Striking a Limit on Lightning Costs
Up to 30% of all power outages are attributable to lightning, at a cost of almost $1 billion annually, say researchers at the Electric Power Research Institute (EPRI). One new product designed to help limit resulting equipment damage combines wireless technology with a battery backup system to take connected PCs and other machines offline when threat arises.
Up to 30% of all power outages are attributable to lightning, at a cost of almost $1 billion annually, say researchers at the Electric Power Research Institute (EPRI). One new product designed to help limit resulting equipment damage combines wireless technology with a battery backup system to take connected PCs and other machines offline when threat arises. And research now underway is looking at transmission-tower designs that could help dissipate lightning-related surges more effectively.
Storm Shelter Electronics, based in Savannah, Ga., expects to introduce its StrikeUPS this summer. The device incorporates a wireless pager set to receive alerts from the National Lightning Detection Network, a private network of lightning sensors. When the network sends an alert that lightning has been sensed in the area, the device switches connected equipment to a battery backup capable of providing up to 45 minutes of power for as many as three appliances. An audible alarm warns that the switch is about to occur, at which point users can override the operation. An all-clear page transfers equipment back to the connected grid power supply.
The manufacturer claims the device can withstand surges of up to 35,000 volts, significantly more than the standard household surge protector. Units are expected to cost approximately $495. Users also will need to subscribe to the National Lightning Detection Network, at $9.95 per month.
To help keep those surges from ever reaching the outlet, researchers at EPRI now are studying new ways to limit the impact of lightning. Scientists are looking at the dynamic resistance of ground electrodes and concrete tower footings, along with the dielectric properties of underlying soils, in hopes of improving current grounding guidelines.
Investigators know that the resistance properties of the concrete footings vary with the magnitude of any given lightning strike. But algorithms attempting to model that variance have, so far, been based on limited measurements and have not accurately represented real-world lightning storms, according to EPRI.
Recent EPRI studies have focused on the electrical properties of various soil types, including sand, clay, loam and crushed rock, to better understand the interaction of soil and electrodes. In addition, researchers measured resistance of full-scale ground electrodes applying current impulses of much higher magnitude than previously used—up to 40 kiloamps.
EPRI will be publishing the findings in a new guidebook for transmission-line grounding systems, scheduled for release this spring. Results also have been incorporated into a new version of the organization's TFlash software, which helps system designers analyze and mitigate lightning's potential effects.