Added Value of Power Control in Improving the Integration of Wind Turbines in Weak Grid Conditions

For economical reasons, wind turbine systems must be located in favourable sites generating a higher pro- ductivity. These are often located in areas with weak electric grid infrastructures. The constraints related to this type of grids limit the penetration levels of wind energy. These constraints are mainly related to power quality in the grid as well as the economical aspects of the project. In this study, we take into account the slow voltage variations and the flicker phenomenon. The models used are based on the development of a set of relations derived from engineering knowledge related to both technical and economical points of view. The maximal penetration level of a fixed speed wind turbine system is determined for a given grid. The power control has been investigated to improve wind turbine system integration. Obtained results show the necessity to adapt technological choices to the requirements of weaker grids. Penetration levels and wind turbine cost may be greatly improved using variable speed systems.

The Design of Stall-Regulated Wind Turbine Blade for a Maximum Annual Energy Output and Minimum Cost of Energy Based on a Specific Wind Statistic

The design of a stall-regulated wind turbine to achieve a maximum annual energy output is still a formidable task for engineers. The design could be carried out using an average wind speed together with a standard statistical distribution such as a Weibull with k = 2.0. In this study a more elaborated design will be attempted by also considering the statistical bias as a design criterion. The wind data used in this study were collected from three areas of the Lamtakong weather station in Nakhonratchasima Provice, the Khaokoh weather station in Phetchaboon and the Sirindhorn dam weather station in Ubonratchathani, Thailand. The objective is to design a best aerodynamic configurations for the blade (chord, twist and pitch) using the same airfoil as that of NREL Phase VI wind turbine. Such design is carried out at a design wind speed point. Wind turbine blades were optimized for both maximum annual energy production and minimum cost of energy using a method that take into account aerodynamic and structural considerations. The work will be carried out by the program “SuWiTStat” which was developed by the authors and based on BEM Theory (Blade Element Momentum). Another side issue is the credibility of the Weibull statistic in representing the real wind measurement. This study uses a regression analysis to determine this issue.

Capacity Optimization Configuration of Hydrogen Production System for Offshore Surplus Wind Power

To solve the problem of residual wind power in offshore wind farms,a hydrogen production system with a reasonable capacity was configured to enhance the local load of wind farms and promote the local consumption of residual wind power.By studying the mathematical model of wind power output and calculating surplus wind power,as well as considering the hydrogen production/storage characteristics of the electrolyzer and hydrogen storage tank,an innovative capacity optimization allocation model was established.The objective of the model was to achieve the lowest total net present value over the entire life cycle.The model took into account the cost-benefit breakdown of equipment end-of-life cost,replacement cost,residual value gain,wind abandonment penalty,hydrogen transportation,and environmental value.The MATLAB-based platform invoked the CPLEX commercial solver to solve the model.Combined with the analysis of the annual average wind speed data from an offshore wind farm in Guangdong Province,the optimal capacity configuration results and the actual operation of the hydrogen production system were obtained.Under the calculation scenario,this hydrogen production system could consume 3,800 MWh of residual electricity from offshore wind power each year.It could achieve complete consumption of residual electricity from wind power without incurring the penalty cost of wind power.Additionally,it could produce 66,500 kg of green hydrogen from wind power,resulting in hydrogen sales revenue of 3.63 million RMB.It would also reduce pollutant emissions from coal-based hydrogen production by 1.5 tons and realize an environmental value of 4.83 million RMB.The annual net operating income exceeded 6 million RMB and the whole life cycle NPV income exceeded 50 million RMB.These results verified the feasibility and rationality of the established capacity optimization allocation model.The model could help advance power system planning and operation research and assist offshore wind farm operators in improving economic and environmental benefits.

Development modes analysis of renewable energy power generation in North Africa

North African countries generally have strategic demands for energy transformation and sustainable development.Renewable energy development is important to achieve this goal.Considering three typical types of renewable energies—wind,photovoltaic(PV),and concentrating solar power(CSP)—an optimal planning model is established to minimize construction costs and power curtailment losses.The levelized cost of electricity is used as an index for assessing economic feasibility.In this study,wind and PV,wind/PV/CSP,and transnational interconnection modes are designed for Morocco,Egypt,and Tunisia.The installed capacities of renewable energy power generation are planned through the time sequence production simulation method for each country.The results show that renewable energy combined with power generation,including the CSP mode,can improve reliability of the power supply and reduce the power curtailment rate.The transnational interconnection mode can help realize mutual benefits of renewable energy power,while the apportionment of electricity prices and trading mechanisms are very important and are related to economic feasibility;thus,this mode is important for the future development of renewable energy in North Africa.

Optimal Scheduling for Flexible Regional Integrated Energy Systemwith Soft Open Point

The Regional Integrated Energy System(RIES)has brought new modes of development,utilization,conversion,storage of energy.The introduction of Soft Open Point(SOP)and the application of Power to Gas(P2G)technology will greatly deepen the coupling of the electricity-gas integrated energy system,improve the flexibility and safety of the operation of the power system,and bring a deal of benefits to the power system.On this background,an optimal dispatch model of RIES combined cold,heat,gas and electricity with SOP is proposed.Firstly,RIES architecture with SOP and P2G is designed and its mathematical model also is built.Secondly,on the basis of considering the optimal scheduling of combined cold,heat,gas and electricity,the optimal scheduling model for RIES was established.After that,the original model is transformed into a mixed-integer second-order cone programming model by using linearization and second-order cone relaxation techniques,and the CPLEX solver is invoked to solve the optimization problem.Finally,the modified IEEE 33-bus systemis used to analyze the benefits of SOP,P2G technology and lithium bromide absorption chillers in reducing systemnetwork loss and cost,as well as improving the system’s ability to absorb wind and solar and operating safety.

Comparison of Cost-effective Distances for LFAC with HVAC and HVDC in Their Connections for Offshore and Remote Onshore Wind Energy

For a cost-effective connection of large-scale longdistance wind energy,a low frequency alternating current(LFAC)transmission scheme(16.7 Hz or 20 Hz)is proposed as an alternative to the conventional high voltage alternating current(HVAC)transmission scheme(50 Hz or 60 Hz)and the recently popular high voltage direct current(HVDC)transmission scheme(0 Hz).The technical feasibility of the LFAC system is demonstrated but the basis for identifying the distance ranges for which LFAC would be preferable to HVAC and HVDC are not established and the dependence of this range on factors,such as power transfer rating,voltage rating and cable/line type,is not investigated.This paper presents an in-depth analysis for the overall cost of LFAC system and then provides an extensive comparison with HVAC and HVDC,to explore the distance ranges over which LFAC is cost-effective over both HVAC and HVDC in connections of offshore and remote onshore wind energy.The results demonstrate that the LFAC system does possess ranges in the intermediate distance for which it is more cost-effective than both HVAC and HVDC,and its overall cost advantage is generally larger in the overhead line(OHL)connection of remote onshore wind energy than the cable connection of offshore wind energy.

Design of Adaptive Robust Guaranteed Cost Controller for Wind Power Generator

According to the increasing requirement of the wind energy utilization and the dynamic stability in the variable speed variable pitch wind power generation system, a linear parameter varying （LPV） system model is established and a new adaptive robust guaranteed cost controller （AGCC） is proposed in this paper. First, the uncertain parameters of the system are estimated by using the adaptive method, then the estimated uncertain parameters and robust guaranteed cost control method are used to design a state feedback controller. The controller s feedback gain is obtained by solving a set of linear matrix inequality （LMI） constraints, such that the controller can meet a quadratic performance evaluation criterion. The simulation results show that we can realize the goal of maximum wind energy capture in low wind speed by the optimal torque control and constant power control in high wind speed by variable pitch control with good dynamic characteristics, robustness and the ability of suppressing disturbance.

SMO Algorithm to Unravel CEED Problem using Wind and Solar

This research proposes a more advanced way to address Combined Economic Emission Dispatch(CEED)concerns.Economic Load Dispatch(ELD)and Economic Emission Dispatch(EED)have been implemented to reduce generating unit fuel costs and emissions.When both economics and emission tar-gets are taken into account,the dispatch of an aggregate cost-effective emission challenge emerges.This research affords a mathematical modeling-based analyti-cal technique for solving economic,emission,and collaborative economic and emission dispatch problems with only one goal.This study takes into account both the fuel cost target and the environmental impact of emissions.This bi-inten-tion CEED problem is converted to a solitary goal function using a price penalty factor technique.In this case,a metaheuristic and an environment-inspired,intel-ligent Spider Monkey Optimization technique(SMO)are used to address the CEED dilemma.By following the generator’s scheduling process,the SMO meth-od is used to regulate the output from the power generation system in terms of pollution and fuel cost.The Fission-Fusion social(FFS)structure of spider mon-keys promotes them to utilize a global optimization method known as SMO dur-ing foraging behaviour.The emphasis is mostly on lowering the cost of generation and pollution in order to improve the efficiency of the power system and han-dle dispatch problems with constraints.The economic dispatch has been reme-died,and the improved result demonstrates that the system’s performance is stable andflexible in real time.Finally,the system’s output demonstrates that the system has improved in resolving CEED difficulties.When compared to ear-lier investigations,the proposed model’sfindings have improved.As the gener-ating units,wind and solar are used to explore the CEED crisis in the IEEE 30 bus system.

基于火电灵活性改造的可再生能源消纳系统成本优化

随着风电等可再生能源的大规模发展,带来了消纳难等新挑战,通过火电灵活性改造可以增强电力系统灵活调节能力、提升可再生能源消纳空间,同时需要考虑火电灵活性改造的经济性和对可再生能源消纳的影响。因此,综合考虑火电机组常规运行成本及灵活性改造后增加的各项成本,结合碳排放成本和弃风成本,建立以总成本最小为目标的火电灵活性改造前后优化调度模型,采用对比差值法计算基于火电灵活性改造的可再生能源消纳系统成本。通过算例,将所建模型应用于对比改造前后、不同碳排放强度、是否考虑弃风等不同方案下的机组运行状况及消纳系统成本大小,并拟合得到可再生能源渗透率和消纳系统成本的关系曲线,验证了模型的有效性。

基于全生命周期经济评估的海上风电发展与思考

现阶段对海上风电经济性评估研究较少,而海上风电亟需经济性评估作为其大面积应用的基础。立足海上风电项目的经济性,首先,梳理了海上风电场的组成及发展,分析目前海上风电的3类6种发展模式;接着,将海上风电项目全生命周期分为初始投资、运营维护及退役回收3个阶段,分析各阶段的成本并搭建其数学模型;然后,引入净现值等6个经济指标评价了一个海上风电案例;最后,归纳海上风电当前发展及研究的不足,指明未来的研究方向,为海上风电更经济化的发展提供支撑和参考。

动力电池智能卷绕技术

在卷绕电芯质量的把控中,极耳对齐精度是一个极为复杂的影响因素,涉及多个工序的质量。为了解决电芯多极耳对齐精度差的问题,本文通过建立极耳位置模型,采用边缘闭环控制算法,对影响对齐精度的各项参数进行检测、矫正和控制闭环,为现有控制技术提供理论参考数据,实现极耳对齐精度的有效控制。同时,极耳位置模型可反映各项参数对极耳位置的影响方式以及极耳错位的表现方式,以便于研发人员理解各项参数对极耳错位的影响程度以及修正极耳错位的方式,并将其表现在控制方法中。仿真分析与实际控制工况的结合结果表明,所采取的控制方法对改善极耳位置有着较高的适应性,且模型也能准确反映出极耳位置的变化趋势。此外,本文进一步探讨了实现智能卷绕整体闭环的逻辑方法,进而优化整个卷绕工艺中的控制闭环,对最终实现卷绕工艺的质量闭环,提高电池性能质量以及生产效率的目标,有着重大的参考意义。

考虑不同约束区间的风电场布局分级优化

为了提高风电场布局优化中尾流模型预测精度,以便能够较好预测风机安装台数和最大限度降低度电成本,本文基于改进三维尾流模型,考虑风力机处于不同约束区间,采用分级优化策略对2 km×2 km风电场进行精确布局优化。首先,利用网格法对风电场进行第一阶优化;其次,考虑不同约束区间,采用坐标法对第一级优化结果进行第二阶优化。研究表明:与Jensen尾流模型相比,改进后的三维尾流模型可以更合理地优化风电场布局;考虑收敛速度及度电成本,当约束区域为l_(imit)=150、200 m时,第二阶算法迭代速度较快,优化后其度电成本为0.8498/W,相比第一阶优化结果,降低了3.33%。

Universal generating function based probabilistic production simulation for wind power integrated power systems

According to the demand of sustainable development and low-carbon electricity, it is important to develop clean resources and optimize scheduling generation mix. Firstly, a novel method for probabilistic production simulation for wind power integrated power systems is proposed based on universal generating function(UGF), which completes the production simulation with the chronological wind power and load demand. Secondly,multiple-period multiple-state wind power model and multiple-state thermal unit power model are adopted, and both thermal power and wind power are coordinately scheduled by the comprehensive cost including economic cost and environmental cost. Furthermore, the accommodation and curtailment of wind power is synergistically considered according to the available regulation capability of conventional generators in operation. Finally, the proposed method is verified and compared with conventional convolution method in the improved IEEE-RTS 79 system.

Stochastic Economic Dispatch Based Optimal Market Clearing Strategy Considering Flexible Ramping Products Under Wind Power Uncertainties

High penetration level of renewable energy has brought great challenges to operation of power systems,and use of flexible resources(FRs)is becoming increasingly important.Flexibility of power systems can be improved by changing generation arrangements,but the interests of some market participants may be harmed in the process.This study proposes a stochastic economic dispatch model with trading of flexible ramping products(FRPs).To calculate changes in revenue and reasonably compensate units that provide FRs,multisegmented marginal bidding for energy is simulated by linearizing generation cost,and an optimal market clearing strategy for FRPs is developed according to changes in clearing energy and marginal clearing price.Then,the correlation between prediction errors of wind speeds among different wind farms is determined based on a joint distribution function modeled by the copula function,and quasi-Monte Carlo simulation(QMC)is used to generate wind power scenarios.Finally,numerical simulations of modified IEEE-30 and IEEE-118 bus systems is performed with minimum comprehensive cost as the objective function.This verifies the proposed model could effectively deal with wind variability and uncertainty,stabilize the marginal clearing price of the electricity market,and ensure fairness in the market.

中欧漂浮式海上风电成本比较与变化趋势研究

近年来,全球漂浮式海上风电装机规模增长较快,但项目建设成本高昂,为掌握项目成本水平,摸清成本变化趋势,梳理了中欧地区漂浮式海上风电项目成本数据,解析双方项目建设成本,剖析项目间的成本差异与影响因素,预测其在2022,2030,2040年的建设投资与平准化度电成本与未来双方成本的变化趋势。研究结果表明:2022年中国项目成本高于欧洲,中国为138欧元/(MW·h),欧洲预计为137欧元/(MW·h),但中国成本下降速率快于欧洲。2030年、2040年中国项目成本将显著低于欧洲,2030年中国为64欧元/(MW·h)、欧洲预计为72欧元/(MW·h);2040年中国为50欧元/(MW·h)、欧洲预计为57欧元/(MW·h)。研究成果可为中欧漂浮式海上风电降本增效提供参考。

考虑微观选址的分布式海上风电制氢容量优化配置

海上风电制氢是提升海上风电场经济性与风电消纳率的重要发展方向,其中,分布式海上风电制氢由于无须配备昂贵的高压海底电缆和海上变电枢纽平台,是深远海风电场制氢可预期的首选方案。然而,尾流效应的存在使得不同微观选址方案下的分布式平台制氢能力存在差异,并进一步影响电解槽的容量优化配置。因此,以分布式海上风电制氢平准化制氢成本(LCOH)最小化为目标,提出了考虑微观选址的电解槽容量优化配置方法。首先,对基于Larsen尾流模型的平台间耦合特性、单个平台内风机与电解槽运行特性进行建模,并嵌入所提出的电解槽容量优化配置模型。其次,在容量优化配置模型中同时考虑平台的微观选址,基于分解-协调的思想,将原问题拆分并迭代求解。最后,以中国江苏省某深远海域实际数据为例进行仿真验证,所得方案的LCOH与既有方案相比大幅降低,验证了所提容量优化配置方法的有效性。

基于均值出力的风电调峰成本量化方法

随着大规模风电的快速发展,电力系统的调峰服务需求越来越多,调峰服务的成本也随之增加。合理的计算由风电引发的调峰服务费用是激发常规机组提供调峰服务的前提。为此,提出了风电引发的调峰成本计算方法——风电均值出力参考法,该方法将某时段内风电电量平均分配到各个调度时段得到风电均值出力线,并进一步得到计算调峰成本的参考场景。以此为基准,可直观地计算和体现具体场景中风电出力曲线是否给系统造成了额外的调峰成本。采用所提方法对一个含风电场的5火电机组系统进行了测试,结果验证了所提方法的正确性和有效性。

考虑出力相关性的海上风电接入系统固定成本分摊方法

在海上风电规模化开发、集群化并网的背景下,如何回收海上风电接入系统的输电成本,公平合理地向各风电场分摊已成为目前海上风电行业亟待解决的问题。针对该问题,提出了一种考虑风电出力相关性的海上风电接入系统固定成本分摊方法。首先,利用藤Copula函数构建多个海上风电场的出力相关性模型,同时假定系统负荷需求模型服从正态分布,发电机服从0-1概率分布;然后,结合蒙特卡洛抽样和顺流概率潮流追踪法计算各海上风电场接入系统的固定成本分摊费用;最后,通过算例仿真分析,验证了所提方法的合理性和有效性。

基于遗传的海上风电集电系统拓扑优化

针对海上风电工程集电线路拓扑的自动优化布置,文章以集电线路的全寿命周期成本作为目标函数,海缆选型和海缆交叉规避作为主要约束条件,建立数学模型,同时基于动态边权最小生成树算法改进遗传算法的种群生成方式以扩大算法的搜索解空间,以期凭借较好的寻优能力求解集电系统拓扑优化问题,提升海上风电场的综合效益。海上风电场项目算例结果验证了方法的有效性和快速性,可为海上风电集电系统规划设计提供具有实用价值的参考。

考虑故障风险与不确定性的海上风电主变压器检修策略

为提高海上风电主变压器检修策略优化的科学性,在保证可靠运行的前提下,提出一种考虑故障风险与不确定性的海上风电主变压器检修策略优选方法。首先,详细分析故障风险成本模型,据此建立海上风电主变压器全寿命周期成本(life cycle cost,LCC)模型,并引入盲数理论将LCC中不确定性参数用数学模型定量进行计算,提高成本估算精度。然后,从成本管理角度出发,分析维修方案对LCC的影响,进而建立以LCC最低为目标的海上风电主变压器检修策略优化模型,并通过改进的布谷鸟搜索算法进行求解。最后,经算例验证,所提模型和检修策略优选方法具有较强的可操作性,能为海上风电主变压器的可靠运行提供一定的参考价值。