Understanding Power Quality: Uninterruptible Power Supplies
Source: Questline
Voltage interruptions, as well as sags and swells, can happen without notice. However, you can expect a sudden swell or loss of power to get noticed in your facility.
Sometimes, you'll need to compensate for these power anomalies. In the short term (think minutes), an uninterruptible power supply, or UPS, will normally do. If an interruption lasts longer than an hour, large-scale battery energy storage or a backup generator will be necessary.
There are generally three types of UPS devices — online, offline and line-interactive. Let's take a closer look at each of them.
An online UPS continuously converts power using a double-conversion process. First, from AC to DC to charge the batteries. Second, from DC back to AC to power the load. Because it continuously powers the load, it has several advantages. These include no switchover time and the best power conditioning.
An offline UPS is the most cost-effective solution, but there are drawbacks. First, the switchover time may be too slow to avoid interruption of the operation of some electronics. Second, the load power is only conditioned during an interruption.
A line-interactive UPS conditions and regulates the AC power generally using only an automated voltage regulator transformer, or AVR. When AC input is present, the AVR block filters the AC power, suppresses voltage spikes and provides some voltage regulation. A line-interactive UPS provides some of the power conditioning while the utility power is being supplied without wearing out or incurring the losses of a continuously operating converter.
Investing in the right uninterruptible power supply can prevent power quality issues from interrupting your operations.