Operation characteristics of low frequency AC cable transmission system for urban grid

With the development of urbanization process and the adjustment of industry structure, the contradiction between increasing power demand and constrained land resources has become more and more serious in metropolis of China. Therefore, the research and development of advanced power transmission technology are of great significance for expansion of urban grid. This paper introduces the low frequency ac (LFAC) transmission system, which is more suitable for power cable in urban area. LFAC has the merits of high reliability and high economy, which can efficiently improve the transmission capacity of power cable. In this paper, the operation characteristic of low frequency transmission system based on the frequency characteristic of power cable ampacity, power loss and voltage deviation was performed. Then the selection approach of optimal transmission frequency was proposed according to the above analysis. At last, transmission capacity and efficiency of LFAC transmission system operating at the optimal transmission frequency under different working conditions are verified by a case study. The analysis result shows that LFAC transmission technique is an advanced approach for improving the power transmission capacity of cable lines, which provides an advanced method for the construction and expansion of urban grid.