Results 1 to 10 of about 4,816 (122)
全球能源互联网, 2023 针对特高压直流闭锁等原因造成的受端电网频率严重跌落问题，提出一种储能紧急频率控制策略。首先，建立储能参与紧急频率控制的数学模型。其次，对于大功率缺额后发电机组惯性响应不足问题，提出了改进的频率变化率（rate of change of frequency，RoCoF）下垂控制策略以提高储能的惯量支撑，根据储能比例分配系数实时调节储能虚拟惯性及下垂控制出力；惯性响应阶段以RoCoF下垂控制为主、虚拟惯性控制为辅，抑制系统频率变化率；结合频率调节需求和储能系统出力特点提出不同区域的调频策略 ...
苏大威, 郝雨辰, 高水朋, 葛乐
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Carbon Neutralization and New Power Systems, 2023 摘要：随着新能源占比的逐渐提升，维持系统频率稳定性成为了当前面临的重大挑战。为了提升新型电力系统下的频率稳定性，本文提出了一种基于电力系统受扰后频率最低点预测的一次调频优化方法。首先为了准确预测电力系统受到扰动后的频率变化特征，分析了频率偏差的产生机理，选取了切机等功率不平衡事件的相关影响变量，结合极限学习机（Extreme learning Machines, ELM），建立了基于ELM 神经网络的电力系统频率最低点预测模型，并采用蜣螂算法（Dung Beetle Optimizer, DBO ...
烨昱 沈 +4 more
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全球能源互联网, 2021 大规模的可再生能源并网使得电网内传统机组占比减小,惯性水平降低,电网的频率稳定性面临严重挑战。储能作为一种优质的调频资源,其调频时的高额注入功率会改变系统原有潮流,可能导致部分线路功率越限,因此提出了考虑系统潮流约束的“储能-输电网”联合规划模型。首先分析系统频率最大偏差与储能装机功率以及机组停运功率的关系,对系统内不同故障下的储能需求进行估计；然后以储能与输电线路扩建总成本最小为目标,建立考虑潮流约束的储能与输电线路扩建联合规划模型；最后基于修正的IEEE-39节点系统进行算例验证 ...
郭嘉庆 +4 more
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工程技术研究, 2020 瓦斯发电机组常出现功率因数波动大，手动调节频率高，机组未采用集中控制，加之人员少等原因，常常造成功率因数偏高或偏低。
Dong-Dong Wang
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People and Nature, Volume 5, Issue 6, Page 2158-2177, December 2023., 2023 Abstract Global change is increasing the frequency and severity of human‐wildlife interactions by pushing people and wildlife into increasingly resource‐limited shared spaces. To understand the dynamics of human‐wildlife interactions and what may constitute human‐wildlife coexistence in the Anthropocene, there is a critical need to explore the spatial,
Christine E. Wilkinson +4 more
wiley +1 more source
Integrative Conservation, Volume 2, Issue 2, Page 95-107, June 2023., 2023 This is a study of the spatiotemporal patterns of Human−Elephant conflict in a community area adjacent to Kuiburi National Park, southern Thailand. We examined temporal and spatial patterns of elephant crop raiding by assessing the locations of elephant raids in conjunction with environmental factors along with crop characteristics and crop ...
Poldej Kochprapa +4 more
wiley +1 more source
Journal of Diabetes, Volume 15, Issue 6, Page 496-507, June 2023., 2023 Highlights Using a large‐scale prospective population‐based cohort study, we found that a higher frequency of daytime napping is associated with an increased risk of incident type 2 diabetes (T2D), and such relations are modified by body fat percentage (BFP) and C‐reactive protein (CRP) levels.
Rui Zhou +9 more
wiley +1 more source
Family Process, Volume 61, Issue 2, Page 571-590, June 2022., 2022 Abstract Several effective interventions have been developed for families with multiple problems (FMP), but knowledge is lacking as to which specific practice and program elements of these interventions deliver positive outcomes. The aim of this study is to assess the degree to which practice and program elements (contents of and structure in which ...
Loraine Visscher +7 more
wiley +1 more source
Gongye shui chuli, 2020 以交流异步电机、多级离心水泵及反渗透膜系统的运行特性为基础，明确了特定反渗透系统在恒通量及恒收率的运行条件下，回流调节、截流调节与变频调速3种系统运行调节方式的特点；分析了3种运行调节方式各自的能耗水平，论证了变频调速方式是反渗透系统最为节能的运行调节方式。
赵冲 +4 more
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锻炼频率对60-74岁低龄老年人抑郁程度的影响：自评健康状况的调节效应
中国医学科学研究背景：中国低龄老年人（60-74岁）面临退休适应、慢病初发等心理健康挑战，尤其在突发公共卫生事件等应激事件中抑郁风险显著升高，同时，低龄老年人抑郁的保护因素如锻炼频率、自评健康等的作用机制尚未明晰。目的：分析中国60-74岁低龄老年人抑郁现状，验证锻炼频率与自评健康对抑郁的独立效应及自评健康状况的调节作用。方法：基于中国家庭追踪调查（CFPS）2022年全国数据，筛选出60-74岁样本，采用流调中心抑郁量表简表（CES-D8量表）评估抑郁程度，通过分层回归及Hayes的SPSS ...
Pu Ge +4 more
semanticscholar +1 more source