Optimised conductor and conductor bundle solutions for long distance HVDC transmission

Early indications are that HVDC will be the technology of choice for the transmission interconnection into Africa. The dominant reasons being the quantities of power to be transferred, the length of the interconnection and the minimising of heating losses. Thus far the highest operational voltage used is the plusmn 600 kV Brazilian Itaipu system. For economical bulk power transfers over several thousand kilometers, calculations have shown that voltages of the order of plusmn800 kV must be considered and power transfers of 6 GW over 4500 km can be realised within acceptable voltage limits and heating losses. For long distance HVDC transmission, the conductor costs will be a dominant component in the total costs of the scheme. The paper presents the results of an initial review of the parameters of HVDC schemes (losses, electric field effects, corona, RI, AN, CL, current densities and voltage drops). An optimisation methodology of the conductor design parameters that will impact on the conductor technology being deployed on long HVDC lines at different operating voltages are discussed in the paper