New Enhanced High Current Winter Lightning Detection Capability

Electric power transmission systems depend increasingly on lightning location information in the design, monitoring and maintenance of their operations. High current lightning strokes are a significant threat to the dependability of electric power transmission, because they can do severe damage to power lines. Being able to detect and locate these events means savings in both time and money as the fault locations can be found more quickly, and electricity can be re-routed to a different path.

In Japan, lightning events along the coast of the Sea of Japan during the winter months emit particularly different waveforms than the majority of other lightning events, which makes them hard to detect or classify properly. To address this problem, Vaisala (Finland) has worked together with Tohoku Electric Power Company and Sankosha Corporation to develop improved lightning sensor software. The result of the joint R&D effort is the Vaisala Thunderstorm CG Enhanced Lightning Sensor LS7001, which delivers double the detection accuracy of high peak current winter lightning discharges compared to older sensors.

New Parameters to Detect Different Electromagnetic Waveforms
The significant improvement in the high amplitude detection performance was achieved by studying electromagnetic waveforms generated by winter lightning and then developing new parameters for their detection. The LS7001 is able to continuously sample and process detected signals eliminating the dead time problems of previous sensor generations. Enhanced self-test and calibration capabilities permit the simulation of more complex waveforms and help achieve a significant improvement in stroke time measurements.

As a part of the cooperative research project, a six sensor network of LS7001 sensors was deployed in the Tohoku region during the 2009/2010 winter lightning season. Data from Lightning Electromagnetic Pulse (LEMP) recording equipment operated by Tohoku Electric Power Company and information from lightning caused failures in Tohoku’s transmission line systems demonstrated significant improvements in lightning detection performance (*).

The project will continue through the 2010/2011 winter lightning season. The algorithm updates employed in the reprocessing will be implemented in sensor software, which will be downloadable into most existing LS sensors, making improved detection performance available for energy and power industries around the world.