Characterization of Local Environmental Data and Lightning-Caused Outages in the IECo Transmission-Line Network.

The lightning-related outages remain a significant factor affecting overhead-line reliability in the Israel Electric Co. (IECo) Power Grid 170 kV. The estimates derived for years 2000–2013 show that the actual failure rate for some lines does considerably exceed the accepted indices. This paper reports on the lightning study whose primary goal was to examine relevant environmental data, including topography, tower footing resistance, and lightning incidence records provided by the IECo lightning location system. This paper presents long-term monitoring experience and local statistical data patterns gained for cloud-to-ground return strokes. The 295 outage-related flashes (265 of negative and 30 of positive polarity) were identified in the IECo database. The median peak current of the negative and positive flashes causing line outages is -12.0 kA and +26 kA, respectively. The local tower footing resistances are found to be lognormal distributed with a median of 4.77 \Omega and an SD of 1.44. The findings imply that revealed failure currents statistics, in combination with local route topography, are key factors controlling shielding performance of IECo lines. The acquired data will be involved in further case studies on IECo lines. [ABSTRACT FROM AUTHOR]