Simulation and performance analysis of organic Rankine cycle combined heat and power system

To improve the overall thermal efficiency of the organic Rankine cycle（ ORC）, a simulation study was carried out for a combined heat and power（ CHP） system, using the Redlich-Kuang-Soave（ RKS） equation of state. In the system,R245 fa was selected as the working fluid. A scroll expander was modeled with empirical isentropic expansion efficiency.Plate heat exchangers were selected as the evaporator and the condenser, and detailed heat transfer models were programmed for both one-phase and two-phase regions. Simulations were carried out at seven different heat source temperatures（ 80,90, 100, 110, 120, 130, 140 ℃） in combination with eight different heat sink temperatures（ 20, 25, 30, 35, 40, 45, 50,55 ℃）. Results showthat in the ORC without an internal heat exchanger（ IHE）, the optimum cycle efficiencies are in the range of 7. 0% to 7. 3% when the temperature differences between the heat source and heat sink are in the range of 70 to90 ℃. Simulations on CHP reveal that domestic hot water can be produced when the heat sink inlet temperature is higher than40 ℃, and the corresponding exergy efficiency and overall thermal efficiency are 29% to 56% and 87% to 90% higher than those in the non-CHP ORC, respectively. It is found that the IHE has little effect on the improvement of work output and efficiencies for the CHP ORC.

Optimization of Minimum Power Output for Combined Heat and Power Units Considering Peak Load Regulation Ability

Northern China has rich wind power and photovoltaic renewable resources. Combined Heat and Power (CHP) Units to meet the load demand and limit its peaking capacity in winter, to a certain extent, it results in structural problems of wind-solar power and thermoelectric. To solve these problems, this paper proposes a plurality of units together to ensure supply of heat load on the premise, by building a thermoelectric power peaking considering thermal load unit group dynamic scheduling model, to achieve the potential of different thermoelectric properties peaking units of the excavation. Simulation examples show, if the unit group exists obvious relationship thermoelectric individual differences, the thermal load dynamic scheduling can be more significantly improved overall performance peaking unit group, effectively increase clean energy consumptive.

Hydrodynamic Characteristics of New Floating Wind-Wave Energy Combined Power Generation Devices Under Typhoon-Wave-Current Coupling

The South China Sea is rich in wind and wave energy resources,and the wind-wave combined power generation device is currently in the concept research and development stage.In recent years,extreme sea conditions such as super typhoons have frequently occurred,which poses a serious challenge to the safety of offshore floating platforms.In view of the lack of safety analysis of wind-wave combined power generation devices in extreme sea conditions at present,this paper takes the OC4-WEC combined with semi-submersible wind turbine(Semi-OC4)and the oscillating buoy wave energy converter as the research object,and establishes a mesoscale WRF-SWANFVCOM(W-S-F)real-time coupling platform based on the model coupling Toolkit(MCT)to analyze the spatial and temporal evolution of wind-wave-current in offshore wind farms during the whole process of super typhoon“Rammasun”transit.Combined with the medium/small scale nested method,the flow field characteristics of OC4-WEC platform are analyzed.The results show that the simulation accuracy of the established W-S-F platform for typhoon track is 42.51%higher than that of the single WRF model.Under the action of typhoon-wave-current,the heave motion amplitude of OC4-WEC platform is reduced by 38.1%,the surge motion amplitude is reduced by 26.7%,and the pitch motion amplitude is reduced by 23.4%.

Application of Combined Cycle in Modernized Retrofit of Old Thermal Power Plants

This article expounds the advantages and three schemes of applying combined cycle to the modernized retrofit of old thermal power plants. Through analyzing and comparing technical economics of these three schemes, it is concluded that to use feedwater heating and heat recovery steam generator (HRSG) is suitable for the units with unit capacity below 100 MW, while to use exhaust gas reburning is suitable for units with unit capacity of 125 MW, 200 MW and above.

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.

Five Major Concerns about China’s Wind Power Development

Economic issue is the very focus of China's wind power development.Although all the security problems can be dealt with through technical measures,the compensation for supportive thermal power units and the subsidy from economically developed regions to resource-outputting regions would require a higher level of strategic considerations.The core purpose of developing wind energy is to reduce pollutant emissions,so planners should take into account the overall cost of all sides,without touching the bottom of social affordability.

风光热储互补发电系统容量配置技术研究

针对无常规电源支撑的风光热储互补发电系统,协调规划装机容量对提高发电系统运行经济性和利用率具有重要意义。提出了一种双层优化配置方法,上层以最小度电成本及弃电率为目标,确定系统装机容量;下层以新能源发电消纳最大为目标,解决功率分配问题。通过反复迭代寻优,得到系统容量配置;然后;通过纳什谈判对优化结果进行选择;最后,对甘肃河西地区数据进行仿真分析。结果表明:风光热储互补发电系统最优容量配置下的度电成本为0.3064元/(k W·h);风电场加光伏电站装机容量与光热电站装机容量的最优比为6:1,对比相同装机容量的风光互补发电系统,风光热储互补发电系统具有更高的稳定性。

含整体煤气化燃料电池-碳捕集电厂的风火储系统分布鲁棒调度方法

整体煤气化燃料电池(integrated gasification fuel cell,IGFC)是与碳捕集技术高度适配的清洁、高效、稳定的绿色煤电技术,有望克服传统碳捕集技术在低浓度CO_(2)环境下产生的高成本、高能耗问题。该文构建含IGFC碳捕集电厂的风火储发电系统。研究IGFC碳捕集电厂的运行机理,对IGFC内部各环节建立数学模型,提出工况匹配时燃烧利用率和阴极空气利用率需要满足的运行条件,并针对该型碳捕集电厂的电碳特性进行分析。为计及风电出力的不确定性,构建风火储系统的两阶段分布鲁棒经济调度模型,引入k阶适应性理论,提出基于正交支撑子集策略的求解方法来获得鲁棒对等式。最后,在改进IEEE-30节点系统中进行算例分析,结果表明,该型碳捕集电厂可利用阳极碳富集的优势,实现系统低碳经济调度的目标,并验证所提优化方法能为可行解提供可解释性。

太阳能辅助热电联产机组供热、发电及调峰性能分析

针对新能源存在不稳定性导致电网调峰问题日益严重的现状,结合较为成熟的光煤互补发电技术及多热源联合供热调峰系统,设计光煤混合供热发电系统,使热电联产机组具有一定的调峰能力。以某300 MW热电联产机组为研究对象,利用Ebsilon Professional软件搭建发电、供热可灵活调节的太阳能辅助热电联产系统,基于供热机组实际双机运行工况,在保证供热负荷前提下,分析太阳能辅助双机热电联产机组耦合方式,比较耦合前后双机调峰性能。结果表明:凝汽器出口与太阳能集热系统换热器间的管道上设置动态节流阀,改变太阳能集热系统辅助供热机组的运行模式,能够实现发电、供热、调峰一体系统的灵活运行;其中,以太阳能集热系统仅用于补充供暖的运行方式调峰能力最强,太阳能辅助单机供热前后调峰容量比值为0.76,太阳能辅助双机供热前后调峰容量比值为0.55,太阳能辅助承担最大供热负荷的1号机组在调峰容量及调峰补偿上效果最佳。

考虑风-光不确定性的风-光-蓄-火联合调度研究

在当前风电和光伏大规模并网的背景下,要确保能源供应的稳定性和高效性,关键任务是确定合适的可再生能源渗透率,并精确配比可再生能源与储能系统的容量。因此,在考虑风、光不确定性的基础上,构建风-光-蓄-火优化调度模型,使用拉丁超立方抽样法模拟模型中风电和光伏出力场景,再基于Kantorovich距离的同步回代消除算法对生成的风、光出力场景进行缩减,并通过改进的粒子群算法对模型进行求解。以白莲河抽水蓄能电站为例,结合当地的实测风速、光照数据,探究有无抽蓄参与以及不同能源容量配比下的调度结果,得到以下结论:①抽蓄电站的加入使得联合系统收益增加了428.06万元,风、光出力的波动性降低了12.24%,可再生能源的弃电率下降了5.62%,污染物排放也得到了减少。②抽蓄与可再生能源装机容量比例在1∶8.33范围内配置较为合理,在1∶5.21时可再生能源弃电率达到最低。③当可再生能源渗透率为71.09%,抽蓄与可再生能源装机容量比例为1∶6.25时,风-光-蓄-火联合运行边际效益最大。

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。

考虑可再生能源配额的风水火多能源电力系统年度调度模型

通过分析配额制的实施对购电策略的影响,建立考虑可再生能源配额的风水火多能源电力系统的年度调度模型。为减小计算负担,将月度的负荷与风电用数个典型场景及其占比来表示。提出能够自动选择最佳聚类数的改进k-means算法,并应用于典型场景生成过程中。将同一天的负荷与风电的历史数据曲线拼接为一条功率曲线,并基于改进k-means算法进行聚类,得到考虑负荷与风电时序相关性的典型场景。仿真结果表明:(1)所提典型场景生成方法对年度电量刻画的精度平均提高了12.7%,由其所生成典型场景的平均符合率提高了20.25%,所提方法具有更好的年度电量刻画效果和更高的平均场景符合率;(2)当绿色证书的价格高于风电与火电价格差值时,实施配额制后能够提高风电的消纳量,这对绿色证书价格的确定具有重要参考价值。

基于时序运行模拟的水火风光储互补系统电源优化配置

系统时序运行模拟是水火风光储互补系统电源规模优化配置的关键环节。对于水火风光储多能互补系统8760逐小时运行模拟,按照小时尺度构建的模型规模很大,直接求解困难。本文提出按时间尺度逐层分解、递进优化的高效求解算法,精确模拟系统全年逐小时调度运行过程。在此基础上,构建双层规划模型对由风电、光伏、水电、火电、抽水蓄能、梯级水电站混合式抽水蓄能和电化学储能等电源组成的并网多能互补系统的电源容量进行优化配置。将模型应用在青海省电网系统中,对风电、光伏、抽水蓄能电站和基于水电站的可逆机组容量进行优化,得到电源最佳配置方案。

考虑风电出力和电价不确定性的水风联合现货市场竞价策略

以风电为代表的新能源参与现货市场已是大势所趋,但出力不确定性导致其市场竞争力较弱,而电价的不确定性又进一步增大了其承担的收益风险。联合具有灵活调节能力的水电是有效的解决途径,而制定符合决策者风险意愿的竞价策略则是其中亟须解决的关键问题。为此,从价格接受者角度提出了水电联合风电参与现货市场的竞价模型。模型中采用笛卡尔积组合后的典型场景集描述风电出力、市场电价等多种不确定性,采用条件风险价值衡量不确定性导致的市场风险,并以风险因子作为决策者风险偏好纳入决策过程。通过引入0/1整数变量,将模型中的非线性函数转换为混合整数线性规划模型予以求解。以中国西南某省梯级水电站和风电场为背景,验证了模型的有效性,并进一步分析了风险偏好对竞价决策的影响。

计及改进阶梯型碳交易和热电联产机组灵活输出的园区综合能源系统低碳调度

为了进一步降低园区综合能源系统(park-level integrated energy system,PIES)碳排放量,优化热电联产(combined heat and power,CHP)机组出力的灵活性,提出一种考虑改进阶梯型碳交易和CHP热电灵活输出的PIES低碳经济调度策略。首先,将遗传算法与模糊控制相结合,设计一种遗传模糊碳交易参数优化器,从而对现有阶梯型碳交易机制进行改进,实现该机制参数的自适应变化;其次,在传统CHP中加入卡琳娜(Kalina)循环与电锅炉(electricboiler,EB),构造CHP热电灵活输出模型,以同时满足电、热负荷的不同需求;然后,提出一种柔性指标——电、热输出占比率,进而计算出电、热输出占比率区间,以衡量CHP运行灵活性;最后,将改进阶梯型碳交易机制和CHP热电灵活输出模型协同优化,以系统运行成本和碳交易成本之和最小为目标,构建PIES低碳经济优化模型。算例分析表明,所提策略可有效降低经济成本和碳排放量,同时还可扩展CHP灵活输出调节范围,能够为PIES低碳经济调度提供参考。

计及电解铝高耗能负荷调控和火电深调的高比例风电系统分层优化策略

对于高比例风电系统,风电出力典型的随机波动性和反调峰特性极大增加了其调峰负担,火电机组深度调峰虽已常态化,但系统调峰资源仍显不足,弃风问题有待解决。提出利用电解铝高耗能负荷(electrolytic aluminum energy-intensive load,EAL)作为新的调峰资源参与电网调度。首先,根据电解铝高耗能负荷的真实生产调节特性,耦合电流、温度及产量等多种因素,建立电解铝负荷参与电网调峰的精细化调节模型;然后,结合火电机组深度调峰模型,以系统弃风量最小和运行成本最小为目标,建立电解铝负荷和火电深调联合调峰的分层优化模型;最后以某实际区域系统为例,采用商业优化软件GUROBI进行求解分析,验证了所提方案可大幅减少系统弃风量,改善系统调峰运行经济性,并优化了火电机组深度调峰结构和发电经济性。

A multi agent-based optimal control method for combined cooling and power systems with thermal energy storage

Combined cooling,heating and power(CCHP)systems have been considered as a potential energy saving technology for buildings due to their high energy efficiency and low carbon emission.Thermal energy storage(TES)can improve the energy efficiency of CCHP systems,since they reduce the mismatch between the energy supply and demand.However,it also increases the complexity of operation optimization of CCHP systems.In this study,a multi-agent system(MAS)-based optimal control method is proposed to minimize the operation cost of CCHP systems combined with TES.Four types of agents,i.e.,coordinator agents,building agents,energy management agents and optimization agents,are implemented in the MAS to cooperate with each other.The operation optimization problem is solved by the genetic algorithm.A simulated system is utilized to validate the performance of the proposed method.Results show that the operation cost reductions of 10.0%on a typical summer day and 7.7%on a typical spring day are achieved compared with a rule-based control method.A sensitivity analysis is further performed and results show that the optimal operation cost does not change obviously when the rated capacity of TES exceeds a threshold.

复合加载下海上风电四筒基础地基承载力特性研究

以福建某海上风电场四筒导管架基础为研究对象,通过数值模拟方法建立四筒基础-地基整体模型,研究四筒基础在V-H(竖向-水平荷载)、V-M(竖向-弯矩荷载)、H-M(水平-弯矩荷载)和V-H-M(竖向-水平-弯矩荷载)作用下的地基失效模式。结果表明:在V-H和H-M加载模式下,四筒基础竖向极限承载力和弯矩极限承载力均随着水平力的增大而减小,且弯矩极限承载力与水平力之间呈现出线性减小的趋势;在V-M加载模式下,随着竖向荷载的不断增大,四筒基础主要运动形式从转动转换为平动;V-H-M加载模式下的承载力包络线随着竖向荷载的增大向外扩张,且竖向荷载的作用明显提高了地基水平和弯矩极限承载力。

集中绕组模块组合式定子结构对低速大功率永磁电机性能影响

针对集中绕组模块组合式定子结构对低速大功率直驱永磁同步电机性能的影响进行研究。首先介绍了模块化定子的分块规则和分块数。基于绕组函数法推导了单个定子单元模块在不同拆分方式下的绕组函数和电感表达式。基于有限元仿真先分析了仅绕组分块对电机性能影响;然后分析了冲片和绕组都分块对电机性能影响。通过对比空载和负载性能,总结出各种定子模块化拆分方案的优缺点,为大功率低速直驱永磁同步电机的模块化设计与制造建立了基础。

计及多时间尺度的梯级水-风-光互补基地储能容量优化配置

含高比例风光发电的清洁能源基地是碳中和的有效途径,但风光发电出力的随机性和波动性严重影响电网的安全稳定运行。为此,提出了一种计及水-风-光互补和电池分组运行的多时间尺度嵌套清洁能源基地储能容量优化配置方法。在含梯级水-风-光的清洁能源基地中加入电池组,并研究其三分组充放电控制运行策略。构建计及水-风-光互补的多时间尺度嵌套双层储能容量优化配置模型,其中内层利用水-风-光互补性,平抑大时间尺度的风光出力大波动,外层计及衰减度对储能进行优化,以平抑小时间尺度的风光出力小波动。通过算例分析表明所提模型能充分利用灵活调控的水电与快速响应电池的互补优势有效平抑清洁能源基地功率波动,并对比验证了所提三电池组分组控制策略在节约成本以及减缓损耗方面的有效性。