The CBS ArcSafe® PD Alert safety vest is a newly developed personal safety tool for detecting dangerous levels of partial discharge (PD) in power switchgear and warning the wearer of potential arc-flash danger. The vest incorporates the proven PD Alert system into a functional, wearable format, allowing users to carry PD detection capability with them at all times. If dangerous levels of PD exist in an area, the vest will provide audible, visual, and haptic feedback to the wearer, telling them to exercise great caution to avoid arc-flash-related injury.

PD arises when small charges migrate from high-voltage conductors through an insulating medium and then go to ground. The discharges are indicated by small transient earth voltage (TEV) fluctuations, ultrasonic sound emissions, radio waves, and small amounts of light and heat. A number of different factors can contribute to severity. These include high humidity, moisture or dirt contamination on insulators, and material or manufacturing defects on insulators. As more PD occurs, conductive tracks develop across or through the insulation, allowing the leakage of even more charge. Eventually, this tracking will pass a critical point and an arc flash can take place, endangering personnel and damaging equipment. While spot-checking and periodic testing can catch many insulation PD issues before they become catastrophic, these methods cannot identify every issue, which leaves workers vulnerable to accidents.

The PD Alert vest is intended to fill that gap. Users can wear the high-visibility vest at all times while working around electrical equipment. The vest includes colored lights to indicate status, vibration motors, and a speaker to warn the wearer if critical levels of PD are detected. A 12-hour battery life keeps the vest operating through an entire work shift.

While the vest does not take the place of regular PD testing of equipment, it serves as a critical safety check for workers around high-power systems, determining whether conditions there are safe.