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.

Assessment and Countermeasures for Offshore Wind Farm Risks Based on a Dynamic Bayesian Network

Wind power is a kind of clean energy promising significant social and environmental benefits, and in The Peoples Republic of China, the government supports and encourages the development of wind power as one element in a shift to renewable energy. In recent years however, maritime safety issues have arisen during offshore wind power construction and attendant production processes associated with the rapid promotion and development of offshore wind farms. Therefore, it is necessary to carry out risk assessment for phases in the life cycle of offshore wind farms. This paper reports on a risk assessment model based on a Dynamic Bayesian network that performs offshore wind farms maritime risk assessment. The advantage of this approach is the way in which a Bayesian model expresses uncertainty. Furthermore, such models permit simulations and reenactment of accidents in a virtual environment. There were several goals in this research. Offshore wind power project risk identification and evaluation theories and methods were explored to identify the sources of risk during different phases of the offshore wind farm life cycle. Based on this foundation, a dynamic Bayesian network model with Genie was established, and evaluated, in terms of its effectiveness for analysis of risk during different phases of the offshore wind farm life cycle. Research results show that a dynamic Bayesian network method can perform risk assessments effectively and flexibly, responding to the actual context of offshore wind power construction. Historical data and almost real-time information are combined to analyze the risk of the construction of offshore wind power. Our results inform a discussion of security and risk mitigation measures that when implemented, could improve safety. This work has value as a reference and guide for the safe development of offshore wind power.

Development and Application of On-line Wind Power Risk Assessment System

Because of the large-scale integration of wind power,the dynamic characteristics of power system have many uncertain effects.Based on deterministic analysis methods,traditional on-line security assessment system cannot quantitatively estimate the actual operating conditions of the power system for only considering the most serious and credible accidents.Therefore,the risk theory is introduced into an on-line security assessment system and then an on-line risk assessment system for wind power is designed and implemented by combining with the dynamic security assessment system.Based on multiple data integration,the wind power disturbance probability is available and the security assessment of the power grid can obtain security indices in different aspects.The operating risk index is an expectation of severity,computed by summing up all the products of the result probability and its severity.Analysis results are reported to the dispatchers in on-line environment,while the comprehensive weak links are automatically provided to the power dispatching center.The risk assessment system in operation can verify the reasonableness of the system.

Offshore wind power projects set sail

China will choose the sea off eastern Jiangsu Province to build the country’s first batch of offshore wind power projects. The four

Landscape Visual Environment Impact Analysis of Wind Power Project in Plain Region--Case in One Wind Power Farm Project of Zhanjiang

The construction of wind power project is conducive to saving energy,reducing emissions and regulating energy structure. But it inevitably causes some impacts on the environment in the construction process. Because that the height of wind power generator generally exceeds 100 m,and visual range in plain region is farther,it is necessary to scientifically and rationally evaluate and analyze landscape visual environment impact of wind power generator in plain region. One wind power farm project of Zhanjiang is located in typical plain region of Guangdong coast. Referring to traditional analytic method of landscape visual impact and comparing with actual situation for the same kind of project in the region,results show that it is ＂ extremely sensitive＂ area at 0- 2. 5 km from wind power generator, ＂ very sensitive＂ area at 2. 5- 5. 0 km, ＂ sensitive＂ area at 5- 10 km, ＂generally sensitive＂ area at 10- 20 km,and non-sensitive area outside 20 km.

Offshore Wind Power Evaluation Based on Nearshore Wind Power Correlations

As the increasing number of wind energy is integrated into the national power grid,analyses of wind energy are becoming increasingly more crucial.The interaction between the topography and the northeast(NE)monsoon brings abundant wind resources to the Taiwan Strait in autumn and winter.The offshore area has stronger and more stable wind resources,so deployment of offshore wind power is also actively being carried out.However,development of offshore wind power systems requires stricter evaluation and decision-making.Therefore,this study implements a multi-site measurement verification to establish the relationship between the wind resources of the nearshore wind turbine system and a potential offshore power site in Chanbin.In the absence of a wind turbine at a specific location,potential of offshore wind energy is analyzed through wind resources.The findings showed that although the distance between these two sites is substantial,the nearshore and offshore areas at Chanbin experience similar wind conditions,and nearshore wind turbine can respond well to changes in wind speed and generate power accordingly.Afterwards,on this basis,the offshore power potential was evaluated and compared with the nearshore wind turbine systems.The results suggested the advantages of offshore wind power.A further analysis of the differences between power generation on a monthly basis was carried out to determine the distribution of wind turbine operation modes and illustrate the influence of the NE monsoon.

Criterion of aerodynamic performance of large-scale offshore horizontal axis wind turbines

With the background of offshore wind energy projects, this paper studies aerodynamic performance and geometric characteristics of large capacity wind turbine rotors （1 to 10 MW）, and the main characteristic parameters such as the rated wind speed, blade tip speed, and rotor solidity. We show that the essential criterion of a high- performance wind turbine is a highest possible annual usable energy pattern factor and a smallest possible dimension, capturing the maximum wind energy and producing the maximum annual power. The influence of the above-mentioned three parameters on the pattern factor and rotor geometry of wind turbine operated in China＇s offshore meteoro- logical environment is investigated. The variation patterns of aerodynamic and geometric parameters are obtained, analyzed, and compared with each other. The present method for aerodynamic analysis and its results can form a basis for evaluating aerodynamic performance of large-scale offshore wind turbine rotors.

海上风电筒型基础入土沉放风险分析

将基于核极限学习机的响应面法应用于筒型基础的入土沉放风险评估,以海域1(安装成功)和海域2(安装失败)某风电场6.45 MW筒型基础为研究对象,采用蒙特卡洛抽样法随机生成地勘静力触探(CPT)中的锥尖阻力(qc),并用基于CPT推荐值、最大值的方法预测沉放需要压差,以水泵和水压可提供的最大压差为风险控制标准,得到两个机位入土沉放失效概率,评估两个机位的入土沉放风险。结果表明:土体的空间变异性越大,筒型基础入土沉放风险越大。当土体变异系数CV≤0.3,使用CPT推荐值计算各深度的失效概率均小于10-4时,风险较低,可用于指导施工。

Resilience-oriented Restoration Strategy by Offshore Wind Power Considering Risk

Global climate changes have created intense naturaldisasters such as typhoons, which may cause serious damage topower systems. As an emerging renewable energy resource, offshore wind power has great potential in power systems resilienceenhancement with its rapid start-up capability and developmentof anti-typhoon technology. In this paper, a restoration strategyby offshore wind power considering risk is proposed to speedup the restoration process and enhance system resilience. Specifically, a failure risk model of an individual wind turbine andthen the whole wind farm is built for predicting severe weather’simpact, with focus on failure probability. Further, a quantificationmodel of resilience enhancement and risk cost, based on customerinterruption cost assessment method, is introduced. Then, a twostage optimized decision-making model is proposed to solve thescheme of offshore wind power and conventional power unitsin load restoration process. Case studies are undertaken on amodified IEEE RTS-79 system and results indicate the proposedrestoration strategy can shorten duration of restoration andreduce customers’ economic losses meanwhile ensuring systemsafety.

山东半岛附近海域风、浪能资源联合评估

采用ERA5风场驱动第三代浅海海浪数值模式(SWAN),构建山东半岛附近海域波浪模型,得到30 a同步风浪数据,对海上风能和波浪能进行联合评估。评估分析海上风能和波浪能的能源潜力、稳定性及两种资源的相关性、互补性,可为未来风浪资源联合开发提供依据。研究结果表明,该海域风能和波浪能资源丰富,有明显的季节变化特征,冬季资源最为丰富且稳定性较高。两种资源在近岸海域的互补性更强,在渤海西部和黄海北部的近岸海域相关性相对较低,具有更高的联合开发潜力。

国内外静力触探液化判别方法对比检验

静力触探试验(cone penetration test,简称CPT)具有独特优势,使其成为了海上风电工程的主要勘察方法。海上风电工程位于液化易发区,因此研究基于CPT液化判别方法的适用性和可靠性就成为亟待解决的突出问题。详细介绍了4种国内外具有代表性的CPT液化判别方法,并采用理论分析及大量CPT液化实测数据检验,对现行的美国国家地震工程研究中心(National Center for Earthquake Engineering Research,简称NCEER)方法、《岩土工程勘察规范》(GB50021-2001)方法(岩规法)、《软土地区岩土工程勘察规程》(JGJ 83-2011)方法(软土规程法)和《建筑工程抗震性态设计通则》(CES 160:2004)方法(通则法)等4种方法进行对比检验,提出了4种主要方法的评价结果。结果表明:NCEER法液化判别临界线在低烈度区存在不合理的回弯现象,在高烈度区存在临界值增大过快的问题,在Ⅶ度区深层偏于危险,在Ⅸ度区深层明显偏于保守,在Ⅶ、Ⅸ度区浅层和Ⅷ度区判别结果较好;岩规法液化判别临界线存在很大的问题,液化判别临界线随深度递减,液化判别时在Ⅶ度区浅层偏于危险,在深层明显偏于危险,在Ⅷ、Ⅸ度区浅层偏于保守,在深层偏于危险;软土规程法液化判别临界线在土层深度约6 m处存在不合理的回弯现象,在Ⅶ度区浅层判别较好,在Ⅸ度区浅层偏于保守,在不同烈度区深层均偏于危险;通则法液化判别临界线是符合目前认知的,在不同烈度区和深度下的判别效果是最好的。研究成果可为相关规范修订和工程应用提供参考与支持。

海上风电安全风险管理研究与实践

从海上风电项目的全生命周期深入探讨了安全风险的成因,对海上风电施工运维阶段特有的8类作业、34项作业工序,共计69条风险源进行了全面风险辨识、风险评价、风险控制研究。首先,利用LEC法对具体风险源进行了评价分级,同时运用AHP法计算了各类风险的权重,通过加权平均计算各类作业及作业工序的风险分值,得出了风险的相对高低程度。其次,基于统计分析结果,给出了相应的防范措施。最后,从主体责任、行业联动、科技赋能3方面提出了海上风电安全管理建议,以期推动该行业健康、可持续发展。

海上风电水下资产质量缺陷及检测方法

海上风电场水下资产的成本在海上风电项目总成本中占比不高,但水下资产的质量对海上风电场的安全稳定运行具有重要意义。分析海上风电场内风力发电机组、海上升压站的水下钢结构和基础,以及海底电缆在工程期和运维期出现的各类质量问题,基于已实施的海上风电项目案例,对相关标准的检测要求和检测方法进行评估,针对不同质量缺陷给出了完整、有效的现场检测方案,并在实际项目上进行应用和验证,形成了行业内标准规范。这对海上风电场水下资产的质量管控和运行维护,具有重要的技术指导意义和参考价值。

基于综合效益评估的远海风电柔直并网拓扑方案优选

为解决远海风电柔直并网拓扑方案优选时缺乏对多方面性能定量分析与重要性衡量的现状,文中基于综合效益评估的角度对其展开研究。构建涵盖经济性、利用率、可靠性三个因素的多指标评估体系并给出各指标的计算模型,定量表征拓扑间的各项性能差异;基于改进AHP-熵权-NASH均衡法确定多指标权重,合理衡量各方面性能的重要程度;利用TOPSIS法联合指标数据与权重信息对各拓扑方案进行优选;算例中对如东海上风电柔直工程的点对点、环形、星形三种典型拓扑类型进行了综合效益评估与方案博弈,结果表明,所提改进AHP能够有效降低一致性检验误差,决策过程具备性能与权重的定量化、可视化,验证了文中方法的有效性与合理性。

中国海上油气田风能资源评估

利用持续30年的CCMP分析风场数据,对中国海上油气田开发海域进行了风能资源评估。评估结果表明:不同海区的油气田风能资源分布差异较大,其中东海油气田群的海面风能资源最为丰富,风资源等级可达7级以上,海上油气平台周围10km范围内风能资源技术可开发量可达98~106万kW,风能资源稳定性最好;南海东部油气田群次之,一般可达6级以上,海上油气平台周围10km范围风能资源技术可开发量可达90~104万kW,风能资源月变化和季节变化较强;南海西部油气田群又次之,风资源等级一般可达4级,海上油气平台周围10 km范围风能资源技术可开发量可达58~78万kW,风能稳定性总体月变化较季节变化强,且区域内不同油气田风能稳定性指数数值差异较大;渤海油气田群除渤海南部及中东部外,海面风能资源大多在4级以下,海上油气平台周围10 km范围风能资源技术可开发量一般在42~58万kW之间,风能短期变化较强,月变化和季节变化较弱。相关研究结论可为我国海上油气田海域的海洋清洁能源规划与开发利用提供基础科学依据。

海上风电施工中海缆敷设张力影响因素权重分析

为分析挖掘海缆敷设监测数据中对施工质量的有益成果,研究影响海缆敷设张力因素权重量化问题,本文基于某海缆敷设工程施工数据,利用随机森林方法,分析研究海缆敷设施工对海缆张力的有关影响因素。以张力作为因变量,根据地理位置信息和作业时间计算得出实际航行速度,以航行速度、水深、侧向力和埋深作为自变量,在对施工数据进行清洗挖掘的基础上,利用随机森林方法分析各因素对张力的影响权重,得出特征重要性排序。结果表明:海缆张力的影响,航行速度在所有特征中的特征重要性最高,权重占比0.57,其次是埋深和水深,权重分别占比为0.23和0.18。研究所得结果与已有文献分析进行了对比,体现了所得结果的有效性和优势,为海上风电工程施工和海缆敷设施工质量安全提供帮助和参考。

海上固定式风电平台基础结构延寿评估技术研究

针对海上风电平台逐渐开始步入老龄化所面临的问题,分析了老龄海上风机平台主要面临的风险和设施拆除对生态环境的影响。对比了完全拆除、部分移除、全面改造、部分改造和延长寿命5种到期场景的成本效益,指出延长海上风电平台使用寿命是老龄海上风电场增值的有效方式。系统介绍了海上风电平台延寿评估的流程、依据、方法和策略,对评估过程中各阶段需要完成的主要工作内容和需要重点关注的问题进行了详细的阐述。对延寿评估存在的实际问题和困难给出了有针对性的建议和应对措施,提出了基于风险的检验(RBI)策略,可为未来海上风电平台的延寿提供有益参考。

新能源风电并网对配电网运行风险的影响研究

新能源风电因具有清洁高效等优良特性而获得快速发展,但其功率的随机性会对配电网的运行风险造成较大的影响。在对新能源风电功率特性和风电并网后配电网潮流变化进行理论分析的基础上,提出了一种适应含新能源风电并网的配电网运行风险评估方法。建立含风电并网的配电网运行风险仿真计算模型,通过对风电不同并网容量和不同并网方式下运行风险的计算,获得了新能源风电并网对配电网运行风险的影响规律。研究成果可为新能源风电的并网优化及配电网运行风险的降低提供有效的参考和技术指导。

220 kV内桥接线海上升压站典型保护配置与运维风险管控

海上风电是我国加快能源清洁低碳转型、构建新型电力系统的重要战略支撑。介绍了220 kV海上风电场升压站电气二次一种典型接线方式——内桥接线方式的保护配置,总结了其跳闸、远跳、启动失灵的关键回路,并提出了相关的运维风险管控措施,为今后类似工程的验收及部分设备的停电检修工作提供了参考。

海上风电场风机整机拆卸风险管控

为填补国内缺乏海上风机拆卸风险分析和管控措施的现状,以山东某海上风电场8.5 MW(风机参数:叶片长度112m、轮毂中心高度+130m)风机整机拆卸为实例,在满足起重风速小于10 m/s和涌浪高度小于0.6 m的海况下,起重设备工作半径为40 m时起重载荷大于401.5 t、起重高度高于+144 m的作业条件下,从风机整机拆卸作业的安全风险辨识和安全管控措施角度出发,分析出风机整机拆卸作业存在海缆保护、叶片拆卸、电缆下放、构件过驳重要风险,提出风险防控措施。为同类型风机维修、拆卸作业风险防控,提供借鉴。