Abstract: DC transmission voltage levels above 600KV are viewed as very attractive for long distance transmission of large blocks of power from remote generating plants to load centers. Therefore, research in this field has been pursued but up to new primarily for the design of the transmission line. There is lack of information concerning the DC converter station equipament that is subjected to DC stresses.
To overcome this, a project has been initiated to study the critical problems in developing HVDC converter stations for voltages above the present design limit of 600kV. This report present the engineering study part of the project aimed at the determination of the converter station characteristics and DC transmission economic aspects.
Calculations to evaluate the characteristics of the major pieces of equipament for the converter stations are present here. The components that have been considered are: converter transformer, DC filters, reactive compensation equipment power, arresters and by-pass breakers. Insulation coordination aspects have also been addressed. These calculations are used to produce simplified equipament specifications (mini-specs) which are considered as guidelines for contatcts with manufacturers and utilities on this subject and also for collecting information on equipament dimensions, weight and costs.
An analysis of possible converter station lay-out and estimate of the land requirements are also included.
Finelly, the suggestion of an economic transmission voltage level with regard to distance and transmitted power is presented. This determination is based on an over-all economic analysis including costs of the lines, line losses and extrapolaction of present day converter station costs.