A Case Study: Soil Composition, Thermal and Electrical Resistance in the Context of Cable Line Design

The report presents a feasibility study in the context of the preparation of a preliminary design for a wind farm in northeastern Bulgaria. The aim of the study is to make field measurements to establish the thermal resistance of soils at control points along routes where medium voltage cables will be laid. The thermal resistance is a significant factor in the thermal sizing of cable power lines. This is especially critical when the latter will be operated close to their current carrying capacity. In addition, the specific electrical resistance of the soils has been measured, which is necessary for the correct sizing of the grounding installations of the electricity sites. Data on soil thermal resistance and specific electrical resistance was collected in order to seek a correlation between the two characteristics and facilitate and reduce the cost of field measurements.