Effect of dry zone formation around underground power cables on their ratings

Thermal analysis of high‐voltage cables with several types of insulation for different configurations in the presence of harmonics

“…As the thermal resistivity of the soil may vary under loading conditions due to the dissipated heat from cables, the cable ampacity is estimated at different cable configurations under different test conditions. The ampacity of the cable is calculated for both average moisture soil (1.2 K.m/W) and dry soil with low‐moisture content (2.45 K.m/W) at different ambient temperatures ranging from 25°C to 55°C [29]. The unfavourable effect of dry zones formation around the underground power cables under loading conditions due to the migration of soil moisture on cable ampacity is also studied.…”

Optimizing of the underground power cable bedding using momentum-type particle swarm optimization method

“…The computations, presented in this paper, do not include directly the dry zones formation effect in a vicinity of cable [8] that can cause a rapid increase in cable core temperature. Therefore, for a given temperature, the corresponding q v values calculated from Eq.…”

“…However, water existing in pores may locally evaporate in the immediate vicinity of the cable thus the socalled 'dry zones' are created. Dry zones are usually formed around underground power cables under loading conditions due to the moisture migration within the soil [8]. The presence of dry zones around the cable results in a significant soil thermal conductivity drop since the thermal conductivity is over 20 times lower for a vapor than for liquid.…”

Investigations of cable termination thermal analysis under continuous current loading

“…The thermal analysis of the underground power cable and its combined accessories is an important subject, which has received extensive research in the present years [1–4]. The maximum current carrying capacity of the underground power cable is affecting by numerous factors such as the cable construction, ambient condition, the cable buried depth, method of laying, dry zone formation around the cable, used joints and termination types and the soil thermal characteristics [5–9]. The unsuccessful choice of all these factors, according to standards, reduces the underground cable capacity up to 40% of its rated capacity [3].…”