基于多时间尺度和多源储能的综合能源系统能量协调优化调度

考虑源荷不确定性及储能设备配置对综合能源系统IES(integrated energy system)优化调度的影响,提出基于多时间尺度和多源储能的IES能量协调优化调度策略。该策略以系统运行经济最优、滚动控制时域内购能成本与储能惩罚成本之和最低以及设备输出功率调整量最小为目标,分别建立了日前、日内滚动和实时反馈3个时间尺度的优化调度模型。在日前考虑多种储能模式对IES经济性的影响;日内利用场景分析法描述滚动预测的不确定性来提高系统经济运行稳定性;再基于模型预测控制方法,构建日内与实时的反馈闭环优化,平抑由预测误差导致的系统功率波动。仿真结果表明:多源储能模式有助于提高IES的经济性;多时间尺度调度既可以保证IES运行的经济性,又能有效降低不确定性对系统实际运行的影响,减轻电网平抑功率波动负担。     

Crack initiation and propagation in braided SiC/SiC composite tubes: Effect of braiding angle

Crack initiation and propagation in three braided SiC/SiC composite tubes with different braiding angles are investigated by in situ tensile tests with synchrotron micro-computed tomography. Crack networks are precisely detected after an image subtraction procedure based on Digital Volume Correlation. FFT based simulations are performed on the full-resolution 3D images to assess elastic stress/strain fields. Quantitative measurements of the crack geometries are performed using a novel method based on grey levels. The results show that braiding angle has no obvious effect on the location of crack onsets (initiation always occurs at tow interfaces), whereas it significantly affects the paths of crack propagation. This work provides an explicit demonstration of the crack propagation scenarios with respect to the mesoscopic fibre architectures.     

分布式多元随机动态场景生成及快速精准场景降维算法

高比例新能源及多源耦合是电力系统发展的重要特征,这也为系统稳定经济运行提出了新挑战。该文以园区型多能系统为对象,研究了分布式多元随机动态场景分析,从多时空角度有效量化不确定因素给系统造成的影响,可为系统灵活重构、多维度协同运行与决策提供有力模型与场景支撑。首先由预测误差驱动拟合多元功率预测误差概率分布,全面反映随机功率出力信息,提高模型泛化性;以时序相关范围参数为数据驱动关联变量,高效动态控制波动强度;最终场景生成利用逆变换映射思想保证置信度。然后针对典型场景提取,提出一种综合递归聚类思想的多段嵌套削减算法,结合改进Wasserstein距离指标,兼具准确、时效、稳定方面的优势。最后由对比实验论证该方法的前沿有效性。     

Job accessibility impacts of intensive and multiple land-use scenarios for the Netherlands’ Randstad Area

This paper examines job accessibility impacts of intensive and multiple land-use scenarios in the Netherlands’ Randstad Area for the period 1996–2030. The scenarios involve a heavy increase in the density and diversity of activities around railway stations. Accessibility impacts are examined using location-based accessibility measures and utility-based accessibility benefit measures within a high-resolution land-use/transport interaction modelling framework, taking into account the regional demand for economic activities and possible market responses. It is concluded that extreme concentrations of economic activities at central urban locations well served by public transport are not to be preferred over less heavy concentrations of economic activities at more locations. Heavy concentrations of new firms may firstly repel existing firms in the neighbourhood and secondly result in decreasing marginal returns of accessibility benefits for public transport users.     

私人部门性质对PPP项目产出绩效监管的影响及其优化建议——基于情境模拟实验研究

现阶段PPP项目产出绩效监管尤为重要。针对私人部门为国有企业和私营企业,通过已构建的PPP项目产出绩效监管框架筛选出实验变量,继而对变量进行情境设计,并进行问卷调查对比分析不同性质私人部门的PPP项目产出绩效监管。最后,为政府部门面对不同性质私人部门类PPP项目产出绩效监管提出三条优化建议。     

杭州市三江汇地区森林植被固碳抵消能源 排放能力评估及情景预测研究

森林植被固碳服务是生态系统服务评估的重要内容之一，在区域碳中和发挥着重要的碳汇作用。以生物量法和CASA模型法相结合，评估杭州市三江汇地区森林植被固碳能力；采用CEADs县级碳排放清单估算三江汇地区的能源碳排放量；综合碳汇和碳排评估该地区森林植被固碳对能源碳排放量的抵消率。从碳减排和增汇2个方面，对森林植被抵消能源碳排放的能力进行未来情景预测。研究结果表明：1)2017年三江汇地区森林植被固碳量为4.98×10⁴t，能源碳排放量为2.07×10⁶t，森林植被能源碳排放的抵消率为2.41%，三江汇森林植被能源碳抵消率呈现出“东低西高、北低南高”的空间格局；2)研究设置9个情景对2030年森林植被碳抵消率进行定量预测，预测结果显示研究区森林植被面积增加有利于提升森林植被对能源碳排放量的抵消能力，森林面积每增加5%，森林植被对能源碳排放量抵消率可提高0.12%～0.29%；减少人均能源碳排放对提高森林植被碳抵消能力的效果更为显著，人均能源碳排由2.77t/人降低为0.90和0.72t/人，森林植被碳抵消率可分别提高2.21%～2.43%和3.36%...     

LNG槽车瞬态泄漏特性及事故后果研究

我国每年危化品道路运输量占总货运量的30%以上,运输安全事故发生率居高不下。通过构建槽车泄漏事故,针对液相泄漏经典模型对于瞬态研究的局限性,结合罐内气体状态方程和复合积分法改进泄漏模型,研究了卧罐泄漏速率与时间耦合关系。结果表明,泄漏速率随时间推移呈二阶指数衰减关系,利用泄漏速率函数与时间叠加修正高斯模型,将修正后的关系运用到火灾爆炸事故后果计算中,得出泄漏最远距离为37.5 m,喷射火和沸腾液体扩展蒸汽爆炸(Boiling Liquid Expand Vapor Explosion, BLEVE)分别造成15和298 m内人员致死率达37%,蒸气云爆炸15 m内人员致死率为1%。利用Fluent和Aloha模型验证了模型精度,可为危险液体储罐泄漏定量风险评价和突发事件事前预判提供理论依据。     

Effect of alloying element on microstructure,mechanical property,and oxidation resistance of Zr─Me─C (Me═Si/Y) coatings

Accident-tolerant fuels (ATFs) are proposed to provide improved safety response to a loss of coolant accident (LOCA) scenario while maintaining good operational characteristics under normal conditions. In this work, Zr─Me─C (Me═Si or Y) was proposed as candidate coatings for ATF applications. The influence of Si and Y with varied concentration on microstructural evolution, mechanical property, and oxidation resistance of Zr─Me─C coatings were investigated. Based on combined results of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy, it was found that Si or Y doped ZrC_0.55 coatings presented tunable composition and microstructure. Improved air oxidation and spallation resistance were achieved with the incorporation of Me atoms, attributing to the formation of SiO₂ and ZrSiO₄ and/or the stabilization of zirconia. Under a simulated LOCA condition, decreased weight gains of 13.6 at.% Si and 22.5 at.% Y coated Zry-4 alloys were achieved. nc-ZrSiC/nc-ZrSi (13.6 at.% Si) coating exhibited enhanced mechanical property and oxidation resistance in both high-temperature air and LOCA conditions, which could be regarded as potential candidate for the applications in ATFs.     

风电爬坡事件对系统运行充裕性的影响评估

风电爬坡事件具有大波动性和强不确定性的特点,可造成系统中发用电的严重不平衡,从而导致负荷损失。在分析风电爬坡事件特征和爬坡预测研究现状的基础上,建立了风电爬坡事件模型,定量表示爬坡事件表征量与风电功率曲线之间的关系;同时考虑负荷预测的不确定性,采用场景削减方法生成风电爬坡过程对应的典型净负荷场景集。构建了评估系统运行充裕性的指标体系,推导了缓冲失负荷概率指标的计算公式;将系统状态分为充裕、失负荷和临界3种,分别计算各状态对应概率及失负荷严重程度。以甘肃电网为例,典型事件的评估结果验证了所述方法和指标体系的有效性和合理性,分析了常规机组爬坡速率及系统备用比例在防范风电爬坡事件不利影响方面的作用。