Conductor selection and economic analysis of D.R. congo–guinea ±800 kV UHVDC transmission project

Africa is embracing new opportunities featured with industrialization, urbanization and regionalization. Based on co-development of ‘Electricity, Mining, Metallurgy, Industry and Trade’ and grids interconnection proposed by Global Energy Interconnection Development and Cooperation Organization (GEIDCO), the high-quality hydropower resource of the Congo River can be exploited in large scale under the wide-range interconnected framework of African Energy Interconnection (AEI), forging a new engine for Africa economy. The transmission distance of the Congo River hydropower reaches 6,000 km at its farthest end in North Africa, which brings forth challenges to economics of proposed projects. Under this novel continental energy interconnection scheme in Africa, economics of those projects have not yet been in detail studied. This paper has implemented China’s mature engineering experiences and analytical tools of UHVDC project planning into the AEI structure, through exploring the economic behavior of ultra-long distance UHVDC projects in the scope of conductor selection in the Congo River hydropower transmission for the first time, and has provided concerned parties with a technical and analytical results of their economics comparison. This paper has chosen the D.R. Congo - Guinea ±800 kV UHVDC project as a typical example. Its preliminary system planning is introduced and three types of conductor are selected for scheme comparison. Later in this paper, the transmission loss, total investment and equivalent annual cost of the project have been calculated and analyzed. In the final part, sensitivity analysis results of the annual cost to utilization hours, transmission loss, loss tariff and construction cost has been provided     

Development of the interconnected power grid in Europe and suggestions for the energy internet in China

The European power grid is one of the largest regional interconnected power grids in the world. It realizes a multinational grid operation, which is rare. The total installed capacity of the European power grid is the largest throughout the world. In addition, the integration and utilization of renewable energy in this grid is a great benchmark for other countries and can help promote energy transformation and achieve a high proportion of renewable energy consumption. Based on the analysis of the existing status of the European interconnected power grid and the development history of this power grid, this paper summarizes four key development stages of the European power grid. In addition, the characteristics of each stage and the development prospect of the European power grid are analyzed. On this basis, this paper gives suggestions for the development and construction of China’s energy internet; this can provide valuable reference for further studies on China’s energy internet.     

Distributed privacy protection strategy for MEC enhanced wireless body area networks

With the rapid development and widespread application of Wireless Body Area Networks (WBANs), the traditional centralized system architecture cannot handle the massive data generated by the edge devices. Meanwhile, in order to ensure the security of physiological privacy data and the identity privacy of patients, this paper presents a privacy protection strategy for Mobile Edge Computing(MEC) enhanced WBANs, which leverages the blockchain-based decentralized MEC paradigm to support efficient transmission of privacy information with low latency, high reliability within a high-demand data security scenario. On this basis, the Merkle tree optimization model is designed to authenticate nodes and to verify the source of physiological data. Furthermore, a hybrid signature algorithm is devised to guarantee the node anonymity with unforgeability, data integrity and reduced delay. The security performance analysis and simulation results show that our proposed strategy not only reduces the delay, but also secures the privacy and transmission of sensitive WBANs data.     

Direct Observations on Structure Evolutions in Polyamide 6 during Deformation at High Temperatures with WAXS and SAXS

The deformation induced structure evolutions of polyamide 6 (PA6) during uniaxial tension at high tensile temperatures (60 °C and 90°C) were investigated with in situ wide- and small-angle X-ray scattering (WAXS and SAXS) technologies. The obtained data on structure evolutions revealed that they were different from the results measured at low temperature (30 °C). The α-phase got oriented once upon the beginning of deformation. After yielding the γ-phase started to be oriented following the α-phase. While, the breakdown of PA6 crystals along a and c axis overcame partial crystalline orientation at the high tensile temperatures (60 and 90 °C). The competition between stretch of amorphous phase and slippage of lamellae after yielding affected the deformation behavior of PA6. The collapse of lamellae was also confirmed from SAXS analysis and such disrupted lamellar structure resulted in the decrease of long spacing of PA6. The results showed that PA6 materials may show higher ductility at high temperatures. Therefore the crystals could be broken more easily and the formed lamellar fragments of PA6 could be preserved at larger strain at 90 °C. In addition, the yielding of PA6 and γ-phase orientation depended on the lamellar slippage during the deformation. POLYM. ENG. SCI., 60:581–586, 2020. © 2019 Society of Plastics Engineers     

Energy consumption and emission mitigation prediction based on data center traffic and PUE for global data centers

With the rapid development of technologies such as big data and cloud computing, data communication and data computing in the form of exponential growth have led to a large amount of energy consumption in data centers. Globally, data centers will become the world’s largest users of energy consumption, with the ratio rising from 3% in 2017 to 4.5% in 2025. Due to its unique climate and energy-saving advantages, the high-latitude area in the Pan-Arctic region has gradually become a hotspot for data center site selection in recent years. In order to predict and analyze the future energy consumption and carbon emissions of global data centers, this paper presents a new method based on global data center traffic and power usage effectiveness (PUE) for energy consumption prediction. Firstly, global data center traffic growth is predicted based on the Cisco’s research. Secondly, the dynamic global average PUE and the high latitude PUE based on Romonet simulation model are obtained, and then global data center energy consumption with two different scenarios, the decentralized scenario and the centralized scenario, is analyzed quantitatively via the polynomial fitting method. The simulation results show that, in 2030, the global data center energy consumption and carbon emissions are reduced by about 301 billion kWh and 720 million tons CO2 in the centralized scenario compared with that of the decentralized scenario, which confirms that the establishment of data centers in the Pan-Arctic region in the future can effectively relief the climate change and energy problems. This study provides support for global energy consumption prediction, and guidance for the layout of future global data centers from the perspective of energy consumption. Moreover, it provides support of the feasibility of the integration of energy and information networks under the Global Energy Interconnection conception.     

超高、超长、弧形混凝土墙体施工

针对超高、超长、弧形、抗渗、清水混凝土墙体一次性整体施工的要求,介绍了其钢筋、模板、混凝土分项工程施工所采取的施工工艺,分析了该施工工艺的特点及具有的优越性。     

刚性防水板在国家大剧院壳体屋面上的应用

国家大剧院工程屋面防水原设计方案是柔性防水,材料为进口的EPDM,实际采用刚性防水板,根据结构形式经向分成五层,纬向分成若干段,均为下大上小的扇形,采用锁边机锁边,施工相对简单,施工速度快,漏水的风险很小。综合比较,刚性防水施工工期比柔性防水施工工期缩短了近两个月,刚性防水造价比柔性防水造价减少了约4000万元,为业主节约了大量的资金。     

小城镇污水处理采用SBR工艺的控制系统

针对SBR工艺在小城镇污水处理中的应用现状,提出了以PLC为核心的控制系统,并对SBR工艺各阶段进行了控制标准模块化设计.     

清洁低碳发展背景下跨国互联电力系统规划方法

在全球应对气候变化清洁低碳发展的宏观背景下,当前跨国互联电力系统研究在地域范围、时间跨度、多层次协调等方面都存在一定不足。提出了协同有序完整的跨国互联电力系统规划研究体系框架,重点介绍情景设置、网源协同规划、环境气候-经济-社会效益分析等关键技术模型;基于“工作体系”和“支撑体系”,设计了总体工作流程;以实现《巴黎协定》温控约束为目标,对全球电力需求、电源结构、电能流动等问题开展了情景分析,评估研究综合效益。最后对规划研究方法进行了总结,并提出了提升建议。