【作者】 王鹤荀；

【导师】 纪玉龙； 孙玉清；

【作者基本信息】 大连海事大学 ， 轮机工程， 2014， 博士

【摘要】 随着船舶自动化程度的逐步提高以及电力推进船舶的出现,船舶电气系统也随之日益复杂,船舶电缆在船舶电气系统中担任着传输能量和信号的重要任务。众所周知,船舶电缆的工作环境复杂,在温度、湿度、机械振动等众多因素的综合影响下,电缆绝缘层材料容易老化,进而导致电缆的绝缘性能下降甚至失效,从而导致船舶电气系统失效,甚至引起船舶火灾。可见,船舶电缆绝缘状态和老化程度直接影响着整个船舶的安全和生产。另外,我国正在服役的老旧船舶众多,其上使用的依然是最初的船舶电缆(丁苯橡胶电缆为主),其绝缘性能的好坏无从知晓。为消除船舶电缆稳定运行中的安全隐患,明确电缆更换时机,就迫切需要对其绝缘老化寿命进行快速检测。在影响绝缘材料的众多老化因素中,温度占主导地位。目前对船舶电缆绝缘寿命进行预测主要是依据GB/T11026和IEC60216标准,在实验室对船舶电缆开展高温加速老化实验,通过测量老化试样的断裂伸长率来推断其在实际使用温度下的寿命。这种方法是破坏性试验,在试验过程中需要从船舶电网中截取待检测电缆；同时需要很长的试验周期才能得到实验结果；另外,船舶电缆穿越不同舱室,其工作环境必然存在差异,这意味着所截取的样品只能代表局部,无法对全船电缆的绝缘寿命进行检测。综上,若能提出一种在线、快速的电缆寿命检测方法,无论是对船舶的安全性还是减少盲目更换电缆都具有重要意义。针对该问题,本文以目前众多老旧船舶上广泛应用的丁苯橡胶电缆为研究对象,尝试建立一种基于硬度的船舶电缆绝缘老化寿命快速检测方法,主要完成了如下几方面工作：(1)依据相关标准,选取135℃、150℃、165℃、180℃四个老化温度点,对新的丁苯橡胶电缆进行加速老化试验,并分别对老化后试样的硬度、断裂伸长率、密度和绝缘电阻等性能指标进行测量,获得了船舶丁苯橡胶电缆绝缘老化的定量规律。结果发现随着老化时间的延长即老化程度的加深,绝缘层硬度增大,断裂伸长率减小,密度缓慢增加,绝缘电阻在老化后期呈明显下降趋势。其中,硬度以及断裂伸长率与其老化程度之间线性关联明显,为对电缆绝缘寿命进行快速无损检测,选取硬度为特征参量。(2)建立了丁苯橡胶电缆绝缘层伸长比、断裂伸长率以及老化交联密度等与其硬度之间的理论模型,阐明丁苯橡胶伸长比、断裂伸长率以及交联密度等与其硬度之间的变化关系。提出剩余硬度保留率概念,参考GB/T11026和IEC60216标准中规定的数据处理方法对所测硬度数据进行了统计验证以及系统分析,进而提出基于剩余硬度保留率的船舶丁苯橡胶电缆绝缘寿命快速检测新方法。(3)参照GB/T11026和IEC60216标准,对丁苯橡胶电缆绝缘寿命快速检测新方法进行检验,结果表明所提出的基于剩余硬度保留率的检测新方法具有与上述标准较高的相符性,不但结果准确而且具有简单快速的优点。并提出以剩余硬度保留45%作为新方法的检验失效标准,即丁苯橡胶电缆的寿命终点。另外绝缘电阻测试结果也从侧面证明了基于剩余硬度保留率对船舶丁苯橡胶电缆绝缘老化寿命进行快速检测的有效性。通过本文的研究工作,揭示了船用丁苯橡胶电缆绝缘层老化规律,在此基础上提出了一种基于硬度的船舶电缆绝缘老化寿命快速检测方法,在应用该方法时,首先需按照文中所述过程建立基于剩余硬度保留率的寿命预测模型(不同电缆模型不同),在实船检验时只需对要检验的船舶电缆绝缘部位进行硬度测试,随后带入相应模型便可得知其剩余使用寿命。这意味着检验人员可以在船上随时对不同部位的船舶电缆进行检验,不需再反复进行取样以及漫长的老化试验过程。更多还原

【Abstract】 With the gradual improvement of the ship automation, as well as the emergence of electric-driven ship, marine electrical systems are increasingly complex. Cables of ship electrical system play an important role of power and signals transmission. It is well known that, the working condition of ship cables is very complex, including high temperature, humidity and mechanical vibration, which accelerate the thermal aging of ship cable. As the thermal aging of cable insulation material going on, insulation status of the cable declines. This results in ship electrical system failure, even causing fire. So, the state of cable insulation affects the ship safety and working. In addition, there are a lot of old ships are on active service. The initial ship cables (styrene-butadiene rubber is mainly used) are still used on these ships. The state of these cables insulation is unknown. To eliminate the potential safety hazard of electrical system, and to define the cable change time, it is urgent to make rapid life prediction of ship cables.Among those factors affecting insulation status of ship cables, temperature is the dominant factor. At present the ship cable life prediction is mainly based on the standards of GB/T11026and IEC60216. High-temperature accelerated aging of ship cable is conducted in laboratory firstly, and then the ship cable life in the actual use temperature can be predicted by measuring the elongation at break of the aging test specimen. But this method is destructive, sample cables should be cut from the ship electrical system; and it usually takes a long time to get the life assessment results. In addition, ship cable pass through different cabins on the ship. So, the working condition for the cables in different cabins is different. This means the sample cable can only represent a small part of the whole ship cable. So, we can not get the life assessment results of the whole ship cable.From the above, a kind of online and rapid ship cable life prediction method is needed. This is important for the ship safety and the time choice to change the cable. In this study, styrene-butadiene rubber (SBR) insulated cable which is widely used on old ship was used as the research object. A rapid detection method to evaluate the insulation thermal aging status based on hardness was developed and tested. Following work was done:Firstly, accelerated aging experiment of styrene butadiene rubber was carried out at four aging temperatures of135℃,150℃,165℃and180℃which were chosen based on relevant standards. Performance indicators of the aged samples were measured, such as hardness, elongation at break, density, and insulation resistance. The test results show that as the aging process goes on, hardness of the rubber increases, elongation at break decreases, density increases slowly and insulation resistance decreases at the end the aging process. Among them, there is a significant liner correlation between hardness and degree of aging. In order to realize the quick nondestructive testing of the life of cable insulation layer, hardness is chosen as the characteristic parameter.Secondly, the mathematical model of hardness with elongation ratio, elongation at break and crossling rate of SBR was developed. The relation of the cross linking rate of SBR cable and elongation ratio with its hardness was illuminated bassed on the model. Based on this, residue hardness retention rate (RHRR) was defined. The hardness experimental data was verified and analyzed based on the standards of GB/T11026and IEC60216. And then, a new rapid life prediction method of styrene-butadiene rubber insulated ship cable was put forward.In the end, based on the same standards of GB/T11026and IEC60216, the new rapid detectioin method was verified. There was a high consistency between the new method and the standards. The new method is accurate, rapid and simple. At the same time, the failure criteria of the new method is suggested to RHRR=45%. In addition, the test results of insulation resistance also proved the validity of the new method.In this study, the agine law of the SBR insulated ship cable was studied. Based on this, a new rapid method to predict ship cable life based on RHRR is developed. When using this method, the life prediction model (different models for different types of ship cable) based on RHRR should be developed firstly according to the process discussed in the study. The cable insulation hardness of the part which is intended to be tested should be measured. Then choose a suitable RHRR life prediction model based on the working condtion. The remaining useful life of the ship cable can be calculated then. This means the inspector can check the insulation status of any part of the ship cable at any time on board. There is no need to sample repeatedly, and the long experiment time is also eliminated.更多还原