Design and Study of the Renovation Project to Increase the Capacity of Nanning 220 kV Overhead Power Transmission Grid

The current transmission capacity of power grid is no longer be able to cope with the demand with increas-ing power loads.At present,the power transmission by new type of conductors is going to be matured both theoretical-ly and practically.Use of large size conductors and heat-resisting conductors in power grid renovation can not only greatly increase the transmission capacity but also reduce land requisition and meet the requirement for city construc-tion as well.In this paper,the technical level and application in electric engineering of the power transmission by large size conductors and heat-resisting conductors are presented.The work principle,characteristics,advantages and scope of application of these two types of new conductors are discussed.An engineering design to increase the capaci-ty of power lines was carried out taking the Lingwu line in Nanning 220 kV overhead power transmission grid as an ex-ample.Comprehensive comparison was made between the large size conductors and heat-resisting conductors in terms of static and dynamic investments.Finally,an optimized program for the renovation to increase the capacity of Lingwu line was put forward based on the minimum annual cost method.