基于时间延迟理论的海上风电机组不定期检修策略

由于海上环境特殊,海上风电机组发生故障时适宜采取部件整体更换方式。实施状态检修选取合适的更换周期是降低运维成本的一个有效策略,但海上状态监测和健康诊断等技术还不够完善。针对此问题,以海上风电场运维日志为基础,借鉴状态检修中设备存在潜在故障—功能故障间隔的思想,将时间延迟理论引入海上风电机组维修中,对部件从潜在故障到功能故障的发展规律进行建模,并在此基础上提出一种适用于海上风电机组的不定期检修策略,优化部件更换周期。案例分析表明,所述方法能够确定一组最优的运维策略,使部件单位运行成本期望值处于一个较低水平,同时灵敏度分析结果能对优化出的策略进行运行风险评估。     

计及劣化状态和随机故障的光伏发电系统视情维修模型以及最优检修策略

针对现有光伏发电系统维修策略研究中通常仅考虑劣化状态导致维修决策不合理等问题,提出了一种计及劣化状态和随机故障的光伏发电系统视情维修模型及最优检修策略。首先,以离散状态下的Markov过程为基础,将随机故障对维修策略的影响引入到光伏发电系统视情维修建模中,建立光伏发电系统计及劣化状态和随机故障状态的视情维修模型,定期检测光伏发电系统的状态。当系统状态超过预防性维修阈值时进行不完全维修;出现随机故障时进行最小维修;达到故障状态时进行更换。然后,以光伏发电系统长期稳定运行的最小总成本率为目标,采用一种改进的黏菌优化算法求取光伏发电系统最佳检测周期和预防性维修阈值。最后,以某光伏发电系统为例,通过对模型参数的灵敏度分析和传统不考虑随机故障维修模型的对比研究,验证了所提模型及策略的有效性和可行性。     

电力系统停电检修的工作流程

正电力系统检修任务按工作性质、内容及范围,可以划分为A、B、C、D四类检修。其中A、B、C类是停电检修,D类是不停电检修。A类检修是指设备的整体解体性检查、维修、更换和试验;B类检修是指设备局部性的检修,部件的解体检查、维修、更换和试验;C类检修是对设备常规性检查、维护和试验;D类检修是对设备在不停电状态下进行的带电测试、外观检查和维修。     

基于可及度评估的海上风机机会维修策略

海上风电机组的维修费用较高,在一定程度上限制了海上风电产业的发展。针对此现象,提出一种将故障维修与预防性维修相结合的机会维修策略。考虑海上天气情况对维修活动的影响,采用马尔科夫法和动态时间窗描述海上天气状况,提出可及度指标评估海上风电机组维修的可及性。运用蒙特卡洛法模拟部件的随机故障,并选择合适的周期,以周期内成本期望值最小为目标,对仅考虑更换措施以及考虑不完全维修、更换措施的机会维修策略的维修阈值进行优化。以某海上风电机组为例进行仿真,结果表明,考虑不完全维修、更换措施的机会维修策略对降低海上风电维修成本的效果更为可观,从而证明该策略的有效性。     

电力设备机会维修决策模型

状态检修背景下,针对具有2类故障(突发性故障和劣化故障)的电力设备,深入研究故障间相互关联引起的风险对设备检修决策的影响,将设备突发性故障情景的处理有机融入其中,提出设备机会维修决策的数学模型。该模型从不同类型故障的失效规律出发,建立马尔科夫过程描述设备的状态转移过程。进一步,在机会维修策略引导下,推导了设备风险和系统运行风险的解析表达。最后,以设备风险和系统运行风险二者之和最小为目标,构建设备机会维修决策模型,并基于成熟的遗传算法予以求解。算例分析表明,该模型能够充分反映机会维修对设备性能以及系统运行性能的影响,为优化设备检修策略提供必要的理论基础。     

发电设备点检周期模型

给出了点检定修策略的技术内涵以及适用性准则。针对目前发电设备点检周期决策缺乏理论支持、只能依据经验进行判定的现状,基于延迟时间模型理论,以设备潜在故障状态以及P-F间隔为出发点,建立了单部件系统点检周期决策的费用模型及风险模型。考虑不同故障模式导致的后果和企业的风险偏好,以平均单位时间检修费用最小化为目标,建立了点检周期决策费用模型;以功能故障发生的风险小于可接受水平为目标,建立了点检周期决策风险模型。所建立的模型适用于单部件系统精密点检以及解体点检周期的决策问题。给出了实际应用算例,证明了点检周期决策模型的有效性。     

基于整体优化的状态维修策略与实践

介绍大连供电公司在设备维修策略方面所进行的探索及所取得的经验。实践表明．通过网络化的计算机综合管理信息系统(MIS)，对设备状态进行跟踪管理和趋势分析，可早期获取设备劣化信息，为适时地对设备进行适度维修提供依据．可避免某些故障的发生。认为制定基于电网整体优化的维修策略，才能有效减少诸如变压器烧损这类突发性故障的发生。多级电网实时信息的集成将使运行电网的优化成为可能。     

一起风电场110kV变压器接地故障分析及诊断

某风电场110kV#1主变投运后频繁出现轻瓦斯报警，最终导致重瓦斯、压力释放阀动作跳闸故障。结合现场检查、试验、油色谱分析结果及解体检查情况，分析认为，#1主变低压绕组存在绝缘缺陷，长期带缺陷运行过程中，缺陷劣化发展为电弧放电，最终导致低压绕组b相对铁心和夹件等接地体放电是造成#1主变接地故障损坏的根本原因，最后提出了相应建议。     

应用磁场分布特征提取的35 kV XLPE电缆劣化评估

35 kV交联聚乙烯电缆在配电网中得到了广泛应用,但在运行中热、机械、电等因素会引发电缆绝缘劣化.为提高电力电缆状态评估的可靠性,本文提出了一种基于磁场分布特征分析的电缆绝缘劣化评估方法.基于搭建的35 kV单芯交联聚乙烯电缆仿真计算模型,分析了主绝缘气隙和半导电层凸起缺陷时电缆磁场分布特征,建立了缺陷类型、大小、位置和劣化程度与磁场强度和磁场畸变特征的关系,利用磁场畸变特征检测电缆故障,提升了电缆故障检测的有效性和准确性.     

66 kV变电站变压器油色谱异常缺陷诊断

针对某66 kV变电站2号变压器油色谱异常进行缺陷诊断,分析了乙炔组分异常存在的原因,采取科学、合理的监测周期,保证了该设备运行状态可控、在控.当油中乙炔组分再次异常变化时及时作出反应和判断,运用正确的检测手段来诊断缺陷的故障性质和危险性,并有效地指导变压器厂家进行设备返厂解体检查和缺陷故障部位的查找.     

发电设备组合检修策略模型

给出了发电设备组合检修策略的定义,分析了影响组合检修工作有效性的关键因素。针对目前该策略检修周期与检测周期决策缺乏模型支持、只能依据经验进行判定的现状,基于延迟时间模型理论,以复杂设备为研究对象,建立了组合策略模型,包括费用最小化的设备定期检修周期的决策模型和检修周期内满足可接受风险水平的非理想状态检测的检测周期的决策模型,并给出了应用示例。     

Development of an innovative monitoring system for vacuum circuit breakers - [News from Japan]

Switchgear used in power distribution systems is usually in service for more than 10 years. To ensure stable and highly- reliable operation, proper maintenance is of prime importance. In conventional maintenance of switchgear, preventive time-based maintenance (TBM) is carried out, involving periodic inspection at certain pre-determined intervals, e.g., once every six months, and replacement of nondurable components if appropriate. In order to conduct TBM properly, it is important to determine a maintenance time interval which balances cost and risk of failure. Usually this is very difficult. Alternatively, in condition-based maintenance (CBM) the replacement of each component is carried out following automated continuous inspection of its condition.     

The effect of transformer maintenance parameters on reliability and cost: a probabilistic model

Transformer is an equipment common to most power systems. Preventive maintenance is performed to extend the equipment lifetime. Models relating probability of failure to maintenance activity are proposed in [Panida Jirutitijaroen, Chanan Singh, Oil-immersed transformer inspection and maintenance: probabilistic models, in: Proceedings of the 2003 North American Power Symposium Conference, pp. 204–208]. The model parameters which are mean time in each stage, inspection rate of each stage, and probabilities of transition from one stage to others, have an effect on reliability and cost of maintenance. In order to establish a cost-effective maintenance process, analysis of model parameters should be conducted thoroughly.This paper develops detailed models relating maintenance parameters to reliability and cost and then investigates the effect of varying model parameters. Simulation results from the proposed model are shown and corroborated by mathematical analysis of a simpler equivalent model. The analysis covers mean time to the first failure, maintenance cost, inspection cost, and failure cost.     

无人值班变电站巡视周期的仿真计算

为保障变电站巡视工作的合理性和有效性,以可靠性为中心,基于故障树分析法和层次分析法,利用变压器、断路器、TA、TV、隔离开关等变电站设备的缺陷信息,通过蒙特卡罗分析法建立了计算巡视周期的仿真模型;计算了不同可靠度要求下的巡视周期;提出了一种确定变电站巡视周期的仿真计算方法。该方法利用Monte-Carlo法模拟各种设备缺陷时间的随机性,适于设备的状态维修,为更加合理制定无人值班变电站巡视周期提供了一种方法。     

Improved Inspection of Facilities for High‐Voltage Class Using Data Mining

The inspection of power supply facilities can now be conducted with high accuracy using remote monitoring technology. In contrast, it is difficult to install sensors at demand facilities because their scale and installation environment differ among customers. As a result, the demand facilities are inspected at fixed time intervals. In this paper, we propose condition‐based maintenance (CBM), which improves maintenance quality at demand facilities. The proposed method was developed using maintenance data from demand facilities, collected using time‐based maintenance, and we conduct the analysis primarily using failure data. We use data mining to analyze transaction data that we modeled on the basis of the maintenance data and to construct a “failure predictive model” that can predict the failure of facilities and its causes from the results of the analysis. By using the constructed model, we will be able to identify the objects requiring maintenance which may most likely lead to failures in the future, and this study can contribute to improvement of maintenance technologies for demand facilities using the proposed CBM.     

220kV断路器分闸不成功原因分析及防范措施

查明220 kV线路转检修操作过程中2055断路器分闸不成功原因并提出防范措施。通过对该故障断路器进行检查、测试及分析,指出该断路器发生机械故障,机构内分闸线圈固定螺钉松动,撞针与触发器间隙变大导致撞针无法顶触发器,是断路器分闸不成功的主要原因。提出防止断路器发生此类机械故障的预防措施,为同类设备的运行维护提供参考。     

Review of condition assessment of power transformers in service

As transformers age, their internal condition degrades, which increases the risk of failure. To prevent these failures and to maintain transformers in good operating condition is a very important issue for utilities. Traditionally, routine preventative maintenance programs combined with regular testing were used. The change to condition-based maintenance has resulted in the reduction, or even elimination, of routine time-based maintenance. Instead of doing maintenance at a regular interval, maintenance is only carried out if the condition of the equipment requires it. Hence, there is an increasing need for better nonintrusive diagnostic and monitoring tools to assess the internal condition of the transformers. If there is a problem, the transformer can then be repaired or replaced before it fails. An extensive review is given of diagnostic and monitoring tests, and equipment available that assess the condition of power transformers and provide an early warning of potential failure.     

Pulp friction: reconditioning pulp and paper mill generators for reliable service

Generators are very efficient and are typically quite reliable. This article describes, key preventive maintenance actions, along with recommended cycle times of the generator. Initially, the basic preventive maintenance tasks such as visual inspection of generator components, particularly the stator windings, rotors and wedge system is discussed. An extensive generator health assessment should be done to determine what problems are most severe and need priority attention.     

电站给水泵组RCM定量分析方法的研究

在电站辅机RCM定量分析中，提出一种新的RCM定量分析单位：检修单元，简化维修，故障费用计算，提高可靠性统计数据的可信度，实现以最小维修，故障费用为寻优目标求解最佳维修周期。该文提出了划分电站辅机检修单元的基本原则，给出了给水泵组检修单元划分的示例。根据辅机的容量配置及其故障对机组的影响，将电站重要辅机分为5类，并研究了这5类辅机检修单元维修，故障费用的简化计算方法。最后以200MW机组DGT750-180给水泵组芯包为研究实例，进行了RCM定量分析。以年平均维修，故障费用为评价指标，比较了4类维修策略(现行的和优化的)下的维修成本/效益。     

论以可靠性为中心的火电机组的维修

大型火电机组为复杂设备,维修时可应用以可靠性为中心的火电机组维修(RCM) 原理。大型火电机组的故障率应遵循德雷尼克定理,即故障率随着时间的增大而趋于平均故障间隔时间的倒数l/ MTBF。目前我国执行的机组检修规程存在弊端,执行3 年大修1 次的定时维修并没有使机组的可靠性有明显改善。因此,需逐步转变为以RCM 原理指导的维修体制,应根据设备及部件的可靠性状况,运用逻辑分析来确定维修内容、维修类型、维修间隔期和维修级别;设计、制造和检修部门共同制定以可靠性为中心的维修大纲,以该维修大纲为指导,对大型火电机组进行维修。