Supporting Facilities and Utilities with a Voltage Sag Generator

Digital electronics and devices often require extremely stable power and tend to be sensitive to transient voltage events, or brief shifts in voltage levels. Voltage can fluctuate, for example, when something changes on a circuit — a piece of equipment starts up or is taken offline. One way it can fluctuate is by dropping and then rebounding quickly, a pattern known as voltage sag.

Voltage sag is graded in two measures: 1) the percentage of voltage seen, or how much it dips, and 2) its duration, which can range from milliseconds to a minute, according to the Institute of Electrical and Electronics Engineers (IEEE). But even momentary voltage sags can cause equipment to stop and can have significant consequences in many facilities. However, if facilities know their equipment is susceptible to voltage sag, they can make improvements to its design or add technologies, such as uninterruptible power supplies or constant voltage transformers, to mitigate the issue.

Recognizing the potential harm that voltage sags can cause, we recently invested in a voltage sag generator. A voltage sag generator, as it sounds, can produce a voltage sag — or its inverse, a voltage swell — to emulate what might be seen in the real world. Our model is a 3-phase Omniverter unit that is rated at up to 480 volts and 60 amps. It can generate single-phase or polyphase sags and swells.

We are set up to test to multiple standards that exist for voltage sag assessments, including but not limited to IEEE 1668, IEC 61000-4-11, IEC 61000-4-34 and SEMI F47. Initially, we’ll be using the equipment to conduct exploratory lab testing for our utility members, but in the future, we hope to perform product testing for manufacturers, verifying what’s known as the “voltage sag immunity” for various devices and components. Through successful testing, a manufacturer would be able to say that its products are sag-resistant to particular levels — such as to the criteria outlined in the standards mentioned above — giving buyers more confidence in their purchase.

With the continued growth of digital electronics, transient voltage events will remain a concern. Having a voltage sag generator — one of the few in the U.S. available for commercial use — should allow us to help lessen that concern and better serve the current and upcoming needs of utilities and manufacturers.