UPSs & SPDs: A powerful duo

Typography
Opinion

Batman and Robin, Mario and Luigi, Wallace and Gromit. In film, the role of the sidekick is crucial in aiding the protagonist to achieve their overall goal. John Mitchell, global sales & marketing director at CP Automation, explains the necessity of protecting uninterruptable power supply (UPS) systems with a surge protection device (SPD) that accounts for transient surges.

The role of a UPS is to provide a secondary or backup power in the event of loss of utility power. The UPS protects electrical and electronic systems, process controllers and data against the loss of the primary power source.

A common misconception is that SPDs are unnecessary due to the built-in protection already provided by UPS systems themselves. The downside of this "built in" suppression is that the typical UPS, if subjected to a line to ground transient, may allow a significant amount of the transient downstream to the loads.

Transient protection should exist at the input to all electronic loads, and the UPS is no exception. This is where SPDs come in, to prevent excess voltage appearing at the terminals of sensitive equipment. Integrating one of these devices into a system's architecture ensures the life of the UPS and importantly any equipment to which the UPS is supplying power.

High voltage surges are normally covered by surge protectors. However, traditional SPDs do not account for low level transient surges. These transient surges in the sine wave are very damaging to electrical equipment, as the additional peaks and troughs in the sine wave cause confusion to sensitive devices and machines downstream. Transient surges can lead to false zero crossings of the sine wave — the instantaneous point at which there is no voltage present.

During maintenance and downtime on the UPS, the SPD will filter out the transients and surges from the line during the static by-pass mode or maintenance by-pass mode of operation, protecting the connected computer equipment from damage.

However, not all SPD technology is the same. The SineTamer cascade system for example, offers much more than a standard surge protection device. It is an engineered transient disturbance filter, designed to monitor all 360 degrees of the sine wave. Using 360-degree monitoring, the device can prevent issues caused by false zero crossings of the sine wave.

If an organisation has already committed to investing in sophisticated computer equipment and a UPS unit to protect against power outages, the investment in an SPD is minimal by comparison and a very natural progression. The benefits of this additional protection can be significant, resulting in fewer maintenance problems and less downtime, which can reap havoc for businesses.

While a UPS may function on its own, the SPD is a reliable and necessary sidekick, providing complementary functions in the fight against power failure problems.