Comprehensive Evaluation of Distributed PV Grid-Connected Based on Combined Weighting Weights and TOPSIS-RSR Method

To effectively quantify the impact of distributed photovoltaic(PV)access on the distribution network,this paper proposes a comprehensive evaluation method of distributed PV grid connection combining subjective and objective combination of assignment and technique for order preference by similarity to an ideal solution(TOPSIS)—rank sum ratio(RSR)(TOPSIS-RSR)method.Based on the traditional distribution network evaluation system,a comprehensive evaluation system has been constructed.It fully considers the new development requirements of distributed PV access on the environmental friendliness and absorptive capacity of the distribution grid and comprehensively reflects the impact of distributed PV grid connection.The analytic hierarchy process(AHP)was used to determine the subjective weights of the primary indicators,and the Spearman consistency test was combined to determine the weights of the secondary indicators based on three objective assignment methods.The subjective and objective combination weights of each assessment indicator were calculated through the principle of minimum entropy.Calculate the distance between the indicators to be evaluated and the positive and negative ideal solutions,the relative closeness ranking,and qualitative binning by TOPSIS-RSR method to obtain the comprehensive evaluation results of different scenarios.By setting up different PV grid-connected scenarios and utilizing the IEEE33 node simulation algorithm,the correctness and effectiveness of the proposed subject-object combination assignment and integrated assessment method are verified.

Performance Assessment of a Real PV System Connected to a Low-Voltage Grid

The generation of photovoltaic(PV)solar energy is increasing continuously because it is renewable,unlimited,and clean energy.In the past,generation systems depended on non-renewable sources such as oil,coal,and gas.Therefore,this paper assesses the performance of a 51 kW PV solar power plant connected to a low-voltage grid to feed an administrative building in the 6th of October City,Egypt.The performance analysis of the considered grid-connected PV system is carried out using power system simulator for Engineering(PSS/E)software.Where the PSS/E program,monitors and uses the power analyzer that displays the parameters and measures some parameters such as current,voltage,total power,power factor,frequency,and current and voltage harmonics,the used inverter from the type of grid inverter for the considered system.The results conclude that when the maximum solar radiation is reached,the maximum current can be obtained from the solar panels,thus obtaining the maximum power and power factor.Decreasing total voltage harmonic distortion,a current harmonic distortion within permissible limits using active harmonic distortion because this type is fast in processing up to 300 microseconds.The connection between solar stations and the national grid makes the system more efficient.

High Efficiency PCS with Scan-Type MPPT Control for a Grid-Connected PV Power Generation System

For a standalone PV （photovoltaic） power generation system, the author previously proposed a new MPPT （maximum power point tracking） control method in which the I-V characteristics are scanned with a detection interval control that operates at specified intervals and monitors the maximum power point. The author has obtained satisfactory results using this new MPPT control method. This paper investigates the application of the new MPPT control method for a PCS （power conditioning system） in a grid-connected type PV power generation system. The experimental results clearly demonstrate that the developed PCS offers outstanding effectiveness in tracking the maximum power point in partially shaded environments.

Grid-Connected PV Solar Energy Converter with Active and Reactive Power Control

This work proposes a 12 kW three-phase grid-connected single stage PWM DC-AC converter destined to process the energy provided by a photovoltaic array composed of 57 KC200GT PV modules with high power factor for any solar radiation. The PWM inverter modeling and the control strategy, using dqO transformation, are proposed in order to also allow the system operation as an active power filter, capable to compensate harmonic components and react power generated by the non-linear loads connected to the mains grid. An input voltage clamping technique is proposed to impose the photovoltaic operation on the maximum power point. Simulation and experimental results are presented to validate the proposed methodology for grid connected photovoltaic generation system.

Evaluation of the Performances of the First Grid-Connected Photovoltaic System in Sénégal

This document presents the evaluation and the monitoring of the performances of the first grid-connected photovoltaic system installed in the Center of Studies and Researches on the Renewable Energies (CERER) inaugurated on December 4th, 2012 by the governmental authorities of Senegal and Tenerife. This mini power plant of 3.15 kWc is a perfect example of the political will of the government which is to reduce the production cost of the electricity, with the diversification of the sources of production, and the greater use of the other sources such as the natural gas, the coal, the renewable energies. The evaluation of the performances of the installation is realized by using the indicators of efficiency and performance as the photovoltaic surface yield, the ratio of photovoltaic performance, the photovoltaic specific yield, and the losses of captures. The obtained results show that a big part of the energy shone during the period of observation was not able to be used further to circumstances such as the losses of conductivity, the heat losses or for example the defects on components. The analysis also shows that a large part of the produced energy is not injected because of the dilapidation of the network, the defects of landing but especially one disjunction sees frequently at the level of the point of injection.

Influence of Control Modes of Grid-Connected Solar Photovoltaic Generation on Grid Power Flow

Integration of Solar Photovoltaic (PV) generation into an existing distribution system has many impacts on the system, with the power flow being one of the major issues. This impact is not generic for any network, but it may manifest itself either positively or negatively, depending on the grid configuration, interface control modes, operation mode, and load profile. Grid-connected PV systems have three control options of the local voltage controller of the interface DC-AC converter. These control modes are Power Factor control, voltage control, and Droop Voltage control. This paper aims at evaluating and comparing the impacts of those control modes on the grid power flow. A set of evaluation criteria and indices is defined and mathematically formulated. Based on the requirements of the used program (Power Factory Dig Silent V14.1.3), a computation plan (algorithm) has been proposed. The algorithm has been applied to a typical weak network and a wide range of simulations has been carried out. Simulation results have been thoroughly discussed and important findings have been concluded.

探讨集中式光伏项目光伏区施工组织结构矩阵模型

阐述光伏项目标段划分的惯例原则和小型光伏项目的组织结构,从专业维度和空间维度将集中式光伏项目常见的劳务分包模式及相应的组织结构抽象为组织结构模型,分析其优缺点,进一步探讨了具有普遍适用性的光伏区施工组织结构矩阵模型。

西藏自治区超高海拔牧区光伏支架桩基础的施工质量控制研究

西藏自治区超高海拔牧区的气候环境、地质条件、环保要求等与内地的不同,因此在此类地区建设光伏电站时,光伏支架桩基础施工时需要考虑的因素,以及设备、材料等的选择也存在很大差异。以西藏山南曲松罗布沙850 MW牧光互补光伏发电项目中光伏支架桩基础的施工为例,对西藏自治区超高海拔牧区光伏支架桩基础的施工质量控制开展研究。首先结合项目所在地的地质条件和环保要求,选择出最合适的桩基础类型;其次对光伏场区内3种施工设备的施工效率、经济性、稳定性、环保性进行了比较;最后通过严格落实施工工艺及采用钢丝绳定位的方式确保了桩基础的施工质量。研究结果表明:此类地区的光伏支架桩基础采用“以螺旋钢桩基础为主、微孔灌注桩基础为辅”的方案,能同时满足环境保护、施工效率和力学性能的要求;为确保施工进度,施工设备可选择240型普通挖改钻机;介绍的螺旋钢桩基础和微孔灌注桩基础的施工工艺及施工质量控制措施效率高、效果明显,能确保桩基础施工后的力学性能满足设计要求。研究结果为其他同类型光伏发电项目桩基础的施工提供了可借鉴的经验。

光伏发电绿色创新示范项目的建设与实践

广州南沙某工业园区光伏发电绿色创新示范项目的建设与实践具有重要意义。项目旨在助力建筑碳达峰、实现节能减排,同时进行科学研究和展示宣传。项目安装了多种类型的光伏组件和逆变器,并采用了自发自用,余电上网的并网方式。此外,外观上还进行了光伏与建筑景观一体化设计施工,打造了融合光伏科技元素的园林休闲空间。项目的长期运行将带来显著的经济效益和环境效益。通过并网运行和余电上网的方式,项目能够为企业节省电费支出并享受政府补贴政策,同时还可以降低顶层房间夏天空调能耗费用,减少碳排放,助力节能减排目标的实现。

基于项目研究的“PV新技术”创新课程建设

开展研究型教学是提高人才培养质量,树立学生的创新思想和创新意识,培养尖端人才的重要手段。本文结合基于项目研究的创新课程"PV新技术",探讨了其教学环节、教学方法、教学手段和教学实践中遇到的一些问题,经过几年的教学循环逐步积累了一定的经验,并取得了满意的效果。

基于煤矿排土场的光伏发电项目方案优化

[目的]通过“以光治荒”的方式推进煤矿排土场光伏发电项目的建设,将生态保护与绿色高效能源战略有机融合,以达到良好经济发展和生态环境治理的效果。[方法]以某煤矿排土场光伏发电项目优化为例,原方案采用的全固定支架形式,考虑到红线调整、地质影响、施工进度可控等因素,现调整为固定支架+柔性支架组合方案,场地较平缓部分区域考虑布置固定支架,柔性支架主要设置在坡面与跨沟处,占比为40%~45%。结合固定倾角、发电效率、光伏组串布置间距等因素进行优化,方案一固定支架倾角按16°,柔性支架东西向固定倾角按4°,南向及偏南方向顺坡布置。方案二根据最佳倾角确定,固定支架倾角采用24°,柔性支架固定倾角采用19°。[结果]方案一比方案二增加8 MWp左右;25 a总发电量:方案一比方案二增加10%~15%。发电系统总效率:方案一比方案二减少2%左右。[结论]研究表明本方案的优化保证其装机容量、工程安全等的同时,煤矿排土场边坡布置柔性支架增加了本工程创新性,为后续相关工程起到示范作用。在工程设计优化过程中,不仅仅考虑效率因素,更多的是需关注多目标因素优化带来的经济效益。

光伏发电项目LCOE的研究与思考

针对光伏发电项目的平准化度电成本(LCOE)展开研究,介绍了其相关概念,分析了其各个影响因素;并有针对性地提出了降低LCOE的相关方法和建议。研究结果显示:1)在目前的市场行情下,光伏发电项目LCOE的3个组成部分中,初始投资部分LCOE的占比最大,达到了72%~76%;2)发电量是项目LCOE非常敏感的影响因素,应寻找光照资源条件较好的地区建设光伏发电项目,并且减少弃光率,提升上网电量,有助于降低项目LCOE;3)折现率对项目LCOE的影响很大,但其与项目本身无关,主要取决于行业的基准收益率和项目投资者设定的项目预期收益率;4)光伏发电系统年衰减率和运维成本对项目LCOE的影响不大;5)寻找融资利率低的贷款可在一定程度上降低项目LCOE;6)降低项目初始投资和提升发电量是降低项目LCOE最主要的两个途径,也是光伏工作者最需要努力的两个方向。以期研究结果可为光伏发电技术的发展和光伏发电项目的开发建设提供参考。

无人机机载LiDAR在光伏发电项目大比例尺地形图测量中的应用

当前,光伏电站多建设在海拔高且高差大、植被多的地区,常规实时动态载波相位差分技术(RTK)测量方法效率较低,无人机倾斜摄影测量方法无法准确获取多植被区域的地面高程。基于此,提出一种在光伏发电项目大比例尺地形图测量中应用的无人机机载激光雷达(LiDAR)测量方法。首先从外业采集、内业数据处理两个方面介绍无人机机载LiDAR测量方法的技术流程,然后根据光伏发电项目应用实例数据对该测量方法的应用效果进行具体分析。研究结果表明:无人机机载LiDAR测量方法的植被穿透力强,可以快速获取植被下方高精度的地面点3D坐标,操作简单,且不需要布设大量像控点,外业采集的效率高;该测量方法的点云高程精度优于平面位置精度,可生产高精度数字高程模型(DEM)成果,直接提取等高线用于地形图成果绘制,内业数据处理的速度快。无人机机载LiDAR测量方法可以更好地满足在高山多植被地区的光伏发电项目建设的时间节点要求和精度要求,可以很好地应用于山区大高差的光伏发电项目大比例尺地形图测量作业。

山地光伏电站线路工程设计中改进无功补偿容量计算方式的研究

近年来,随着并网光伏电站数量及并网装机容量的迅速激增,光伏发电对电网的稳定和安全运行造成了较大影响,为了保证电网稳定性,无功补偿装置成为光伏电站必备设备之一。但在实际运行中发现,大多数光伏电站存在无功补偿容量配置过剩的问题,导致项目投资成本增加。针对典型复杂山地光伏电站的无功补偿容量配置问题,考虑到汇集线路及送出线路工程的特殊性,结合光伏电站建设的经济性,通过理论计算分析的方式,在线路工程设计环节对无功补偿容量的计算方式进行了改进,并进行了对比计算。研究结果表明:1)增加送出线路的电缆敷设长度、降低送出线路架空线路长度、汇集线路负载分段计算均可以降低光伏电站无功补偿容量配置;2)采用改进后的计算方式可使光伏电站前期投资额节约数十万元,提升了光伏电站的整体收益。

卫生健康项目绩效损失及治理研究--基于PV-GPG理论

目的:探索卫生健康项目绩效损失情况及其影响因素,提出治理策略。方法:基于PV-GPG理论,以A市219个市级卫生健康项目为样本,对绩效自评数据进行分析,对访谈资料进行三级编码,分析卫生健康项目绩效损失影响因素。结果:卫生健康项目的绩效生成是社会价值建构、组织管理与协同领导系统综合作用的结果,3类要素中的1个或多个出现缺陷都会导致卫生健康项目的绩效损失,其中,社会价值建构是核心影响因素。结论:合理避免绩效损失,建立适宜的预算绩效管理机制,提高绩效评价质量。

PV Power Short-Term Forecasting Model Based on the Data Gathered from Monitoring Network

The degree of accuracy in predicting the photovoltaic power generation plays an important role in appropriate allocations and economic operations of the power plants based on the generating capacity data gathered from the geographically separated photovoltaic plants through network. In this paper, a forecasting model is designed with an optimization algorithm which is developed with the combination of PSO （Particle Swarm Optimization） and BP （Back Propagation） neural network. The proposed model is further validated and the experiment results show that the predication model assures the prediction accuracy regardless the day type transitions and other relevant factors, in the proposed model, the prediction error rate is worth less than 20% in all different climatic conditions and most of the prediction error accuracy is less than 10% in sunny day, and whose precision satisfies the management requirements of the power grid companies, reflecting the significance of the proposed model in engineering applications.

基于PV-GPG理论框架的公共项目绩效损失问题研究——以G省世界银行项目为例

公共项目极大促进了经济社会发展。但与此同时,技术治理路径下公共项目失败问题也在逐渐显现。论文选取G省世界银行项目为案例、将以公共价值为基础的政府绩效治理理论(PV-GPG)作为理论基础,通过扎根理论与认知地图相结合的研究方法,旨在研究公共项目失败的本质、影响因素及发生机理。理论分析发现,公共项目失败是公共项目中存在绩效损失的表现形式,而损失又可以依据"项目的产出差距"与"项目的需求偏离"分为两类。论文研究表明,社会价值建构过程不充分引起的项目设计与忽视资源禀赋问题组织管理中的激励故障与管理流程问题以及协同领导系统中的冲突与沟通问题共同导致了治理缺陷型绩效损失发生,"文化与制度差异""激励不足"与"缺乏压力"是解释治理缺陷型绩效损失的关键要素;社会价值建构过程的缺乏引起了项目概念与优先项选择错误问题,是导致价值偏离型绩效损失发生的充分条件,由于政治原因社会优先项被忽视是解释价值偏离型绩效损失的关键。

浅谈PVsyst软件在光伏发电项目阴影遮挡设计中的应用

在光伏发电项目设计过程中,由于光伏阵列布局不合理或周围环境影响,光伏组件经常会发生阴影遮挡问题,造成光伏发电项目发电量的损失。以天津市某光伏发电项目的设计为例,通过应用PVsyst软件,对项目所在地的光伏阵列之间的阴影遮挡及周边地形地貌的阴影遮挡进行模拟和计算分析,得出前后排光伏阵列间距及周边建构筑物阴影遮挡范围对光伏阵列的影响,验证了光伏阵列布局的合理性及准确性,以提高光伏发电项目的可行性及经济效益。研究结果可为光伏发电项目阴影遮挡设计提供参考,熟练采用相关光伏发电设计软件,能够更加准确测算项目的可行性,充分提高项目的经济效益。

Testing PV Central Inverters＇ Compliance with International Grid Codes

In many electrical grids worldwide, the rising amount of installed PV （photovoltaic） power entails a considerable influence of PV systems on grid quality and stability. Consequently, in the wake of the revised German medium voltage directives issued in 2009, new requirements for PV inverters have been established internationally. At Fraunhofer ISE＇s Inverter Laboratory, approximately 25 large PV inverters with a nominal power of up to 880 kVA have been characterized in the past three years. In this period, the focus of many inverter manufacturers has begun to shift from traditional European markets towards an international perspective. Therefore, experiences with numerous different grid codes have been gained by our team. This work summarizes the similarities and differences between these grid codes. Additionally, several requirements that have proved to be critical will be examined. Finally, the adequacy of these grid codes to guarantee the safe and reliable operation of electrical grids is discussed.

Comparison between the Energy Required for Production of PV Module and the Output Energy Througout the Product Life Time

Electrical energy consumption is growing and is necessary to improve the technologies related to energy production. We have carried out a pilot study about environmental impacts during the manufacturing process of PV （photovoltaic） modules and compared between the energy requirement for the production of PV cells and modules and generation throughout the life time of the finished good that is PV module. It was taken into account the generation of environmental aspects and impacts in the manufacture of monocrystalline silicon PV modules （consisting of three components： silicon cell, fiat tempered glass and aluminum frame）, and an analysis of a grid-connected PV system using an energetic alternative in residences was considered. Results show that, this kind of renewable energy is really clean and can be considered as a way to change the energy technology.