Load cycling of underground distribution cables including thermal soil resistivity variation with soil temperature and moisture content

Investigations of cable termination thermal analysis under continuous current loading

“…The unsuccessful choice of all these factors, according to standards, reduces the underground cable capacity up to 40% of its rated capacity [3]. Many of the authors discussed the effect of these factors on the current carrying capacity of cables and their accessories under steady state and cyclic loading conditions [10, 11]. As it is known, the cable terminations provide the transition from buried insulated cables to the network components such as transformers, distribution boxes and overhead lines.…”

On‐line monitoring device for dry zone formation in the soil surrounding underground power cables

“…The thermal stability around the cable is necessary to keep the cable conductor and insulation temperatures within the allowable limits [1][2][3][4]. Because of the soil temperature increase, the surrounding back-fill soils around underground power cables lose their moisture content, forming dry areas [5][6][7][8][9][10]. This leads to an increase in the soil thermal resistance and decreases the maximum current carrying capacity of the underground power cables.…”

“…Soil thermal resistivity is affected mainly by soil composition, degree of compaction, dry density, gradation, water content and temperature rise [1][2][3][4][5][6][7][8][9][10]. The problem of coupled heat and water flows around buried cables was investigated by several authors [11][12][13][14][15][16][17][18][19][20].…”

Algorithm for load cycling correction to minimise the dry zone influences on the cross‐linked polyethylene (XLPE) cable insulation

“…The soil temperature increase causes the moisture content to migrate and there will be dry zone formation in the surrounding soil. This leads to an increase in the soil thermal resistivity and slow rate of heat dissipation from the cable to the surrounding soil [5–11]. Increasing conductor and insulation temperatures lead to the decrease of the current rating of the cable, since the UGPC conductor temperature is limited by the insulating material type [12, 13].…”

“…The thermal analysis of UGPCs is discussed by many researchers using theoretical and experimental methods [3–20]. IEC 60853‐2 [21] provides a method for determining transient temperature, but unfortunately, this standard ignores the possibility of dry band formation around the UGPC.…”