XLPE绝缘电缆可靠性与寿命预测算法研究

发布时间：2019-01-10 09:19

【摘要】：20世纪70年代以来，我国在交联聚乙烯（XLPE）电力电缆的生产和应用方面得到了快速的发展。随着电缆数量的增多及运行时间的延长，XLPE电缆的老化故障频繁，存在重大安全隐患，甚至造成停电事故，给生产和人民生活带来诸多不便，并造成重大的经济损失。因此，开展XLPE电力电缆的寿命预测研究，对于制定恰当的维护检修策略，判断电缆何时进行更换，保证电网的安全稳定运行有着重要的安全意义与经济价值。经发现，电缆投入运行后，绝缘层会受到电、热、机械力、环境等因素的作用而发生绝缘老化，导致电缆失效。因此为了评估电缆寿命，对绝缘材料的老化分析研究是非常有必要的。本文首先综合分析了各种因素所导致的电缆绝缘老化现象与老化机理，及其对电缆安全运行的影响。然后，对电、热单独应力作用下的电缆绝缘老化寿命模型与加速老化试验原理进行研究，在此基础上分析了多因素老化的协同作用，对比研究了描述联合电热老化的诸多模型，及其对电热协同作用的表示方法。通过对电缆故障原因的统计分析发现，除绝缘老化外，外力破坏与安装不当等原因造成的电缆故障也占很大比重，并且使得电缆在到达绝缘寿命前就已经发生故障。因此，为了正确评估电缆的实际运行寿命，提供有实际价值的决策信息，除了考虑电缆绝缘寿命，还需要结合电缆运行中的可靠性进行评估。本文通过对XLPE电缆绝缘寿命与各老化应力之间的关系、多因素老化模型、电缆故障分析以及电缆可靠性进行了研究，提出了一种新的基于可靠性的电缆寿命预测方法，给出了XLPE电缆寿命预测指标体系与系统模型。根据失效数据的概率预测以及电缆的老化特性，建立了基于Weibull分布的电缆可靠性模型，并对模型参数进行研究，针对电缆失效的小样本情况，采用LS-SVM回归方法进行参数估计，并与常用的最小二乘法进行比较。最后通过对8.7/10KV XLPE电缆进行寿命预测与可靠性分析，验证了绝缘老化寿命模型与可靠性模型的有效性，积累了一些经验，，为实际应用奠定了基础。
[Abstract]:Since the 1970s, the production and application of XLPE (XLPE) power cables have been developed rapidly in China. With the increase of the number of cables and the prolongation of operation time, the aging faults of XLPE cables are frequent, and there are serious hidden dangers of safety, even leading to power outages, which bring inconveniences to production and people's lives, and cause great economic losses. Therefore, the research on life prediction of XLPE power cable has important safety significance and economic value for making proper maintenance and repair strategy, judging when to replace the cable and ensuring the safe and stable operation of power grid. It is found that when the cable is put into operation, the insulation layer will be subjected to electrical, thermal, mechanical, environmental and other factors, resulting in insulation aging, leading to cable failure. Therefore, in order to evaluate the cable life, it is necessary to analyze the aging of insulation materials. In this paper, the aging phenomenon and mechanism of cable insulation caused by various factors and its influence on the safe operation of cable are analyzed synthetically in this paper. Then, the aging life model and accelerated aging test principle of cable insulation under the action of electric and thermal single stress are studied. Based on this, the synergistic effect of multi-factor aging is analyzed, and many models describing combined electrothermal aging are compared and studied. And its expression method for electrothermal synergism. Through the statistical analysis of the cable fault reasons, it is found that the cable faults caused by external force failure and improper installation also account for a large proportion in addition to the insulation aging, and make the cable fault before reaching the insulation life. Therefore, in order to correctly evaluate the actual operating life of cables and provide valuable decision information, it is necessary to evaluate the reliability of cables in combination with the insulation life of cables. In this paper, the relationship between insulation life of XLPE cable and various aging stresses, multi-factor aging model, cable fault analysis and cable reliability are studied, and a new method of cable life prediction based on reliability is proposed. The life prediction index system and system model of XLPE cable are presented. According to the probability prediction of failure data and the ageing characteristics of cable, the reliability model of cable based on Weibull distribution is established, and the model parameters are studied. The LS-SVM regression method is used to estimate the parameters, and the results are compared with the usual least square method. Finally, through the life prediction and reliability analysis of 8.7/10KV XLPE cable, the validity of insulation aging life model and reliability model is verified, and some experience is accumulated, which lays a foundation for practical application.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM247

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