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排序方式: 共有104条查询结果,搜索用时 375 毫秒
1.
随着电力物联网概念的提出,暂态稳定评估在电力系统规划运行中扮演着越来越重要的角色.由于同步相量测量单元(PMU)的广泛配置,基于机器学习和PMU在线量测数据的暂态稳定实时评估方法展现出了巨大的发展潜力.针对这类方法在应用中可能因PMU失效而严重影响精度的问题,文中提出了一种考虑数据缺失的电力系统暂态稳定自适应集成评估方法.首先,在保证全网节点可观性的基础上构建考虑PMU重要性的PMU子集集合搜索算法.然后,根据PMU子集对应的特征集训练暂态稳定评估子模型.最后,在任意可能的PMU失效情况下采用自适应加权融合机制构建集成暂态稳定评估模型.在新英格兰10机39节点电力系统上的仿真表明,文中提出的方法在PMU失效造成的数据缺失下仍然能够准确、可靠地进行暂态稳定评估,在鲁棒性、计算量及准确率上相比已有的方法均具有较大优势. 相似文献
2.
Quoc Ahn Tran Bastien Chevalier Miguel Angel Benz-Navarrete Pierre Breul Roland Gourvès 《Soils and Foundations》2019,59(6):2348-2355
This paper presents a calculation method for obtaining the continuous variation in stress between the tip and the soil during dynamic penetration tests, particularly in the case of using the Panda 3® penetration testing device. The originality of the method is that the tip stress can be computed continuously throughout the driving process. For each impact of the hammer on the penetrometer, data are recorded by sensors located at the top of the apparatus. Then, the stress at the tip and the displacement of the apparatus are calculated with a method based on the propagation of waves in the device. A three-dimensional numerical model of the penetration test, based on the Panda 3® specifications and using the discrete element method (DEM), is proposed in this paper. The purpose of the simulations is to validate the calculation method by comparing the curves of the tip stress versus the penetration distance obtained in two different ways, the first being the distance directly observed at the tip and the second being the distance calculated from the data recorded at the top of the penetrometer, as with the experimental device. The entire apparatus is represented, including the hammer, the rod, and the tip, and is driven into the model soil. The calculation method is applied, and the results are compared to the actual response of the soil to the driving of the penetrometer directly at the tip, which can be obtained with the numerical model. The responses are found to be very similar, confirming the theoretical framework and its underlying assumptions. This method is applied to dynamic penetration tests and provides the opportunity to obtain mechanical parameters other than the tip resistance from the tests. 相似文献
3.
The Critical Clearing Time (CCT) is a key issue for Transient Stability Assessment (TSA) in electrical power system operation, security, and maintenance. However, there are some difficulties in obtaining the CCT, which include the accuracy, fast computation, and robustness for TSA online. Therefore, obtaining the CCT is still an interesting topic for investigation. This paper proposes a new technique for obtaining CCT based on numerical calculations and artificial intelligence techniques. First, the CCT is calculated by the critical trajectory method based on critical generation. Second, the CCT is learned by Extreme Learning Machine (ELM). This proposed method has the ability to obtain the CCT with load changes, different fault occurrences, accuracy, and fast computation, and considering the controller. This proposed method is tested by the IEEE 3-machine 9-bus system and Java-Bali 500 kV 54-machine 25-bus system. The proposed method can provide accurate CCTs with an average error of 0.33% for the Neural Network (NN) method and an average error of 0.06% for the ELM method. The simulation result also shows that this method is a robust algorithm that can address several load changes and different locations of faults occurring. There are 29 load changes used to obtain the CCT, with 20 load changes included for the training process and 9 load changes not included. 相似文献
4.
50th Anniversary Article: Seeing Stresses through the Thermoelastic Lens—A Retrospective and Prospective from an Australian Viewpoint 下载免费PDF全文
Thermoelastic stress analysis (TSA) has been around for the past 30 years, but to date, it is still a very much underrated and under‐utilised experimental technique. Although there are devoted groups of practitioners in some industries, this technology is not well known within the aerospace sector. In contrast, the Aerospace Division of the Defence Science and Technology Organisation (DSTO) in Australia has been in the forefront of this technology for some time, achieving many pioneering feats. This paper gives a brief introduction to the development of this technology from a historical perspective, then focuses on a number of innovations that have stemmed from DSTO, including the development and application of the world's first focal plane array based TSA system and, more recently, the development of small and robust microbolometer based systems. For the latter, it is shown that despite nominally poorer temperature sensitivities, they make ideal TSA devices and can in some cases outperform their much more expensive photon detector counterparts. Because of this, together with the enormous practical advantages of microbolometers, the future of TSA is shown to be brighter than ever. Specifically, it is argued that such TSA systems can play a major role in the pervasive and persistent surveillance of full scale fatigue testing of aircraft structures. By detecting both design and developing faults early, it can effectively relieve cost and schedule penalties that are often associated with unanticipated failures. To realise this capability, integration of this technology with autonomous systems will be important, and some preliminary but promising results from a technology demonstrator program are presented. 相似文献
5.
6.
Min-Bae?Kim Jong-Ho?Moon Chang-Ha?LeeEmail author Hyungwoong?Ahn Wonihl?Cho 《Korean Journal of Chemical Engineering》2004,21(3):703-711
The effect of radial heat transfer on temperature swing adsorption (TSA) was studied by using an air-drying TSA experiment.
The experimental dynamics of water adsorption and thermal regeneration in a fixed bed packed with zeolite 13X were used to
evaluate the predicted results from the developed models. One-and two-dimensional models for energy balance with various equations
describing internal velocity were compared in terms of the prediction of transient dynamics of TSA. Since the heat effect
in adsorption step depended on the isosteric heat of adsorption, a dynamic simulation was performed under adiabatic, near-adiabatic,
and constant wall temperature conditions. A comparison between one-and two-dimensional models was also made under near-adiabatic
condition, which reflected on the experimental condition. There was little difference between adsorption breakthrough curves
predicted by the one- and two-dimensional models because the radial distribution of temperature was negligible at the adsorption
step. In the case of the regeneration step, a small difference between two models was expected just at the early period of
time because the radial effect disappeared with time. One-dimensional model could provide an adequate prediction of the transient
dynamics in this system when the wall energy balance was included. 相似文献
7.
J. M. Dulieu-Barton 《Strain》1999,35(2):35-39
The theory of thermoelastic stress analysis is reviewed and the assumptions in developing the theory are assessed. The equipment for thermoelastic stress analysis is based on infrared detection systems. The commercially available systems are described and appraised. Techniques for calibrating the output from the detectors are also provided. 相似文献
8.
结合车间调度问题本身的特点,采用关键路径块邻域结构,混合禁忌搜索算法和粒子群优化算法,设计了一种快速混合调度算法.该算法对预选择的块邻域解的性能进行快速估计,对不可行解尽早舍去,大大减小了邻域解的搜索空间.仿真结果表明,该算法在求解平均时间和性能方面均具备明显优势. 相似文献
9.
A number of applied thermoelastic stress analysis (TSA) studies on composite components and assemblies are described, for the purpose of illustrating the potential of the technique for use with composite materials. 相似文献
10.
利用灰色理论能适应“小样本、贫信息”的特点,建立了大坝安全监测灰色-时序动态组合模型,为解决大坝安全监测中短序列数据建模难题提供了一条有效的途径。 相似文献