In order to improve the effectiveness and scientificalness of risk assessment of lightning trip-out in power grid and realize the differentiated lightning protection

it is necessary to study the hazard-pregnant environment of lightning trip-out in power grid. Based on 1:50 000 digital elevation model（DEM） and the data of accidents of lightning trip-out on 110 kV and above transmission lines from 2005 to 2013 in Zhejiang Power Grid

the topographic factors of lightning trip-out spots

including elevation

slope

aspect

land use type and river network density are obtained by using the GIS technology. The topographic characteristics of lightning trip-out spots are quantitatively studied. The hazard-pregnant environment evaluating model in Zhejiang Power Gird is established on Analytic Hierarchy Process（AHP） method with elevation

slope

aspect

land use type and river network density as five assessment indices and a hazard-pregnant environment risk zoning map of Zhejiang power grid is drawn. Correlation analysis with the risk distribution of disaster-causing factor shows that the correlation coefficient is 0.451 and the hazard-pregnant environment sensitivity zoning map for Zhejiang Power Grid is reasonable and could be applied to risk assessment of lightning trip-out in Zhejiang Power Grid. From the analysis of the hazard-pregnant environment sensitivity distribution

the high hazard-pregnant environment sensitivity distribution of lightning trip-out in Zhejiang Power Grid is mainly located in the north of northern Zhejiang and the coast of eastern Zhejiang. The low hazard-pregnant environment sensitivity distribution of lightning trip-out in Zhejiang Power Grid is mainly located in the central Zhejiang and the western Zhejiang.