Surge Protection Devices

Although you may be unfamiliar with the term “power quality” (PQ), you are likely aware of the consequences of PQ problems. Losing critical computer data to a blackout or experiencing damage to process or medical equipment due to a lightning strike are just two examples of how these problems can affect your business. Technically speaking, power quality refers to the degree to which electricity is free of disturbances that can cause electricity-consuming devices to malfunction or fail.

PQ problems can affect many types of equipment in your facility, but they’re especially hard on electronic equipment that’s dependent on microprocessors. Computers, network servers, energy management systems, industrial machinery, and food-processing or medical equipment could be damaged or fail prematurely if they are not protected from harmful voltage changes and related disturbances.

Electronic devices function properly as long as the voltage delivered to your facility falls within a consistent range. Power swells, sags, and momentary interruptions occur when the voltage fluctuates outside this normal range. Surge protection devices guard against power transients (low-energy events with a duration of less than 10 microseconds) and power surges (substantially higher energy events with a duration between 10 microseconds and 1 millisecond).

Utilities strive to provide highly reliable and consistent electric power, but it’s impossible to maintain perfectly constant voltage 100 percent of the time. In the course of normal utility operations, voltage will inevitably fluctuate as loads come on to or leave the power system.

PQ events also occur for reasons that have nothing to do with your utility. Lightning strikes can cause major power disturbances. More-subtle PQ problems often originate within the walls of your building and can be traced to the starting and stopping of refrigerator and air-conditioner motors, circuit overloads, or grounding and wiring problems. Onsite switching of power supplies—such as changing to backup power during an outage—is particularly problematic because it can cause PQ fluctuations.

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