Jim Booker wants you to consider these Corona Nuggets:

Transmission Lines:
1. What is the worst factor for corona?
2. What is the second worst factor for corona?
3. What is the corona factor for Relative Air Density (RAD)?
4. Many times a corona source is only an indication of ..
5. What can generate corona on Extra High Voltage (EHV) lines?

Insulation Factors:
1. What can stop corona on EHV insulation?
2. What is the best solution for insulation contamination?
3. What determines the time for action on insulator washing?
4. What is the worst problem with Non-Ceramic Insulation (NCI)?
5. What causes ice flash-overs?

Corona is under the right conditions the precursor to flash-over and sustained arcing. The Relative Air Density (RAD) determines for the same applied voltage when each condition will be present. Ask Dan Ninedorf, Corona Course Coordinator to present the Corona Technology Course for your organization and explain RAD and how to increase the reliability of your transmission and distribution system or the quality of your industrial process.

Technologies to detect corona, flash-over or sustained arcing are based upon the emissions from the source. These sources are variable dependent upon RAD, so the emissions present differ dependent upon the conditions and emission source.

The technologies to reliably detect and locate:
Corona
1. Daylight corona camera all light, night vision camera in low light
2. Audible sound or ultrasound, acoustic thru materials
3. Electromagnetic radiation AM Radio thru UHF

Flash-Over (random arcing)
1. Daylight corona camera all light, night vision camera in low light
2. Audible sound or ultrasound (random is difficult)
3. Electromagnetic radiation AM Radio thru UHF

Arcing (sustained arcing)
1. Daylight corona camera all light, night vision camera in low light
2. Audible sound or ultrasound, acoustic thru materials
3. Infrared camera
4. Electromagnetic radiation AM Radio thru UHF

Electromagnetic radiation is probably the least reliable technology to locate these conditions. One device I have is simply not sensitive enough and the AM radio antenna presents a safety hazard.

Can corona, flash-over, arcing be quantified?
1. NDT Technologies using acoustic and ultrasound has used digital technology to quantify corona, flash-over or arcing energy since 1994. Link at Corona Links webpage.
2. Forsyth Electro-Optics Inc. in November, 2000 introduced an optical corona quantification device that can determine the condition of devices dependent upon emitted energy. Link at Coronalink webpage.

The next CoronaGram will present information about the following
topics:
How much energy is required to produce corona?
What new developments are there in corona detection technology?
What acceptance standards exist to regulate corona emission?
1. For transmission lines and components, substations?
2. For electric motors?
3. For industrial applications?
What test standards exist for corona? Flash-over? Arcing?

Corona on a 500 kV AC Insulator string.