关键词: 输电线路, 地线融冰, 热平衡, 椭圆融冰模型, 工程应用

Abstract:

According to the present situation of ice cover of power system in China, combined with the practical experience of ice melting at home and abroad, this paper analyzed the mechanism of ground wire ice melting. On this basis, an elliptic mathematical calculation model was set up for ice-melting, combined with the theory of heat transfer. In the light of the engineering application, the calculation method of minimum ice-melting current was studied. Through the ice-melting current calculation of three kinds of aluminum clad steel wires （LBGJ-100-20AC,LBGJ-120-20AC, LBGJ-150-40AC）, this paper analyzed the impact of ice thickness, wind speed, ambient temperature, ice melting time and other factors on ground wire ice-melting； calculated the relationship between different wire materials and ice melting current. Finally, the proposed calculation model was used to calculate the minimum ice-melting current of ground wire materials commonly used in transmission line engineering. Through the comparison of the calculation results with those results of Bauers Dolf ice-melting current calculation formula which was commonly used in transmission line engineering, it shows that two kinds of calculation results are in good agreement. The analysis and calculation results show that the ice-melting current is determined collaboratively by ice thickness, ambient temperature, wind speed and ground wire material； ambient temperature, ice thickness and ground wire material all have obvious influences on the ground wire ice-melting current, but the influence of wind speed is relatively small. The proposed calculation model of ice-melting current can provide useful and valid reference for the selection of ground wires ice-melting current and the design of defroster.

Key words: transmission line, ground wire ice melting, heat balance, elliptic ice-melting model, engineering application