Simulation of Charge Carrier Movement for Emulating Conductivity Measurements of Mineral Oil Under DC Stress

HVDC transmission technology is state of the art in transmission of large amounts of energy over long distances. While AC technology is reaching its limits in terms of cost-effectiveness and losses, HVDC technology plays a key role in this area. With HVDC, it is possible to transport large amounts of energy economically and with low losses over long distances. However, the use of this technology also involves new challenges in the field of insulation coordination. Due to the mixed stress consisting of alternating and direct voltage, the equipment must be redesigned and reviewed. Thus, the conductivity undergoes a new significance due to the DC voltage application. The conductivity is the essential parameter in the design of equipment which experiences DC stress. The results presented here treat the conductivity of mineral oil. In addition to the presentation of the field stress dependent conductivity for a 2 mm oil gap, the conductivity is predicted by an Ion-Drift-Model. For the prediction of the conductivity, the knowledge of the charge carrier movement is elementary. For this reason, a model conception is presented, which allows to simulate the charge carrier movement.