Research On Frequency Domain Dielectric Spectroscopy Of Insulation Of Marine Power Cables

In the ship power system, the marine power cables play a pivotal role. They transmit and distribute power to the electrical equipment. With the rapid development of the technology, the automation level of the modern ships becomes more advanced. Therefore, the safe navigation of ships is directly determined by the safety and stability of marine power cables. Ships travel on the sea for many years, which makes the working environment of the marine power cables quite harsh. After long term affected by moisture, heat, vibration and other factors, the insulation of the power cables is bound to be worse, this will make the insulation fault occur. If the fault couldn’t be found immediately, it may cause fire or even more serious accident. Therefore, the study of the insulated state of marine power cables has a great significance.Most of the common methods, used to detect the insulated state of the power cables, are the destructive methods. There will be some damages to the power cables during the detection. Because of this, this paper proposed a new detection method-the frequency domain dielectric spectroscopy method. It made use of the dielectric spectroscopy to analyze the insulation of marine cables, to find whether there was something wrong, in order to provide theoretical support for the latter maintenance or replacement work.Firstly, on the basic of the dielectric behavior of the insulation, dielectric response of the dielectric in electric field was analyzed in time domain and frequency domain. The relaxation phenomena of the dielectric response were also explained by using the knowledge of physics related. The complex dielectric permittivity was introduced to analyze the dielectric behavior as well as dielectric loss tangent. Secondly, this paper presented a mathematical equivalent model of the marine power cable. The relevant electrical parameters in the model were calculated. Also the insulated state of the marine power cables was simulated by using Matlab. Finally, some related experiments were taken by using the instrument IDAX300. The results were compared with the theoretical results, in order to assess the feasibility of the frequency domain dielectric spectroscopy method.Through the research and demonstration of this article, it was found that the frequency domain dielectric spectroscopy method was effective and accurate. Using this method to assess the insulated state of the marine power cables can reflect the insulation of the cables. And this method can qualitatively and quantitatively analyze the insulation. Therefore, the frequency domain dielectric spectroscopy is an applicable, new, effective and non-destructive method proposed to assess the insulated state of marine power cables. It has a major military and real economic value to ensure the safety of both the ship and the entire crew.