银行UPS供电系统可靠性方案探析

本文从银行UPS供电系统总体设计、UPS设备选型主要考虑参数、冗余方式选择、UPS系统的安装、维护等方面进行综合考虑 ,论述提高银行UPS供电系统的可靠性、稳定性的方法 ,以期保障银行业务分分秒秒不间断进行     

Surveillance test policy optimization through genetic algorithms using non-periodic intervention frequencies and considering seasonal constraints

In order to maximize systems average availability during a given period of time, it has recently been developed a non-periodic surveillance test optimization methodology based on genetic algorithms (GA). The fact of allowing non-periodic tests turns the solution space much more flexible and schedules can be better adjusted, providing gains in the overall system average availability, when compared to those obtained by an optimized periodic test scheme. This approach, however, turns the optimization problem more complex. Hence, the use of a powerful optimization technique, such as GA, is required.Considering that some particular features of certain systems can turn it advisable to introduce other specific constraints in the optimization problem, this work investigates the application of seasonal constraints for the set of the Emergency Diesel Generation of a typical four-loop pressurized water reactor in order to planning and optimizing its surveillance test policy. In this analysis, the growth of the blackout accident probability during summer, due to electrical power demand increases, was considered. Here, the used model penalizes surveillance test interventions when the blackout probability is higher.Results demonstrate the ability of the method in adapting the surveillance test policy to seasonal constraints. The knowledge acquired by the GA during the searching process has lead to test schedules that drastically minimize test interventions at periods of high blackout probability. It is compensated by more frequent redistributed tests through the periods of low blackout probability in order to improve on the overall average availability at the system level.     

Cost effective second generation AC-modules: Development and testing aspects

In the framework of the European research project PV2GO, a new AC-module inverter was developed, taking into account all relevant aspects from a European market's point of view (standards, market, application, and research and development goals). The project goal was to achieve the overall system costs of 3 Euro per Wp for a modular plug-and-play photovoltaic system. For the photovoltaic-module, a standard 130-Wp Eurosolare module was chosen. The research and development (R&D) goal was to develop an advanced DC-control system consisting of a state-of-the-art programmable digital device and an Application Specific Integrated Circuit (ASIC) for the AC-control of the inverter. According to the topology concept, thermal and magnetic designs were optimized with regard to production technology and packaging for large-scale production. The new AC-modules were tested in a number of field-test sites in various parts of Europe and their reliability was assessed through Highly Accelerated Stress Tests. Efficiency and power quality have been tested in the laboratory. Further in the PV2GO project an optimization study of the manufacturing process of the new generation of AC-modules for high volume output was done. Another task was the pre-certification procedure to assure compliance with the European guidelines and standards.     

Critical building separation distance in reducing pounding risk under earthquake excitation

A separation distance between adjacent buildings is provided to reduce the risk of pounding of adjacent buildings under seismic excitations. It should be recognized that the evaluation of the critical separation distance is a one-sided barrier crossing problem while the problem of structural design under seismic excitations is a two-sided crossing problem. A procedure for assessing the required separation distance with or without considering possible uncertainty in structural properties was presented based on the reliability methods and random vibration theory. The procedure was used to carry out parametric analyses. It is shown that use of the complete quadratic combination (CQC) rule with the modal responses employed for designing structures may over- or underestimate the critical separation distance, depending on the damping ratios and the closeness of the natural vibration periods of adjacent buildings. This is due to not only one-sided versus two-sided crossing problem but also the approximation in the CQC rule. Further, the effect of the uncertainty in structural properties on the estimated separation is investigated. The results indicate that this uncertainty tends to increase the required critical separation distance.     

Reliability evaluation and optimisation of imperfect inspections for a component with multi-defects

In this paper, a model is developed to evaluate the reliability and optimise the inspection schedule for a multi-defect component. The model uses a non-homogeneous Poisson process (NHPP) method in conjunction with a delay time approach. The inspections are designed to detect any defects in the component, however it can be imperfect. The defect is a definable state before a functional failure happens to the component. Occurrences of defects are assumed to follow an NHPP and a defect will be minimally repaired if it is identified during an inspection. It is shown that the failures occurring in an interval of inspection will also follow an NHPP. The situation of imperfect inspections and non-constant inspection intervals are considered. An algorithm is presented to optimise the intervals of inspections in order to maximise the reliability of the component, and the properties of the algorithm are shown. A numerical example with parametric study is given to show the performance of the model and the algorithm.     

可靠性预计方法及思考

本文介绍了可靠性预计的目的,并对当前较为常见的可靠性预计模型或方法做了比较和说明,也对造成可靠性预计局限性的原因做了分析,最后对在可靠性工程工作中对待可靠性预计的态度做了探讨.     

对某自动驾驶仪可靠性增长的试验研究

对某自动驾驶仪可靠性增长工作进行研究,提出了对现役机载电子设备可靠性增长的一些成功、可借鉴的经验。对增长试验过程中发现的问题和管理方面的不足之处,提出一些建议。     

Complex system reliability modelling with Dynamic Object Oriented Bayesian Networks (DOOBN)

Nowadays, the complex manufacturing processes have to be dynamically modelled and controlled to optimise the diagnosis and the maintenance policies. This article presents a methodology that will help developing Dynamic Object Oriented Bayesian Networks (DOOBNs) to formalise such complex dynamic models. The goal is to have a general reliability evaluation of a manufacturing process, from its implementation to its operating phase. The added value of this formalisation methodology consists in using the a priori knowledge of both the system's functioning and malfunctioning. Networks are built on principles of adaptability and integrate uncertainties on the relationships between causes and effects. Thus, the purpose is to evaluate, in terms of reliability, the impact of several decisions on the maintenance of the system. This methodology has been tested, in an industrial context, to model the reliability of a water (immersion) heater system.     

冗余磁盘阵列的故障容错分析

本文在介绍冗余磁盘阵列(RAID)的故障容错机理之后,着重研究了设备故障对RAID系统可靠性的影响.其平均持续正常工作时间和系统在线修复设备故障容许的平均间隔时间的计算结果表明,只要在一定的容许时间内替换或修复故障磁盘,系统可保持持续正常工作状态.     

K终端可靠度分解算法中多边形→链简化定理的完善

无向网络K终端可靠度的分解算法中,包括多边形→链简化在内的等可靠度简化和分解定理结合,可以降低算法的复杂度。本文完善了边随机无向网络和混合随机无向网络的4#,6#,7#型多边形→链简化定理。计算机编程验证了其正确性。