基于遗传优化规则库的电力变压器故障诊断

提出基于遗传算法优化模糊规则库的故障诊断方法,采用模糊故障诊断系统对电力变压器的初期故障进行检测或诊断.采用遗传算法产生优化的模糊规则库,针对缺少数据样本的情况,采用自举法对数据样本进行处理及扩充,使得不同的故障类型有相等的样本数.仿真结果表明:该故障诊断方法提高了故障诊断精度和正确率,对于电力变压器故障诊断有效、可行.     

基于改进的二代非支配排序遗传算法对电子变压器多目标优化

本文在对多目标、多变量优化方法研究的基础上,提出了改进的二代非支配排序遗传算法。在该算法中,通过增加种群多样性和提高个体竞争力,有效地减少了早熟收敛现象的发生,同时,通过种群分割操作,大大减少了交叉运算的计算量。依据这一改进算法,建立了三维优化模型,对电子变压器进行了多目标优化设计,获得了电子变压器优化设计参数,使其体积更小、效率更高,更容易找到全局最优解。与非支配排序遗传算法(NSGA)和二代非支配排序遗传算法(NSGA-Ⅱ)相比,改进的二代非支配排序遗传算法在电子变压器优化设计方面具有明显的优势。最后,依据优化结果,制作了一台磁芯材料为超微晶合金的高频变压器,温度校核结果表明了此优化方法的可行性。     

应用改进遗传算法的电力变压器优化设计

为了提高遗传算法在电力变压器优化设计中获得全局最优解的能力，对传统遗传算法的编码方案、遗传算子以及约束条件、适应值函数等方面进行改进研究，提出了一种改进遗传算法，并应用经典数学函数进行验证，结果表明改进遗传算法具有较高的寻优效率。在此基础上提出了适应于求解多目标优化的改进遗传算法，并将改进遗传算法首次应用于S9系列电力变压器的单目标和双目标的优化设计中。应用实例表明，文中提出的改进遗传算法（IGA）具有更强的全局寻优能力和更高的求解精度，对电力变压器的优化设计效果明显。     

计及可靠性的配电变压器组年度检修计划优化

针对已有基于经济性的配电变压器组检修计划研究鲜有计及可靠性约束的现状,在设备状态评价的基础上,分析检修模式对变压器故障率的影响,以计划检修费用和随机故障停电损失费用之和最小为目标,建立计及可靠性约束的配电变压器组年度检修计划优化模型。该模型对配电变压器的检修时间和检修模式进行优化决策以得到经济性最优的年度检修计划;并采用基于实数编码的自适应遗传算法进行求解。结合RBTS Bus2系统进行算例分析,计算得到经济性最优的检修计划及经济性指标;并分析可靠性约束对系统总费用的影响。     

遗传支持向量机在电力变压器故障诊断中的应用

针对支持向量机中的参数通常靠交叉试验来确定的状况,提出了遗传支持向量机,即使用遗传算法来优化支持向量机中的参数,并将之进一步应用在基于溶解气体分析的变压器故障诊断中.以变压器油中5种主要特征气体作为支持向量机的输入,以7种变压器状态作为相应的输出,选用径向基核,使用遗传算法得到优化参数,充分发挥了支持向量机具有较高泛化能力的优势.实验表明,本文方法能够在较大范围内准确地找到相应的优化参数,并能有效地进行变压器的故障诊断.     

采用NGA优化的新型BP神经网络模型及诊断应用

针对传统BP神经网络模型收敛速度慢、易陷入局部极小点、网络结构不稳定等缺陷,提出了一种小生境遗传算法优化的BP神经网络模型。该模型充分利用小生境遗传算法的搜索能力和BP神经网络的非线性映射和学习联想能力,通过小生境遗传算法的选择、交叉、变异及小生境淘汰等操作,优化BP神经网络的初始权值和阈值,并采用BP算法对网络进行训练。有效解决了网络初值不合理的问题,提高了网络收敛速度、稳定性。最后结合变压器故障诊断实例。在Matlab7.0平台上进行仿真实验。实验结果证明:与传统方法相比,该模型具有很强的可行性和有效性。     

基于遗传算法的电力系统无功优化

电力系统无功优化主要是指在负荷给定的情况下,有载可调变压器分接头位置、无功补偿的最佳容量和发电机机端电压大小的优化确定。以有功网损最小为目标函数建立了主网无功优化的数学模型,对于目标函数中的无功电压越界和发电机无功出力越界,采用罚函数予以解决。采用遗传算法,针对遗传算法应用于求解无功优化等复杂非线性优化问题中容易发生"早熟"和收敛速度慢等问题,作了一些改进。通过改进,遗传算法能够跳出局部最优解,增强了全局寻优能力,使寻优速度和精度在一定程度上得到了提高。根据上述算法使用C++语言编制了求解程序,并对IEEE-14节点系统进行了优化计算,通过与初始有功网损比较,在各设备的正常运行范围条件下,系统有功网损降低了4%。     

改进遗传算法在配电网无功优化的应用

提出了考虑配电网运行费用和节电效益的综合目标函数,对于目标函数中的电压越界点和无功补偿容量越界点采用惩罚函数予以解决.无功优化主要采用调整变压器分接头和并联电容器2种方法,笔者采用改进遗传算法实现了配电网无功优化计算,该算法有较好的计算效率和全局寻优能力.通过实例验证了该方法的实用性和有效性.     

考虑变频调速时泵站优化调度的改进遗传算法

采用遗传算法对有部分变频调速机组的泵站进行优化调度计算，并对遗传算法进行改进，克服了遗传算法的早熟收敛问题。仿真研究表明，优化效果比传统遗传算法好。     

箔式绕组变压器优化设计

提出了箔式绕组变压器的一种优化设计方法.该方法考虑到箔式绕组电流引线的存在,为了满足铁心与引线之间的绝缘距离,铁心截面在优化设计时采用了不对称结构,与对称铁心截面结构相比,可以很大程度地提高铁心截面积.将一种改进遗传算法应用到铁心截面和整台变压器的优化设计中,基于优化后的不对称铁心截面对两台箔式绕组变压器进行了优化设计,在满足要求的情况下,成本分别降低8.63%和6.82%.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.