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991.
One-second irradiance data from forty-five sensors spaced over a one-mile square section of land were analyzed to characterize the short-term (1-s to 1-min) variability of the solar resource in Northern Arizona. The geostatistical interpolation model known as kriging was applied to our data set to better understand the method's strengths and weaknesses in accurately predicting the variations in the irradiance over this relatively small section of land. Of particular interest was to investigate the ability of the kriging method to show the variation in solar irradiance over the section of land as compared to that measured by the sensors. When using data from all the sensors as input to the prediction method, kriging performed very well compared to the sensors. However, because it is unlikely to have a large number of sensors to characterize the variability at a prospective solar site, it was also of interest to investigate how many sensors are required as input to the kriging technique in order to generate a reliable prediction. Solar data from four characteristic periods (related to the four seasons) were analyzed, and different sensor configurations, consisting of subsets of the actual sensor array, were employed using the method to demonstrate the number of sensors required to correctly characterize the short-term irradiance variability at the site. Using four measurement stations as input to the kriging method was shown to reasonably represent the variability in the 1-s to 1-min timescales. 相似文献
992.
993.
I. Muzik 《Civil Engineering and Environmental Systems》2013,30(5):270-273
The concepts of state and state variables are introduced. From a mathematical point of view the concept of state variables provides the means of transforming a differential equation of any order into an equivalent set of first-order equations. From a physical point of view the state of a system, specified by numeric values of the system state variables at a given time, contains all the relevant information about the system necessary to predict the behaviour of the system in the future. The state variable concept is thus very much suited for analysis of dynamic systems. Examples of the state variable concept applied to analysis of discharge from a reservoir and from two reservoirs operating in series are presented. 相似文献
994.
通过分析钢铁企业烧结烟气脱硫系统运行中的常见故障及其原因,提出了相应的措施和对策,以指导湿式石灰-石膏法烧结烟气脱硫系统的运行管理及其日常维护、保养工作。 相似文献
995.
Abstract—This article proposes a novel zero-current switching series resonant inverter-fed voltage multiplier based high-voltage DC-DC converter. The series resonant inverter in the proposed topology has two power switches (insulated-gate bipolar transistors), two resonant capacitors, and only one high-voltage transformer with center-tapped primary windings. The power switches are connected in the form of a half-bridge network. The leakage inductances of the transformer's primary windings together with resonant capacitors form two series resonant circuits. The series resonant circuits are fed alternately by operating power switches with an interleaved half-switching cycle. The secondary winding of the high-voltage transformer is connected to a voltage multiplier circuit to rectify and boost the voltage. The converter operates in discontinuous conduction mode, and its output voltage is regulated by pulse-frequency modulation. Therefore, all the power switches turn ON and OFF at the zero-current switching condition. The main features of the proposed converter are lower power loss, less cost, and smaller size compared to previously proposed series resonant high-voltage DC-DC converters. The experimental results of a 130-W prototype of the proposed converter are presented both for dynamic and steady-state operation. The results confirm the excellent operation and performance of the converter. 相似文献
996.
997.
998.
基于所提出的评价标准新构架和3个标准的设计思想,针对中国电网运行具体实际,对各标准指标的构造进行了理论探索,给出了3个标准的指标备选方案。其要点是:将行业标准中频率合格百分数指标转化为概率指标,以适应中国的电网质量考核方式;针对频率安全的实际关注点,设计积分型的频率安全标准指标形式,并给出了离散采样情况下的指标样式;无意交换电量标准中时段长度可选,可适应不同的结算时间尺度;对所设计的各项标准的重合度进行分析,明确了各标准同时设置的必要性。 相似文献
999.
1000.