基于温度信号的风电机组发电机实时可靠性监测新方法

实时可靠性监测对降低风电机组的维护成本,提高其运行水平具有重要的意义。文章提出了一种基于温度信号监测的风电机组发电机实时可靠性监测方法。该方法采用正常运行状态下的发电机温度数据,利用线性回归技术,得出了消除环境温度和输出功率影响后的修正温度;然后基于性能可靠性理论,对修正温度进行标准正态变换,建立了发电机运行温度的实时可靠性监测模型。以某机组实际运行数据为例,验证所提方法,结果表明,该方法能利用温度信号监测机组运行的实时可靠度来发现其运行异常状态,达到实时可靠性监测目的。     

采用主成分分析法综合评价电站机组的运行状态

为解决电厂机组运行优化、状态监测与故障诊断中涉及到的机组运行状态的综合评价问题,提出用主成分分析(PCA)方法,建立了电厂机组的综合评价指标的思想.介绍了主成分分析法的原理,并应用该方法对某电厂机组的实际运行状态进行了综合评价.结果表明:该方法消除了主观因素对评价的影响,得到的综合评价指标可对汽轮机进行定量评价,也可为机组状态在线监测提供依据.     

基于实时功率曲线的风电机组出力特性研究

基于实时功率曲线对风电机组出力特性进行分析,主要通过采集风电机组风速、功率、可靠性状态、大气压力、环境温度等历史数据进行过滤修正,计算出能够反映风电机组真实出力情况的实时功率曲线,并与出质保检测功率曲线进行对比,最后结合功率一致性系数对风电机组出力特性进行评价。找出性能下降比较严重的风电机组并及时整改,进而提高风电机组的发电能力。该方法不仅能够在线评价风电机组的性能优劣,且适用于各类型风电机组,具有广阔的应用前景。     

基于动态数据的风电机组维护效果评价方法研究

针对风电机组维护效果评价结果主观性强和解释性差的问题,文章提出了一种基于动态数据的风电机组维护效果评价方法。该方法基于机组设备状态特征,建立了适合机组维护效果评价的指标体系;引入云模型,明确了评价方法的整体流程;采用非线性状态估计（NSET）模型对云模型进行改进,并将描述机组设备状态的动态数据特征进行解析与转化,作为云模型的输入数据,提高了评价模型分析结果的客观性。通过实际案例证明,该方法能够较为客观真实地对机组设备维护效果进行评价,同时,评价结果具有较强的解释性,可为后续维护工作提供必要的技术支持。     

基于状态评价的风力发电设备故障诊断系统的研制

基于状态评价的风力发电设备故障诊断系统,通过实时监控表征风力发电设备运行情况的状态量,依据风力发电设备状态评价导则,对风力发电设备进行状态评价,并依据状态评价的结果,对潜在故障进行诊断分析。同时给出相应的运维策略,通过早期故障预测,变事后维护为事前检修,科学合理地安排检修计划,极大地提高了风力发电设备的运维效率,降低了机组的维护成本,保证了风力发电机组的可靠稳定运行。依据此方法研制的风力发电设备故障诊断系统,已成功应用于南方电网超高压输电公司检修试验中心。实践证明,该方法有效地提高了风力发电设备故障诊断的实时性与准确性。     

基于轴承温度模型的风电机组故障预测研究

采用风电机组状态监测技术可有效提高机组运行的安全可靠性。轴承是风电机组能量传递的重要部件,轴承的状态评估对机组安全运行具有重要意义。文章基于主成分分析方法,选取影响机组轴承温度的参数,提出了改进的线性回归径向基函数神经网络方法,建立了正常运行状态下轴承的温度预测模型;通过机组运行数据的分析比较,采用滑动窗口残差统计方法对机组运行状态进行实时监视评价发现,发电机出现异常时,轴承温度呈现上升趋势,残差值超过设定的置信区间,从而能实现对故障的有效预测。文章的研究结果可为风电机组的安全高效运行提供参考。     

应用直觉模糊集多属性决策Topsis方法评价电站机组的运行状态

针对电厂汽轮机组运行状态的综合评价问题,提出了直觉模糊集多属性决策Topsis方法.在电站机组得到普遍应用的DCS、MIS在提高机组自动化水平和信息管理层次的同时,也提供了大量有关机组的信息.使用直觉模糊集多属性决策Topsis方法对某电厂机组的实际运行状态进行了综合评价.结果表明:该方法的决策原理简单、易于实施,而且得到的综合评价指标可对汽轮机进行定量评价,为机组状态在线监测提供了依据.     

大型汽轮机组状态综合评价的理论与系统研究

作者研究了大型汽轮机组状态综合评价的理论,建立起机组状态综合评价的数学模型,在此基础上,开发出大型汽轮机组状态综合评价的软件系统,本软件系统的主要功能是实现对汽轮机组的当前运行状态的实时综合评价,为实现机组的状态检修提供决策依据。本文作者还将开发出的汽轮机组状态评价软件应用于国产300MW汽轮机组的状态评价。     

基于邻比模型分析的风电机组传感器监测研究

以风速计为例,提出基于邻比模型的风电机组传感器监测方法。风资源相似的多台风电机组(邻比机组)的运行工况和传感器测量值存在较强的相关相似性。采用多台风电机组风速计正常测量数据和非线性状态估计方法来建立多个风速计横向之间的邻比模型,该模型反映了邻比机组风速之间的相关相似关系。模型建立后,将风速计实时测量风速作为模型的输入。当某台机组的风速计出现测量异常时,其与其他邻比机组风速计之间原有的相关相似关系被破坏,邻比模型对该机组风速的预测残差将会显著增大,预示该风速计出现故障。该方法能够实现风电机组传感器状态的实时监测。通过某风电场实际运行数据,验证了该方法的有效性。     

50 MW背压机组冷态启动的暖缸状态实时监测方法

为满足对机组冷态启动时暖缸状态进行实时、全方位监测的需求,提出了一种暖机状态的实时监测方法:首先,通过对机组进行三维建模及热应力分析,获取可充分表征整个缸体温度场的温度测点;然后,在原有DCS蒸汽测点参数的基础上,加入新的缸体局部温度测点;最后,开发了暖缸状态实时监测系统,利用上述温度测点数据对暖缸状态进行可视化,让工作人员可直观判断暖机效果。这既改善了机组整体运行安全系数,避免因暖缸不充分带来的轴振超限(甚至碰摩)等安全问题,又提高了暖机效率,避免因长时间暖机带来大量蒸汽的消耗及对机组并网发电的影响,提高机组整体运行经济性,此外,该方法具有普适性,具有较高推广价值。     

浅谈核电厂纠正行动计划的有效性评价

运行经验的应用是经验反馈流程的终极目标,这包括对事件原因进行正确分析、制定对应的纠正行动并确保其得到有效执行,因此需定期进行纠正行动计划的有效性评价工作。描述了核电厂进行纠正行动计划有效性评价的方法和实践。该有效性评价方法基于纠正行动计划的开发质量要素,通过建立评价准则,对纠正行动计划开发的有效性和纠正行动执行的有效性两方面进行评价。2015年中核运行三厂全年的评价结果表明核电厂纠正行动计划开发质量总体良好。该评价方法和实践可以作为开展核电厂纠正行动计划有效性评价的技术基础,还对核电厂开展有效性评价工作进行了总结和分析,并提出了该工作的改进方向,为后续有效性评价工作的持续优化提供了参考。     

Study on surface states of Pt/TiO2 thin film in different atmospheres

In this paper, the surface states of Pt/TiO₂ thin film were tested in air, H₂ and N₂ flows. Pt/TiO₂ was prepared by means of photoreduction of on anatase nano-TiO₂ powders and was coated on the microscopy glass using powder–sol technique. Powder conductivity method was applied in the analysis of surface states. The experimental results show that a new surface state was formed in air flow; which was 0.43 eV lower than the conduction band edge of TiO₂. In N₂ flow, three surface states, with the energy levels of 0.42, 0.62 and 0.90 eV, respectively, were detected. Compared with that tested in airflow, 0.42 and 0.62 eV could be attributed to Pt and floating bond of TiO₂ respectively, while 0.90 eV might have resulted from the Ti³⁺ formed at high temperature in N₂ flow. The conductivity of the sample tested in H₂ flow increased significantly and was almost unchanged with temperature, which could be interpreted by the dissociative adsorption of H₂ on Pt.     

计及转供电概率的配电网可靠性评估

由于线路间互相联络,配电网通常具有灵活的故障重构能力,因此其供电可靠性评估必须考虑联络线的转供容量。但传统方法忽略了联络线路负荷波动对其转供容量的影响,评估结果容易偏向乐观。通过计及联络线路转供容量的随机性,在此基础上提出了计及负荷转供电概率的城市配电网供电可靠性评估快速算法。采用美国PG&E 69节点配电系统对本文所提出的供电可靠性评估方法进行了分析验证．算例分析证明了本文所提方法的正确性,表明其能够更加全面客观地的评估配电网的供电可靠性。     

A leak-before-break strategy for CANDU primary piping systems

Recent advances in elastic-plastic fracture mechanics have made it possible to assess the stability of cracks in ductile piping systems. These technological developments have been used by Ontario Hydro as the nucleus of an approach for demonstrating that CANDU primary heat transport piping systems will not break catastrophically; at worst they would leak at a detectable rate. This leak-before-break approach has been taken on the Darlington nuclear generating station as a design stage alternative to the provision of pipe whip restraints on large diameter, primary heat transport system piping. Positive conclusions reached via this approach are considered sufficient to exclude the requirement to provide protective devices, such as pipe whip restraints.

In arriving at the proposed leak-before-break approach a review of current and proposed leak-before-break licensing positions of other jurisdictions (particularly those in the United States and the Federal Republic of Germany) was carried out. The approach presented makes use of recent American developments in the area of elastic-plastic fracture mechanics. It also gives consideration to aspects which are unique to the pressurized heavy water (CANDU) reactors used by Ontario Hydro.

The present paper describes the proposed leak-before-break approach and illustrates its use by applying it to the Darlington generating station primary heat transport system pump suction piping.     

Summary of theoretical and experiment development of a novelelectromagnetic technique for remote repositioning of coolant tubespaces in CANDU nuclear reactors

The authors describe the experimental and theoretical development of a novel electromagnetic method to reposition the spacers used between the pressure and calandria tubes in a CANDU nuclear reactor without dismantling the fuel channels. The method was successfully developed and implemented to reposition the dislocation spacers in five CANDU reactors in Ontario,. The savings in reactor repair costs, interest charges, and replacement energy costs were on the order of hundreds of millions of dollars. There are a number of other applications of the electromagnetic technique which may also benefit from the analysis and experimental development, especially for pulse power, electromagnetic metal forming, and fusion technologies     

Methods of observation and elimination of semiconductor defect states

A method of observation of interface states for ultrathin insulating layer/semiconductor interfaces is developed by use of X-ray photoelectron spectroscopy (XPS) measurements under bias. The analysis of the energy shift of the semiconductor core level as a function of the bias voltage gives energy distribution of interface states. When the atomic density of SiO₂ layers is low (e.g., SiO₂ layers formed at 350 °C), only one interface state peak is observed near the midgap, and it is attributed to isolated Si dangling bonds at the interface. For SiO₂ layers with a high atomic density (e.g., SiO₂ layers formed at 700 °C), on the other hand, two interface state peaks, one above and the other below the midgap, are observed, and they are attributed to Si dangling bonds interacting weakly with a Si or oxygen atom in SiO₂. Interface states can be passivated by cyanide treatment which simply involves the immersion in cyanide solutions such as KCN and HCN solutions. When the cyanide treatment is applied to indium tin oxide/SiO₂/mat-textured single crystalline Si metal-oxide-semiconductor (MOS) solar cells, the photovoltage is greatly increased, leading to a high conversion efficiency of 16.2%. When the cyanide treatment is performed on polycrystalline Si (poly-Si)-based MOS diodes, a greater effect in comparison to that for single crystalline Si-based MOS diodes is observed due to the elimination of defect states in poly-Si as well as Si/SiO₂ interface states. The cyanide treatment can also increase the conversion efficiency of pn-junction single crystalline and poly-Si solar cells.     

高压海底电缆锚害事故风险评估

  目的  锚害事故导致电缆受损断电将会造成较为严重的经济损失和社会影响,为降低海底电缆面临的锚害事故风险,提出了一种高压海底电缆锚害事故风险评估方法。  方法  根据事故发生的原因,将锚害事故分为抛锚事故和拖锚事故两种情况分别进行建模计算,并在单根电缆锚害风险研究的基础上,研究了多根电缆的锚害风险。  结果  根据模型计算结果,分析得出锚害事故的重要影响因子为电缆根数、警示距离、船舶速度,同时随着电缆根数减少、警示距离增加、船舶速度增大,高压海底电缆锚害事故风险将会有效降低。  结论  所提模型可有效评估高压海底电缆锚害事故风险,可以为海底电缆的防护及优化设计工作提供理论指导。     

Anti‐windup linear parameter‐varying control of pitch actuators in wind turbines

Operation of wind turbines in the full‐load region mandates that the produced power is kept at a rated value to minimize structural loads and thereby reduce fatigue damage. This is usually achieved by pitching the rotor blades in order to limit the aerodynamic torque in high wind speeds. The pitch actuators usually present a hard constraint in terms of the amplitude and rate of saturation. In this paper, we propose a method to address pitch actuator amplitude and rate saturation by designing anti‐windup controllers in the linear parameter‐varying framework. The proposed design method guarantees the closed‐loop system stability and a prescribed level of performance while it decreases the pitch activity for regulating the generated power to the nominal power during sudden wind gusts. The anti‐windup controller designed to minimize the norm of the closed‐loop system is gain‐scheduled on the basis of the operating condition of the turbine, as well as the states of amplitude and rate saturation of the pitch actuator. The effectiveness of the proposed control design method is demonstrated using high‐fidelity aeroelastic dynamic simulation tools. Copyright © 2013 John Wiley & Sons, Ltd.     

660 MW超临界“W”火焰炉机组磨煤机台数匹配研究

依托某660 MW超临界W火焰炉燃煤机组项目,针对制粉系统配置的磨煤机台数提出了新方案,通过常规6磨方案和4磨新方案的技术经济比较,论证了配置4台双进双出磨煤机方案技术可行,运行可靠,经济效益显著,为该类型机组制粉系统提出了新思路。     

高压注浆法在提高地基剪切波速中的应用

《核电厂抗震设计规范》要求核电厂核安全抗震物项宜坐落在基岩或剪切波速大于400 m/s的地基上,当地基剪切波速小于400 m/s时,需要对其进行换填素混凝土或者加固处理,以满足设计要求。文中通过对台山核电废液储存罐厂房地基处理方案的介绍,从经济和技术两个方面对比分析了开挖换填素混凝土和高压注浆法的优缺点。通过现场实践证明,对于深厚回填土,砂石含量较高时,采用高压注浆法可以将地基的剪切波速提高至400 m/s以上,避免了换填素混凝土时边坡的开挖和支护,施工安全风险小,造价相对较低。高压注浆法特别适用于以提高地基剪切波速为主要目的的深厚回填土的处理。