Sustainability and Technical Constraints for HVDC Conversion of HVAC Overhead Lines

Conversion of already existing HVAC backbones to HVDC operation can be an option of interest for increasing the transmittable power. The paper investigates the possibility of using the HVAC pylons and conductor bundles, taking into account actual environmental (e.g. site equivalent severity) and anthropic sustainability constraints such as acoustic noise and electric field exposure of general public. Results show that, in typical application cases in a polluted and urbanized context, the OHL should be rebuilt on, or adjacent to, the existing line route, to attain a significant operating voltage and transmittable power increase. Acoustic noise and electric field exposure of general public are thus expected to be design constraints for the new 500 kV HVDC OHLs in Italy.