含整体煤气化燃料电池-碳捕集电厂的风火储系统分布鲁棒调度方法

整体煤气化燃料电池(integrated gasification fuel cell,IGFC)是与碳捕集技术高度适配的清洁、高效、稳定的绿色煤电技术,有望克服传统碳捕集技术在低浓度CO_(2)环境下产生的高成本、高能耗问题。该文构建含IGFC碳捕集电厂的风火储发电系统。研究IGFC碳捕集电厂的运行机理,对IGFC内部各环节建立数学模型,提出工况匹配时燃烧利用率和阴极空气利用率需要满足的运行条件,并针对该型碳捕集电厂的电碳特性进行分析。为计及风电出力的不确定性,构建风火储系统的两阶段分布鲁棒经济调度模型,引入k阶适应性理论,提出基于正交支撑子集策略的求解方法来获得鲁棒对等式。最后,在改进IEEE-30节点系统中进行算例分析,结果表明,该型碳捕集电厂可利用阳极碳富集的优势,实现系统低碳经济调度的目标,并验证所提优化方法能为可行解提供可解释性。

The predicted effects of climate change on local species distributions around Beijing,China

To assist conservationists and policymakers in managing and protecting forests in Beijing from the effects of climate change,this study predicts changes for 2012–2112 in habitable areas of three tree species—Betula platyphylla,Quercus palustris,Platycladus orientalis,plus other mixed broadleaf species—in Beijing using a classification and regression tree niche model under the International Panel on Climate Change’s A2 and B2 emissions scenarios(SRES).The results show that climate change will increase annual average temperatures in the Beijing area by 2.0–4.7℃,and annual precipitation by 4.7–8.5 mm,depending on the emissions scenario used.These changes result in shifts in the range of each of the species.New suitable areas for distributions of B.platyphylla and Q.palustris will decrease in the future.The model points to significant shifts in the distributions of these species,withdrawing from their current ranges and pushing southward towards central Beijing.Most of the ranges decline during the initial 2012–2040 period before shifting southward and ending up larger overall at the end of the 88-year period.The mixed broadleaf forests expand their ranges significantly.The P.orientalis forests,on the other hand,expand their range marginally.The results indicate that climate change and its effects will accelerate significantly in Beijing over the next 88 years.Water stress is likely to be a major limiting factor on the distribution of forests and the most important factor affecting migration of species into and out of existing nature reserves.There is a potential for the extinction of some species.Therefore,long-term vegetation monitoring and warning systems will be needed to protect local species from habitat loss and genetic swamping of native species by hybrids.

基于矩不确定性的虚拟发电厂分布鲁棒机组组合

由于分布式能源输出的随机性使得虚拟发电厂难以向独立系统运营商提供具体物理参数。为此,本文建立基于高阶矩模糊集的分布鲁棒优化模型来评估虚拟发电厂的物理特性。首先采用虚拟净负荷的矩信息(例如均值和协方差)来描述风电输出功率和负荷需求的不确定性;然后,在第1阶段优化虚拟发电厂的机组组合,在第2阶段优化机组出力和储能充放电,建立虚拟发电厂的两阶段分布鲁棒优化模型;最后,结合对偶变换将虚拟发电厂分布鲁棒机组组合模型转化为二次二阶锥规划模型,便于采用两阶段迭代求解。通过案例分析验证了本文所建立的虚拟发电厂分布鲁棒机组组合模型的有效性。

计及配电网运行约束的多虚拟电厂合作博弈策略

虚拟电厂(virtual power plant,VPP)作为一种有效的可再生能源聚合利用手段,近年来得到迅速发展,随着VPP并网规模的扩大,多个互联VPP交易博弈问题日益凸显。针对多个VPP间的交易博弈问题,考虑物理网络特性,提出了计及配电网运行约束的多VPP合作博弈策略。首先,考虑配电网运行约束,对VPP内部资源进行整合和建模,建立了VPP能量管理模型。其次,通过引入点对点(peer to peer,P2P)能量交易,实现多VPP系统自主能量管理与协同定价,能够在不损害各方利益的情况下达成P2P能量交易。同时考虑到用电负荷和可再生能源出力的不确定性,利用典型场景生成算法构造了不确定性变量的概率分布模糊集。针对多主体交易产生的隐私性问题,采用列和约束生成算法联合交替方向乘子法对模型进行求解。最后,在IEEE 123节点测试系统上进行算例仿真,仿真结果验证了所提模型和算法的有效性。

计及热惯性的热电联产虚拟电厂韧性提升策略

日益频繁的极端天气给电热耦合系统造成的影响愈发严重。韧性是衡量系统抵御极端事件、减少故障影响并快速恢复的核心指标。为提升电热耦合系统抵御极端灾害的能力,提出一种考虑热惯性的热电联产虚拟电厂(combined heat and power-virtual power plant,CHP-VPP)两阶段三层韧性提升策略。第一阶段以联络开关成本最小为目标,基于最小生成树理论对系统进行重构;第二阶段以运行成本最小为目标,基于分布鲁棒优化理论制定最恶劣的故障场景下的最优决策。采用列与约束生成算法进行迭代求解。基于IEEE 33节点电力系统+6节点供热系统构建CHP-VPP测试系统,仿真结果表明,所提出的方法可有效提升CHP-VPP应对极端灾害的韧性。

Seed Size as Key Factor in Germination and Seedling Development of Copaifera langsdorffii(Fabaceae)

Seed size is a plastic trait of the plants that directly affect seed germination and seedling recruitment. This study aimed to investigate the relationship between seed size, seed germinability and seedling performance of Copaifera langsdorffii by testing four hypotheses: 1) larger seeds have higher germination percentage;2) smaller seeds require less time to germinate and for initial development of the seedlings;3) larger seeds produce more vigorous seedlings and 4) seed size negatively affects seedling root/shoot ratio. In 2011, we selected 30 individuals of C. langsdorffii from which 300 seeds were randomly collected in the plant canopy. All these seeds were weighted and placed in germination tray using vermiculite as substrate. Seed germinability and initial development of seedlings were monitored daily until cotyledons fell. Small seeds have higher germination percentage and germinate faster when compared to large seeds. Nonetheless, seedlings originated from larger seeds have longer development times, resulting in more vigorous seedlings. In addition, seedlings originating from small seeds allocate proportionally greater amount of resources to roots when compared to larger seeds. The fact that small seeds have higher germination percentage and faster germination favors the colonization of transient habitats. However, larger seeds produce more vigorous seedlings, favoring the seedling establishment in more stable habitats. Thus, we argue that high variability in seed size of C. langsdorffii favors its widespread geographic distribution.

Vegetation structure and edaphic factors in veredas reflect different conservation status in these threatened areas

Background:In Cerrado humid areas,veredas are considered as hygrophilous communities,marked by the presence of the Mauritia flexuosa palm tree emerging in the wetter zones.Changes in veredas ecosystems due to drought and changes in the water table,which represent important areas for biodiversity maintenance in the Brazilian cerrado,can lead to the emergence of new landscapes and ecosystems.Assuming that the veredas are changed in species composition due to anthropogenic factors,in this study,we evaluated the flora composition and described the current vegetation profile of two veredas under different disturbances levels that are located in the north of Minas Gerais State,Brazil.Results:Altogether,2,268 individuals of 91 species belonging to 36 families were recorded.Our results demonstrated that the studied veredas were floristically different in terms of the arboreous-shrubby species composition,richness,and diversity.Despite the hygrophilous forest formations and open areas in the two veredas present typical species from these environments(same species with high importance values),the drought in the water table caused an expansion of Cerrado species in the open areas and in the hygrophilous forest.Furthermore,in the hygrophilous forest there was an increase in the abundance of species that occur in less saturated soils.Conclusion:Our results demonstrate that the studied veredas are changing in species composition due to anthropogenic factors which leads to the drought of these formations(water balance effect).These anthropogenic effects cause a modification with the expansion and increase in the abundance of typical species of other areas of Cerrado and resistant to less saturated soils,leading to the veredas collapse.Finally,future studies should investigate other veredas on a broader scale to detect changes in the water table that lead to a consequent change in vegetation structure.In this way,we will have support for the conscientious management and conservation of these areas that represent equilibrium places for the Cerrado biome.

计及用户参与不确定性的虚拟电厂分布鲁棒优化模型

灵活资源的需求响应行为在不同运行状态、激励水平下有很大的不确定性和差异性,需求响应优化方案的精准度有待进一步提高。针对这一问题,提出了一种虚拟电厂中计及用户需求响应不确定性的分布鲁棒优化方法。考虑可中断、可转移、可增长3种灵活资源的响应特性,构建包含用户响应特征参数的精细化需求响应模型;以提升虚拟电厂经济性、电网友好性和用户舒适性为子目标,构建促进多方利益最大化的多目标优化模型;基于数据驱动的分布鲁棒方法,构建精细化响应模型中随机参数的概率分布模糊集,提出虚拟电厂两阶段分布鲁棒优化模型,并采用强对偶理论进行转化求解。算例仿真结果表明所提模型能够提高需求响应精度和虚拟电厂经济收益。

市场环境下考虑多元不确定性的热电联合虚拟电厂竞标策略

“双碳”背景下,热电联合虚拟电厂将热电联产机组、储能设施等聚合为可控集合体以促进新能源消纳,具有广阔的发展空间。电力市场环境下,热电联合虚拟电厂的竞标策略决定了其在市场中的购售电量,对其收益具有重要影响。然而,电价和分布式新能源出力等多元不确定性的存在,给热电联合虚拟电厂竞标策略的制定带来困难。为此,提出了市场环境下考虑多元不确定性的热电联合虚拟电厂竞标策略。考虑电价与虚拟电厂内部风光的不确定性,建立热电联合虚拟电厂参与电力市场的竞标模型。利用蒙特卡洛法和后向场景缩减法,构建刻画电价不确定性的典型场景。基于此,结合随机优化方法与基于Wasserstein距离的分布鲁棒方法,将热电联合虚拟电厂竞标模型转换为分布鲁棒随机优化模型,并利用对偶转换和数据驱动方法将该模型转换为单层模型,以利于求解。最后,通过IEEE 30节点系统验证所提方法的有效性。

Elevation patterns of woody taxa richness in the evergreen Afromontane vegetation of Ethiopia

Plant species distributions show patterns along elevation gradients. Regardless of the diverse Afromontane vegetation in Ethiopia (AFE), studies of elevation patterns of woody plants are limited and they are restricted to small areas or single/few Mountains. Moreover, there is no general consensus on the patterns of woody taxa distribution by elevation. The objectives of this study were to examine the elevation patterns of woody taxa richness and their relationship with elevation in the AFE. Data were collected and compiled from the Flora of Ethiopia and Eritrea (Vols. 1-7). About 5918 plant species of 243 families were examined and their elevational distributions were recorded. The distributional ranges of woody taxa were aggregated at 19 points (sites) at 100?m intervals starting from 1500 to 3400?m a.s.l. Single-factor analysis of variance (one-way ANOVA) was used to test the hypothesis that mean species richness of woody taxa decreases from the lower to the upper limit of AFE. Simple linear correlation and regression were used to show the relationships of woody taxa richness with elevation. We documented the presence of 505 woody taxa (441 species, 31 subspecies and 33 varieties) representing 267 genera and 90 families in the AFE. In terms of habit, 279 taxa are shrubs, 178 are trees and 48 are lianas. The distribution of woody taxa (trees, shrubs and lianas) showed a slight increase at the lower portion and a monotonic decline with increasing elevation. Species richness of trees, shrubs and lianas was negatively and significantly correlated with elevation (r?=??0.985, ?0.984, ?0.981, respectively; all p?<?0.001). Our hypothesis was accepted because mean richness significantly decreased from the lower to the upper limit of AFE (p?<?0.001). Generally, monotonic patterns of decline in richness were observed for trees, shrubs and lianas. The contribution of shrubs to total richness increased with increasing elevation whereas that of trees and lianas decreased.

Gas-phase and particle-phase PCDD/F congener distributions in the flue gas from an iron ore sintering plant

The activated carbon injection-circulating fluidized bed（ACI-CFB）-bag filter coupling technique was studied in an iron ore sintering plant. For comparison, the removal efficiencies under the conditions without or with ACI technology were both evaluated. It was found that the polychlorinated dibenzo-p-dioxins and dibenzofuran（PCDD/F） removal efficiency for total international toxic equivalence quantity（I-TEQ） concentration was improved from 91.61% to 97.36% when ACI was employed, revealing that ACI was very conducive to further controlling the PCDD/F emissions. Detailed congener distributions of PCDD/Fs in the gas-phase and particle-phase of the Inlet and Outlet samples were determined. Additionally, the PCDD/F distribution for the Fly ash-with ACI sample of was also studied.

基于KL散度的储能电站分布鲁棒规划方法

电化学储能的循环寿命受到充放电次数和放电深度的影响,为了更加准确地在新能源电力系统中规划储能电站,提出基于Kullback-Leibler(KL)散度的储能电站分布鲁棒规划方法。根据电化学储能循环寿命的幂函数,建立基于等效全循环次数的储能电站寿命模型,考虑储能电站寿命模型约束和系统运行约束,以储能电站的全寿命周期成本和机组运行成本最小为目标来构建储能电站的规划模型。进一步,将基于KL散度的风电出力不确定性集嵌入到储能电站规划模型中,通过样本平均近似法将储能电站分布鲁棒规划模型转化混合整数线性规划模型求解。在含2个风电场的改进IEEE-30节点系统中验证了所提出的储能电站分布鲁棒规划方法的优势。

THE PIGMENT-PROTEIN COMPLEXES OF HIGHER PLANTS MIGRATION IN THYLAKOID AND THE REGULATION OF LIGHT ENERGY DISTRIBUTION BETWEEN PHOTOSYSTEMS

Appressed and non-appressed lamella membranes of Castor bean leaf chloroplasts were separated by non-ionic detergent Triton-X 100.Appressed membranes showed a high oxygen-evolving activity and low chl a/b ratio. Examining with SDS-PTGE and liquid nitrogen temperature fluorescence measurement showed that they contained only PSII and light-harvesting pigment-protein complexes （LHCP）,and there was no detectable amount of PSI. Freeze-fracture electromicroscopic observation confirmed that this part was really an appressed lamella membrane. Through divalent cation Mg++, the thylakoid membranes were induced to unstack and restack.With the addition of Mg++, the fluorescence intensity was changed instantly. We realized that there existed two processes:One was a rapid process which was accomplished within 30 s. The other was a slow process of which the time duration was about 60 min. This dual effects of Mg++ had not been reported before.We had analyzed the change of F685/F730 and discussed the

基于多层利益共享的虚拟电厂参与电碳市场分布鲁棒优化模型

风电和光伏的高渗透率增加了新型电力系统对灵活性资源需求.虚拟电厂作为一个特殊电厂聚合了可控分布式电源、新能源、储能、碳处理、负荷等各类资源,“对内协同”可以实现内部资源协同调控,“对外统一”可以参与外部电碳市场获利.基于此,本文创新地提出了虚拟电厂参与电碳多类市场分布鲁棒优化模型.为了刻画风电和光伏的不确定性,构造了基于Wasserstein距离的分布模糊集和基于数据驱动的误差不确定集.为了兼顾经济性和鲁棒性,考虑内部运行成本以及外部参与多类市场收益,构建了最坏分布下期望收益最大的两阶段鲁棒优化模型,并提出模型求解方法.为了保证联盟动态平衡,提出了多层利益分配方法.最后,算例分析表明:在“对内协同,对外统一”的经营模式下,有效激发虚拟电厂内各类资源的潜力,参与多个市场后获取共享利益,实现了多方互利共赢.所提模型具有数据驱动、快速求解、灵活可控、经济实用等优越性.多层利益分配方法能够简便、有效地将共享效益传导至各主体.

Allocation and sizing of reactive power compensators considering PV power and load demand uncertainty using beetle-antenna grey wolf optimization

Distributed photovoltaic(PV)systems play an important role in supplying many recent microgrids.The absence of reactive power support for these small-scale PV plants increases total microgrid losses and voltage-instability threats.Reactive power compensations(RPCs)should be integrated to enhance both microgrid losses and voltage profiles.RPC planning is a non-linear,complicated problem.In this paper,a combined RPC allocation and sizing algorithm is proposed.The RPC-integrating buses are selected using a new adaptive approach of loss sensitivity analysis.In the sizing process,the uncertainties in PV power and load demand are modelled using proper probability density functions.Three simulation techniques for handling uncertainties are compared to define the accurate and fast accurate method as follows:Monte Carlo simulation(MCS),scenario tree construction and reduction method,and point estimation method(PEM).The load flow equations are solved using the forward-backward sweep method.RPCs are optimally sized using the beetle-antenna-based strategy with grey wolf optimization(BGWO)to overcome the local minima problem that appeared in the other pre-proposed methods.Results have been compared using particle swarm optimization and conventional GWO.The proposed model is verified using the IEEE 33 radial bus system.The expected power loss has been reduced by 22% and 31% using compensation of 26% and 44%,respectively.The results obtained prove that the BGWO optimal power flow and PEM to handle the uncertainty can significantly reduce the computation time with sufficient accuracy.Under the study conditions,PEM reduces the computation time to 4 minutes compared with 4 hours for MCS,with only a 3% error compared with MCS as an uncertainty benchmark method.

多样化柔性负荷深度互动下的虚拟电厂分布鲁棒购售电策略

随着当前电力改革以及电力市场的不断推进,虚拟电厂的发展已成为其重点组成部分,也是市场交易复杂因素的主要集中部分,其中柔性负荷和清洁能源给虚拟电厂带来了巨大的挑战。考虑不同类别用户柔性负荷的运行特性差异,分别对工业负荷、商业负荷和家用负荷进行了特性分析并建模,充分调动虚拟电厂内部的一些可控资源进行互动,并结合风电、光伏、燃气轮机(gas turbine,GT)运行特性,建立了考虑多样化柔性负荷深度互动的虚拟电厂购售电优化模型。此外,随着清洁能源的发展,针对风电、光伏所带来的不确定性挑战,提出了基于场景数据驱动的两阶段变量的分布鲁棒虚拟电厂购售电优化计算模型,再利用列与约束生成算法求解,算例分析验证了该优化模型的有效性。

Optimization method to obtain appropriate spacing parameters for crop cultivation

Considering the time-consuming and tedious work of the current methods to control plant layout,which is mostly based on expert experience or field trials,we propose an algorithm to optimize and simulate a planting layout based on a virtual plant model and an optimization algorithm.A functional-structural plant model,which combines the structure and physiological function of plants,is used to construct a planting scene.The planting and row spacing are set as the genetic factors and the chromosomes of the genetic algorithm are encoded with a binary method.The photosynthetic yield of the unit planting area is denoted as the fitness value.By using this method,the intercropping of maize and soybean plants and the sole cropping of rice plants are studied.Experimental results show that the proposed method can obtain a high yield planting plan.