计及需求侧管理的电—气集成能源系统协同规划

随着电转气技术的发展,电力系统与天然气系统间的耦合程度不断增强,传统电力系统与天然气系统独立规划的模式已不能满足电—气集成能源系统(IEGES)的需要。另一方面,实施需求侧管理可以优化电力负荷轮廓、实现削峰填谷、提升消纳间歇性可再生能源发电的能力,有利于整个IEGES的安全与经济运行。在此背景下,对计及需求侧管理的IEGES的协同规划问题进行了探讨。首先,基于用户满意度对需求侧管理建模,并以包括投资成本、运行成本和需求侧管理补偿费用的总成本最小为优化目标,建立IEGES中燃气机组、电转气设备、输电线路和天然气管道选址规划的混合整数非线性规划模型。然后,为加快求解速度,对模型中的非线性部分进行线性化处理,将原混合整数非线性规划问题转化为混合整数线性规划问题,并采用AMPL/CPLEX商业求解器求解。最后,以由修改的IEEE 39节点电力系统与比利时20节点天然气系统耦合形成的IEGES为例,对所构造的模型和采用的方法进行说明,并考察了其在节约成本和消纳风电方面的影响。     

电动汽车参与运行备用的能力评估及其仿真分析

电动汽车(EV)作为未来电力系统一种潜在且容量可观的运行备用资源,其调控必须以满足用户出行与充(放)电意愿为前提,因此对电动汽车备用能力的评估需置于合理的、计及用户响应意愿的市场机制下来考察。首先设计出兼顾系统调控需求与用户出行需求的充(放)电合约机制,提出了EV短时备用能力计算方法和响应电价变化的有序充/放电策略。基于上述模型或方法,实例分析了典型EV单体及集群在不同充电策略下,向电网提供多种可调控备用容/电量产品的能力。同时进一步分析了备用容量价格、备用市场设计等因素对EV可申报备用容量的影响。     

一种新型的基于风速预测的风力发电系统

为了使风力发电系统的有功出力波动维持在规定的范围内,同时保证系统的蓄电池储能水平基本保持不变,使系统能有效地应对输入功率突然增加及输出功率急剧下降的紧急情况,在风速预测的基础上提出一种新型的风力发电系统蓄电池充放电控制策略。当预测的风力发电系统输入功率的波动超过规定的功率变化范围时,通过对蓄电池的充放电控制以减弱网侧功率的波动,并且使蓄电池的充放电能量在一个周期内基本平衡,从而保证系统预留一定容量的储能装置以接收大功率输入或补充严重不足的并网功率,有效地减少了风能损失、提高了系统的效率。仿真结果验证了所提控制策略的有效性和可靠性。     

基于系统与元件动态交互量化分析的电力系统连锁故障事故链识别方法

针对现有的连锁故障事故链搜索方法一般只考虑线路的过负荷保护或确定性模拟保护控制的动作等不足,提出了基于系统与元件动态交互量化分析的电力系统连锁故障事故链识别方法。该方法基于事故链模型,提出关键元件保护控制动作评估指标,用于量化关键元件保护控制的动作情况。进一步根据该指标计算临界情况下关键元件保护控制的动作概率,确定连锁故障事故链的后续事件。最后,基于风险指标筛选高风险连锁故障事故链。对2017夏高峰负荷情况下的某实际电网进行仿真,结果验证了所提方法的可靠性和有效性。     

不对称地形下进/出水口明渠段环流特性研究

为研究不对称地形下明渠段内的环流特性,以一抽水蓄能电站上水库为研究对象,对引水明渠内部的流场进行了详细的数值模拟分析。研究发现,由于明渠前方及两侧的地形边界不对称这类不利地形条件,明渠内产生了较大范围的环流,不仅影响明渠内的水流流态,还降低了各进/出水口拦污栅断面水流的均匀性,属不利的水流现象。针对这一情况,提出通过加大明渠连接段长度并扩大明渠一侧开挖范围可以使环流位置远离进/出水口,在一定程度上改善明渠内的水流流态,降低拦污栅断面水流不均匀程度,减小环流的不利影响。本文研究成果可以增大抽水蓄能电站进/出水口选址的灵活性,避免大范围的开挖,为抽水蓄能电站明渠布置方案的设计提供有益的参考。     

能源互联网接入设备关键技术探讨

作为能源系统与信息系统信息-物理深度融合的庞大网络,能源互联网"开放共享"的特征对用户侧能源的接入、控制和传输提出了挑战。针对能源互联网背景下用户侧综合能源管理问题,首先提出了能源互联网接入设备的概念,指明了其区别于能源路由器的特征,并从规划调度、运行管理和能源服务3个维度详细介绍了能源互联网接入设备的应用领域。然后,重点介绍了设备特征识别、需求响应、区块链、大数据、综合能源管理和电力市场等6项关键技术,并深入阐述了能源互联网接入设备与这些关键技术的紧密联系。最后,简要介绍了能源互联网接入设备的实施方案和未来挑战,以期为未来能源互联网下用户设备高效便捷入网提供一些借鉴和参考。     

Demand Side Management for Stand-Alone Microgrid Using Coordinated Control of Battery Energy Storage System and Hybrid Renewable Energy Sources

Abstract

Distributed generation with battery energy storage (BES) system is an alternative solution for stand-alone AC supply systems. This article addresses the issue of voltage variability of stand-alone microgrid with the adoption of intelligent micro-source controllers. The high energy density of the BES system is used to compensate the voltage fluctuation. A control mechanism is designed to regulate the flow of electrical energy from BES system. The control structure of DC–AC microgrid integrated with BES system is proposed, and the study is extended to explore the mechanism of demand side management (DSM) with the incorporation of voltage-droop characteristics. The BES system is interlinked to maintain the voltage to a desirable range and the proposed work is intended to show the introductory concept on DSM accomplished through voltage-reduction at the consumption-side. The proposed control strategy not only achieves frequency-regulation in adherence to IEEE Standard-1547, but also maintains customers’ quality of service while customizing voltage for regulating DSM. The basis of regulating the nickel-metal-hydride battery is state-of-charge of BES system and voltage generated by the hybrid sources consist of photovoltaic and wind energy systems. The adequacy of the proposed control scheme with BES-module is validated using time-domain simulation studies considering voltage-dependent-loads.     

Analysis of the Quaternary Structure of Hemoglobin Beckman Variant and Molecular Interpretation of Its Functional Abnormality: A Mass‐Spectrometry‐Based Approach

Electrostatic attraction between α and β globin chains holds the subunits together in a tetrameric human hemoglobin molecule (α₂β₂). Compared to normal globin chains, the affinity of a mutant chain to its partner globin might be different in genetic variants of hemoglobin. This leads to an unequal abundance of normal and variant hemoglobin in heterozygous samples, even though the rates of synthesis of both the normal and variant chains are the same. The aforementioned affinities across various globin chains might be assessed by quantification of the different forms of the tetramers present in a variant hemoglobin sample. In the present study, by exploiting mass differences between globin chains, differently populated hemoglobin tetramers present in hemoglobin (Hb) Beckman, a β variant (βA135D), were structurally characterized. The relative populations of dissymmetric tetramers (α₂β₂, α₂ββ^V, and α₂β^V₂) indicated that both β and β^V have different affinities towards the α globin chain. Conformational dynamics analyzed from hydrogen/deuterium exchange kinetics of the three peptide fragments of Hb Beckman in its oxy state displayed molecular insight into its functional abnormality. However, in comparison to normal hemoglobin (α₂β₂), the point mutation did not show any change in the collision cross‐sections of the functionally active conformers of the variant hemoglobin molecules (α₂ββ^V and α₂β^V₂).     

RSU-coordinated multichannel MAC protocol in vehicular ad hoc network

A road side unit (RSU)-coordinated multichannel media access control (MAC) (RMM) protocol was proposed in vehicular ad hoc network,which aimed to improve the transmission efficiency of non-safety messages.Under the coordination of RSU,nodes had more opportunities to make SCH reservations on control channel,and the contention-free message transmissions were thus realized.The proposed RMM protocol could use the service channel during the whole synchronization interval for non-safety message transmissions,and thus the saturated network throughput and channel utilization were improved,and the transmission delay was reduced.Compared with other existing protocols,extensive analysis and simulation results demonstrate the superiority of the RMM protocol.     

基于表面压电波动测量的钢管砼剥离检测试验

钢管混凝土结构结合了钢管与混凝土两者的力学优点,具有优越的力学性能,被广泛应用于超高层建筑和大跨度桥梁中,但钢管管壁与内部核心混凝土间的界面剥离将会对其承载力等力学性能带来负面影响。该文提出一种通过在钢管壁同侧布置压电陶瓷片作为驱动器和传感器,基于表面波动测量的矩形截面钢管混凝土构件的界面剥离缺陷检测方法,通过在一矩形截面钢管混凝土柱钢管的四面内壁设置不同程度剥离缺陷进行测试,对比简谐激励下健康工况和不同尺寸缺陷工况下压电传感器测量信号幅值,定义界面损伤指标实现了管壁界面剥离缺陷检测。结果表明,基于表面波动测量的钢管混凝土柱内部界面剥离缺陷状况检测方法有效,损伤指标与损伤程度相关。