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柔直异步互联后送端区域电网动态特性变化及稳定控制 [PDF]
全球能源互联网, 2018 为减小直流故障对交流电网的冲击影响，降低稳定控制措施的复杂程度，交直流混联区域电网与区外电网间的同步互联格局可转化为纯直流异步互联格局。随互联格局变化，电网动态特性将发生深刻改变。分析了区域电网结构特征；构建了区域电网交直流外送系统模型，从动态行为约束方程和时域受扰响应对比两个方面，研究了区域电网动态特性的变化，并梳理了主要影响因素。在此基础上，针对渝鄂背靠背柔性直流工程投运后的西南区域异步互联电网，提出了改善电网受扰特性的稳定控制措施，大扰动暂态仿真验证了措施的有效性。
郑超 +6 more
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Gaoya dianqi, 2023 大型电力变压器绕组的固有振动特性影响其在短路冲击电流下的振动响应及抗短路能力。为了弄清楚固有振动特性与绕组机械参数间的关系，文中建立了计及压板和线圈的绕组轴向振动“质量—弹簧—阻尼”模型，提出了等效质量、刚度和固有振动特性的计算方法。在此基础上，分析了一台SFSZ8-40000/110变压器低压绕组的模态频率和振型，研究了垫块弹性模量、数量和端圈垫块厚度等因素对绕组固有振动特性的影响规律。研究结果表明，绕组各阶轴向振动模态频率之间满足倍数关系，各阶频率对应的振型为绕组不同位置线饼沿轴向的同向和反向振动 ...
刘力卿 +6 more
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Gaoya dianqi, 2022 机械故障是断路器发生的主要故障之一，断路器分合闸过程中产生的振动信号可以有效反应其运行状态。针对现有的时频域分析等线性分析方法在提取断路器振动信号时存在的局限性，提出并探讨了一种基于相空间重构的断路器振动信号边缘特征提取方法，用于刻画断路器的非线性特征，为断路器的状态诊断提供依据。搭建故障模拟平台模拟断路器正常状态、触头磨损、线圈老化、低操作电压、合闸弹簧失效的振动信号；结合分形理论和边缘检测算法提取振动信号的边缘图像和边缘特征量，从边缘图像形态 ...
盛健 +6 more
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智能科学与技术学报, 2023 目前同时定位与地图构建技术多假设外部环境是静态的，忽略了动态目标对SLAM系统的影响，这一假设很大程度上影响了无人系统自主导航的定位精度与鲁棒性。针对这一问题，提出了一种结合目标检测语义信息与多视图极线几何约束的动态SLAM系统，根据运动概率来判别与剔除系统中的动态特征点，并在TUM数据集及实机平台上进行了算法性能测试。实验结果表明在高动态环境下，该系统相较于ORB-SLAM2在绝对轨迹误差上至少可减小94%以上，相对位移轨迹和旋转角度误差分别至少降低了41%和40%，表明该算法能够有效剔除动态特征点 ...
李嘉铭, 解明扬, 张民, 王从庆
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Wildlife Letters, EarlyView.Eimeria saudiensis represents a genus of apicomplexan parasites capable of inducing coccidiosis in Arabian oryx. Our research concentrated on the morphological and molecular investigation of Eimeria spp. in the captive oryx herd in Oman. The therapeutic and management practices employed at the Mammals Breeding Center were reassessed to diminish ...
Khalid Al‐Habsi +7 more
wiley +1 more source
Wildlife Letters, EarlyView.Using a 3‐year, broad‐scale camera‐trap network in western Kansas, we tested whether coyotes and American badgers exhibit spatiotemporal patterns consistent with coordinated hunting. Despite high diel activity overlap, detection‐conditioned co‐detections occurred far less frequently than expected under independence, and short‐term temporal sequencing ...
Ty J. Werdel +3 more
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Local Ecological Knowledge Reveals the Distribution of Cryptic Nocturnal Wildlife
Wildlife Letters, EarlyView.Many nocturnal animals are difficult to study because they are rarely seen, including nocturnal primates, galagos and pottos, in West Africa. Working with over 600 people in 52 villages in southern Guinea‐Bissau, we found that communities frequently recognized galagos by their red eyeshine and distinctive calls, while pottos were not known.
Chloe Chesney +6 more
wiley +1 more source
Functional Ecology, EarlyView.Read the free Plain Language Summary for this article on the Journal blog. Abstract Decomposition is the transformation of dead organic matter into its inorganic constituents. In most biomes, decomposition rates can be accurately predicted with simple mathematical models, but these models have long under‐predicted decomposition in globally extensive ...
Heather L. Throop +8 more
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Functional Ecology, EarlyView.Read the free Plain Language Summary for this article on the Journal blog. Abstract Human‐driven landscape change, particularly urbanization, is reshaping pollinator communities, yet the functional traits that mediate species persistence remain poorly understood. Dietary specialization is commonly used to predict species vulnerability.
Yan Yang +5 more
wiley +1 more source
Gaoya dianqi, 2008 针对27.5kV永磁机构真空断路器并根据其动作特点,进行了基于Ansoft和Matlab软件的静态、动态特性仿真。首先,建立有限元模型,利用Ansoft软件包对永磁机构的静态特性进行仿真。其次,根据耦合电压平衡方程和达朗贝尔机械运动特征方程,在静态仿真基础上采用Matlab构建永磁机构断路器的运动模型,对永磁机构动铁心、断路器动触头运动特性进行了仿真分析。最后,对设计的样机进行了动态测试,测试结果表明仿真的正确性。
周丽丽 +5 more
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