基于IGA-BPNN的水电站厂房振动响应预测

为实现水电站厂房结构振动的整体运行状态智能预测,解决多振源耦合与振动响应随机性等问题,以某一河床式水电站厂房振动响应为例,提出了一种基于IGA-BPNN的水电站厂房振动响应预测模型。首先利用IGA对BPNN初始权重值和阈值进行优化,充分发挥IGA高效并行、全局搜索的特点,再通过BPNN网络训练得到结构振动位移预测值。原型观测实例表明,测点振动位移预测值的最大相对误差不超过11%;IGA-BPNN模型与其他模型相比,在预测精度和收敛性能等方面有了明显提升,说明该预测方法有效,可为其他类型水电站的振动研究提供参考。     

基于传递熵的水电站厂房振动传递路径识别

水电站厂房空间结构复杂,同时振动测试信号中常混杂各种噪声,使得水电站厂房结构振源传递路径的分析难度增大;论文将传递熵方法与基于EMD分解的小波熵阈值去噪方法相结合,实现水电站厂房振动传递路径的识别。首先采用EMD分解和小波熵方法自适应地根据信号能量特征确定对应尺度的去噪阈值,对振动测试信号去噪;然后采用传递熵的方法识别厂房结构振源的传递路径。通过模拟信号的分析证明了该方法在判断信号传递方向方面的合理性。将该方法应用到一大型水电站厂房,结合现场实测振动数据对尾水涡带的垂向传递路径进行了识别,并计算了测点之间的信息传递率。结果表明尾水涡带引起的垂向振动主要传递路径为:尾水管→机墩(定子基础、下机架基础)→厂房上部结构楼板。     

基于CEEMDAN和小波包分解的闸门振动信号降噪研究

针对闸门监测振动信号去噪问题,提出基于CEEMDAN（经验模态分解）和小波包分解的闸门振动信号降噪算法,通过采用CEEMDAN和小波包分解方法进行信号去噪,可以有效处理水电站泄洪闸门振动信号中受到的外部干扰。CEEMDAN方法能够将信号分解成多个本征模态函数（IMF）,每个IMF代表不同频率的振动成分,使得外部干扰和真实信号成分可以分离。随后,小波包分解能够将每个IMF进一步分解成不同尺度和频率的子频带,这有助于更准确地定位和分离干扰成分。对每个子频带应用阈值去噪技术,可以有效去除噪声,保留真实信号。由测试结果可知,该算法能很好地剔除闸门振动信号中的无用噪声,有效提高闸门振动信号的准确性。     

基于CEEMDAN-IPSO-LSTM的水电机组振动预测研究

针对水电机组振动的非线性、非平稳特点,提出一种完全自适应噪声集合经验模态分解(CEEMDAN)方法和长短期记忆(LSTM)神经网络相结合的振动预测模型,利用改进的粒子群优化算法(IPSO)对调节参数进行优化以提高预测精度,采用CEEMDAN算法将振动数据计算展开为多个固有模态函数(IMF),通过计算相关系数筛选出有效的IMF,最后将筛选结果重构后输入LSTM进行模型预测,并与LSTM、支持向量回归(SVR)、CEEMDAN-IPSO-SVR进行对比。结果表明,提出的CEEMDAN和LSTM相结合的振动预测模型可以有效识别水电机组不同运行工况下的振动信号,为故障预警、水电机组安全高效运行提供依据。     

水电站厂房楼板振动分析

在岩滩厂房振动研究的基础上,建立了较精确的水电站厂房楼板结构模态分析和在机组水力激振作用下动力响应分析的有限元计算模型.利用该模型,对岩滩水电站主厂房振动进行了数值分析,其计算成果与实测数据非常吻合;对三峡水电站厂房振动做了分析预测,结果表明,在最不利情况下,三峡厂房楼板将有可能发生与岩滩厂房相同强度的振动.     

不同排架模拟方法对水电站厂房振动特性仿真结果的影响

水电站地面厂房发电机层楼板高程以上存在排架结构。为研究厂房上部排架简化模拟方法对厂房振动特性仿真结果的影响,运用ANSYS软件建立了3种有限元模型,分析了厂房的自振特性和机组振动荷载作用下的响应特点。研究表明:在开展水电站地面厂房的自振特性分析时,当主要期望了解楼板、立柱等结构的自振特性时,为简化计算,可以将发电机层楼板高程以上的排架结构采用质量单元来模拟,或者直接省略掉,均不会对结果造成较大影响;在机组振动荷载作用下,排架结构的振幅和动应力并不是厂房结构中最大的部分,除非要了解排架结构的振幅和动应力,否则均可以将排架结构进行简化处理,该简化处理对厂房结构振幅和动应力的影响程度不大。     

水电站厂房结构振动响应的神经网络预测

水电站厂房结构振动主要是水力、机械和电磁三大类振源引起的,厂房结构与机组之间存在明显的耦联作用,厂房结构和机组振动系统呈明显的动态耦合效应和非线性特征。本文在对实测厂房结构与机组振动响应关系分析的基础上,提出应用神经网络预测方法可在不考虑结构精确的数学力学模型的前提条件下,得出被研究对象的非线性振动特性,即通过机组的振动和尾水脉动的监测数据预测厂房结构的振动。该方法应用于三峡水电站厂房结构的振动预测,结果与实测结果基本吻合。     

某水电站内源振动引起厂房结构振动反应分析

水电站机组运行时产生的各种激振力诱发的振动能量很大,将会直接影响作为机组支撑体系的厂房结构,严重时会直接威胁到厂房结构安全。为此,基于线弹性动力有限元计算理论,利用有限元计算软件ANSYS建立某水电站地下厂房三维有限元模型,对其进行了动力计算,主要研究了内源振动对厂房结构的影响。研究结果表明,机组振动荷载对楼板、风罩机墩等部位作用较明显,该厂房整体结构能够满足水电站安全运行的要求。     

景洪水电站厂房结构振动响应实测与分析

景洪水电站总装机容量为1 750 MW,水电站引水钢管直径高达11.2 m,机组运行水头变幅可能较大,机组振动特性及厂房结构重要构件的振动特性可能与其他已建常规水电站有所不同。文章对支撑机组的机墩结构以及作为辅助设备基础的楼板的振动状态进行了重点的监测分析。     

水电站地下式厂房边界条件的识别及动力特性分析

以某大型水电站地下式厂房工程为计算实例,通过应用有限元分析软件ANSYS建立厂房三维有限元模型,研究了不同边界条件对厂房结构固有振动特性的影响;并利用开停机信号,应用随即减量法,提取楼板结构的自由振动信号,得出楼板结构的自振频率。同时分析在水力脉动作用下,厂房上部板梁柱结构的振动特性,根据谐响应计算结果,判断上部结构的共振频率。     

生活污水对蚕豆的氧化损伤实验研究

研究了某污水处理厂不同取样点的污水对蚕豆根部和叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性及丙二醛(MDA)含量的影响。结果表明:各取样点的污水引起蚕豆根部和叶片SOD活性增加和叶片中POD和CAT活性的增加;随着各取样点CODCr增加,根部的CAT和POD的活性均表现为先升后降。且除了B沉外,各取样点的污水均使得根部和叶片的MDA含量显著增高。由于加氯消毒,出水的毒性高于B沉池污水。     

Automatic load-frequency control of the united power system of Siberia

A centralized system for automatic load-frequency control (ALFC) has been developed by the Siberian Division of the Central Computing Center of the Power Industry and realized on the basis of a commercial OMRON controller that performs all control functions. The algorithmic and software support of ALFC performs several new functions, i.e., helps to produce control actions on regulating stations with allowance for the specified daily output, perform second-after-second (cumulative sum) accounting for the power produced by a power station due to participation in the control, initiate combined regulation of power flow and frequency (APFR), ensure maintenance of a 1-sec archive with a depth of over 30 days for any telemetry (TM) used in the ALFC, etc. The software has been developed with the help of special language based on the IEC 1131-3 standard.Translated from Élektricheskie Stantsii, No. 11, November 2004, pp. 17 – 20.     

城市河道溢流堰对水体溶解氧及氮和磷的影响

研究了河道溢流堰对水体DO及氮、磷的影响,结果表明:经溢流堰后,水体DO平均增加1.75 mg/L。当水温超过15℃,堰下DO低于4.00 mg/L时,堰下TN低于堰上,堰下DO高于4.00 mg/L时,堰下TN低于堰上。当水温低于15℃,堰下DO高于4.00 mg/L时,堰下TN高于堰上,TN升高。当DO增加较少时,堰下TP高于堰上,DO增加较多时,堰下TP低于堰上,TP得到一定降低。     

黑龙江省西部地区玉米需水量与灌溉制度制定

黑龙江省西部地区频发的干旱情况影响该地区农业水循环与粮食安全,研究玉米水分供需关系对于理解该地区干旱机理有重要意义。根据FAO-56单作物系数法,计算玉米生育期参考作物蒸散量(ET0)、作物需水量(ETc)和灌溉需水量(Ir),依托CROPWAT模型制定灌溉制度,并通过计算作物水分盈亏指数(CW)分析玉米水分盈余情况。结果表明：1960—2015年黑龙江省西部玉米生育期ET0和ETc呈下降趋势,有效降水量(Pe)、Ir和CW呈上升趋势;平均ET0、ETc、Pe和Ir分别为639.64、438.13、224.40和273.87 mm;由于不同水文年干旱条件不同,Pe并不能在所有年份满足玉米水分需求,丰水年、平水年、枯水年和特枯水年的平均净灌溉定额分别为152.43、236.33、276.53和353.47 mm。黑龙江省西部玉米生育期水分供需关系的研究和灌溉制度的制定有助于区域水资源调控和农业发展     

Ecological Water Requirement (EWR) Analysis of High Mountain and Steep Gorge (HMSG) River—Application to Upper Lancang–Mekong River

As “corridor” in the south–north and “barrier” in the west–east direction, Lancang River, the upstream of Lancang–Mekong River, has an obvious spatial–temporal characteristic and unique regional attributes. Recently, the hydropower development of the mainstream along Lancang River has disturbed the regional ecosystem to have unstable factors, and threatened the ecosystem health. This paper used the couple model of Grading Coefficient of ecological water requirement (GCEWR) and the ecological runoff (ER) to simulate the ecological water requirement (EWR) of Lancang River, in a broad sense, this method belongs to hydrology–ecology methodology. In the GCEWR–ER, We adopted ecological characteristic indexes (ECI) and hydrological characteristic variables (e.g. variance index) to calculate the GCEWR, and used three methods to calculate the basic variable (e.g. ER) of EWR: the first method directly used annual average runoff as ER; the second method was used frequency method and took year as basic time unit, and the third method took season (e.g. flood season, non-flood season) as the basic time unit to evaluate ER. Finally, in order to demonstrate applicability of this developed methodology, this paper adopted GCEWR–ER method to calculate the EWR of Lancang River in the Longitudinal Range-Gorge Region. By the systematic analysis of the results, we could get the minimum, satisfying and optimal EWR for the Lancang River, which were 142.53 × 10⁸, 286.46 × 10⁸ and 385.96 × 10⁸ m³. The three EWR respectively occupied 25.10%, 50.46% and 67.98% of the average measured run-off (567.75 × 10⁸ m³) of the Lancang River, and respectively occupied 18.63%, 37.45% and 50.45% of the natural run-off (765 × 10⁸ m³) of the Lancang River.     

Regionalization of natural flow regime: application to environmental flow optimization at ungauged sites

In this work we use the regionalization approach (RA) to derive the natural flow regime at an ungauged site. The derived natural flow regime, expressed by the regional cdf models of 32 indicators of hydrologic alteration (IHA) is used in the histogram matching approach (HMA) to seek the optimal environmental flows for a proposed multiobjective diversion weir in Taiwan. The results reveal that the outcomes associated with the planning constant scheme are significantly improved by the optimal time‐varying scheme. The histogram dissimilarities of 32 IHA associated with the planning scheme are consistently greater than those associated with the optimal scheme, especially for low‐flow IHA. Despite the inherent discrepancy between different approaches to generating flow data at the ungauged site, the optimal outcomes resulting from the RA‐based natural flow regime appear to be plausible and consistent with those reported in the previous work, thus validating the RA used in this work. We also explore the effect of weighting factors on the optimal outcomes. The results reveal that the weighting factor of the ecosystem needs objective dominates all optimal outcomes, while those of the agricultural demands and interbasin transfers objectives have minor effects on the optimal outcomes. The global optimal solution is obtained with a full or null weighting assigned to the ecosystem needs objective, while the least optimal solution is obtained as the interbasin transfers objective is given a null weighting and the agricultural demands objective is weighted more than the ecosystem needs objective. River managers and decision makers may select more balanced weir operation strategies based on the results presented in this work. Copyright © 2008 John Wiley & Sons, Ltd.     

壬基酚聚氧乙烯醚(NPEOs)在净水厂中的监测

低浓度内分泌干扰物长期作用会对人体健康产生不可忽视的负面影响.较详细地研究了北方某给水厂现有净水处理工艺对低浓度NPEOs的控制特性,结果表明,该厂常规工艺单元(无预氯化)对NPEOs(聚合度n＝4～15)基本上没有去除作用,后续活性炭单元对NPEOs的去除作用也不是很明显,有待进一步研究.由于氯的强氧化作用的存在,加氯能明显降低水中的NPEOs浓度.     

Connecting the second exhaust-heat boiler to the operating first one under the conditions of flow circuits of combined-cycle plants with two gas-turbine units and one steam turbine

Problems arising with connecting the second exhaust-heat boiler to the first exhaust-heat boiler under load in the case of flow circuits of combined-cycle plants of type PGU-450 are considered. Similar problems exist for two-boiler single-turbine units of type PGU-325 and for two-boiler single-turbine units of traditional steampower plants with an output of 200–300 MW upon connection of the second furnace of a two-furnace boiler to the operating first furnace. Analysis of the temperature-induced stressed state and of the cyclic strength of thick-walled elements of the steam-water conduit of PGU-450 and of two-furnace boilers of two-boiler single-turbine units with an output of 200–300 MW (the check valve, the inlet header of the water economizer) is used for determining the steam temperature differences in the high-pressure conduits to the steam turbine and the order of connection of the second exhaust-heat boiler to the operating fist one. Modes of enabling a two-boiler single-turbine unit of a combined-cycle plant, which are most “rigid” from the standpoint of thermal strength, are determined. __________ Translated from élektricheskie Stantsii, No. 2, February 2006, pp. 11–17.     

智能数据采集系统(IDAS)简介

IDA系统是Sinco公司近年来投入市场的新产品。IDA是智能数据采集的缩写。 该系统的主要器件有:传感器、多路模块,接口重发器、终端箱、I/R模块、电源、个人计算机、传感电缆、总线、各种雷击保护器、总线电源控制器、过压保护器、人工读数适配器及便携式读数显示器等。 多路模块把传感信号转换成数字形式并通过IDA总线将其传输到现场的个人计算机中。PC机将转换从工程单位中获得的数据并将其存入软盘。如果需要,PC机也可以分析比较输入数据来预置报警界限和发出警报。数据能打印、显示并能多次不断的从前置PC机反回到后置PC机。 前置PC机用于数据记录而后置机则用于数据分析,数据由调制解调器或软磁盘传输。 后置PC机负责数据库的数据归档,数据分析、绘图和生成报表。 美国田纳西州工程管理局(TVA)在方泰娜坝的监测中采用了IDAS,该系统运行良好,亦可用于滑坡和尾矿坝的监测。     

INCOMPRESSIBLE MULTI-RELAXATION-TIME LATTICE BOLTZMANN MODEL IN 3-D SPACE

Multi-Relaxation-Time Lattice Boltzmann Method(MRT LBM) is of better numerical stability and has attracted more and more research interests.The previous MRT LBM included artificial compressible effects.To overcome the disadvantage,an incompressible MRT LBM has been proposed in two dimensions recently.In this article,we present incompressible MRT LBMs in 3-D space,with example of nineteen-velocity.The equilibria in momentum space are derived from an earlier incompressible Lattice Bhatnagar-Gross-Krook(LBGK) ...