Study On Vulnerability Evaluation Model Of Overhead Transmission Lines To Landslides

With the development of economy and the ever-increasing of electricity demand,“nationwide interconnection, sending power from west to east, mutual supply betweensouth and north” has become a national strategy of the people’s livelihood engineeringin the new century. In this project, as the backbone of power grid, overhead powertransmission lines have to tramp over hill and dale inevitably, and face all kinds ofnatural disasters, especially landslide disaster. Hence, it is particularly important tostudy the vulnerability of overhead power transmission lines under landslide disaster.Based on the basic theory of vulnerability evaluation, the vulnerability of overheadpower transmission lines under landslide disaster has been researched systematically,and the main research contents are as follows:①Based on the theory and method of risk assessment, the hazard and the factorsof overhead power transmission lines under landslide disaster are analyzed thoroughly,and the vulnerability assessment model for overhead power transmission lines is set upfrom two aspects of hazard and loss.②The risk of overhead transmission lines under landslide disaster is quantifiedand analyzed. Using the binomial Logistic regression analysis, based on the rainfall, thecalculation formula for forecasting landslide probability is obtained. Combined with thespatial structure characteristics of overhead transmission lines, the overheadtransmission line could equal to a serial model. The damage probability model ofoverhead transmission lines under landslide disaster is established, based on thefirst-order bounds method of comell probability theory.③The evaluation model for economic loss of overhead transmission lines underlandslide disaster is set up. The evaluation model of economic losses are divided intodirect economic loss and indirect economic losses. The power supply and equipmentdamage are major considerations for direct economic loss, and the proportionalitycoefficient of population density, GDP of per unit area, damage area and outage time arein the calculation of indirect economic loss, which overcomes the simplistic and roughsolution to define indirect economic loss in a disaster according to the ratio of indirectloss and direct loss.④The landslide disaster vulnerability assessment of “Yanshui972Line” inYunyang county Qingshui Tujia Township has been accomplished. And the failure probability of line under the light rain, heavy rain and torrential rain is calculatedrespectively. The probability value is7.2%in the case of light rain, The probabilityvalue is27%in the case of rainstorm, and The probability value is92%in the case oftorrential rain. With the increase of rainfall intensity, overhead transmission line damageprobability gets significantly bigger, overhead transmission lines are in a extremelydangerous state especially in the case of torrential rain. The economic losses of thisdisaster is35.7million yuan.Under the light rain conditions, the vulnerability rating isclass Ⅰ;under the heavy rain conditions, the vulnerability rating is class Ⅱ;Under thetorrential rain conditions, the vulnerability rating is class Ⅲ.