Multi-Time Scale Optimal Scheduling of a Photovoltaic Energy Storage Building System Based on Model Predictive Control

Building emission reduction is an important way to achieve China’s carbon peaking and carbon neutrality goals.Aiming at the problem of low carbon economic operation of a photovoltaic energy storage building system,a multi-time scale optimal scheduling strategy based on model predictive control(MPC)is proposed under the consideration of load optimization.First,load optimization is achieved by controlling the charging time of electric vehicles as well as adjusting the air conditioning operation temperature,and the photovoltaic energy storage building system model is constructed to propose a day-ahead scheduling strategy with the lowest daily operation cost.Second,considering inter-day to intra-day source-load prediction error,an intraday rolling optimal scheduling strategy based on MPC is proposed that dynamically corrects the day-ahead dispatch results to stabilize system power fluctuations and promote photovoltaic consumption.Finally,taking an office building on a summer work day as an example,the effectiveness of the proposed scheduling strategy is verified.The results of the example show that the strategy reduces the total operating cost of the photovoltaic energy storage building system by 17.11%,improves the carbon emission reduction by 7.99%,and the photovoltaic consumption rate reaches 98.57%,improving the system’s low-carbon and economic performance.

Multi-time scale analysis of precipitation variation in Guyuan, China:1957-2005

Morlet wavelet transformation is used in this paper to analyze the multi time scale characteristics of pre cipitation data series from 1957 to 2005 in Guyuan region.The results showed that(1) the annual precipitation evo lution process had obvious multi time scale variation characteristics of 15 25 years,7 12 years and 3 6 years,and different time scales had different oscillation energy densities;(2) the periods at smaller time scales changed more frequently,which often nested in a biggish quasi periodic oscillations,so the concrete time domain should be ana lyzed if necessary;(3) the precipitation had three main periods(22 year,9 year and 4 year) and the 22 year period was especially outstanding,and the analysis of this main period reveals that the precipitation would be in a relative high water period until about 2012.

Bio-Inspired Optimal Dispatching of Wind Power Consumption Considering Multi-Time Scale Demand Response and High-Energy Load Participation

Bio-inspired computer modelling brings solutions fromthe living phenomena or biological systems to engineering domains.To overcome the obstruction problem of large-scale wind power consumption in Northwest China,this paper constructs a bio-inspired computer model.It is an optimal wind power consumption dispatching model of multi-time scale demand response that takes into account the involved high-energy load.First,the principle of wind power obstruction with the involvement of a high-energy load is examined in this work.In this step,highenergy load model with different regulation characteristics is established.Then,considering the multi-time scale characteristics of high-energy load and other demand-side resources response speed,a multi-time scale model of coordination optimization is built.An improved bio-inspired model incorporating particle swarm optimization is applied to minimize system operation and wind curtailment costs,as well as to find the most optimal energy configurationwithin the system.Lastly,we take an example of regional power grid in Gansu Province for simulation analysis.Results demonstrate that the suggested scheduling strategy can significantly enhance the wind power consumption level and minimize the system’s operational cost.

The Impact of Model Based Offset Scaling Technique on the Amplitude Variation with Offset Responses from 3D Seismic Data Acquired from the Tano Basin, Offshore Ghana

Amplitudes have been found to be a function of incident angle and offset. Hence data required to test for amplitude variation with angle or offset needs to have its amplitudes for all offsets preserved and not stacked. Amplitude Variation with Offset (AVO)/Amplitude Variation with Angle (AVA) is necessary to account for information in the offset/angle parameter (mode converted S-wave and P-wave velocities). Since amplitudes are a function of the converted S- and P-waves, it is important to investigate the dependence of amplitudes on the elastic (P- and S-waves) parameters from the seismic data. By modelling these effects for different reservoir fluids via fluid substitution, various AVO geobody classes present along the well and in the entire seismic cube can be observed. AVO analysis was performed on one test well (Well_1) and 3D pre-stack angle gathers from the Tano Basin. The analysis involves creating a synthetic model to infer the effect of offset scaling techniques on amplitude responses in the Tano basin as compared to the effect of unscaled seismic data. The spectral balance process was performed to match the amplitude spectra of all angle stacks to that of the mid (26°) stack on the test lines. The process had an effect primarily on the far (34° - 40°) stacks. The frequency content of these stacks slightly increased to match that of the near and mid stacks. In offset scaling process, the root mean square (RMS) amplitude comparison between the synthetic and seismic suggests that the amplitude of the far traces should be reduced relative to the nears by up to 16%. However, the exact scaler values depend on the time window considered. This suggests that the amplitude scaling with offset delivered from seismic processing is only approximately correct and needs to be checked with well synthetics and adjusted accordingly prior to use for AVO studies. The AVO attribute volumes generated were better at resolving anomalies on spectrally balanced and offset scaled data than data delivered from conventional processing. A typical class II AVO anomaly is seen along the test well from the cross-plot analysis and AVO attribute cube which indicates an oil filled reservoir.

Multitime scale variations of sea surface temperature in the China seas based on the HadISST dataset

The variability of the sea surface temperature（SST） in the China seas has been studied in seasonal,interannual and interdecadal scales based on the monthly data of HadISST spanning from 1870 to 2007. The main results obtained are SST in the China offshore changes most actively at the seasonal scale with the intensity diminishing from north to south,as the temperature differences between summer and winter reaching 17 and 4 C in the northern and southern areas,respectively. Moreover,seasonal variation near the coastal regions seems relatively stronger than that far from the coastline;significant interannual variations are detected,with the largest positive anomaly occurring in 1998 in the overall area. But as far as different domains are concerned,there exists great diversity,and the difference is also found between winter and summer. Differed from the seasonal variations,where the strongest interannual variability takes place,resides to the south of that of the seasonal ones in the northern section,nevertheless in the South China Sea,the most significant interannual variability is found in the deep basin;interdecadal changes of summer,winter and annual mean SST in different domains likewise present various features. In addition,a common dominant warming in recent 20 a are found in the overall China offshore with the strongest center located in the vicinity of the Changjiang Estuary in the East China Sea,which intensifies as high as 1.3 C during the past 130 a.

Low-carbon generation expansion planning considering uncertainty of renewable energy at multi-time scales

With the development of carbon electricity,achieving a low-carbon economy has become a prevailing and inevitable trend.Improving low-carbon expansion generation planning is critical for carbon emission mitigation and a lowcarbon economy.In this paper,a two-layer low-carbon expansion generation planning approach considering the uncertainty of renewable energy at multiple time scales is proposed.First,renewable energy sequences considering the uncertainty in multiple time scales are generated based on the Copula function and the probability distribution of renewable energy.Second,a two-layer generation planning model considering carbon trading and carbon capture technology is established.Specifically,the upper layer model optimizes the investment decision considering the uncertainty at a monthly scale,and the lower layer one optimizes the scheduling considering the peak shaving at an hourly scale and the flexibility at a 15-minute scale.Finally,the results of different influence factors on low-carbon generation expansion planning are compared in a provincial power grid,which demonstrate the effectiveness of the proposed model.

IMPACT OF LARGE-SCALE CIRCULATION ON THE INTERDECADAL VARIATIONS OF THE WESTERN NORTH PACIFIC TROPICAL CYCLONE

Based on the annual frequency data of tropical cyclones from 1960 to 2005 and by the polynomial fit and statistical analysis, this work has discovered that TC activity in the 46a exhibits significant decadal-scale variability. It has two high frequency periods (HFP) and two low frequency periods (LFP). Significant differences in the number of TCs between HFP and LFP are found in active TC seasons from July to October. Differences of large-scale circulation during HFP and LFP have been investigated with NCEP/NOAA data for the season. In HFP, the condition includes not only higher sea surface temperature, lower sea level pressure, larger divergence of upper air, larger relative vorticity at low levels and smaller vertical shear, but also 500-hPa wind vector being more available for TC activity and moving to western North Pacific, the position of the subtropical anticyclone over the western Pacific shifting more northward, and South Asian Anticyclone at 100-hPa being much smaller than that in LFP. The precipitation of western North Pacific has no clear influence on TC activity.

Interdecadal Variations of Phase Delays Between Two Nino Indices at Different Time Scales

Phase delays between two Nino indices-sea surface temperatures in Nino regions 1+2 and 3.4 (1950-2001)-at different time scales are detected by wavelet analysis. Analysis results show that there are two types of period bifurcations in the Nino indices and that period bifurcation points exist only in the region where the wavelet power is small. Interdecadal variation features of phase delays between the two indices vary with different time scales. In the periods of 40-72 months, the phase delay changes its sign in 1977: Nino 1+2 indices are 2-4 months earlier than Nino 3.4 indices before 1977, but 3-6 months later afterwards. In the periods of 20-40 months, however, the phase delay changes its sign in another way: Nino 1+2 indices are 1-4 months earlier before 1980 and during 1986-90, but 1-4 months later during 1980-83 and 1993-2001.

Variational Assimilation of GPS Precipitable Water Vapor and Hourly Rainfall Observations for a Meso-βScale Heavy Precipitation Event During the 2002 Mei-Yu Season

Recent advances in Global Positioning System （GPS） remote sensing technology allow for a direct estimation of the precipitable water vapor （PWV） from delayed signals transmitted by GPS satellites, which can be assimilated into numerical models with four-dimensional variational （4DVAR） data assimilation. A mesoscale model and its 4DVAR system are used to access the impacts of assimilating GPS-PWV and hourly rainfall observations on the short-range prediction of a heavy rainfall event on 20 June 2002. The heavy precipitation was induced by a sequence of meso-β-scale convective systems （MCS） along the mei-yu front in China. The experiments with GPS-PWV assimilation cluster and also eliminated the erroneous rainfall successfully simulated the evolution of the observed MCS systems found in the experiment without 4DVAR assimilation. Experiments with hourly rainfall assimilation performed similarly both on the prediction of MCS initiation and the elimination of erroneous systems, however the MCS dissipated much sooner than it did in observations. It is found that the assimilation-induced moisture perturbation and mesoscale low-level jet are helpful for the MCS generation and development. It is also discovered that spurious gravity waves may post serious limitations for the current 4DVAR algorithm, which would degrade the assimilation efficiency, especially for rainfall data. Sensitivity experiments with different observations, assimilation windows and observation weightings suggest that assimilating GPS-PWV can be quite effective, even with the assimilation window as short as 1 h. On the other hand, assimilating rainfall observations requires extreme cautions on the selection of observation weightings and the control of spurious gravity waves.

Research on multi-time scale doubly-fed wind turbine test system based on FPGA+CPU heterogeneous calculation

As the proportion of renewable energy increases, the interaction between renewable energy devices and the grid continues to enhance. Therefore, the renewable energy dynamic test in a power system has become more and more important. Traditional dynamic simulation systems and digital-analog hybrid simulation systems are difficult to compromise on the economy, flexibility and accuracy. A multi-time scale test system of doubly fed induction generator based on FPGA+ CPU heterogeneous calculation is proposed in this paper. The proposed test system is based on the ADPSS simulation platform. The power circuit part of the test system is setup up using the EMT(electromagnetic transient simulation) simulation, and the control part uses the actual physical devices. In order to realize the close-loop testing for the physical devices, the power circuit must be simulated in real-time. This paper proposes a multi-time scale simulation algorithm, in which the decoupling component divides the power circuit into a large time scale system and a small time scale system in order to reduce computing effort. This paper also proposes the FPGA+CPU heterogeneous computing architecture for implementing this multitime scale simulation. In FPGA, there is a complete small time-scale EMT engine, which support the flexibly circuit modeling with any topology. Finally, the test system is connected to an DFIG controller based on Labview to verify the feasibility of the test system.

ANALYSIS OF THE RELATIONSHIP BETWEEN THE CHINA ANOMALOUS CLIMATE VARIATION AND ENSO CYCLE ON THE QUASI-FOUR-YEAR SCALE

The relationship between the ENSO and abnormal variation of precipitation and temperature in China is investigated based on the monthly data. Firstly, interannual variability of precipitation and temperature are discussed in different sub-areas using Rotational EOF (REOF). Then, the variation of precipitation and temperature in different phases of ENSO cycle is each investigated with Complex Singular Value Decomposition (CSVD). Results show that, during the period of El Nio, precipitation in the eastern China, especially in the northeastern China and Yangtze River valley, is much more than normal and is apt to flood. Precipitation in northern China and Huanghe River valley, especially in the middle reach of Huanghe River, is less than normal and is apt to be less. Precipitation in the Yangtze River valley is closely related to the SSTA in the central and eastern tropical Pacific on the QFO scale, and the precipitation variation lags behind SSTA by about 3 months. For the variation of surface temperature, during the period of El Nio, it is usually colder than normal in northeastern China, and in other regions, especially in the region of Great Bend of the Yellow River and southwestern China, is warmer than normal. The temperature in northeast China is closely associated with SSTA in eastern Pacific on the QFO scale and the surface temperature variation in the northeast China lags behind that of SSTA about 2 months.

Trait variation and functional diversity maintenance of understory herbaceous species coexisting along an elevational gradient in Yulong Mountain,Southwest China

Characterizing trait variation across different ecological scales in plant communities has been viewed as a way to gain insights into the mechanisms driving species coexistence.However,little is known about how changes in intraspecific and interspecific traits across sites influence species richness and community assembly,especially in understory herbaceous communities.Here we partitioned the variance of four functional traits(maximum height,leaf thickness,leaf area and specific leaf area)across four nested biological scales:individual,species,plot,and elevation to quantify the scale-dependent distributions of understory herbaceous trait variance.We also integrated the comparison of the trait variance ratios to null models to investigate the effects of different ecological processes on community assembly and functional diversity along a 1200-m elevational gradient in Yulong Mountain.We found interspecific trait variation was the main trait variation component for leaf traits,although intraspecific trait variation ranged from 10% to 28% of total variation.In particular,maximum height exhibited high plasticity,and intraspecific variation accounted for 44% of the total variation.Despite the fact that species composition varied across elevation and species richness decreased dramatically along the elevational gradient,there was little variance at our largest(elevation)scale in leaf traits and functional diversity remained constant along the elevational gradient,indicating that traits responded to smaller scale influences.External filtering was only observed at high elevations.However,strong internal filtering was detected along the entire elevational gradient in understory herbaceous communities,possibly due to competition.Our results provide evidence that species coexistence in understory herbaceous communities might be structured by differential niche-assembled processes.This approach ee integrating different biological scales of trait variation ee may provide a better understanding of the mechanisms involved in the structure of communities.

Morphological variation of star dune and implications for dune management: a case study at the Crescent Moon Spring scenic spot of Dunhuang, China

Aerial photographs and 3-D laser scans of a 90-m high star dune at the Crescent Moon Spring scenic spot in Dunhuang,China,are used to investigate the changes in dune morphology on timescales from months to decades.The result revealed that relative-equilibrium airflow strength in three wind directions of northeast,west and south was an important condition for the stability of star dunes with limited migration.Transverse and longitudinal airflows exerted a crucial impact on variation processes of star dune morphology.Controlled by transverse airflows,the easterly winds,the east side was dominated by wind erosion;and strong deposition occurred on the south-south-east arm with a maximum deposition rate of 0.44 m/a in the 46-a monitoring period,causing the east side becoming steep and high.Controlled by longitudinal airflows,the westerly winds,the west-north-west side was mainly eroded and the north arm migrated from west to east with a rate of 0.30 m/a,causing the dune slope becoming gentle and elongate.The local air circulation(southerly winds)exerted a significant impact on the development process of the star dune.Due to the influence of human activities,the south side present surface processes from a concave profile to a convex profile in 46 a,which is a potential threat to the Crescent Moon Spring.The results indicate that rehabilitating the airflow field at most is a crucial strategy to the protection of Crescent Moon Spring from burial.Opening up the passage of easterly,westerly and southerly winds through intermediately cutting the protection forest,demolishing the enclosed wall and changing the pavilion into a porous pattern have been suggested to protect the Crescent Moon Spring from burial.

Diurnal Variation of Tropical Convection during TOGA COARE IOP

Diurnal variation of tropical convection and kinematic and thermodynamic conditions was investigated for different large-scale environments of the convectively active and inactive periods by using satellite observations and surface measurements during the Intensive Observation Period （IOP） of the Tropical Ocean Global Atmosphere/Coupled Ocean-Atmosphere Response Experiment （TOGA/COARE）. During the convectively active period, the features of nocturnal convection appear in vertical profiles of convergence, vertical velocity, heat source, and moisture sink. The specific humidity increases remarkably in the middle troposphere at dawn. On the other hand, the altitude of maximum convergence and that of the upward motion is lower during the convectively inactive period. The specific humidity peaks in the lower troposphere in the daytime and decreases in the middle troposphere. Spectral analyses of the time series of the infrared （IR） brightness temperature （TBB） and amounts of rainfall suggest multiscale temporal variation with a prominent diurnal cycle over land and oceanic regions such as the Intensive Flux Array （IFA） and the South Pacific Convergence Zone （SPCZ）. Over land, the daily maximum of deep convection associated with cloud top temperature less than 208 K appears at midnight due to the daytime radiative heating and the sea-land breeze. Over the ocean, convection usually tends to occur at dawn for the convectively active period while in the afternoon during the inactive period. Comparing the diurnal variation of convection with large-scale variables, the authors inferred that moisture in the middle troposphere contributes mostly to the development of nocturnal convection over the ocean during the convectively active period.

STUDY OF THE EQUIVALENT THEOREM OF GENERALIZED VARIATIONAL PRINCIPLES IN ELASTICITY

The relations of all generalized variational principles in elasticity are studied by employing the invariance theorem of field theory. The infinitesimal scale transformation in field theory was employed to investigate the equivalent theorem. Among the results found particularly interesting are those related to that all generalized variational principles in elasticity are equal to each other. Also studied result is that only two variables are independent in the functional and the stress-strain relation is the variational constraint condition for all generalized variational principles in elasticity. This work has proven again the conclusion of Prof. Chien Wei-zang.

Seasonal Variation Features of Western North Pacific Tropical Cyclone Tracks with Their Predictability

Analysis is done of monthly and seasonal variations as climatic features of the tracks from 1196 tropical cyclones originating in the western North Pacific over the period 1949 to 1980, followed by the investigation of 301 onland cyclone tracks over China mainland in terms of methodology for nonlinear system. Obtained by computing the accumulated distance distribution function of the tracks Cm (l) is the characteristic chaos quantity for the related dynamic systems and then the fractual dimensionality d = 4.86 and Kolmogorov entropy approximation K2 = 0.0164, thereby leading to the predictability time scale = 2.54 days. It is found that the reference path among the onland typhoon No.23 of 1971, or Bess in the international nomenclature. Our results could be of operational use as a kind of reference.

Seed germination of Albizia procera(Roxb.)Benth.in Bangladesh:a basis for seed source variation and pre-sowing treatment effect

An experiment in seed morphology and seed germination techniques of Albizia procera was carried out in the nursery of the Forestry and Wood Technology Discipline, Khulna University, Bangladesh in order to discover the source variation in seeds and pre-sowing treatment effects on seed germination. Mature seeds ofA. procera were collected from healthy trees in home garden plan- tations from five different districts in Bangladesh and treated with four pre-sowing treatments, i.e., control, immersion in cold water （4~C for 24 h） and immersion in hot water （80~C for 10 min and 100~C for 1 min）. The average length, width and thickness of seeds were calculated as 0.502 ＋ 0.485, 0.420 ~ 0.060 and 0.191 ~ 0.118 cm, respectively. Germination was conducted in poly-bags with a mixture of topsoil and cow dung in a ratio of 3：1. The results revealed that pre-sowing treatments affected the rate of germination of seeds, which significantly increased the germination percentages of seeds in hot water treatments compared with those in control （60.60%） and the cold water treatment （4℃ for 24 h, 63.53%）. The highest germination success was 82.07% in the treatment of im- mersion in hot water （80℃） for 10 min, followed by 79.00% in immersion in hot water （100℃） for l rain. Germination started 4 to 6 days after seed sowing and completed in a period of 22 to 25 days in all treatments. ANOVAs showed statistically significant dif- ferences （p 〈 0.05） in seed germination starting dates, closing dates, germination percentages and rates of germination among treat- ments, but no significant differences in seed germination starting dates, closing dates, germination period, germination percentages and rates of germination among the seed sources. The study also revealed that the interaction between seed source variation and treat- ment effect significantly differed in seed germination starting dates, closing dates, germination percentages and rates of germination. The hot water （100℃ for 1min） treatment is recommended for seed germination ofA. procera in rural Bangladesh.

Research on Influencing Factors of Spatial Variation of Soil Nutrients

Based on previous studies,the research methods and influencing factors of spatial variation of soil nutrients are summarized.It is concluded that the spatial variation of soil nutrients is studied generally by geostatistics methods,and the spatial distribution of nutrients is visually observed by using Kriging interpolation method.The influencing factors mainly include topography,sampling method,sampling spacing,sampling density and sampling scale.The influence of random sampling and grid sampling on interpolation is analyzed based on the specific conditions of the actual study area.The influence of sampling density and topography on the spatial variation of soil nutrients cannot be ignored,especially on available nutrients.When samples are collected in a large area(under a small and medium scale),the spatial variation of soil nutrients is large,and they have strong spatial autocorrelation;in a small area(namely under a large scale),the spatial variability of soil nutrients is small,and they have obvious spatial autocorrelation.This study can provide intuitive and convenient reference materials for the following researchers.

CMA-MESO千米尺度变分同化系统中极小化控制变量的重构

重构GRAPES(Global/Regional Assimilation and Prediction System)全球、区域一体化变分同化系统中的极小化控制变量,提升中、小尺度同化分析能力,为中国气象局业务区域数值预报系统CMA-MESO提供千米尺度适用的同化方案。新方案用纬向风速(u)和经向风速(v)替代原有流函数和势函数作为新的风场控制变量,采用温度和地面气压(T,ps)替代原有非平衡无量纲气压作为新的质量场控制变量,同时不再考虑准地转平衡约束,而是采用连续方程弱约束保证分析平衡。背景误差参数统计和数值试验结果表明,采用重构后的极小化控制变量,观测信息传播更加局地,分析结构更加合理,避免了原方案在中、小尺度应用时存在的虚假相关问题。连续方程弱约束的引入,限制了同化分析中辐合、辐散的不合理增长,帮助新方案在分析更加局地的同时保证分析平衡。为期1个月的连续同化循环和预报试验结果表明,新方案可以减小风场和质量场分析误差,CMAMESO系统地面降水和10 m风场的预报评分显著提升。

小净距隧道掘进爆破及其振动响应规律研究

为了研究爆破荷载作用下小净距隧道中夹岩区的动力稳定性问题,依托小龙门隧道爆破工程,开展了现场爆破振动监测试验。通过改进的变分模态分解(variational mode decomposition,VMD)与多尺度排列熵(multi-scale permutation entropy,MPE)算法对爆破振动信号进行消噪处理,基于此分析了掏槽孔与周边孔爆破在后行洞左拱腰(非中夹岩区)、右拱腰(中夹岩区)中产生的振动特征差异。结果表明:采用改进的自适应VMD-MPE算法可以有效消除振动信号中的噪声,并降低了主观决策的影响;此外,相对于非中夹岩区,中夹岩对爆破振动具有明显的放大效应,其质点峰值振速明显大于非中夹岩区,但中夹岩区的振动衰减速度更快;同时,通过对比非中夹岩区与中夹岩区各测点振动频率特征可以发现,中夹岩区小于40 Hz的低频振动能量占比较大,更易引起支护结构的共振,发生损伤与破坏的风险更高,应重点关注;受“转角削弱”作用以及地震波传播路径的影响,在比例距离SD小于等于11.57 m·kg^(1/3)范围内,周边孔爆破在掌子面后方围岩中产生的振速大于掏槽孔。