You've heard of Thursday's incident at a Con Edison substation in New York City, which temporarily cut off power at LaGuardia airport and stopped the night sky with glowing a weird aquamarine. We asked ourselves: what did BLAU do?
Con Ed first tweeted a ridiculously subliminal commentary to describe the massive explosion seen by thousands, if not hundreds of thousands of people: at our substation in Astoria, where some electrical transformers were involved and a transfer waste was caused in the environment. "
But this morning, Con Ed said was neither a fire nor a transformer explosion. According to WABC-TV, "The electrical failure of the 138,000 volt equipment caused a sustained arc that was visible over a wide area. The affected equipment was isolated in a single section within the substation.
Arc flashes occur when electrical current flows through a normally nonconducting medium, such as air, on its way between two electrodes. This ionizes the medium and creates an "electric arc" between the electrodes, which is characterized by high current, high temperature and visible lightning – the result of ionization in the medium. This concept is used in arc welding and even in lamps in the late 19th century. Despite other reports, it's not the same as the flash, which is a spark or a discharge. Bows are usually held for a longer period of time.
The blue color was the result of excited air molecules. If you remember the high school, different stimulated gases release different colors. Transformer explosions of the past also led to bluish glow.
"It's a corona," said Peter Sauer, a professor of electrical and computer engineering at the University of Illinois, to Gizmodo. "It always happens when there is a bow. On high-voltage power lines, a bluish light is emitted, which is triggered by corona discharge, especially when it is damp. It is the ionization of the air. "
Basically it's a short circuit in the high voltage line, he said. It could have been caused by faulty insulation, deposits or something else. We will not be sure until Con Ed investigates.
Arc flashes are particularly bright and hot, and companies are using a variety of methods to prevent arcing between the electrodes. Obviously, one of these methods failed yesterday. Although scary, the blue lightning was not aliens and not necessarily so strange. It was just some faulty electrical equipment and a lot of ionized air.