| In 2009,China’s first UHV power transmission project 1000 KV Jin dong nan-Nan yang-Jing men UHV AC test demonstration project put into commercial operation officially,it indicates that China’s UHV power transmission has entered a new era of long distance 、 large capacity and low loss.The UHV power transmission lines distributed in a wide range areas of china,the areas show different climate and geography,the lines will ice because of the action of nature wind under the special climate conditions,finally the shape of transmission wire was changed into non-circular cross section, which is easy to cause the low frequency 、 large amplitude waves and causes serious damage and irreparable economic losses to transmission tower and other important structures.In order to solve this problem,two kinds of single wire and UHV bundled conductors were studied based on the combined method of wind tunnel test and numerical analysis in this paper,the main work is as follows:First,the paper established iced transmission wire model modelled on the reality of iced transmission wire based on the wind tunnel test according to fluid mechanics computing software FLUENT and the model uses two-dimensional model considering the frequent engineering status and the particularity of iced transmission wire.Second,the paper calculated the three component coefficients of two kinds of single wire.and analyzed the diameter of transmission wire which influenced on the three component coefficients of iced transmission wire.Finally,the paper analyzed the attack angle area of two kinds of single conductor gallop based on the den Hartog galloping mechanism and Nigel galloping mechanism.The results show that the drag coefficient curve and lift coefficient curve exists large difference between tine wire and thick wire,but the torque coefficient curve has little difference.The easy galloping region of the real thin iced transmission wire and thick wire model is in α=170°~180°.According to the Nigel criterion, the easy galloping region of the real thin iced transmission wire and thick wire model is in α=10°~50°and α=150°~170°. Compared with real thin iced transmission wire, the real thick iced transmission wire has a larger aerodynamic negative damping zone and negative peak.According to the experimental model to calculate the resistance coefficient and lift coefficient of eight divided crescent ice conductor,the difference of numerical calculation results and wind tunnel test results is small, the accuracy of the model was verified. The paper calculated to get large difference of drag coefficient and lift coefficient curve of the ice free conductor and iced conductor,based on the den Hartog galloping mechanism, it is concluded that the galloping phenomenon of the ice free conductor may not happen; Calculated the resistance coefficient and lift coefficient of the two diameter(30 mm and 40 mm)under the ice conductor as a whole is consistent, the resistance coefficient of the30 mm diameter wire is larger in the Angle of attack of α=50°~130°; Calculated the wind speed effect on drag coefficient curve is obvious, with the increase of wind speed, the impact gradually weakened; The impact on the lift coefficient curve is not obvious.The conductor cross-sectional area 、 the distance between each other and wake interaction have a significant impact on drag coefficient and lift coefficient of each wire.According to the den Hartog galloping mechanism and Nigel galloping mechanism, the factor has important influence of conductor galloping phenomenon occurs.The comparison of the variation of Den Hartog coefficients under wind tunnel test and numerical calculation indicated that the galloping attack angle area are the same,which verified that the numerical calculation could be used to analyze the possibility of galloping qualitatively. |
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