Welcome to Club NEETRAC: Where Lightning Strikes Twice
by Andrew Kerr
February 2009

In Forest Park, GA, 20 minutes south of downtown Atlanta, there is a place where lightning strikes twice. At the National Electric Energy Testing Research and Applications Center (NEETRAC), artificial lightning is generated to test the durability of outdoor electrical equipment. Items to be tested are brought into the lab, then given a sound whack of lightning delivered by a 2.2 million-volt impulse generator. Part of Georgia Tech’s School of Electrical and Computer Engineering, NEETRAC is supported by 32 equipment manufacturers and utility companies that provide nearly 60 percent of the electricity used in the United States.

Electrical equipment is typically protected by "lightning arrestors." Like a tough club bouncer, lightning arrestors stand between the millions of volts a lightning bolt packs (like a too-big crowd pushing to get inside a trendy club) and the mere hundreds of volts that course through a typical house or apartment (the beautiful people dancing inside the club). And just as you don't want to hire too many bouncers to cover one entrance while another remains unprotected, one needs to determine the smallest number and best arrangement of lightning arrestors to protect the power grid.

“You want to distribute them on the system frequently enough to protect it, but not so frequently that you are wasting money," says Rick Hartlein, NEETRAC’s director. So NEETRAC fires artificial lightning at various configurations of lightning arrestors in order to determine the ideal number and arrangement of those arrestors.

A weird thing about lightning arrestors is that when a lightning bolt hits them they suddenly switch from being electrical blockers (insulators) to conductors. The reason for this is so that they can quickly guide the lightning bolt away from the electrical equipment they are protecting and send it straight into the ground. After they perform this quick change they turn back into insulators again.

A variety of other weather conditions are replicated in the NEETRAC lab, including corrosive salt fog. But for sheer entertainment value Club NEETRAC's fog machines just can't compete with their multi-million voltage light show.

Some elements of this piece appear in this Georgia Tech press release: "Research Helps Protect Against Lightning Damage."