power resistor manufacturer, Cressall.