Electrical energy losses and costs evaluation of HVDC and UHVDC transmission lines

Reduction in electrical energy consumption requires power utilities to employ most efficient ways of electrical energy delivery from generation to distribution infrastructures. For bulk power transfer over long distances improved transmission efficiency is a primary target to ensure less electrical energy losses and costs. Application of conventional HVDC schemes at 500 kV dc is said to be economically substantial up to a power capacity of 3500 MW for a single bipolar system. Increase in the operating voltage and or number of poles is required at increased power levels; and therefore for a power transfer of 6400 MW over a transmission distance of 2500 km a ±800 kV UHVDC bipolar system is utilised. In this paper, the effectiveness of electrical energy losses and costs of UHVDC transmission lines are assessed in comparison with those of ±500 kV and ±600 kV double bipolar systems and single bipolar systems with parallel twelve-pulse converter valve circuits applications.