To spot electrical faults in fully energised systems, thermal imaging has become the industry standard.
It provides premonition of failure so costly down-time is avoided, which is a huge benefit in the management of critical systems. The early warning the technology provides also helps prevent fire, a factor substantiated by the European electrical contractor, EGI.
This company originally invested in a FLIR T360 infrared camera to meet its customers’ increasing demand for thermal inspection in line with insurance requirements. It is now commonplace for insurance cover to be conditional upon regular thermal inspections in order to minimise both production losses and fire risk.
EGI now counts large industrial companies amongst its list of customers for this service. EGI’s Michael Weigt commented, “Control rooms can include up to 40 electrical cabinets and they have to be inspected every four years. This is not only stipulated by law but is required by insurance companies for fire prevention.”
In his view this approach makes a lot of sense as old cable coating can become porous. External factors such as UV radiation can also cause changes to the plastic coating making it more brittle and prone to breakage. In addition to this, contact points oxidize and fuses become overloaded.
The FLIR camera detects these problems immediately whilst the system is under load so their replacement can be scheduled during the next planned shutdown.
EGI also uses FLIR thermal imaging to detect asymmetrical loads and the reason for this is not always faulty modules. If an older system is extended over time, the upgraded electrical circuit can be exposed to a greater load than was originally intended. This requires immediate action as excess load can generate heat and pose a fire hazard.
FLIR thermal imaging has become such an important part of the EGI business that the company has recently upgraded its thermal imaging hardware to take advantage of the latest detection technology. It recently took delivery of a new FLIR T440, a feature of which is Multi Spectral Dynamic Imaging (MSX).
The benefit of MSX is thermal image detail in real time, while allowing easier target identification without compromising temperature data. Unlike traditional thermal fusion that inserts a thermal image into a visible light picture, FLIR MSX embeds digital camera details into thermal video and stills.
A 25° lens is standard with this camera but as EGI engineers often work in confined spaces, the company specified an additional, interchangeable 45° wide angle lens. Even when the distance to the electrical cabinet is just 80cm, the wide angle lens provides clear detail and a complete image of the target area.
The FLIR T440 also introduced EGI to Meterlink. This makes it possible to transfer, via Bluetooth, the data acquired by an Extech clamp meter to the corresponding thermal image. Speedier inspection is the result as all values are automatically included in the inspection report.
“We used to note the values of a clamp meter separately and allocate them to the thermal image later on,” explained technician Andre Bacht. “And this posed the risk of mistakes.” Meterlink eliminates this risk and it is complemented by integrated wireless LAN that allows thermal images to be transferred to a PC or mobile device.
