Voltage Sags - Utility

Like all sags, utility-based sags are the result of load changes and system impedance. In this case, however, the customer has no control over the load changes. As far as the customer is concerned, the source voltage at the service entrance dipped.

When a sag occurs, the power supply inside electronic devices uses some of its stored energy to compensate for the loss of input voltage. If enough energy is lost due to the sag, then the power supply may lose its ability to maintain an exact DC voltage to all the integrated circuits inside the device - even for a few milliseconds. Well, this is time enough for a the 1's and 0's inside to get confused, and data can get lost or corrupted.

Some form of voltage regulator or energy storage device is needed to remedy these types of disturbances. Products that provide longer ride-through such as enhanced power supplies, that regulate the voltage such as tap-switching conditioners, or that switch to temporary back-up power like an SPS will all suffice.