Deterministic and stochastic assessment of the harmonic currents consumed by discharge lamps

The paper examines the deterministic and stochastic behavior of magnetic ballast discharge lamps. Expressions to deterministically calculate the harmonic currents of discharge lamps are provided and analytical expressions of the probability density functions of these harmonic currents are obtained. The results are validated with experimental measurements.     

百万千瓦机组一次风机RB过程汽温控制策略研究

为减少一次风机故障减负荷(runback,RB)过程中蒸汽温度的波动范围,针对百万千万超超临界机组,对影响超超临界机组RB过程汽温波动的主要因素进行了研究,分析了燃水比、过剩空气系数等影响汽温波动的因素,阐述了机组正常运行时燃料、给水、总风量的调节控制关系,提出了RB过程中的燃料量、给水流量和总风量的控制关系及有效的RB过程汽温控制策略,给出了一次风机RB过程主汽温度、再热汽温度、机组负荷、主汽压力等机组参数的变化结果。大唐潮州电厂4号机组应用及试验结果表明,本文提出的RB控制策略对过热汽温、汽压等参数控制效果良好,对同类机组RB过程的实施具有重要的参考价值。     

一种三相交流混合磁轴承数学模型与性能分析

提出了一种新型的三相交流二自由度径向混合磁轴承,由嵌入式永磁体提供静态偏置磁通,三相通电线圈产生控制磁通.采用等效磁路法导出了偏置磁通的计算公式,推导了径向悬浮力的数学模型.针对实验样机的性能要求,设计了磁轴承参数,在设计交流磁轴承控制系统基础上,利用Matlab/SIMULINK工具箱构建了仿真系统,对磁轴承的起浮性能、抗干扰等特性进行了仿真.最后用ANSYS8.0电磁场有限元分析软件对磁轴承实验样机的磁路和转子受力性能进行了计算和分析,证明了该设计的正确性.     

Development and test in grid of 630 kVA three-phase high temperature superconducting transformer

Abstract A 630-kVA 10.5 kV/0.4 kV three-phase high temperature superconducting (HTS) power transformer was successfully developed and tested in a live grid. The windings were wound by hermetic stainless steel-reinforced multi-filamentary Bi2223/Ag tapes. The structures of primary windings are solenoid with insulation and cooling path among layers, and those of secondary windings consist of double-pancakes connected in parallel. Toroidal cryostat is made from electrical insulating glass fiber reinforced plastics (GFRP) materials with room temperature bore for commercial amorphous alloy core with five limbs. Windings are laid in the toroidal cryostat so that the amorphous core operates at room temperature. An insulation technology of double-half wrapping up the Bi2223/Ag tape with Kapton film is used by a winding machine developed by the authors. Fundamental characteristics of the transformer are obtained by standard short-circuit and no-load tests, and it is shown that the transformer meets operating requirements in a live grid. __________ Translated from Proceedings of the CSEE, 2007, 27(27): 24–31 [译自:中国电机工程学报]     

基于分布式网络计算技术的控制系统与虚拟仪器在电厂中的应用分析

本文结合笔者在从事项目执行过程中的一些经验教训,分析了电厂常规控制系统的局限性,针对当今控制技术的发展和应用,介绍了现场总线的框架体系,给出了基于现场总线概念的统一全厂辅控系统的大型分布式测控系统应用,并分别阐述了虚拟仪器和嵌入式处理器的设计思想;在此基础上提出了现场总线技术和虚拟仪器在电厂中的未来应用展望。     

丙烯酰胺基交联聚合物微球的制备及其对钻井液性能的影响

为揭示水分散聚合方法制备的丙烯酰胺基交联聚合物微球的结构特征及其对钻井液性能的影响规律,以硫酸铵水溶液为反应介质,丙烯酰胺(AM)、丙烯酸(AA)、甲基丙酰氧乙基三甲基氯化铵(DMC)为共聚单体,2,2-偶氮二(2-甲基丙基咪)二盐酸盐为引发剂,N,N'-亚甲基双丙烯酰胺复配物为交联剂制备了丙烯酰胺基交联聚合物微球。采用红外光谱、粒度分析等方法表征了交联聚合物微球的结构,研究了丙烯酰胺基交联聚合物微球对钻井液性能的影响。结果表明,交联聚合物微球的合成工艺条件对产物的降滤失性影响较小,但对产物在钻井液中的增黏作用影响显著。随AM和交联剂加量增加,聚合物微球对钻井液的增黏作用增强;存在对钻井液增黏作用最小的引发剂加量和AA与DMC摩尔比。采用水分散聚合方法可制备出平均粒径8.04μm(粒径范围2.43数53.72μm)的丙烯酰胺基交联聚合物微球。该交联聚合物微球对钻井液具有显著的降滤失作用和一定的增黏作用,耐温性能优良,150℃高温老化不会降低交联聚合物微球的降滤失作用,但可降低对钻井液的增黏作用,减小其对钻井液流变性的影响。     

InRout - A QoS aware route selection algorithm for industrial wireless sensor networks

Wireless sensor networks are a key enabling technology for industrial monitoring applications where the use of wireless infrastructure allows high adaptivity and low cost in terms of installation and retrofitting. To facilitate the move from the current wired designs to wireless designs, concerns regarding reliability must be satisfied. Current standardization efforts for industrial wireless systems lack specification on efficient routing protocols that mitigate reliability concerns. Consequently, this work presents the InRout route selection algorithm, where local information is shared among neighbouring nodes to enable efficient, distributed route selection while satisfying industrial application requirements and considering sensor node resource limitations. Route selection is described as a multi-armed bandit task and uses Q-learning techniques to obtain the best available solution with low overhead. A performance comparison with existing approaches demonstrates the benefits of the InRout algorithm, which satisfies typical quality of service requirements for industrial monitoring applications while considering sensor node resources. Simulation results show that InRout can provide gains ranging from 4% to 60% in the number of successfully delivered packets when compared to current approaches with much lower control overhead.     

三网融合中广电面临的问题及应对思路

根据当前广电在三网融合试点中的现状以及所面临的问题,提出了加快理顺体制机制、制定广电统筹发展战略、依托IPTV播控平台和网络资源优势、大力开发适合广电网络传输特性的IPTV服务业务、积极与电信运营商对接合作的应对思路。     

基于DMPSK调制的直扩信号全数字解调算法研究

在数字通信系统中,DMPSK解调包括常用的DQPSK和DBPSK的两种方式,本文首先分析了DMPSK直扩中频全数字解调的基本原理及系统组成,然后对解调算法和载波同步算法进行了理论分析,最后通过仿真说明该算法的可行性。     

络合法去除油田硫酸钡的研究与应用

以二乙烯三胺五乙酸（DTPA）为螯合剂主剂,配以氢氧化钾中和至pH值为13,并添加一定量的无机盐,对重晶石粉末进行溶出研究。结果表明,在DTPA质量分数一定的情况下,由于溶液黏度影响,钾盐的助溶效果为钠盐的2倍;随着无机盐质量分数的增加,碳酸钾、氟化钾和氯化钾对重晶石的助溶效果相应增加,碳酸钾添加量为10%时,溶出率达到最高的47.79%;反应4 h时,由于重晶石结块导致反应面积增大,碳酸钾的助溶效果比氟化钾高10.56%;反应12 h时,反应趋于完全,由于盐效应影响反应终点,氟化钾的助溶效果比碳酸钾高12.39%;对DTPABa3-离子进行了计算机模拟,得到了其稳定构象,并分析了钡离子络合常数低的原因;最终将该螯合剂应用于某堵塞油井,并对返排液中的无机盐组分、硫酸盐沉淀组分进行了XRD分析,并在沉淀中检测出钡元素,证明油井解堵成功,应用良好。