The state-of-the-arts of the study on grid interconnection between Iberian Peninsula and West Maghreb region

With the change of energy structure in Europe and the trend of diversification of energy supply, the interconnection of the power grid in the Mediterranean region has gradually become a hotspot in European energy research. This paper introduces the power supply, load demand, power grid construction and the present situation of multinational interregional interconnection in the Iberian Peninsula of the Tour of Mediterranean in Europe (Portugal and Spain) and the Western Maghreb countries (Morocco and Algeria). And the driving force and influence factors of regional power grid interconnection are also analyzed. According to the MEDGRID project aimed at realizing the Mediterranean power grid interconnection, this paper presents the interconnection schemes of the Iberian Peninsula and the Western Maghreb. Furthermore, the subsequent technical problems need to be solved are also expounded.     

Index system and methods for comprehensive assessment of cross-border power grid interconnection projects

With the global economy integration and progress in energy transformation, it has become a general trend to surpass national boundaries to achieve wider and optimal energy resource allocations. Consequently, there is a critical need to adopt scientific approaches in assessing cross-border power grid interconnection projects. First, considering the promotion of large-scale renewable energy resources and improvements in system adequacy, a comprehensive assessment index system, including costs, socio-economic benefits, environmental benefits, and technical benefits, is established in this study. Second, a synthetic assessment framework is proposed for cross-border power grid interconnection projects based on the index system comprising cost–benefit analysis, with market and network simulations, iterative methods for indicator weight evaluation, and technique for order preference by similarity to an ideal solution (TOPSIS) method for the project rankings. Finally, by assessing and comparing three cross-border projects between Europe and Asia, the proposed index system and assessment framework have been proved to be effective and feasible; the results of this system can thus support investment decision-making related to such projects in the future.     

青藏直流联网后藏中电网安全稳定控制系统的重构

青藏直流联网初期,作为青藏直流受端的藏中电网短路容量较小,电网网架较薄弱,导致交直流系统安全稳定问题较为突出,给青藏直流以及藏中电网的安全稳定运行带来诸多挑战。针对青藏直流联网后电网存在的各种稳定问题进行了深入分析,提出了相应的控制对策;提出建设分层分区的藏中电网安全稳定控制系统来保障青藏直流工程和藏中电网安全稳定运行。     

Analysis of profit models for cross-border power interconnection projects

With the increasing demand worldwide for power grid interconnection, a growing number of related projects are under planning or construction. Despite the rapid growth of cross-border interconnection projects, the systematic research on profit models for these projects is insufficient. This paper first analyzes the profit sources of interconnection projects. Based on the analysis results, profit models are considered under different regulatory systems for three types of crossborder interconnection projects: fully market-oriented, semi-marketization, and fully supervised. Finally, measures for increasing the profitability and sustainable development of power interconnection projects are proposed.     

西北电网外送暨宁东—山东±660 kV高压直流联网示范工程浅议

分析了西北与华北电网宁东-山东±660kV高压直流输电工程中的近10项“世界第一”技术创新特点．从系统联网角度阐述了该工程建设的经济和社会效益。根据国家“西电东送”战略要求,通过国家电网的统一规划、建设和调配,西北750kV骨干电网作为“三华”送端电网的格局已经形成,该直流联网示范工程将西北黄河上游水电、宁东火电打捆外送,对于西北地区煤电、水电、风电等能源大规模外送具有显著的示范作用,将实现更大范围的能源资源优化配置与利用。     

新疆与西北联网后电力交易及转运网损补偿机制研究

新疆电网是西北送端电网的重要组成部分,参与西北电网跨区、跨省交易,才能发挥联网工程的电量效益。结合西北电网跨区、跨省交易现状,分析了现阶段疆电东送的目标市场,提出了转运网损补偿方案,对新疆电力交易工作具有参考意义。     

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     

Analysis of basic conditions of the power grid interconnection among Xinjiang,Pakistan, and five Central Asian countries

Inter-regional and transnational grid interconnection is necessary for energy development. Xinjiang, which is rich in renewable energy resources, is adjacent to countries in Central Asia and has great potential for interconnection with its neighbors. This paper outlines China’s relevant policies for transnational power interconnection, and introduces the energy structure, load demand endowments, and power supply status of Xinjiang, Pakistan, and five Central Asian countries. Further, it analyzes the advantages of the multinational power interconnection from the aspects of power supply and load complementation. Finally, from the perspective of technical support and practical basis, the feasibility of interconnection between Xinjiang, Pakistan, and five Central Asian countries have been analyzed. This paper provides a theoretical basis for promoting and implementing China’s “Belt and Road” power transnational interconnected development strategy.     

基于CVaR方法的风力发电项目投资风险度量

风力发电项目具备较为独立的特点,将CVaR方法引入风力发电项目的投资风险度量,不仅可以全面衡量技术风险、经济风险、政策风险等相关风险因素,同时可以最大限度地考虑投资者的损失承受底线。借助蒙特卡洛方法模拟风力发电的上网电量,很好地计量了风力发电的不确定性所带来的风险。以内蒙古地区某一风力发电项目为实例,分别计算了其VaR值和CVaR值。计算结果表明,CVaR方法能够更加谨慎有效地估计风力发电项目投资者的潜在损失。文章进一步研究了贴现率和电价等风险因素对风力发电项目整体风险的影响,认为较低的贴现率和较高的电价水平能够帮助投资者很好地规避投资风险。     

Factors affecting economics of clean energy transmission channel in Southeast Asia

This paper addresses the issues regarding the economics of clean energy transmission channels in Southeast Asia. The research developed an improved comprehensive model for the generation and transmission planning considering variable renewable energy characteristics, and it simulated the hourly resolution operation condition of a cross-regional interconnection grid of Southeast Asia, China, and South Asia. Additionally, we conducted a sensitivity analysis, and the assessment of the channels’ economics covered a variety of factors such as clean energy penetration, CO₂, and pollutant reduction. Conclusions are drawn regarding the influence of different parameters and conditions on the economics of the transmission channel. Subsequently, several recommendations were proposed based on these analyses, which could support the development of the scheme of Southeast Asia power grid and the interconnection of the Belt and Road initiative.     

青藏直流联网工程负荷特性对短路电流计算影响的分析

随着格尔木—拉萨直流输电工程的开工建设,该工程项目的实施对于促进全国联网,推动直流输电装备技术进步,促进西北地区能源资源在更大范围内优化配置,推动西藏乃至西北社会经济又好又快发展意义十分重大。在西藏电网与青海电网的联网,是我国乃至世界上海拔最高的直流输电工程项目,作为项目的最基础性研究,确定换流站接入处交流系统的强度无疑是至关重要的。基于综合潮流程序PSASP及电磁暂态仿真软件PSCAD/EMTDC进行了相关问题的仿真研究,针对不同负荷特性对确定系统短路比的影响做出分析研究,为更加真实反应青海电网强度提供可靠的技术支撑。     

A production-cost-simulation-based method for optimal planning of the grid interconnection between countries with rich hydro energy

Cross-border grid interconnection is a critical means to achieve wide-area share of hydro and other clean energy. Economic benefit assessment of cross-border grid interconnection projects should be carefully performed during early stage. In this paper, a method based on cost-benefit economic assessment for optimal planning of cross-border grid interconnection is proposed. An economic index for comprehensively assessing the cost of a transmission project and its resulting benefits of more usage of hydro energy is designed first. A chronological production cost simulation model considering hydro energy spillage due to transmission congestion and thermal operational limitation is then proposed to calculate the economic index. A case study is performed using the proposed method to determine the optimal capacity of a potential transmission link between Brazil and Argentina, which have rich and complementary hydro energy resources.     

Analysis of the impact of electricity grid interconnection between Korea and Japan—Feasibility study for energy network in Northeast Asia

This study analyzes the impact of an electricity grid interconnection between Korea and Japan on their energy systems. Both countries seriously consider energy security as the most important policy issue because of a lack of domestic energy resources. In addition, public concern for the environment is recently rising up in response to the global warming. Electricity grid interconnection has strong potential to cope with such complicated problems cost-effectively. We have developed the interconnection model, which includes the electricity grid interconnection between the electricity sectors of Korea and Japan, considering both technological and economic efficiency. The result of the study reveals the significant cost-effectiveness of the interconnection, in particular, under stringent condition such as nuclear phase-out in Japan and CO₂ emission target in Korea and Japan. In the case that Japan's nuclear power plants will be phased out, the interconnection attains further cost reduction of constructing substitutive thermal power plants. On the other hand, when Korea and Japan set a joint CO₂ emission target, it achieves the emission target more efficiently than they reduce the emission individually.     

正交设计灰色模型在年电力负荷预测中的应用

基于正交设计和灰色系统理论．提出一种预测年电力负荷的新方法。采用新陈代谢技术和加权最小二乘参数辨识法对标准GM（1,1）模型进行改进。以背景值系数OL、建模所需数据个数m和加权参数q作为可控因素,根据专家经验设计了三因素三水平正交表。以平均绝对百分比误差为输出目标,通过信噪比分析,得出最优参数水平组合,并通过方差分析,进一步得出各可控因素对预测效果的影响程度。对2个电网的负荷进行预测,结果验证了所提方法的可行性和有效性。     

考虑特高压和复杂接线的直流偏磁风险治理

准东—皖南特高压直流工程是世界上首个±1 100kV特高压输电工程,避免其可能造成的直流偏磁风险意义重大。为此,结合安徽电网规划情况,对接地极附近165km范围内的大地构造调研和现场实测反演得到等效的土壤模型,依据场路耦合理论建立安徽电网交流系统直流电流分布计算模型,计算各个变电站主变中性点电流,分析了直流偏磁对安徽省交流电网影响范围、影响程度及主要的影响因素,并探讨了换流站和特高压站变压器受直流偏磁的影响,针对各电压等级变电站提出直流偏磁抑制措施,制定治理原则,进一步探究综合治理方案,从而使治理效果、治理经济性达到较好的平衡。     

African electricity infrastructure interconnections and electricityexchanges

This paper discusses African electrical energy resources: feasibility studies, interconnection of power systems, the present state of the electric power sector, future expansion of African power systems, and implementation of an African power grid network. It examines involvement of the World Bank with African electricity infrastructure, Grand Inga interconnection projects, the Great Lakes project, and prospects for evaluation of a unified power system in Africa. First, the poorness of African countries and their limited electricity infrastructure is discussed. Objectives for electricity infrastructure development in response to perceived needs is examined and the development challenge for the future, with ways of meeting that challenge defined. Grand Inga interconnections projects are then reviewed. The Democratic Republic of Congo's potential is equivalent to 88400 MW of continuous energy; 42000 MW is located in the Inga region. Development of the Great Lakes interconnected network which links Burundi, Rwanda and Democratic Republic of Congo is also reviewed. The paper discusses existing power systems in Africa and presents the idea of dividing the continent into five main regions of about the same surface area for electricity trade. Feasibility studies of an HVDC line from Democratic Republic of Congo to Egypt and other studies to South Africa and Europe are discussed. A scenario for energy balance for the 2050 is presented, and export of electricity to neighboring continents, mainly Europe, in excess of 200 TWh/year by 2050 is outlined. Implementation of an integrated African grid network is discussed     

Use of renewable sources of energy in Mexico case: San Antonio AguaBendita

This paper presents a project undertaken in Mexico to electrify the remote village of San Antonio Agua Bendita (SAAB) using a custom designed hybrid power system. The hybrid power system will provide grid quality electricity to this community which would otherwise not have been electrified via traditional distribution lines. The hybrid power system was designed to electrify the entire community, incorporate multiple sources of renewable power with on-demand power, operate autonomously, and be cost effective in dollars per watt of electricity generated over the system's usable life. A major factor in the success of this project is the use of renewable energy for economic development and community partnership. Many rural electrification projects have provided power for domestic use but few have successfully provided power to improve the economic condition of the people served by the system. The SAAB hybrid avoids this pitfall by providing 120 VAC power at 60 Hz to anticipated industrial loads in the village, as well as providing grid quality power for domestic use. The system consists of the following modules: a controller, battery storage, a PV array, two 1O kW wind turbines, a diesel generator, a micro-hydro generater, power output control     

Delphi和AHP集成的火电建设工程模糊综合评价方法

根据系统工程的原理,通过专家论证法和德尔菲法构建火电建设工程的多层次综合评价指标体系;应用层次分析法,建立较为完善的火电建设工程综合评价模型和方法,确定火电建设工程综合评价的程序和方法。实际案例计算表明,应用多层次指标体系和多目标综合后评价方法,可以将影响火电建设工程诸多因素定量表达出来,从而确保工程项目后评价的客观性和准确性。本文在火电建设工程的多层次综合评价指标体系的建立、指标权重的确定及模糊综合评价模型的建立等方面进行了探索。     

Differentiation degree combination weighting method for investment decision-making risk assessment in power grid construction projects

Power grid construction projects are distinguished by their wide variety, high investment, long payback period, and close relation to national development and human welfare. To improve the investment accuracy in such projects and effectively prevent investment risks, this paper proposes an investment optimization decision-making method for multiple power grid construction projects under a certain investment scale. Firstly, an in-depth analysis of the characteristics and development requirements of China’s power grid projects was performed. Thereafter, the time sequence and holographic method was adopted to conduct multi-dimensional, multi-perspective risk assessment of different parts of power grid projects, and a holographic risk assessment index system was developed. Moreover, an investment decision model considering the comprehensive risk based on combination weighting was developed according to the output and input of power grid construction projects. A new combination weighting optimization method that takes into account the investment willingness of enterprises was designed to improve the current weighting evaluation methods. Finally, the validity and applicability of the proposed evaluation method were verified by case examples.     

电网结构对直流换流站无功 补偿分组容量影响分析

大容量、远距离输电已经成为我国电网发展的趋势,而直流输电技术在大容量、远距离输电中占有极其重要的地位。针对青海-西藏±400kV直流联网工程中的青海侧格尔木换流站的无功补偿容量的分组,分析了电网结构对无功补偿容量分组的影响。