Understanding Power Quality: Interruptions

Power interruptions can happen anywhere and be caused by a number things, typically outside your facility. Potential causes include weather, animal interference, human interference, vegetation or aging components.
 

A voltage interruption can be one of four types, depending on how long it lasts:

1. Instantaneous — up to 30 cycles
2. Momentary — 30 cycles to 3 seconds
3. Temporary — 3 seconds to 1 minute
4. Sustained — more than 1 minute

So, can any equipment survive an interruption? Yes, if the interruption is extremely short, say less than 1 cycle. But most of the time, you will need to compensate for a power interruption.

In the short term, an uninterruptible power supply, or UPS, will normally do. There are three types of UPS devices:

1. Online that uses a double conversion process.
2. Offline that's only engaged when power is lost.
3. Line interactive that provides limited power conditioning and full backup only when needed.
    

If an interruption lasts longer than an hour, large-scale energy storage or a backup generator will be necessary. Each comes with trade offs, including capital costs, which vary greatly between these systems. The installation itself will cost roughly 50% of the purchase price. On top of that, you'll need to factor in maintenance costs for any of the systems.

UPS and backup generators are an investment, but they're an investment that can help prevent power quality interruptions from interrupting your operations.