The influence of mechanical stress on cable service life-time

On-line monitoring and analysis of the dielectric loss in cross-bonded HV cable system

“…It was noted in [2] and [18] that, as a result of moisture deterioration in XLPE insulation, DL factor shows an increasing trend due to the decrease of the insulation resistance. In other insulation deterioration, such as thermal deterioration [19], mechanical deterioration [25], oxidation deterioration [24], radiation deterioration and electrical deterioration [23], the indications are that insulation capacitance does not change much during the deterioration. Increase in the DL angle results from decrease in the insulation resistance, such as in the case of water tree aging due to moisture deterioration.…”

Analysis of Thermal and Mechanical Properties of Cable Insulations Designed for Operation under Emergency Conditions

“…The 50 % limit is the most frequently used acceptance criterion for LOCA cables qualification. [15] On the other hand values of elongation at break of thermoplastic material (HELB) decreases in whole temperature interval. The first decrease is not too noticeable, but the next one is steep and at 60 °C materials amounts to only 30 % of initial value of elongation at break.…”

Electrical and Mechanical Condition Assessment of Low Voltage Unshielded Nuclear Power Cables Under Simultaneous Thermal and Mechanical Stresses: Application of Non-Destructive Test Techniques

“…The functionality and integrity of cables are tested by qualification. The NPP cables should undergo a qualification process to ascertain their intended function not only during the normal operation of NPPs but, also during the design basis events (DBE), such as loss of coolant accident (LOCA) [16]- [18]. The 50% elongation at break (EaB) is an acceptance criterion for the assessment of NPP cables insulation.…”

“…This work aims to extend the knowledge of the dielectric response analysis, the return voltage measurement as well as, the assessment of the mechanical properties of low voltage unshielded cables which are promising tools for the lifetime management of polymeric insulations in NPPs. Most of the studies use irradiation and elevated temperature for accelerated ageing, however some locations at NPPs, the bending radius of cables reaches critical values and the effect of mechanical ageing can be significant [18]. The presented work investigates the whole insulation of low voltage power cables used in nuclear facilities under simultaneous thermal and mechanical stresses since the entire cable has been subjected to an accelerated aging tests where both the core insulation and outer jacket were kept intact.…”