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    Coronagraphy

    Coronagraphy

    Corona :

    • Corona is in UV region ( 240nm to 280 nm)
    • When voltage on an electrical conductor exceeds threshold value, the air around it begins to ionize to form a blue or purple glow. Corona is the polarization of air molecules due to energy on high voltage.
    • When voltage on an electrical conductor exceeds threshold value, the air around it begins to ionize to form a blue or purple glow.
    • Corona is the polarization of air molecules due to energy on high voltage.
    • When Ac potential difference is applied across two conductors whose spacing is large as compared to their diameters and the Pd. is increased then a point is reached when a faint luminous glow of bluish color appears along the length of the conductors and at the same time a hissing noise is heard. This bluish discharge is known as corona.

    This process is accompanied by excitation of Nitrogen molecules and by chemical reactions, leading to:

    • Production of corrosive chemicals like: Ozone and Nitrogen Oxides. At high humidity the oxides will create Nitric acid – a very corrosive material which removes the plating & causes corrosion of steel parts, conductors and insulators.
    • Corona on insulators is an indication of ionization voltage at that point due to contamination or damage, either of which can lead to flashover. Ozone is harmful to human lungs & eyes.
    • Radio interference.
    • Audio noise.
    • Emission of UV radiation.

    Defects due to High Corona :

    Defects due to High Corona

    We are having most advanced daytime corona imaging equipment for predictive and preventive maintenance. The technical features DayCor® camera  superb include:

    • Built in Video recording and image captive system.
    • 512 MB Flash card.
    • USB Card Recorder.
    • 2 Rechargeable 13 V Nimh batteries.
    • Battery house.
    • 1 Smart battery charger.
    • AC, 12 V adapter.
    • MicroPhone
    • Ruggedized transport case.
    • Ofil data base & reporting s/w etc.
    • We have facility of detection of corona in the daytime since this camera can work in solar blind UV band.
    Corona observed at 400 kV

    Corona observed at 400 kV S/s

    Desision chart