Using iNocturn SUV to ensure 24/7 availability of critical electrical infrastructures

Such infrastructures are regularly inspected and maintained to ensure the required level of availability. However, some defects might be hard to detect and will eventually lead to a service disruption. This is particularly true for defects such as electrical discharge or Corona effect, which affect electrical components exposed to dust, humidity and solar radiation. The combination of those three environmental troublemakers slowly causes permanent damages on insulators. At some point, the conductive part of the electrical cables will be in direct contact with the air and will lead to an ionization of the surrounding air (Corona effect) and finally to electrical discharges. Those phenomena produce very low light emission in the UltraViolet (UV) spectrum, which can be detected by ultra-sensitive sensors such as Photonis iNocturn SUV.

SUV camera : iNocturn’s specifications

Photonis unique solution, the iNocturn SUV camera, combines a Photonis scientific grade deep UV image intensifier tube (IIT) with the Nocturn, a camera built around Photonis low light Lynx CMOS.

Exploded view of the SUV iNocturn, with the IIT (three first components from the left) and Lynx CMOS (on the right)

The UV Image Intensifier Tube amplifies the light signal more than 100,000 times. The amplified signal is then collected by Photonis ultra-sensitive CMOS, enabling the iNocturn SUV to be single-photon sensitive into the UV spectrum, without the need for the long exposure time meaning that any detection of events will be in real-time.

As the solar light which hits the Earth surface still includes a lot of UV radiation despite the natural shielding of the atmosphere, the detection of luminous signal emitted by electrical defects is hardly impossible, being much lower than the natural UV light.

For electrical infrastructures located inside a building, UV light coming from the sun does not affect the detection of electrical defects such as Corona or electrical discharge by the iNocturn SUV.

For outside detection of the same defects, using the iNocturn SUV in combination with a solar-blind filter – an optical filter which cuts light coming from the sun – is mandatory to detect any electrical defects.

Thanks to Smart Tube Management, the iNocturn SUV is compact and light, which make easier its integration into larger devices.

SUV camera : iNocturn’s application

A combination of the iNocturn SUV with a solar-blind filter and a 25mm UV lens was used in an outside electrical substation located near Paris. The weather was cloudy with some rain from time to time. To know in which direction the iNocturn SUV was looking at, a side-by-side standard day camera were also used. Images coming out of both cameras were then fused to precisely locate electrical defaults.

The setup was efficient enough to successfully detect electrical discharges in the substation, like the one displayed below.

Detection of an electrical discharge (red dots) at the extremity of an insulator

The iNocturn SUV is particularly well adapted to the detection of electrical discharge because it features :

• A high sensitivity in the UV spectrum, even if used outside,
• A capability to display events in real-time, without the need for long exposure time.

Thanks to those capabilities, the SUV iNocturn can also be used during manufacturing processes of electronic appliances such as batteries to detect any electrical defects and avoid dramatic consequences of fire or blast.