共查询到20条相似文献,搜索用时 31 毫秒
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电力是国民经济的动力,而5.12汶川发生8.0级大地震后,变压器相当于经历了一次超出相应承受能力的破坏性试验,损失严重。为科学了解和分析变压器受灾情况,以确保现有投运变压器的安全可靠运行,有必要对震后变压器的受损程度及剩余寿命进行调研和评估,从而为变压器的全寿命周期管理和安全运行提供依据。该研究把统计学、数值分析、神经网络、管理科学及建筑学等多类学科融入到变压器震后剩余寿命评估中,建立了基于可靠性的变压器震后剩余寿命评估柔性模型。通过对汶川地震后四川省十三个地区变压器震前和震后的数据抽样收集、整理,并结合国内外地震数据库的资料和现场抽样试验方法,计算了失效率寿命分布曲线,为震后变压器的安全可靠运行提供了依据。 相似文献
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提出一种基于层次分析法的变压器剩余寿命预测模型。通过层次分析法建立了变压器试验健康指标体系,并与基本信息健康评估指标融合得到综合健康指数,同时考虑热累积效应、故障缺陷次数等相关因素对变压器健康状态影响的基础上,对变压器健康指数进行修正,采用健康指数老化公式对变压器的剩余寿命进行评估。采用该模型分析和计算某变压器的健康指数、剩余寿命,实例验证表明:该模型具有一定的合理性和有效性。 相似文献
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针对传统单性能退化量的油浸式电力变压器油纸绝缘剩余寿命预测方法难以全面反映油纸绝缘退化行为,且缺乏对多性能退化量间相关性的考虑,该文充分考虑退化过程的随机性和非线性,提出了一种基于二元非线性Wiener随机过程的变压器油纸绝缘剩余寿命预测方法。首先,基于非线性Wiener随机过程建立单性能退化量的油纸绝缘退化模型,刻画油纸绝缘退化过程的随机性和非线性;然后,基于Copula函数建立两性能相关的退化模型,更加全面地分析两性能退化量所反映的变压器油纸绝缘联合退化行为;最后,采用MCMC-Gibbs抽样算法估计模型未知参数,实现变压器油纸绝缘剩余寿命预测。该文以糠醛和甲醇含量作为性能退化量,依托加速热老化实验数据进行实例验证,对比单性能、两性能独立、两性能相关三种情况下的可靠度曲线及剩余寿命预测结果,结果表明,该文所提方法能够更加合理全面地描述退化过程,可靠度曲线更贴近真实结果。 相似文献
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This paper presents novel techniques for life assessment of the insulation of the generator stepup units in power plants. Load and ambient temperatures are two important factors that influence the life of insulation in transformers. Hourly load and ambient temperatures obtained through condition monitoring are used to assess the operating profile of the equipment. Modeling techniques for estimating load factors and the ambient temperatures using the operating history are discussed in this paper. The estimated load factors and ambient temperatures are input to the IEEE life consumption models to assess the consumed life of insulation. A full simulation approach and a renewal process approach have been presented to evaluate the time to failure of the insulation. Estimation of some relevant reliability parameters such as B/sub X/ life, time-to-reach design life, and probability of failure at a given time are also presented. The methods discussed are useful for estimating residual life of insulation to support the repair and maintenance policies of transformers. 相似文献
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XLPE-insulated cables and wires are becoming more widespread. For this reason, it is becoming necessary to control the state of insulation over its total operating life. Online monitoring of the effects on the insulation and determination of its remaining life becomes possible using modern equipment. In this paper, a method of determining the remaining lifetime of the cross-linked polyethylene insulation of the powertransmission line is presented. An insulation-aging model developed at the previous stage of the research was used. It is proposed to control the destructive effects on the insulation and calculate the remaining life based on the obtained data. The results of the research showed that the probability of failure is subject to the normal character of distribution (Gaussian distribution) as the insulation in the process of operation is exposed to a large number of effects (partial discharges, thermal actions, effect of the environmental factors, etc.). The remaining lifetime is defined as a function of inverse failure probability. The proposed method can be used to develop a set of devices for determining the remaining life of polyethylene insulation. 相似文献
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Partial discharge (PD) measurement has long been used as a test to evaluate different insulation system designs, and as a quality control test for new equipment. However, in the past 20 years, PD measurement has been widely applied to diagnose the condition of the electrical insulation in operating apparatus such as switchgear, transformers, cables, as well as motor and generator stator windings. Improvements in the capabilities as well the lower cost of sensors, electronics and memory is partly the reason for the increased popularity of PD diagnostics. Another reason has been the development of methods-including the use of ultrawide band detection-to improve the reliability of the PD measurement in the presence of noise. In addition, rapid progress is being made in automated pattern recognition techniques that also helps to suppress noise. This paper reviews the various PD measurement technologies that have been specifically developed to improve PD diagnostic methods, and outlines how they have been implemented for stators, cables, transformers and switchgear. Areas for further research are also presented. 相似文献
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Gulski E. Smit J.J. Wester F.J. 《Dielectrics and Electrical Insulation, IEEE Transactions on》2005,12(2):223-239
This paper discusses practical experiences in the Netherlands with insulation condition assessment of distribution power cable networks by partial discharge diagnosis and database support. In particular, practical steps are discussed in collecting, analysing and processing the diagnostic data for decision support of utility asset management. 相似文献
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为提高油浸式变压器运行的可靠性及降低其全寿命周期成本,将状态检修引入大型油浸式电力变压器势在必行。由于油纸绝缘的寿命决定整个变压器的寿命,所以完善的变压器油纸绝缘的状态评估方法的建立是变压器状态检修的实现的前提。文中将进化雷达图引入油纸绝缘的状态评估过程,提出了将单指标初步评价与多指标综合评估相结合的油浸式变压器油纸绝缘状态进阶评估方法,并确立了完整的评估流程,实现了对油纸绝缘状态的定性及定量评估。通过算例分析,证明了该方法具有步骤简洁、快捷有效且易于在线实现的特点,为油浸式变压器油纸绝缘状态评估的实现提供了新的思路。 相似文献
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油浸纸绝缘套管作为变压器的关键组件,其绝缘受损会威胁变压器主设备的运行安全。针对此现状,提出一种基于多源融合的油纸绝缘套管缺陷辨识及绝缘状态评估方法。首先,根据实际运行工况制备典型缺陷试验套管,并开展频域介电响应、局部放电及红外热成像联合试验,辨识套管缺陷种类。然后,提取套管绝缘指标量,引入隶属度函数及状态得分算子,建立基于博弈论组合赋权法的套管绝缘状态评估模型。最后,分别采用组合赋权法和单一赋权法的评估模型,对正常以及缺陷套管进行算例分析。结果表明:联合试验可以准确辨识套管缺陷种类。组合赋权法弥补了单一赋权法评估结果片面的不足,且正常套管的模型评估分数均高于缺陷套管。评估结果与套管实际绝缘状态一致,验证了套管绝缘状态评估模型的正确性及有效性。 相似文献
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实现更加贴近电力变压器实际运行状态的评估,对于电网合理、经济、科学安排检修具有重要意义。针对主观、客观权重单一评估或者简单将二者拟合造成整体评估片面性的问题,提出了基于最小方差理论的最优组合赋权方法,使得权重得到更加合理的分配。将雷达图法的特征量计算方法应用到变压器评估中,使得评估结果更加直观、简洁,也避免数据信息在归一化过程中的遗漏。运用该方法对实际变压器数据进行了分析,验证了方法的可行性和合理性。 相似文献
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智能电网的发展对设备的使用效率提出了更高的要求,结合状态检修结果以及传统故障率的推算,提出了设备健康负荷指数的新指标.该指标能够同时反应出设备的健康状态和设备的负载率情况,实现均衡设备健康状态与负荷情况的目标.结合该指标,又进一步对调度策略研究.通过一条手拉手线路算例验证了该指标可以实现变压器负载率能够随着变压器健康状态的变化而做合适的调整,再综合考虑线损率等传统的经济运行指标,实现运行方式优化的目的,对未来的智能调度有一定指导意义. 相似文献
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《电子测量与仪器学报》2015,(11)
为了将回复电压法(RVM)用于评估变压器油纸绝缘的老化状态,通过RVM5461回复电压测量仪对现场变压器进行测试试验,研究不同老化状态下回复电压特征量(回复电压最大值、中心时间常数、初始斜率)的变化规律。针对原有的回复电压特征量无法反映回复电压曲线整体的弛豫信息,首次提出一种能用于评估油纸绝缘状态的新特征量——半峰值周期。该特征量不仅反映了绝缘整体的极化速率,而且与变压器油纸绝缘老化程度有着密切关系。研究结果表明:充电时间影响着回复电压特征量的变化;随着老化程度的加剧,回复电压最大值增加,中心时间常数减小,初始斜率增大,半峰值周期减小。 相似文献