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Modeling cascading failures and mitigation strategies in PMU based cyber-physical power systems

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Journal of Modern Power Systems and Clean Energy 2018年第5期6卷 944-957页

作者： Yuqi HAN Chuangxin GUO shiying ma Dunwen SONG College of Electrical Engineering Zhejiang University China Electric Power Research Institute

This paper presents a model of cascading failures in cyber-physical power systems(CPPSs) based on an improved percolation theory, and then proposes failure mitigation strategies. In this model, the dynamic development of cascading failures is divided into several iteration stages. The power flow in the power grid, along with the data transmission and delay in the cyber layer, is considered in the improved percolation theory. The interaction mechanism between two layers is interpreted as the observability and controllability analysis and data update analysis influencing the node state transformation and security command execution. The resilience indices of the failures reflect the influence of cascading failures on both topological integrity and operational state. The efficacy of the proposed mitigation strategies is validated, including strategies to convert some cyber layer nodes into autonomous nodes and embed unified power flow controller(UPFC) into the physical layer. The results obtained from simulations of cascading failures in a CPPS with increasing initial failure sizes are compared for various *** cascading failures can be separated into rapid and slow processes. The interdependencies and gap between the observable and controllable parts of the physical layer with the actual physical network are two fundamental reasons for first-order transition failures. Due to the complexity of the coupled topological and operational relations between the two layers, mitigation strategies should be simultaneously applied in both layers.

关键词： Cyber physical power system Cascading failure Improved percolation theory Interdependent network Mitigation strategy

Threshold pressure gradient of fluid flow through multi-porous media in low and extra-low permeability reservoirs

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Science China Earth Sciences 2014年第8期57卷 2808-2818页

作者： DOU HongEn ma shiying ZOU CunYou YAO ShangLin Research Institute of Petroleum Exploration & Development PetroChina

After analyzing many studies of fluid flow theory of multi-porous media in low and extra-low permeability reservoirs and the numerical simulation of non-Darcy flow, we found that a negative flow rate occurs in the existing non-Darcy flow equation, which is unreasonable. We believe that the existing equation can only be considered as a discriminant to judging Darcy flow or non-Darcy flow, and cannot be taken as a fluid flow governing equation of multi-porous media. Our analysis of the experimental results shows that the threshold pressure gradient(TPG) of low and extra-low permeability reservoirs is excessively high, and does not conform to fluid flow through multi-porous media in the actual reservoir situation. Therefore, we present a reasonable TPG ranging from 0.006 to 0.04 MPa/m at the well depth of 1500 m and oil drainage distance of 500 m. The results of our study also indicate that the non-Darcy flow phenomenon will disappear when the TPG reaches a certain value. In addition, the TPG or non-Darcy flow in low and extra-low permeability reservoirs does not need to be considered in the productivity prediction and reservoir numerical simulation. At present, the black oil model or dual-porous media is suitable for simulating low and extra-low permeability reservoirs.

关键词： low permeability extra-low permeability non-Darcy flow threshold pressure gradient matrix fracture dual-porositymedia

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基于关键支路受扰轨迹凹凸性的暂态稳定判别及紧急控制

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中国电机工程学报 2016年第10期36卷 2600-2610页

作者：郑超苗田马世英中国电力科学研究院北京市海淀区100192 华北电力大学电气与电子工程学院河北省保定市071003

基于局部受扰信息,判别大扰动冲击下互联电网暂态功角稳定性,具有本地量测信息量少、实时响应实时判别、稳定判别计算量小等突出技术优点。该文首先分析了稳定与失稳两种情况下,发电机相轨迹与网络交流支路相轨迹几何特征的一致性;提出... 详细信息

基于局部受扰信息,判别大扰动冲击下互联电网暂态功角稳定性,具有本地量测信息量少、实时响应实时判别、稳定判别计算量小等突出技术优点。该文首先分析了稳定与失稳两种情况下,发电机相轨迹与网络交流支路相轨迹几何特征的一致性;提出了基于临界断面中交流关键支路受扰相轨迹凹凸性的暂态稳定判别新方法;通过与快速失步解列装置整定参数的协调配合,获得了具备工程实施条件的时间裕度,在防控暂态稳定的第二道防线失效时,可作为避免失稳的紧急追加控制措施;交直流混联外送电网和特高压跨大区互联电网仿真结果,均验证了稳定判别方法和紧急追加控制的有效性。

关键词：暂态稳定局部受扰信息相轨迹凹凸性稳定判别紧急追加控制协调配合

U-Pb zircon geochronology of basaltic pyroclastic rocks from the basement beneath the Xisha Islands in the northwestern South China Sea and its geological significance

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Acta Oceanologica Sinica 2024年第2期43卷 83-93页

作者： Yu Zhang Kefu Yu shiying Li Guangxi Laboratory on the Study of Coral Reefs in the South China Sea Guangxi UniversityNanning 530004China Coral Reef Research Center of China Guangxi UniversityNanning 530004China School of marine Sciences Guangxi UniversityNanning 530004China Key Laboratory of Ocean and marginal Sea Geology South China Sea Institute of OceanologyChinese Academy of ScienceGuangzhou 510301China

As one of the micro-blocks dispersed in the South China Sea(SCS), the basement of the Xisha Islands has rarely been drilled because of the thick overlying Cenozoic sediments, which has led to a confused understanding of the pre-Cenozoic basement of the Xisha Islands. Well CK-1, a kilometer-scale major scientific drill in the Xisha Islands in the northwestern SCS, penetrated thick reefal limestone(0–888.4 m) and the underlying basement rocks(888.4–901.4 m). In this study, we present the zircon U-Pb ages of basement basaltic pyroclastic rocks from Well CK-1 in the Xisha Islands of the northwestern SCS to investigate the basement nature of the Xisha microblock. The basement of Well CK-1 consists of basaltic pyroclastic rocks on the seamount. The zircon grains yielded apparent ages ranging from ca. 2 138.9 ma to ca. 36 ma. The old group of zircon grains from Well CK-1 was considered to be inherited zircons. Two Cenozoic zircons gave a weighted mean 206Pb/238U age of(36.3 ± 1.1) ma,Mean Squared Weighted Deviations(MSWD) = 1.2, which may represent the maximum age of the volcano eruption. The Yanshanian inherited zircons(116.9–105.7 ma and 146.1–130.2 ma) from Well CK-1 are consistent with the zircons from Well XK-1, indicating that the basement of Chenhang Island may be similar to that of Well XK-1. We propose that the Xisha micro-block may have developed on a uniform Late Jurassic metamorphic crystalline basement, intruded by Cretaceous granitic magma.

关键词： South China Sea Xisha Islands basaltic pyroclastic rocks zircon

An unexpected stereochemical effect of thio-substituted Asp in native chemical ligation

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Chinese Chemical Letters 2024年第8期35卷 278-281页

作者： Min Fu Pan He Sen Zhou Wenqiang Liu Bo ma shiying Shang Yaohao Li Ruihan Wang Zhongping Tan State Key Laboratory of Bioactive Substance and Function of Natural Medicines Institute of Materia MedicaChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100050China Center of Pharmaceutical Technology School of Pharmaceutical SciencesTsinghua UniversityBeijing 100084China Chemical Engineering College Hebei Normal University of Science and TechnologyQinhuangdao 066600China

This study presents an unexpected finding that the cis isomer of β-thio-Asp exhibits higher ligation ac-tivity than the trans *** discovery sheds light on the intricate nature of native chemical ligation and highligh... 详细信息

关键词： Native chemical ligation Stereochemistry Ligation activity β-Thio-Asp Intramolecular hydrogen bond

DSG型抛物面槽式太阳能热电站热力系统实时动态仿真模型研究

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中国电机工程学报 2014年第11期34卷 1787-1798页

作者：崔凝徐国强马士英北京航空航天大学北京市海淀区100191 保定华仿科技有限公司河北省保定市071051

采用模块化建模方法研究了无蓄热装置再循环方式直接产生蒸汽型抛物面槽式太阳能热动力发电站(solar thermal power plant using direct steam generation in parabolic trough collectors filed,DSG-PTCs-STTP)热力系统动态仿真模型。依照守恒定律和热力学、传热学、流体力学等基本关系式,在一定简化条件下,研究了抛物面槽式聚光集热系统的聚光器、预热段、蒸发段、过热段及汽水缓冲分离器的数学模型,结合其他已有的仿真模型(如流体网络、汽轮机、凝汽器、除氧器、水泵、发电励磁等过程及设备模型等),建立了完整的DSG-PTCs-STTP热力系统实时动态仿真模型。仿真试验表明所开发的仿真模型能够正确反映研究对象热力系统动态特性和全工况运行过程,模型运算稳定可靠。可用于DSG-PTCs-STTP机组实时仿真系统的开发,还可为机组运行特性研究和控制系统验证提供良好的非线性对象模型。

关键词：直接产生蒸汽抛物面槽式聚光集热太阳能热力电站动态模型仿真

近振荡中心直流逆变站对系统阻尼的影响及优化措施

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中国电机工程学报 2015年第19期35卷 4895-4905页

作者：郑超马世英盛灿辉中国电力科学研究院北京市海淀区100192

我国地域辽阔,一次能源与负荷中心呈逆向分布特征。特高压直流跨区送电,并经特高压交流接续送电,是实现电力大容量、远距离、经济高效输送的重要方式,将成为交直流混联电网的典型格局之一。大扰动冲击下,与振荡中心近电气距离的大容量... 详细信息

我国地域辽阔,一次能源与负荷中心呈逆向分布特征。特高压直流跨区送电,并经特高压交流接续送电,是实现电力大容量、远距离、经济高效输送的重要方式,将成为交直流混联电网的典型格局之一。大扰动冲击下,与振荡中心近电气距离的大容量直流逆变站,其功率动态变化,会对系统振荡阻尼特性产生影响。该文研究了交流电压大幅波动条件下,直流逆变站非线性无功特性;从并联无功补偿支路提供振荡正阻尼条件和振荡等面积原理两个方面,揭示了直流逆变站弱化振荡阻尼的机制;基于低压限流单元(voltage dependent current order limiter,VDCOL)限流特性曲线对逆变站无功特性的影响分析,提出改善混联系统振荡阻尼的优化措施。准东—重庆?1 100 k V/10 000 MW特高压交直流混联电网大扰动时域仿真结果,验证了措施对抑制混联电网低频振荡的有效性。

关键词：特高压直流逆变站功率特性振荡中心振荡阻尼

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多馈入直流系统协调控制综述

电力系统自动化 2009年第3期33卷 9-15页

作者：郭小江马世英卜广全汤涌中国电力科学研究院北京市100192

基于多馈入直流系统的强非线性、强耦合特征,分析了多馈入直流系统对协调控制技术应用于工程实际的迫切需求,从线性和非线性控制、集中和分散控制等角度综述了多馈入直流系统协调控制技术发展过程及研究现状。首先,讨论了经典线性控制... 详细信息

基于多馈入直流系统的强非线性、强耦合特征,分析了多馈入直流系统对协调控制技术应用于工程实际的迫切需求,从线性和非线性控制、集中和分散控制等角度综述了多馈入直流系统协调控制技术发展过程及研究现状。首先,讨论了经典线性控制、非线性控制、最优控制、鲁棒控制、自适应控制等控制方法在多馈入直流系统协调控制中的应用。然后,针对多馈入直流系统集中协调控制方法需要反馈大量远方和不可测量信号存在的工程应用问题,阐述了近年来基于分散建模理论与关联测量、分布式闭环反馈、广域测量信号反馈等方法相结合的多直流分散协调控制研究成果。最后,探讨了协调控制应用于多馈入交直流系统所面临的重要问题和未来研究方向。

关键词：多馈入直流协调控制线性控制非线性控制分散控制

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基于动态仿真模型的ISCCS热力特性研究

中国电机工程学报 2016年第4期36卷 1025-1035页

作者：马士英崔凝刘洋吴铭棉华北电力大学河北省保定市071003 保定华仿科技股份有限公司河北省保定市071051

设计了6套不同容量和流程的直接产生蒸汽型槽式聚光集热系统(direct steam generation in parabolic trough collectors,DSG-PTC);提出以DSG-PTC为辅助热源的整体太阳能联合循环发电系统(integrated solar combined cycle system,ISCCS)的6种集成方案;基于已取得的研究成果,研究ISCCS系统实时动态仿真模型。利用模型从系统层面分析了ISCCS系统的运行特性,反映了2个能源系统间工质流和能量流的匹配规律;揭示控制系统在ISCCS中的适用性并提出了控制策略的改进建议;研究ISCCS系统动态响应特性,提出ISCCS系统改进措施;从热力学的角度计算分析不同集成方式的ISCCS系统热经济性,给出了最佳集成方案。

关键词：直接产生蒸汽抛物面槽式聚光集热整体太阳能联合循环发电热力特性运行