CORONA CAMERA USER MANUAL
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9-1 What is Corona?
Corona discharges in the high electric field region of an insulator are linked
to an ionization process involving the continual transfer of electrons being
knocked from orbit and recaptured. This phenomenon releases energy in the
form of photons, which manifests as a glow commonly observed on some power
infrastructure during low light conditions. Interestingly, this glow can also be
detected during daytime using a solar blind UV camera.
The ionization process is initiated by a high local electric field, which causes the
excitation of Nitrogen molecules and leads to the emission of UV radiation. This
UV radiation falls within the range of 230 nm to 405 nm.
As the ionization process progresses, ionized Nitrogen reacts with other
components in the air, forming corrosive nitric acid and ozone. This buildup
of ionization becomes problematic when an electron gains enough speed to
exceed a critical value, resulting in increased coronal activity. Consequently, the
buildup of corrosive substances can lead to the corrosion of wires and insulators
in power infrastructure.
Understanding the mechanisms behind corona discharges and their effects
is essential for the maintenance and longevity of power systems. The ability
to detect and monitor UV radiation emissions, as achieved with ICI’s Corona
Camera, offers valuable insights into these processes, even during daylight
hours. By managing and mitigating the ionization-induced corrosive effects, the
reliability and safety of power infrastructure can be significantly enhanced.
9-2 Where does Corona Occur?
Corona devices play a crucial role in detecting corona, partial discharge, and
arching in electric grid components. Various factors can lead to corona, such
as the degradation of polymer insulators, corrosion, physical damage to
components, broken strands, loose hardware, and faulty ground connections.
Additionally, environmental factors like pollution, dust, or dirt accumulation on
the insulators can contribute to corona occurrences.
The locations where corona most commonly appears are on points, along
sharp edges, and inside cavities. Detecting corona in these areas is essential
for maintaining the integrity and reliability of the electric grid and preventing
potential issues that may arise from the phenomenon. With the help of corona
devices, these problem areas can be identified and addressed promptly, ensuring
the smooth operation of the power infrastructure.
9.
Fundamentals of Corona Discharge
