Dynamic and Power Generation Features of A Wind-Wave Hybrid System Consisting of A Spar-Type Wind Turbine and An Annular Wave Energy Converter in Irregular Waves

Combining wave energy converters(WECs)with floating offshore wind turbines proves a potential strategy to achieve better use of marine renewable energy.The full coupling investigation on the dynamic and power generation features of the hybrid systems under operational sea states is necessary but limited by numerical simulation tools.Here an aero-hydro-servo-elastic coupling numerical tool is developed and applied to investigate the motion,mooring tension,and energy conversion performance of a hybrid system consisting of a spar-type floating wind turbine and an annular wave energy converter.Results show that the addition of the WEC has no significant negative effect on the dynamic performance of the platform and even enhances the rotational stability of the platform.For surge and pitch motion,the peak of the spectra is originated from the dominating wave component,whereas for the heave motion,the peak of the spectrum is the superposed effect of the dominating wave component and the resonance of the system.The addition of the annular WEC can slightly improve the wind power by making the rotor to be in a better position to face the incoming wind and provide considerable wave energy production,which can compensate for the downtime of the offshore wind.

Effect of photovoltaic panel electric field on the wind speed required for dust removal from the panels

Methods to remove dust deposits by high-speed airflow have significant potential applications,with optimal design of flow velocity being the core technology.In this paper,we discuss the wind speed required for particle removal from photovoltaic(PV)panels by compressed air by analyzing the force exerted on the dust deposited on inclined photovoltaic panels,which also included different electrification mechanisms of dust while it is in contact with the PV panel.The results show that the effect of the particle charging mechanism in the electric field generated by the PV panel is greatly smaller than the effect of the Van der Waals force and gravity,but the effect of the particle charged by the contact electrification mechanism in the electrostatic field is very pronounced.The wind speed required for dust removal from the PV panel increases linearly with the PV panel electric field,so we suggest that the nighttime,when the PV electric field is relatively small,would be more appropriate time for dust removal.The above results are of great scientific importance for accurately grasping the dust distribution law and for achieving scientific removal of dust on PV panels.

Analysis and Power Quality Improvement in Hybrid Distributed Generation System with Utilization of Unified Power Quality Conditioner

This paper presents a comprehensive study that includes the sizing and power flow by series and parallel inverters in a distributed generation system(DGs)that integrates the system of hybrid wind photovoltaic with a unified power quality conditioner(UPQC).In addition to supplying active power to the utility grid,the system of hybrid wind photovoltaic functions as a UPQC,compensating reactive power and suppressing the harmonic load currents.Additionally,the load is supplied with harmonic-free,balanced and regulated output voltages.Since PVWind-UPQC is established on a dual compensation scheme,the series inverter works like a sinusoidal current source,while the parallel inverter works like a sinusoidal voltage source.Consequently,a smooth alteration from interconnected operating modes to island operating modes and vice versa can be achieved without load voltage transients.Since PV-Wind-UPQC inverters handle the energy generated through the hybrid wind photovoltaic system and the energy demanded through the load,the converters should be sized cautiously.A detailed study of the flow of power via the PV-Wind-UPQC is imperative to gain a complete understanding of the system operation and the proper design of the converters.Thus,curves that allow the sizing of the power converters according to the power flow via the converters are presented and discussed.Simulation results are presented to assess both steady state and dynamic performances of the grid connected hybrid system of PV-Wind-UPQC.This investigation is verified by simulating and analyzing the results with Matlab/Simulink.

Simulation of Dynamic Response of Small Wind-Photovoltaic-Fuel Cell Hybrid Energy System

Renewable energy systems are of importance as being modular, nature-friendly and domestic. Among renewable energy systems, a great deal of research has been conducted especially on photovoltaic effect, wind energy and fuel cell in the recent years. This paper describes dynamic modeling and simulation results of a small wind-photovoltaic-fuel cell hybrid energy system. The hybrid system consists of a 500 W wind turbine, a photovoltaic, a proton exchange membrane fuel cell (PEMFC), ultracapacitors, an electrolyzer, a boost converter, controllers and a power converter that simulated using MATLAB solver. This kind of hybrid system is completely stand-alone, reliable and has high efficiency. In order to minimize sudden variations in voltage magnitude ultracapacitors are proposed. Power converter and inverter are used to produce ac output power. Dynamics of fuel-cell component such as double layer capacitance are also taken into account. Control scheme of fuel-cell flow controller and voltage regulators are based on PID controllers. Dynamic responses of the system for a step change in the electrical load and wind speed are presented. Results showed that the ability of the system in adapting itself to sudden changes and new conditions. Combination of PV and wind renewable sources is made the advantage of using this system in regions which have higher wind speeds in the seasons that suffers from less sunny days and vice versa.

Hybrid PV/Wind/Diesel Based Distributed Generation for an Off-Grid Rural Village in Afghanistan

Afghanistan has a tremendous resource potential of renewable energy especially solar and the wind. Therefore, utilization of these resources has a special rule for the remote areas where access to the electrical grid or secure power supply is a dream for most of the people. This paper presents a feasibility and usefulness of hybrid power generation based on PV/wind/diesel generator for an off-grid rural village that feeds the load at a rate of average 7.9 kWh/day with 1.32 kW peak load. GsT （geospatial toolkit） is used to obtain the solar and wind data of the site. Windographer software is used to analyze the wind resource data of the site. HOMER Pro software package is used to select the suitable and reliable hybrid generation system and calculate the optimal capacities and costs of the components. Through the study, it is found that this state of the art adaptation could provide vast opportunities for off-grid rural communities such as in Afghanistan where enough high penetration of renewable energy is available.

Intelligent hybrid power generation system using new hybrid fuzzy-neural for photovoltaic system and RBFNSM for wind turbine in the grid connected mode

Photovoltaic(PV)generation is growing increasingly fast as a renewable energy source.Nevertheless,the drawback of the PV system is intermittent because of depending on weather conditions.Therefore,the wind power can be considered to assist for a stable and reliable output from the PV generation system for loads and improve the dynamic performance of the whole generation system in the grid connected mode.In this paper,a novel topology of an intelligent hybrid generation system with PV and wind turbine is presented.In order to capture the maximum power,a hybrid fuzzy-neural maximum power point tracking(MPPT)method is applied in the PV system.The average tracking efficiency of the hybrid fuzzy-neural is incremented by approximately two percentage points in comparison with the conventional methods.The pitch angle of the wind turbine is controlled by radial basis function network-sliding mode(RBFNSM).Different conditions are represented in simulation results that compare the real power values with those of the presented methods.The obtained results verify the effectiveness and superiority of the proposed method which has the advantages of robustness,fast response and good performance.Detailed mathematical model and a control approach of a three-phase grid-connected intelligent hybrid system have been proposed using Matlab/Simulink.

Optimal Sizing of Solar/Wind Hybrid Off-Grid Microgrids Using an Enhanced Genetic Algorithm

This paper presents a method for optimal sizing of an off-grid hybrid microgrid (MG) system in order to achieve a certain load demand. The hybrid MG is made of a solar photovoltaic (PV) system, wind turbine (TW) and energy storage system (ESS). The reliability of the MG system is modeled based on the loss of power supply probability (SPSP). For optimization, an enhanced Genetic Algorithm (GA) is used to minimize the total cost of the system over a 20-year period, while satisfying some reliability and operation constraints. A case study addressing optimal sizing of an off-grid hybrid microgrid in Nigeria is discussed. The result is compared with results obtained from the Brute Force and standard GA methods.

High Wind Power Penetration Large-Scale Hybrid Renewable Energy System Design for Remote Off-Grid Application

This study looks into the resource assessment, technology economics and modeling of different energy alternatives and proposes a rechargeable battery storage-based large-scale wind/photovoltaic hybrid power system to meet an average electrical load demand of 2.4 MW and peak load of 2.9 MW for a remote rural district in Ethiopia called Geladin. The district is 682 km away from nearby grid. The site enjoys high solar and wind resources that can be harnessed for electric power generation to electrify the community. HOMER simulation software is used for optimal sizing and techno-economic analysis. The diesel generator is used as back up to fill the gaps in case both resources are out. Average monthly solar irradiation data of 6.2 kWh/m2 is determined from measured sunshine duration data by implementing a suitable specific model for the site. NASA satellite based estimated wind speed data of 10 years average at hub height of 50 m for the site in question is extracted from the SWERA (Solar and Wind Energy Resource Assessment) database (with annual average of 6.1 m/s) and its weigh-bull distribution parameter, k of 1.98 is estimated which indicates a fair wind speed distribution of the site to generate electric power using wind turbine. The proposed optimal system results electricity generation indicates that 92% from wind turbine, 3% from photovoltaic, 5% from diesel generator and managed to obtain a much lower cost of energy (COE = 0.11USD/kWh) than other alternatives investigated in this study such as grid extension and diesel generator.

边防哨所风光耦合制氢系统的配置优化

为解决边防哨所地处偏远、环境复杂、对能源需求大且上网成本高的问题,利用风光资源的互补性及氢能的能量密度高、绿色清洁等特点,提出了建立以风能和太阳能作为主要发电能源的风光耦合制氢系统,并选择氢能单元作为系统的储能单元,以满足边防哨所对能源多样性的需求,提高哨所从周边环境获取能量的能力。建立风光耦合制氢系统各子系统数学模型,以减小系统成本、提高可再生能源利用率、增大氢能产量为目标进行系统建设配置优化,选择系统各组件的额定功率作为设计变量,具体地区气象数据作为输入,利用第三代非支配排序遗传算法(NSGA-Ⅲ)进行求解,对优化得到的帕累托解集进行决策。通过层次图的绘制实现多维帕累托前沿可视化,得到了最优配置方案,并与未优化配置方案等进行对比,保障供电可靠性的同时可大幅度提高能源利用率、降低配置成本。

计及风光不确定性的风-光-光热联合发电系统中光热电站储热容量优化配置

传统新能源电站之间联合形式单一且未考虑风光出力不确定性,弃风、弃光现象严重。为此,提出了一种考虑风光不确定性的风-光-光热联合系统的光热电站储热容量优化配置策略,利用电转热技术使风光电站和光热电站有效耦合,明确联合系统框架与原理;采用改进拉丁超立方抽样方法抑制风光出力的不确定性。最后,构建基于风光出力典型场景的光热电站储热容量双层优化配置模型,并进行算例求解,结果表明所提方法显著降低了系统总投资与运行成本,提高了清洁能源消纳能力。

An investigation into the feasibility of a hybrid generator-photovoltaic-wind farm with variable load profile:case of headland south-west of Morocco

A hybrid system proposed by three different specifications for the equipment of a tourist lodge in the headland of south-west Morocco was sized by analysing the limits of load profile constraints,such as hour-to-hour variability(HHR),day-to-day variability(DDR)and the operating reserve rate(ROR).Based on the three-factor Doehlert matrix recommendations,the simulations employed an energy-sizing tool for hybrid renewable-energy systems.Testing was conducted with DDR at 5-30%,HHR at 10-30%and ROR at 0-20%.Under these conditions,a second-order polynomial relationship with a correlation rate of~90%was found between the net present cost(NPC)of the system,the levelized cost of electricity and the various constraint factors.The first specification,SPC(1),composed of generators and batteries,was introduced to control and validate the simulation independently of renewable energy,which showed a positive manifestation with the imposed constraints.The analysis expanded by introducing solar and wind energy resources.The SPC(2)configuration added PV modules to the SPC(1)and the SPC(3)configuration added wind turbines to SPC(2).The effect of DDR,HHR and ROR in the trials was significant by linear regression.At the same time,only DDR had a significant quadratic regression.The others,with their pairwise interactions,were insignificant.The desirability procedure made it possible to calculate the maximum limits of load profile constraint variables leading to targets of LCOE=0.41 US$/kWh and NPC=US$320080.1 of the load profile constraints:the DDR=15.47%and the HHR=26.55%at an ROR rate of 17.77%.

风光储一体化水电联产系统的优化设计及调度

水和能源短缺严重制约沿海以及海岛经济的发展。将可再生能源与水电联产系统耦合,可有效解决这一问题。本文建立了风光储一体化水电联产系统的优化和调度模型。首先,建立了各单元的数学和经济模型,以系统的总年费最低为目标。然后运用遗传算法(GA)求解,优化得到春、夏、秋、冬4个典型日的系统最佳结构及容量配置。系统中水电的满足率大于99%,并且弃风、弃光率小于2%。最后确立了各典型日的最佳运行方案,包括风力、光伏、反渗透单元的生产负荷,供需匹配关系及各单元设备运行状态。结果表明:各典型日中风光互补供给功率均比较平稳,反渗透单元的运行负荷变化较大,但额定功率运行的时长均为50%左右。抽水储能单元也充分发挥其削峰填谷的作用,在各典型日的运行时长占比均超过75%。本文设计的系统为水电联产系统工业化运行提供指导。

考虑风-光-储协同的电池储能系统综合评价体系和选型方案研究

针对不同类型电池储能系统的选型规划和充放电功率分配难以协调其技术性、经济性和环境性的问题,提出一种考虑风-光-储协同的电池储能系统综合评价体系,进而对电池储能系统充放电策略进行优化并选型。首先,建立电池储能系统全寿命周期内的效益模型,采用模糊层次分析法对上述电池储能系统的效益模型进行分层分析,将其划分成不同的准则和指标,并计算出其相应的权值;其次,建立风-光-储协同下电池储能系统的充放电功率优化模型,并将上述权值与电池储能系统全寿命周期内的经济性、技术性和环境性相结合,确定目标函数;再次,提出一种灰狼优化算法和莱维飞行策略相结合的混合优化算法,对电池储能系统一天内每小时充放电功率的分配进行优化,并得出电池储能系统的荷电状态曲线;最后,基于新疆某地的气象和负荷数据分析对比5种电池储能系统经济性、环境性和技术性的各项指标,根据算例结果为电池储能系统的综合选型方案和充放电功率分配提出建议,并验证所建模型的可行性和求解算法的优越性。

七一灌区新型测控一体闸门的设计与应用

测控一体闸门在灌区的应用对提高灌溉水利用效率和推进信息化建设至关重要。根据七一灌区不同的渠道类别,设计了各种规格的新型测控一体闸门。其中,闸体采用一体式双导轨结构,配备直流电机驱动闸门启闭以控制流量,旋转编码器记录闸门开度,雷达水位计采集闸门上下游水位,应用闸孔出流原理计算渠道流量;闸门测控终端显示电机运行状态和渠道水位流量信息,通过4GTD-LTE宽带无线通信专网远程传输至管理站和各级水务机构;采用风光互补的供电方式为测控一体闸门供能,能够满足至少10 d无风或阴雨天气用电需求。测控一体闸门的应用,改变了灌区以往水位流量曲线测流的方式,提高了测流精度,减少了灌溉用水的浪费。

Application of Power Electronics Converters in Renewable Energy

Against the backdrop of global energy shortages and increasingly severe environmental pollution,renewable energy is gradually becoming a significant direction for future energy development.Power electronics converters,as the core technology for energy conversion and control,play a crucial role in enhancing the efficiency and stability of renewable energy systems.This paper explores the basic principles and functions of power electronics converters and their specific applications in photovoltaic power generation,wind power generation,and energy storage systems.Additionally,it analyzes the current innovations in high-efficiency energy conversion,multilevel conversion technology,and the application of new materials and devices.By studying these technologies,the aim is to promote the widespread application of power electronics converters in renewable energy systems and provide theoretical and technical support for achieving sustainable energy development.

基于人工鱼群算法的水风光联合调峰优化模型

本文提出基于多Agent人工鱼群算法(MAAFAS)的,以剩余负荷均方差最小为目标函数的梯级水风光短期调峰优化调度模型。该模型充分结合了Agent算法的自主性和人工鱼群算法的全局寻优性,降低了约束的复杂性,易于获得复杂问题求解下的最优解。并以我国南方地区某流域的6座水电站,11座风电场,4座光伏电站组成的风光水电源互补系统为研究对象,从不同来水场景下(汛期、枯期)进行实例分析。结果表明:该模型可以有效地利用水电能源的调峰能力,平均提高负荷峰谷差降幅率到44.65%,缩小原始负荷峰谷差3300 MW,剩余负荷趋于平稳,便于风光能源的更好消纳,是一种实用性较强的水风光短期调峰优化方法。

风电光伏混合系统中的储能技术研究与应用

介绍风电光伏混合系统的基本概念、组成以及运行特点,强调系统在提供稳定、可靠电力方面的优势。探讨电化学、机械和热储能等的优缺点及其在可再生能源系统中的应用,详细分析储能技术如何提升风电光伏混合系统的稳定性、经济性以及环境适应性,并通过实证数据和比较分析展示储能技术在系统优化中的效果,提出结合储能技术的系统优化策略,如模型预测控制(Model Predictive Control,MPC)等,强调其在提高系统效率和应对复杂气候条件中的关键作用。

具有混合储能的独立光伏风能供电系统的规模优化

讨论了具有混合储能的独立光伏风能供电系统的规模优化问题,提出了一种新的技术用于优化储能系统外的多源电力系统曲线,研究了各种能源的建模和构成,有效实现了能源的优化。本文的研究目标是最小化需求的供电概率损失(LPSP),此外,成本最小化也是本文的另一个研究目标。使用遗传算法解决了相关问题,实现了系统的可靠运行。通过实验验证了本文算法的有效性,并将其优化结果与多目标粒子群优化结果进行了比较。

Cumulant-based correlated probabilistic load flowconsidering photovoltaic generation and electric vehiclecharging demand

This paper applies a cumulant-based analytical method for probabilistic load flow (PLF) assessment in transmission and distribution systems. The uncertainties pertaining to photovoltaic generations and aggregate bus load powers are probabilistically modeled in the case of transmission systems. In the case of distribution systems, the uncertainties pertaining to plug-in hybrid electric vehicle and battery electric vehicle charging demands in residential community as well as charging stations are probabilistically modeled. The probability distributions of the result variables (bus voltages and branch power flows) pertaining to these inputs are accurately established. The multiple input correlation cases are incorporated. Simultaneously, the performance of the proposed method is demonstrated on a modified Ward-Hale 6-bus system and an IEEE 14-bus transmission system as well as on a modified IEEE 69-bus radial and an IEEE 33-bus mesh distribution system. The results of the proposed method are compared with that of Monte-Carlo simulation.

基于蒙特卡罗模拟法的柔性交直流混联配电网概率潮流计算

随着高压直流输电和新能源并网技术的快速发展,电力系统运行工况愈加复杂多变。为更好评估现代电力系统的不确定性,文中研究了分布式发电中的风力发电和太阳能发电的随机出力对配电系统电压质量的影响,提出一种能够计及风光互补特性和换流站控制特性,基于蒙特卡罗模拟求解含有电压源换流器的交直流混联系统概率潮流计算方法。首先,针对换流站不同的控制方式,给出利用交替迭代法进行常规交直流潮流的计算模型。其次,建立了考虑风力发电、太阳能发电和负荷不确定性的概率潮流计算模型。最后,在修改后的IEEE-34节点系统上采用蒙特卡洛法计算节点电压、线路功率的均值和标准差。该方法能较为准确的反映新能源固有的不确定性及穿透率的影响,并有着良好的收敛性。