Dynamic optimal allocation of energy storage systems integrated within photovoltaic based on a dual timescale dynamics model

Energy storage systems(ESSs)operate as independent market participants and collaborate with photovoltaic(PV)generation units to enhance the flexible power supply capabilities of PV units.However,the dynamic variations in the profitability of ESSs in the electricity market are yet to be fully understood.This study introduces a dual-timescale dynamics model that integrates a spot market clearing(SMC)model into a system dynamics(SD)model to investigate the profit-aware capacity growth of ESSs and compares the profitability of independent energy storage systems(IESSs)with that of an ESS integrated within a PV(PV-ESS).Furthermore,this study aims to ascertain the optimal allocation of the PV-ESS.First,SD and SMC models were set up.Second,the SMC model simulated on an hourly timescale was incorporated into the SD model as a subsystem,a dual-timescale model was constructed.Finally,a development simulation and profitability analysis was conducted from 2022 to 2040 to reveal the dynamic optimal range of PV-ESS allocation.Additionally,negative electricity prices were considered during clearing processes.The simulation results revealed differences in profitability and capacity growth between IESS and PV-ESS,helping grid investors and policymakers to determine the boundaries of ESSs and dynamic optimal allocation of PV-ESSs.

Isotopic Chronological Study of the Huangsha-Tieshanlong Quartz Vein-Type Tungsten Deposit and Timescale of Molybdenum Mineralization in Southern Jiangxi Province,China

The Huangsha-Tieshanlong quartz-vein tungsten polymetallic ore deposit, located in the northern Pangushan-Tieshanlong tungsten ore field in eastern Ganxian-Yudu prospecting areas of the Yushan metallogenic belt, is a well-known tungsten deposit in southern Jiangxi province, China. SHRIMP-determined dating of zircons from the Tieshanlong granite yields ages of 168.1±2.1 Ma （n=11, MSWD-1.3）. Rhenium and osmium isotopic dating of molybdenite from the Huangsha quartz-vein tungsten deposit determined by ICP-MS yields a weighted average ages of 153-3 Ma and model ages of 150.22.1 Ma - 155.4-2.3 Ma. The age of the Huangsha tungsten deposit is 10 to 15 Ma later than the Tieshanlong granite, which shows that there might have been another early Late Jurassic magmatic activity between 150 and 160 Ma, a process which is closely related with tungsten mineralization in this area. The Tieshanlong granite, the Hnangsha tungsten deposit and the Pangushan-Tieshanlong ore field were all formed around 150-170 Ma, belonging to products of a Mesozoic second large-scale mineralization. According to the collected molybdenite Re-Os dating results in southern Jiangxi province, the timescale of the associated molybdenum mineralization is 2-6 Ma in the tungsten deposit and the timescale of independent molybdenum mineralization is 1-4 Ma, implying the complexity of tungsten mineralization. Times of molybdenum mineralization are mainly concentrated in the Yanshanian, which includes three stages of 133-135 Ma, 150-162 Ma, and 166-170 Ma, respectively. The 150-162 Ma-stage is in accordance with ages of large-scale WoSn mineralization, which is mainly molybdenum mineralization characterized by associated molybdenum mineralization with development of an even greater-intensity independent molybdenum mineralization. Independent molybdenum mineralization occurred before and after large-scale W-Sn mineralization, which indicates that favorable prospecting period for molybdenum may be in Cretaceous and early late Jurassic.

Nonlinear evolution characteristics of the climate system on the interdecadal-centennial timescale

To better understand the physical mechanism of the climate change on interdecadal-centennial timescale, this paper focuses on analysing and modelling the evolution characteristics of the climate change. The method of wavelet transform is used to pick out the interdecadal timescale oscillations from long-term instrumental observations, natural proxy records, and modelling series. The modelling series derived from the most simplified nonlinear climatic model are used to identify whether modifications are concerned with some forcings such as the solar radiation on the climate system. The results show that two major oscillations exist in various observations and model series, namely the 20- 30a and the 60-70a timescale respectively, and these quasi-periodicities are modulated with time. Further, modelling results suggest that the originations of these oscillations are not directly linked with the periodic variation of solar radiations such as the 1-year cycle, the 11-year cycle, and others, but possibly induced by the internal nonlinear effects of the climate system. It seems that the future study on the genesis of the climate change with interdecadal-centennial timescale should focus on the internal nonlinear dynamics in the climate system.

The relationship between the canonical ENSO and the phase transition of the Antarctic oscillation at the quasi-quadrennial timescale

A correlation analysis is performed to investigate the relationship between El Nino-Southern Oscillation （ENSO） and the Antarctic oscillation （AAO） at the quasi-quadrennial （QQ） timescale.It is found that the cold tongue index （CTI） and the AAO index （AAOI） are negatively correlated with about a 7-month lead-time,while they are positively correlated with about a 15-month lag-time.To further explore this relationship,complex empirical orthogonal function analysis is employed in the QQ sea level pressure （SLP） anomalies from 1951 to 2002.The results indicate that,during the ENSO cycle,there exists one kind of global tropical wave of wavenumber 1 （GTW1） propagating eastward.With the traveling of GTW1,the tropical SLP anomaly tends to intrude into the southern mid-latitudes.Accordingly,three strong signals travel synchronously along the circumSouth-Pacific path,and a relatively weak signal extends eastward and poleward over the South Ocean in the Atlantic-Indian Ocean sector.Following the propagation of these signals,the AAO phase tends to be reversed progressively.As a result,there exists an evident lead-lag correlation between CTI and AAOI.It can be concluded that ENSO plays a key role in the phase transition of AAO at the QQ timescale.It is also noticed that this regular relationship is only evident in the canonical ENSO events,for which sea surface temperature （SST） anomalies extend westward from the tropical eastern Pacific.On the other hand,the similar relationships are not found among those atypical ENSO events for which SST anomalies spread eastward from the central Pacific,such as the 1982-1983 ENSO event.

A Timescale Decomposed Threshold Regression Downscaling Approach to Forecasting South China Early Summer Rainfall

A timescale decomposed threshold regression （TSDTR） downscaling approach to forecasting South China early summer rainfall （SCESR） is described by using long-term observed station rainfall data and NOAA ERSST data. It makes use of two distinct regression downscaling models corresponding to the interannual and interdecadal rainfall variability of SCESR. The two models are developed based on the partial least squares （PLS） regression technique, linking SCESR to SST modes in preceding months on both interannual and interdecadal timescales. Specifically, using the datasets in the calibration period 1915-84, the variability of SCESR and SST are decomposed into interannual and interdecadal components. On the interannual timescale, a threshold PLS regression model is fitted to interannual components of SCESR and March SST patterns by taking account of the modulation of negative and positive phases of the Pacific Decadal Oscillation （PDO）. On the interdecadal timescale, a standard PLS regression model is fitted to the relationship between SCESR and preceding November SST patterns. The total rainfall prediction is obtained by the sum of the outputs from both the interannual and interdecadal models. Results show that the TSDTR downscaling approach achieves reasonable skill in predicting the observed rainfall in the validation period 1985-2006, compared to other simpler approaches. This study suggests that the TSDTR approach, considering different interannual SCESR-SST relationships under the modulation of PDO phases, as well as the interdecadal variability of SCESR associated with SST patterns, may provide a new perspective to improve climate predictions.

Impacts of Multi-Scale Solar Activity on Climate.Part Ⅱ:Dominant Timescales in Decadal-Centennial Climate Variability

Part II of this study detects the dominant decadal-centennial timescales in four SST indices up to the 2010/2011 winter and tries to relate them to the observed 11-yr and 88-yr solar activity with the sunspot number up to Solar Cycle 24. To explore plausible solar origins of the observed decadal-centennial timescales in the SSTs and climate variability in general, we design a simple one-dimensional dynamical system forced by an annual cycle modulated by a small-amplitude single- or multi-scale ＂solar activity.＂ Results suggest that nonlinear harmonic and subharmonic resonance of the system to the forcing and period-doubling bifurcations are responsible for the dominant timescales in the system, including the 60-yr timescale that dominates the Atlantic Multidecadal Oscillation. The dominant timescales in the forced system depend on the system＇s parameter setting. Scale enhancement among the dominant response timescales may result in dramatic amplifications over a few decades and extreme values of the time series on various timescales. Three possible energy sources for such amplifications and extremes are proposed. Dynamical model results suggest that solar activity may play an important yet not well recognized role in the observed decadal-centennial climate variability. The atmospheric dynamical amplifying mechanism shown in Part I and the nonlinear resonant and bifurcation mechanisms shown in Part II help us to understand the solar source of the multi-scale climate change in the 20th century and the fact that different solar influenced dominant timescales for recurrent climate extremes for a given region or a parameter setting. Part II also indicates that solar influences on climate cannot be linearly compared with non-cyclic or sporadic thermal forcings because they cannot exert their influences on climate in the same way as the sun does.

Timescales of geological processes: Preface

1.Introduction One of the major challenges in Geoscience is to understand how the formation and evolution of the Earth System are governed by timescales-that is,how the various geological processes that continue to contribute to its present-day structure and composition operated in the deep past.The traditional view of such processes refers to events that occur at immense spatial scales and over hundreds of millions of years,constrained in most cases by the ages of rocks determined using isotopic dating methods or the fossil record.However,the modern view of geological processes has increasingly acknowledged that their durations can be significantly shorter than previously thought possible,or indeed detectable without recent analytical innovations.Earthquakes are a prime example of rapid,high energy and episodic events that have a profound effect on subsequent processes such as metamorphism,fluid transport,and ore formation e the evidence of which is written in microstructures,compositional zoning,and P-T records.Experimental studies have also revealed that the reaction rates between fluids and rocks can be extremely rapid relative to geological timescales.This has led to the notion that geological processes are not necessarily continuous over millions of years but may,in fact,be sporadic,with long periods where essentially no reactions take place punctuated by periods of intense activity.

Submonthly timescale oscillation characteristics of the East Asian winter monsoon and its effect on the temperature of southwest China in 2010

Using NCEP/NCAR R2 reanalysis daily data and daily meteorologicalobservational data of southwest China in 2010, this paper studied the submonthlytimescale oscillation characteristics of the East Asian winter monsoon (EAWM) and itseffect on the temperature of southwest China in 2010 by bandpass filtering, wavelettransformation, composite analysis and correlation analysis. The main conclusions areas follows: The EAWM in 2010 was dominated by low-frequency oscillations of about 7-,12-, and 30-day periods. There existed obviously negative correlation between theEAWM and the winter temperature in southwest China on submonthly, quasi-weeklyand quasi-biweekly timescales, and negative correlation was more obvious on thequasi-biweekly than the quasi-weekly timescale. There was significant difference in thedistribution of high, middle and low layer of the troposphere when the EAWM was onthe submonthly, quasi-one-week and quasi-two-week timescales in the positive andnegative phase. In the positive EAWM phase, the upper-level subtropical westerly jet isstronger and the East Asia trough is deeper, thus it is favorable for the dominance ofmore powerful north wind and lower temperature in southwest China. On the contrary,in the negative EAWM phase, the upper-level subtropical westerly jet is weaker and theEast Asia trough is shallower, thus unfavorable for the north wind and lowertemperature in southwest China.

New Integrative Stratigraphy and Timescale for China Released

New integrative stratigraphy and timescales for 13 geological periods in China from the Ediacaran to the Quaternary have recently been published in a special issue of SCIENCE CHINA Earth Sciences.The research summarizes the latest advances in stratigraphy and timescale as well as discusses the correlation among different blocks in China and with international timescales.

Multi-timescale Collaborative Optimization of Distribution, Distributed Generation and Load in Microgrid

The distribution loads, output of distributed generations (DGs) and dynamic power price present obvious time-sequence property, the typical property is studied in this paper. The model of microgrid (including adjustable load, DGs, storage and dynamic power price) is studied. A multi-timescale collaborative optimization model is built towards microgrid;main measures in different timescale optimization are realized. An improved adaptive genetic algorithm is used to solve the optimization problem, which improved the efficiency and reliability. The proposed optimization model is simulated in IEEE 33 node system;the results show it’s effective.

改进下垂控制下的中压直流配电系统双时间尺度分层调控方法

针对中压直流配电系统,在负荷激增、可再生能源出力突变等特殊工况下,传统优化调度方案与协调控制策略存在系统运行经济性有待提升、直流母线电压易越限的问题。为此,提出一种基于改进下垂控制的中压直流配电系统双时间尺度分层调控方法。首先,构建一种具备直流故障穿越能力的3端混合型模块化多电平换流器(modular multilevel converter,MMC)环状±10 kV中压直流配电系统,该系统含电动汽车充电站、储能系统、分布式光伏与风电等灵活性资源。其次,制定各单元协调控制策略,并采用tan函数改进传统下垂控制,以提高系统应对大幅功率波动的能力。然后,基于改进控制策略提出一种双时间尺度分层优化调控方法:在长时间尺度的系统调度层,以运行总成本最小为优化目标,确定各换流器参考功率;在短时间尺度的换流器间协调控制层,改进下垂曲线,并优化控制系数,以兼顾系统运行经济性与电能质量。最后,以典型算例验证该文所提优化调度方案及协调控制策略的有效性:通过灵活调度多种柔性资源,系统运行总成本可降低约11%;在某数据中心负荷激增100%的工况下,各直流母线电压波动仍能维持在±3%UN(额定电压)的允许范围内。

结合数据驱动与物理模型的主动配电网双时间尺度电压协调优化控制

高比例电动汽车、分布式风电、光伏接入配电网,导致电压频繁地剧烈波动。传统调压设备与逆变器动作速度差异巨大,如何协调是难点问题。该文结合数据驱动与物理建模方法,提出一种配电网双时间尺度电压协调优化控制策略。针对短时间尺度(min级)电压波动,以静止无功补偿器、分布式电源无功功率为决策变量,以电压二次方偏差最小为目标函数,针对平衡与不平衡配电网,基于支路潮流方程,计及物理约束构建了二次规划模型。针对长时间尺度(h级)电压波动,以电压调节器匝比、可投切电容电抗器挡位、储能系统充放电功率为动作,当前时段配电网节点功率为状态,节点电压二次方偏差为代价,构建了马尔可夫决策过程。为克服连续-离散动作空间维数灾,提出了一种基于松弛-预报-校正的深度确定性策略梯度强化学习求解算法。最后,采用IEEE 33节点平衡与123节点不平衡配电网验证了所提出方法的有效性。

渤海湾盆地沾化凹陷古近系沙三下亚段旋回地层学分析及地层划分

湖相细粒沉积多具有连续性,能记录和保存显著的天文旋回信号,是进行天文旋回分析的理想地层。通过对渤海湾盆地沾化凹陷重点井沙三下亚段自然伽马数据进行MTM频谱分析和FFT进化谐波分析,建立了“浮动”天文年代标尺,并在单井上进行了天文旋回地层划分及连井地层对比,为全区搭建了地层格架。研究结果表明:(1)渤海湾盆地沾化凹陷沙三下亚段记录了显著的天文旋回信号,匹配出最优沉积速率为9.0×103cm/Ma;由长偏心率、短偏心率、斜率和岁差周期产生的旋回地层厚度分别为42.3 m,9.0 m,2.4~4.7 m和1.3~1.9 m;(2)沙三下亚段比较稳定的记录了6个长偏心率旋回、25个短偏心率旋回,可将短偏心率曲线作为地层划分依据来进行高精度地层对比。(3)运用天文旋回理论进行岩相发育规律、岩相空间配置关系的预测,可为湖盆沉积中心页岩油气地质“甜点”的精细勘探提供依据。

多时间尺度下智能楼宇异构负荷协同调度研究

为应对大规模具有异构特性的灵活负荷接入智能楼宇,解决可再生能源随机性与灵活异构负荷不确定性造成楼宇的负荷波动问题,需对灵活异构负荷进行合理管控,提出一种计及多时间尺度下智能楼宇异构负荷协同调控方法。首先,考虑异构负荷用电特性及响应特性差异,将智能楼宇内异构负荷等效为可转移负荷与可削减负荷。进而,综合可再生能源波动性与异构负荷时域互补性,建立日前-日内两阶段联合优化调度模型。算例仿真表明,异构负荷之间协调互动和多时间尺度滚动优化,能有效减少系统负荷波动,显著提升整体运行经济性。

双IRS辅助大规模MIMO系统中基于双时间尺度的信道估计方案

在双智能反射面(IRS)辅助的大规模多入多出(MIMO)通信系统中,为获取信道状态信息(CSI)而进行的信道估计需要较大的导频开销。考虑到基站(BS)-IRS信道与IRS-IRS信道具有高维且准静态的特性,而IRS-用户(UE)信道具有低维且时变的特性,本文提出一种基于双时间尺度的信道估计方案。首先,对于准静态信道,由BS发送导频并基于坐标下降算法和最小二乘法分别估计BS-IRS信道和IRS-IRS信道。然后根据准静态信道的估计结果进一步基于最小二乘法估计IRS-UE信道。仿真结果表明,本文所提出的方案可以采用低于对比方案50%的导频开销来获取低于对比方案近10 dB的估计归一化均方误差(NMSE),实现用更少的导频开销获取更高的信道估计精度。

综合能源系统源-荷能量的多时间尺度预测

为应对可再生能源利用和用户负荷的不确定性,提出一种多时间尺度预测方法。预测过程分日前、日内滚动和实时3个阶段进行,时间尺度分别为1 h、15 min和5 min。首先,采用基于差值统计的预测方法完成气象参数的3个阶段预测;其次,在负荷预测的日前和日内阶段,建立了信号分解与机器学习相结合的回归预测模型,实时阶段建立了机器学习时间序列预测模型;接着,以测试集的预测精度指标为依据确定了日前和日内滚动阶段对典型日负荷的最佳预测方法;最后,将预测方法应用于典型日的能量预测,验证了方法的可行性。研究结果显示:3个阶段典型日气象参数预测结果的决定系数R~2都在0.8以上;在日前和日内滚动阶段,多元负荷的预测任务应采用不同的信号分解方法,实时阶段负荷预测结果的R~2值均超过0.9,平均绝对误差百分比(mean absolute percentage error, MAPE)接近0。

虚拟电厂下灵活资源多时间尺度调频控制

随着能源结构转型的推进,可再生能源的使用逐渐增加,仅依靠传统机组调节频率偏差难以满足需求。因此,为了解决此问题,考虑利用分布式资源(DR)参与调频辅助服务,DR主要考虑空调、电动汽车充电桩以及储能。首先,考虑了DR的特性和满意度评价方法;然后,基于状态势博弈理论对DR进行协调控制,将DR集中起来使其对外呈现为一个整体参与调频辅助服务;最后,通过算例仿真证明了该方案下对DR聚合并协调控制参与调频辅助服务的可行性和有效性,并对多时间尺度下储能、电动汽车充电桩以及可控负荷参与快速调频进行了验证。

电力电子化电力系统多时间尺度时变动态小干扰稳定问题

面向国家能源安全和双碳战略的重大需求,大规模多样化的电力电子装备以不同的形式和功能参与到现代电力系统源-网-荷各环节中,受多样化电力电子装备多时间尺度时变动态影响的电力电子化电力系统稳定机制发生根本性改变。近年来,国内外电力系统中持续出现与电力电子装备相关的各种机理不明的振荡事故,表现为振荡频率范围较宽的多时间尺度时变动态问题,严重威胁电力电子化电力系统的安全稳定运行。该文从多样化电力电子装备原始特征出发,归纳电力电子化电力系统多时间尺度时变动态基本特性,并分别从小干扰建模和动态稳定分析归纳对不同理论方法的基本认识,随后从适用于电力电子化电力系统多时间尺度时变动态小干扰稳定快速分析计算为根本目标,凝练基于线性周期时变理论小干扰建模和动态稳定直接分析的研究思路。

基于奖惩阶梯型碳价机制的能源枢纽低碳优化策略

为进一步降低碳排放水平以及源-荷不确定性对系统运行的影响,文中提出一种基于奖惩阶梯型碳价机制和分布式模型预测控制(distributed model predictive control,DMPC)的能源枢纽(energy hub,EH)日前-日内-实时多时间尺度低碳优化调度策略。引入奖惩阶梯型碳价计算方法,构建EH日前低碳优化调度模型,并制定基于DMPC的日内滚动和实时调整的反馈闭环优化策略,降低源-荷预测误差,提高传统模型预测控制(model predictive control,MPC)的求解效率。在日内阶段,构建以阶梯型碳成本、运行成本和储能调整惩罚成本之和最小为目标的日内滚动优化模型;在实时阶段,分解整体优化问题,建立基于DMPC的多智能体实时调整模型。算例结果表明,文中所提策略能够有效提升系统经济效益,降低源-荷不确定性,实现EH的低碳经济、稳定可靠运行。

基于谱聚类的主动配电网多时间尺度无功优化策略

高比例分布式光伏接入配电网后,传统优化方案无法有效平抑电压波动,分布式光伏逆变器的无功调控能力难以充分利用。为此,提出一种基于谱聚类的主动配电网多时间尺度无功优化策略,该方法分为日前优化和日内实时优化两个阶段。首先,对离散设备的时间耦合性进行解耦,以配电网网损、平均电压偏差、电压波动严重程度为目标函数,建立基于社交网络搜索算法的日前无功优化模型,确定离散设备静态最优档位序列;其次,通过谱聚类的方法进行耦合,确定离散设备动态最优档位序列,结合改进的分布式光伏逆变器就地控制策略,建立日内实时优化模型,从而抑制日前预测数据偏差导致的电压波动;最后,基于改进后的IEEE33节点系统进行仿真实验。仿真结果表明,所提策略可以有效降低运算难度、提高求解效率,验证了该策略的有效性和优越性。