Research on Economic Optimization of Section Areas of Conductors for UHVDC Projects

To meet the demand of electric power growth trend and the energy distribution pattern in China, 30 ultra high voltage(UHV) DC transmission projects in China will be built.Selection of total cross-section and split type for transmission line conductor is an important factor in obtaining good economic benefits during the entire life-cycle of DC power transmission projects. Starting from the accumulative net present value formula, this paper considered two aspects of construction investment and operation loss, studied the impact of line loss hours, on-grid power tariff, line construction cost of DC power transmission projects on conductor economic current density, and derived the calculation formulas of DC power transmission conductor economic current density. By collecting a large number of actual data about construction and operation of projects, completed HVDC projects were calculated. Combining with current construction cost and the price level, the paper proposed that transmission conductor economic current density should be around 0.6 A/mm2for long-term overloaded DC transmission systems.