基于Adaboost算法的输电线路舞动预警方法

输电线路舞动是目前尚未被全面准确认识的世界性难题,已严重威胁输电系统的安全稳定运行。文章分析影响舞动的外界气象环境因素,并在此基础上提出一种基于Adaboost集成学习算法的输电线舞动预警方法。采用基于Gini指标的决策桩作为弱分类器,通过对多个弱分类器的训练及加权求和,输出舞动预测结果及其置信度,可为电网运维人员提供决策支撑。最后,使用历史数据进行验证性实验,结果证明了所提方法的有效性。     

电网可靠性评估的网络静态等值模型分析

为缓解大电网可靠性评估的计算复杂性，采取等值参数联合概率密度分布建模的方式开展了外网静态等值研究。在常规确定性静态Ward等值技术基础上，考虑外部区域发电机和线路随机故障，通过计算各种随机故障状态下的外网等值参数，即外网等值注入功率和外网等值串联支路阻抗，基于概率密度估计技术建立了等值参数的联合概率密度分布。外网静态概率等值模型克服了常规确定性静态Ward等值技术的不足，充分计入外网等值参数的随机性，减少了电网可靠性评估计算时间的同时提高了计算精度。对两区域RBTS系统和RTS79系统研究验证了其有效性和准确性。     

茄子果实形状的主基因+多基因遗传分析

果实形状是园艺作物商品性的主要指标之一。明确茄子果实形状的遗传规律可为开发相关分子标记以及选育消费者喜欢的果形新品种提供依据。本研究以卵圆茄BC01和长条茄Rf为亲本，构建P₁、P₂、F₁、F₂世代遗传群体，利用主基因+多基因混合遗传模型分析方法对果实纵径、横径和果形指数进行遗传分析。结果表明，茄子果实纵径、横径和果形指数之间呈极显著相关性，F₂代的果实纵径、横径和果形指数均呈双峰偏态分布。果实纵径由1对加性-显性主基因控制，遗传效应以加性效应控制为主，主基因起增效作用，在F₂代的遗传率为73.41%；果实横径由2对等加性主基因控制，主基因起减效作用，在F₂代的遗传率为90.99%；果形指数由1对加性主基因控制，在F₂代的遗传率为81.46%。     

基于层次分析法的信息安全风险评估要素量化方法

信息安全风险评估是保障信息系统安全的重要基础性工作，但现有风险评估标准和相关研究提供的评估模型和计算方法的评估结果不能有效体现信息系统资产在保密性、完整性、可用性上的不同安全需求和面临的不同风险。利用层次分析法建立风险评估层次分析模型，在借鉴通用脆弱性评分系统指标评价体系基础上改进脆弱性要素量化方法，利用构建的层次分析模型偏量判断矩阵计算“安全事件损失”“安全事件可能性”和“风险值”。通过实验验证，与现有方法相比，所提方法的评估结果能够直观体现资产在保密性、完整性和可用性上面临的不同风险，能为制定风险控制措施提供更加准确、合理的建议。     

基于PSR模型的珠三角都市农业生态安全综合评价

随着工业化、城镇化和现代化建设进程的加快，城市资源环境约束力不断加大，都市农业生态安全值得关注。报告在PSR模型的基础上构建了珠三角都市农业生态安全评价指标体系，运用综合指数法、熵值法和障碍度模型，对珠三角地区都市农业生态安全进行综合评价和相关障碍因素分析。结果表明：2006-2015年珠三角都市农业生态安全形势逐步好转；深圳和中山市的都市农业生态压力较大，东莞市的都市农业生态状态较差，肇庆和江门市的都市农业生态响应较弱；城镇化率、人均耕地面积等指标是当前影响珠三角都市生态安全的主要障碍因素。珠三角地区应大力加强耕地资源保护，继续推进城市生态环境和农业面源污染治理，从而保证都市农业生态安全的稳定发展。     

基于隶属度函数和主成分分析的耕地土壤肥力评价

以山东省高密市为研究区域，研究该区内耕地土壤肥力状况，摸清土壤肥力状况空间分布，通过对表层土壤进行网格化采样和分析测试，取得了土壤p H、有机质、全氮、全磷、全钾、碱解氮、有效磷、速效钾等8项肥力指标，基于模糊数学隶属度函数模型确定各指标隶属值，通过主成分分析确定各指标权重，结合隶属值和权重，计算土壤肥力综合指数，并进行插值绘图。结果表明：研究区土壤以碱性为主，样本数占比37.77%，其次为中性，样本数占比29.52%。有机质、碱解氮、速效钾以较缺乏为主，全氮、全钾以中等为主，全磷、有效磷以丰富为主。有机质和全氮的隶属值显著低于其他指标，是耕地土壤肥力的主要限制因子。全氮的权重值最大，对土壤肥力的贡献最大，碱解氮的权重值最小，对土壤肥力的贡献也最小。研究区耕地土壤肥力综合指数空间分布以中等为主。     

用灰色系统GM（1，1）模型预测棉花生产

近年来由于自然灾害、比较效益等因素的影响，棉花生产出现较大波动，这种非线性变化给预测工作带来了困难。本预测对以往灰色系统ＧＭ（１，１）模型进行了二点改进：（１）利用高斯主元素消去法解算未知参数，在计算方法上是一大改进，同时提高了运算速度和计算精度；（２）加入了迭代计算。通过建立误差方程式，给定收敛条件和趋近次数，使模型的拟合精度提高。预测２０００年棉花面积将达到６２８万公顷，总产５７６．５６万吨，标准误差分别为７４．３８公顷和±８９．４４万吨。考虑到９０年代以来棉铃虫的危害，预测值加上标准差下限，就是未来较低水平下的棉花生产趋势。     

基于机器视觉的棉花群体叶绿素监测

研究了利用机器视觉技术快速获取棉花群体叶绿素信息的方法，以期获得预测性高的颜色特征参数。结果表明，RGB颜色系统的G－R、(G－R)/(G+R)、r与g的组合值和棉花功能叶叶绿素含量、群体绿色指数呈极显著相关，而且拟合度较高；HIS颜色系统的Hue值和棉花功能叶叶绿素含量、群体绿色指数之间也极显著相关。对筛选出的两组模型进行检验，预测精度在84.07%~93.04%之间，推荐预测精度最高的G－R参数作为获取棉花群体叶绿素信息的最佳颜色指标。G－R预测叶绿素含量和群体绿色指数的模型分别为y=－1.3008+0.2125(G－R)－0.0038(G－R)2（R²=0.8669**）和y=－0.9726+0.1227 (G－R)－0.0016(G－R)²（R²=0.7487**）。     

甘肃部分小麦品种萌发期抗旱性鉴定及评价

为筛选出甘肃旱地尤其是播种期间气候经常干旱地区适宜的小麦品种。本研究以8份甘肃主栽的小麦品种和骨干亲本为供试材料，采用PEG-6000模拟干旱胁迫进行了萌发期抗旱性鉴定，测定了发芽率、根长、干物质转运率等8项指标；通过相关分析、主成分分析及抗旱隶属函数值计算，进一步利用抗旱性度量值（D值）对供试材料萌发期抗旱性进行了综合评价。结果表明，8个萌发期性状中，鲜重和干物质转运率对PEG-6000模拟干旱的胁迫反应迟钝，胚芽鞘长、发芽指数次之，发芽率、根长、发芽势和干重则较为敏感；综合评价结果显示，8份小麦品种萌发期抗旱性排序依次分别为：西旱2号>陇春27号>兰天10号=兰天19号>和尚头>宁春4号=兰大211>兰天132。     

衢州市早稻低温冷害风险评估及大气环流背景分析

应用衢州市1960—2012 年日气象观测资料,针对早稻苗期出现低温冷害灾害,从气象因子入手,建立定量评估模型,分析较严重的早稻春季低温冷害年大气环流背景,为提高春季低温冷害预报和预警水平,应对春季低温冷害对早稻构成的严重威胁。采用主分量分析法确定主分量及表达式,建立综合评价指标模型,计算出综合评价指标,并且对历年综合指标进行了评价。应用NCEP 1°×1° 500 hPa、850 hPa 资料,分析了较严重春季低温冷害年的大气环流背景。结果表明：从1960—1997 年春季低温冷害发生频率3~4 年出现一次,强度为1987—1997 年最强,2000 年以后,春季低温发生次数甚少。1987年、1993 年、1996 年、2010 年出现了较严重的早稻春季低温冷害,相对应的气候异常。综合评价指标和早稻产量相关密切,能客观地反映低温冷害的风险程度。较严重的早稻春季低温冷害年4 月上中旬亚欧地区呈径向型环流,使冷空气活动频繁南下,导致长江中下游地区气温偏低,而副热带高压强度强,南支槽、西南暖湿气流活跃,造成长江中下游地区持续阴雨天气。西风带、副热带、热带系统的有利配置,是造成早稻春季低温冷害发生的大气环流背景。     

Reliability Evaluation for Bulk Power System Including Dependent Outage of Transmission Line

In order to calculate and analyze the effect of two transmission lines in parallel on the reliability evaluation of bulk power system, a model including independent outage, common mode outage and dependent outage of these lines is deduced and a new algorithm corresponding to the model is presented. Two transmission lines in parallel including common mode outages and dependent outages can be really simulated as a multi-state component. While reliability indices are calculated, the probability and frequency of independent outage, common mode outage and dependent outage of a system failure state can be calculated at the same time, and computation complexity is reduced. The proposed model and algorithm are applied to the RBTS system, IEEE One Area RTS96 system and a real power system for reliability computation and analysis. Results show that the new algorithm is credible and validity.     

Power Lines Icing Characteristics of the Three Gorges District and a Model of the Accumulation of Ice on Electric on Electric Power Lines

Based on the study of accidents investigation of the electrical power lines because of icing in the district of Three Gorges,this paper analyzes the icing conditions and characteristics of various ice accreted and develops a model of the accumution of hard rime on electrical lines.     

Research on reliability evaluation model for frequency collapse of power grid

In order to comprehensively consider the possibility and the severity of frequency instability risk, this paper proposes the risk evaluation model and algorithm for frequency collapse of power grid. The uncertainties in generating dispatch, network topology and component outage are considered. The calculation method for system frequency variation is depicted while considering the active power deficiency arising from random failure of generating units, and then various probabilistic risk indices for frequency collapse are defined. The presented method can provide important reference information for evaluating the frequency collapse risk of power grid. The non-sequential Monte Carlo simulation-based results of IEEE-RTS79 show the correctness of the method.     

Simulation of ice shedding on transmission lines considering ice shedding velocity effect

Ice shedding on transmission lines results in longitudinal unbalanced forces on adjacent transmission towers,which significantly threaten the safety of transmission lines.The methodology of ice shedding simulation on transmission lines is developed by using the finite element method and validated by comparing the simulation results with those obtained from the model scale experiments done by previous researchers.The responses of the tower line system induced by simultaneous ice shedding on the conductor and ground wire are analyzed.The developed methodology is then applied to study ice shedding considering unzipping effect,in which the influence of the velocity of ice shedding on the responses is investigated.Results from this study show that the longitudinal unbalanced forces induced by simultaneous ice shedding from the ground wire are greater than those from the conductor under similar condition.During the analysis of ice shedding considering unzipping effect,the slower the velocity of ice shedding is,the closer the responses are to those resulting from static unloading;and the faster the velocity of ice shedding is,the closer the responses are to those resulting from simultaneous ice shedding.     

Dynamic responses of ultra high voltage transmission line ice shedding

Numerical models of typical 500 kV ultra high voltage (UHV) transmission lines are set up in ABAQUS/CAE software. The dynamic response of the transmission lines with different structure parameters under various ice shedding load cases are analyzed, and th     

Control Method of Voltage-reactive Power of Substation Based on the Real Time Adjusting Voltage Calculation

The main means of the voltage-reactive power control of substation are adjusting the taps of load-tap-changing transformer or the reasonable capacity of parallel compensating capacitors according to the operation condition of substation.The "nine-area control strategy" is widely used to adjust voltage in the stated range and reduce the transmission capability of reactive power for power system at present.By analyzing the existent shortages of nine-area control mode for voltage-reactive power,an adjusting voltage calculation method is put forward,input data of which are the real time data of current,voltage and power of the substation.Then operation decision of voltage-reactive power control method of substation is made.By the simulating analysis,predigesting method of upper system is built,based on which an applied real time calculating model and calculating steps is given.     

Formula for jump height of overheadtransmission lines after ice shedding

This paper numerically investigates the jump heights of overhead transmission lines after ice shedding by the finite element method, and simulates the dynamic responses of the transmission lines, with different structure parameters, in different ice shedding conditions. Based on the results, it obtains the quantitative relations between the jump height of conductor and the amplitude difference of the two static states of the conductors before and after ice shedding, and proposes a simplified formula for the jump height of conductors in continuous span after ice shedding for the determination of the clearance distance between the conductors at different phases in the design of high voltage transmission lines located in heavy ice zones.     

AN A. C. LOAD FLOW ANALYSIS OF THE RELIABILITY EVALVATION OF COMPOSITE GENERATION AND TRANSMISSION SYSTEMS

An A. C. load flow analysis of the reliability evaluation of composite generation and transmission systems is presented on the basis of a fast outage simulation algorithm and an optimal model of active and reactive power adjustment after outage contingencies. The information of the first -level outage events is utilized for simulating higher -level outage events in the fast outage simulation algorithm ; the optimal model is satisfactory in speed and accuracy with the application of concentric relaxation and linear increment constraint on the comprehensive adjustment of active and reactive power. As an example. the IEEE Reliability Test System is tested and the results show that the method is accurate and well-matched in speed with the method studied by R. Bllinton, et al.     

Numerical Modeling of Ice Slurry Flow Pressure Drop in Horizontal Pipes

To predict pressure drop of ice slurry flow in horizontal pipes, a mixture CFD model was applied to simulate the two-phase flow without considering ice melting. Based on the specific flow features, the Newtonian and non-Newtonian rheological expressions were employed respectively. It is found that in high speed the Thomas viscosity equation behaves well in representing the mixture fluid viscosity; whereas in low speed the Bingham model is more suitable for describing the mixture fluid rheology. Compared with the published pressure drop correlations, the current numerical model can involve with various factors and has a good balance between precision and suitability. The results of numerical model are in excellent agreement with the experimental data and the relative errors are limited to ±15%.     

智能变电站二次设备状态的灰色层次聚类评估

智能变电站作为智能电网建设的核心部分,其二次设备运行状态关系着电力系统的安全性和稳定性。针对智能变电站二次设备故障原因错综复杂以及运行状态信息不完全的特征,建立智能变电站二次设备状态评估层次模型和指标体系,引入灰色聚类对智能变电站二次设备状态进行灰色分类以及构建灰色白化权函数,并利用层次分析法计算状态指标权重,结合层次分析法与灰色聚类对智能变电站二次设备进行定性和定量的状态评估。实例分析验证了文中方法有效易行,为智能变电站二次设备状态检修工作提供了理论依据。