Thermal Imaging for temperature sensing and Electrical inspection

electrical

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##What is thermal imaging technique?

Thermal imaging is the non-contacting temperature sensing technique. Thermal imaging cameras(TIC) uses infrared radiation sensors and it provides a graphic display of objects in its view according to their temperatures. The thermal imaging technique using the heat given off by an object to produce an image of it or to locate it.

Thermal imaging Cameras uses different colours to show different temperature scale of equipment, hot objects typically registering as red tones and cold objects typically registering as blue tones. The thermal imaging sensor provides the surface temperature, not the temperature within the object.

thermal imaging

A thermal imager can work in environments without any ambient temperature and can penetrate obscurants such as smoke, fogs and haze. Thermal imaging is also useful in performing “energy audits” of buildings and other heated structures, providing a means of revealing points of heat escape through walls, windows, and roofs.

##Working on thermal imaging camera:

A thermal image camera (TIC) scenes the infrared energy emitted, reflected, transmitted by an object with an infrared detector. The detector senses and sends the signal to the signal processing unit, where the output will be an image.

The Image is processed and an output will be provided according to the temperature distribution throughout the object. Finishing the image processing the output is displayed.

##Electrical inspection using TIC:

thermal imaging

Technicians use thermal cameras to inspect electrical appliances and cables. Each equipment has their own temperature distribution on working, and it is sensed and recorded. The instrument and cables are inspected continuously for maintenance when there is a change in temperature distribution the imagery changes and hot spot area becomes more brighter. Thus sensing the error is done without contact and trouble is sensed before it affects the system.

A cross-hair cursor on the display serves to locate a particular spot in the image, which in this case is contrasted against a reference spot chosen in an earlier step. The instrument automatically subtracts the current and reference spot temperatures to give a _delta_T indication

##Applications:

  • Condition monitoring

  • Thermal mapping

  • Nondestructive testing

  • Missing insulation check

  • Liquid level checking

  • Transformer connection check and liquid level check

  • Evaluation of solar panel

  • Leakage, corrosion, level, blockage check-in process plant tanks.

##Advantages:

  • Can sense the faults before it occurs by sensing the temperature change in particular areas.

  • Can measure temperature without contact

  • Immediate temperature sensing and help in fault detection.

  • Capable of catching moving targets in real time

  • Capable of sense in low light

  • Can cover large area

  • Easy to install

  • Wide range for temperature sensing: -50°C to over 2000°C

##Disadvantages:

  • Cameras are expensive

  • Only surface temperature can be measured

  • Cannot be used to sense the objects in underwater

  • Not accurate as contact type temperature sensing instruments