Prediction method of power cable insulation remaining life considering the uncertainty of influencing factors

Due to the complex working environment of marine cables, the prediction of residual insulation life of power cables has become a concern. This study mainly discusses the power cable insulation residual life prediction method considering the uncertainty of influencing factors. The aging time points were 0 h, 72 h, 144 h, 264 h, 432 h, 600 h, 844 h and 1152 h. Finally, the elongation at break, the dielectric loss angle of frequency domain dielectric spectrum and space charge distribution are explored. At the beginning of aging, the decline trend of elongation at break curves was gentle, from 510% to 499.6%, 480.6%, and 470.2%. The results show that the difference value of the life prediction method designed in this study is small, which can be effectively used to predict the residual life of power cable insulation.

Influence of Bending Stiffness on Snap Loads in Marine Cables: A Study Using a High-Order Discontinuous Galerkin Method

Marine cables are primarily designed to support axial loads. The effect of bending stiffness on the cable response is therefore often neglected in numerical analysis. However, in low-tension applications such as umbilical modelling of ROVs or during slack events, the bending forces may affect the slack regime dynamics of the cable. In this paper, we present the implementation of bending stiffness as a rotation-free, nested local Discontinuous Galerkin (DG) method into an existing Lax–Friedrichs-type solver for cable dynamics based on an hp-adaptive DG method. Numerical verification shows exponential convergence of order P and P+1 for odd and even polynomial orders, respectively. Validation of a swinging cable shows good comparison with experimental data, and the importance of bending stiffness is demonstrated. Snap load events in a deep water tether are compared with field-test data. The bending forces affect the low-tension response for shorter lengths of tether (200–500 m), which results in an increasing snap load magnitude for increasing bending stiffness. It is shown that the nested LDG method works well for computing bending effects in marine cables.

IMPLEMENTATION OF SEISMIC SURVEY TECHNOLOGIES WITHINTRANSITION ZONES OF THE NORTH OF WESTERN SIBERIA

From the viewpoint of seismic survey, transition zone is a shallow water area where it is impossible to use marine cables because of low depth, there are difficulties in terms of coordination between geophones and environment, usage of explosives is prohibited, usage of air guns is ineffective. And besides, there are in-creased requirements concerning ecological safety. In order to solve this problem it is necessary to use multiva-riant systems of emergence, reception and registration, that is complex usage of explosions, surface sources, air guns, bottom and surface geophones and hydrophones. It is necessary to use overlapping and special technolo-gy for combination of data received from different systems and different field seasons (summer, winter).