Conductor design of ±1100 kV UHVDC transmission lines based on electromagnetic environment conditions

There is no well-accepted reference for the conductor selection of ±1 100 kV ultra high voltage direct current (UHVDC) transmission projects. Thus, based on the requirements of the electromagnetic environment, the conductor selection and its bundle structure for ±1100 kV UHVDC transmission projects are studied. Adopting calculation and analysis methods that are internationally recognized, practically verified and widely used, including analytical method of synthesis field strength, EPRI calculation method of audible noise, and CISPR calculation method of radio interference, we studied influence of the structural parameters of the transmission lines on total ground electric fields, audible noise, and radio interference. These structure parameters include the splitting number, the sectional area of sub-conductors, the splitting-wire spacing, the conductor elevation to the ground, and the pole conductor distance. It is found that audible noise is the main factor deterring the conductor scheme. Economic comparison is carried out with regard to different conductor schemes that meet the requirements of electromagnetic environment. According to the electromagnetic environment forecast analysis and the economic comparison results, it is concluded that the conductor pattern-JL/G3A-1000/45 with a splitting number of 8-meets the electromagnetic environment requirements while having the lowest annual costs.