DC electric fields in HVDC stations

The paper considers aspects related to DC electric fields and their limitation as a part of measures towards safety in HVDC converter stations. It is shown that the existing traditional approach based on DC electric field limitation on DC transmission lines crossing open public areas where human beings can be affected by long term exposure to electric fields is not applied to HVDC converter stations where only occupational personnel has limited access to and no public is permitted. Given that, it is recommended that assessment of risks (if any) associated with electromagnetic field exposure to occupational personnel involved in operational and maintenance activities shall be based on assessment of the assigned works and tasks according to recommendations of HVDC manufacturer and world-recognized best practices of safe maintenance in HVDC converter stations. Instead of introducing of exposure limits for DC electric fields making the compact design solutions complicated, the alternative ways and work methods for providing occupational safety are proposed together with the advances in the safe maintenance approaches as well as the latest achievements in digital maintenance and diagnostic technologies. Implementation of the available safe maintenance techniques makes possible to completely avoid the DC electric field exposure from consideration.