High-voltage testing

Catastrophic failure of high-voltage equipment, whilst uncommon, can cause serious injuries, fatalities and substantial disruption to the site and local community. When an arc flash occurs, there may be several explosions within milliseconds, and the pressure wave from the blast is similar to that of an explosion from a hand grenade.

Arcing, corona and tracking discharge emits ultrasound at the site of emission. Bus bars, circuit breakers, insulators, junction boxes, relays, transformers and switchgear can all be checked whilst on-line and without direct access, as ultrasound naturally escapes through gaps in the air vents and seals, etc.

On oil-filled or resin-cast equipment, we'd recommend the use of a stethoscope module to physically contact on and listen to the internal ultrasound being generated. It is also possible to use a magnetically mounted stethoscope module and extension cable to carry out tests from a safe distance.

Another technology to consider is Transient Earth Voltage detection, which is completely non-invasive and can detect internal partial discharge. Radio Frequency detection is another technique still used at some sites, although it isn't all that effective at accurately pinpointing the source of a problem.

Low-voltage testing

Electrical problems experienced at 440 volts or below can cause process problems and downtime, and potentially result in a fire hazard. Nearly everything gets hot before it fails, which makes infrared an ideal technology for checking low-voltage systems.

Modern thermal imaging cameras are portable and battery-powered, and display a real-time image comprised of invisible heat radiation. This allows operators to quickly scan electrical panels, loose connections, motors and pumps, overhead bus ducts, stand-by batteries and much more.

To compliment an infrared programme, some companies also install thermographic inspection windows, which allow thermographers to quickly inspect live components running behind closed doors, as infrared cameras are unable to see through materials such as steel.