How the Right UPS Can Help Mitigate Many Power Quality Problems

Power quality problems are an unfortunate fact of life. The U.S. utility grid is under strain and cannot maintain much of a “cushion” against ever-increasing demand. Even if utilities can generate more power, many distribution networks are already at capacity.

That’s a big problem for data centers that rely upon high-quality power for sensitive electronic equipment. A wide range of power quality problems can potentially damage IT equipment and mechanical systems. These issues include:

• Transient (spike) — short-term increase in current or voltage
• Sag — reduced voltage lasting up to one second
• Undervoltage (brownout) — reduced voltage lasting several seconds or longer
• Swell — increased voltage lasting up to one second
• Overvoltage — increased voltage lasting several seconds or longer
• Harmonic distortion (noise) — random fluctuations in current or voltage

The right uninterruptible power supply (UPS) can help reduce the impact of many power quality problems. High-quality UPS units offer power conditioning and overvoltage protection and can switch to battery backup if power problems impact the operation of IT equipment.

Why Power Quality Matters

Most data center operators are concerned about staying online 24x7 and thus focus on preventing power outages as much as possible. A data center with “five 9s” (99.999 percent) availability experiences less than 5.26 minutes of downtime each year.

However, those numbers do not necessarily address the issue of power quality. Data centers are likely to have undetected power quality issues such as transients, sags, and swells that result in data loss or application errors. These events aren’t considered “downtime” because power is not lost.

Back in the 1970s, the Computer and Business Equipment Manufacturer’s Association (CBEMA) produced a curve denoting the AC voltages that most IT equipment can withstand without experiencing shutdowns or malfunctions. The curve was updated by CBEMA’s successor, the Information Technology Industry Council (ITIC), in 2000. The curve shows how IT equipment can be impacted by power quality problems.

How the Right UPS Can Help

A UPS is designed to provide a source of backup electrical power when the utility power source is lost. As such, it can protect against sags and undervoltage events. Most UPS units also regulate incoming voltage and provide power conditioning to smooth out changes in input frequency.

However, a UPS should not be considered a primary defense against transients, swells, and overvoltage events. The data center power system should include two layers of surge protection on the utility side to absorb the brunt of the energy before it reaches the UPS. This helps protect the UPS from the most serious events and ensure that it’s available to provide backup power for the IT equipment.

Enconnex Rack Mount Uninterruptible Power Supplies