With the acceleration of the urbanization development process,the application scale of large capacity,long distance and large cross section power cable lines in the transmission network of major cities is on the rise.Due to the limited length of the traditional cable design,the number of cable connectors per unit length is relatively large,which leads to the increase of the investment of the project,and the probability of the operation of the power cable line also increases.This essay will start its research from the large-length power cable design,transfer test,operation and maintenance and other aspects of the study,for large long-term cable induced voltage,partial signal attenuation and other factors,high-voltage power cable to increase the key technology feasibility analysis.The demonstration project of 220 kV Qiuteng-Gaowang line provides the theoretical basis and relevant data for the practical application of cable engineering in the future.