Investigation of grounding related problems in AC/DC converterstations

An investigation of grounding-related problems in AC/DC substations is reported. The investigation is based on analytical studies and published experimental results. The following grounding related problems have been investigated: (1) ground potential rise in converter stations and DC grounds and its effect on safety; (2) touch, step, and transfer voltages in and around DC converter stations and DC grounds; and (3) effects on soil thermal stability during monopolar operation. Several conclusions have been reached, and the findings of the investigation are summarized in a proposed procedure for the safety assessment of DC grounding systems