Theoretical And Experimental Study On Residual Life Prediction Of Shipboard Low-voltage Cable

With the acceleration of global economic integration and prosperity of world trade, vessels have become indispensable tools for defense operations at sea, and for passengers and cargo transportation. Shipboard cable, responsible for the transmission of electrical energy and signals, is an integral part of the marine electrical system. As we all known, under the influence of multi-factors, the insulating materials can be easily damaged, resulting in the decline and even failure of the insulation, thereby affecting the safety and stability of the marine electrical system, replacing the cable can to be an approach to deal with the issues. Because of the high cost, complex process, cable replacement is very expensive and onerous. How to reduce the blind replacement cable is the main purpose of this study, how to effectively predict the residual Life of the marine cable is the scientific problem to be solved. From the aging mechanism of marine cables, using a variety of methods to predict the residual life of the marine cable, and reduce the blind replacement of the cable to ensure the safety of the ship. Major achievements are as follows:Firstly, according to the international standards, Ethylene Propylene Rubber (EPR) cable and Styrene Butadiene Rubber (SBR) cable were given the hot air aging tests in the thermostat drier. The aging time lasted for two thousand hours, and138aging samples of SBR and492samples of EPR were collected and630sets of experimental data were analyzed.Secondly, the chemical reaction rate was used to depict the shipboard cable aging mechanism under the influence of temperature. Based on the first order dynamic model, the second order dynamic model was introduced to describe the cable aging process. TTSP theory was led to verify that the mechanism of accelerated aging and that of normal aging were of no difference. Moreover, an improved model based on the second order dynamic model and TTSP for cable thermal lifespan prediction was proposed, which took full advantage of the experimental data collected at varying temperatures. TTSP displacement factor aT was adopted to predict cable lifespan at extrapolated temperatures. Thirdly, by constructing an aging experimental system and collecting the aging data, the impacts of temperature and concentration of oil mist on cable lifespan were discussed systematically for the first time. Based on the nonlinear regression theory, a model for prediction of cable lifespan under the influence of temperature and oil mist was built and tested. The technical data of the EPR cable was used to testify the correctness of the model.Fourthly, by applying the Grey Theory, an unequal GM (1,1) model has been constructed to predict the cable lifespan. Furthermore, parameter a GM of the improved PSO-based grey model and inertia weight c0were brought in to improve the prediction accuracy and increase search speed. The accuracy of the model was tested by the technical data of the SBR cable.