Power quality testing resources and case studies are designed to give you a better understanding of potential causes of poor power quality, help you identify energy waste, and interpret power quality issues like voltage dips, swells, transients, unbalance, and harmonics.
This collection of resources aims to improve engineers and technicians knowledge and skills related to power quality measurements and power quality analysis, ultimately helping everyone to solve power problems in their respective workplaces.
Taking power quality measurements can help you identify the sources of poor power quality and energy waste. This can help your facility save money and help protect your equipment from future damage.
The electrical power issues that most frequently affect industrial plants include voltage sags and swells, harmonics, transients, and voltage and current unbalance. The proper tools to correct these issues include knowledge and electrical test instruments ideally suited for each task.
“Let's just oversize the motor and we can run it lightly loaded—that will save us some money and be easier on the motor.” This is a false belief among some who select and install motors. Properly sizing motors for a given load results in driving loads more efficiently, saving energy, and saving dollars. Motors typically are most efficient when they are 90 % to 95 % loaded. Just because a motor says “25 Hp” on the nameplate does not mean the motor is producing twenty-five horsepower as it operates.Clamp meter readings: Problems and Solutions
Since information technology (IT) installations are particularly sensitive to power supply fluctuations and distortions, they typically rely on an uninterruptible power supply (UPS) to compensate. Some installations even include a second UPS supplied by a separate feeder, and a standby generator that can be set to start automatically three minutes after detecting a power interruption.
Critical systems run smoothly with regular maintenance and reliable tools Everybody knows that consistent, dependable electrical power is critical to any plant's function. But perhaps even more critical is a reliable uninterruptible power supply (UPS) system. UPS systems are the silent partners that just sit and wait until there's a break in power. At that point, the UPS system is the most important system in the plant. It has to be ready to spring into action in milliseconds to keeps things running for anywhere from seconds to hours.
To determine the best solution for mitigating unwanted harmonics, start by investigating the equipment suspected of producing the bulk of the harmonic currents. Most often these are Variable Frequency Drives (VFD's). Use measuring equipment to measure and analyze the frequencies and amplitudes of the harmonics. This is much simpler than it sounds.
Power factor correction capacitors reduce energy costs by avoiding the premium rates that utilities charge when power factor falls below specified values.
Monitoring three-phase power quality is a must. Whether you troubleshoot mysterious electrical problems or provide additional services to a client, it is three-phase power that is provided to commercial and industrial customers and three-phase power that is distributed throughout a facility.
Voltage stability may be a problem in areas where loads are cycling on and off during the day. Large compressors, motors, welding machines, arc furnaces, power factor correction capacitors and other large electrical machinery along with system impedance can easily cause voltage dips, swells, and transients.
Downtime is costly, both in terms of patient wellbeing and monetary costs - the X-Ray, mammography, and other systems themselves cost millions and a failure can also idle technicians or surgical teams. Most of the facilities have motor/generators and can maintain operations independent of the utility, making the power system robust but also complex.
As we have seen, power problems have a bad effect on electronic devices. To detect a power problem, a technician will first check out the power supply to a device to make sure it is functioning properly.
In 2005, most facilities viewed their monthly electrical utility bill as a standard cost of doing business. When oil topped $100 per barrel, attitudes changed practically overnight, generating a surge of interest in energy-conscious retrofits that previously would not have been cost-efficient. Yet, when the energy costs came down, attitudes and practices did not entirely revert. The United States was still trying hard to shake a recession. Global competition for providing products and services had grown even more intense. American facilities had found a potential new source of margin and profitability in the form of their monthly energy bill, and they weren't giving it up.