光伏发电并网大电网面临的问题与对策

妥善解决光伏发电系统接入大电网后2部分都能安全、高效运行是光伏发电技术大规模工业化应用的关键之一。分析了光伏发电系统及其并网的技术特点,简要阐述了光伏发电并网问题的研究现状。指出光伏发电大规模并网使大电网在研究与实验验证手段、对光伏发电系统影响大电网机理的认识、新型配电系统的规划、电网运行控制、电网监测保护与控制装备、技术标准与规范等方面面临新的问题,并提出了应对这些问题的策略。     

Generating capacity adequacy evaluation of large-scale,grid-connected photovoltaic systems

Large-scale, grid-connected photovoltaic systems have become an essential part of modern electric power distribution systems. In this paper, a novel approach based on the Markov method has been proposed to investigate the effects of large-scale, grid-connected photovoltaic systems on the reliability of bulk power systems. The proposed method serves as an applicable tool to estimate performance (e.g., energy yield and capacity) as well as reliability indices. The Markov method framework has been incorporated with the multi-state models to develop energy states of the photovoltaic systems in order to quantify the effects of the photovoltaic systems on the power system adequacy. Such analysis assists planners to make adequate decisions based on the economical expectations as well as to ensure the recovery of the investment costs over time. The failure states of the components of photovoltaic systems have been considered to evaluate the sensitivity analysis and the adequacy indices including loss of load expectation, and expected energy not supplied. Moreover, the impacts of transitions between failures on the reliability calculations as well as on the long- term operation of the photovoltaic systems have been illustrated. Simulation results on the Roy Billinton test system has been shown to illustrate the procedure of the proposed frame work and evaluate the reliability benefits of using large-scale, grid-connected photovoltaic system on the bulk electric power systems. The proposed method can be easily extended to estimate the operating and maintenance costs for the financial planning of the photovoltaic system projects.     

高原高寒地区光伏组件背板冷却对输出功率影响的实验研究

针对光伏组件表面温度影响光伏电站出力的技术难题,以2行4列的光伏阵列为例,在拉萨搭建光伏阵列输出功率实验测试平台,采用液冷方式在背板铺设冷却循环管道构建背板冷却系统,并基于冷却系统的连续运行（实验Ⅰ）、先停后启（实验Ⅱ）、先启后停（实验Ⅲ）3种运行工况,分别进行光伏组件有无背板冷却的对比实验,探究高原高寒地区组件表面温度对光伏阵列输出功率的影响规律。研究表明：采用背板冷却技术降低光伏组件的表面温度,可有效提升光伏阵列的输出功率,在实验Ⅰ、Ⅱ、Ⅲ中光伏阵列输出功率分别提升了1.4%、1.3%、1.0%;光伏组件采用背板冷却技术时,冷却介质循环泵耗功高于光伏阵列提升的输出功率,但在高原高寒地区可回收利用冷却介质吸热量,加热生活用水,可使采用背板冷却的光伏阵列综合效益提高。     

光伏发电系统功率预测方法研究综述

光伏发电大规模并网给电网的稳定运行带来巨大挑战,提高光伏发电功率预测水平对光伏能源并网安全具有重要意义.光伏发电系统功率输出具有明显的非线性、间接波动性和不确定性特点,须采用数学模型结合多尺度预测方法实现较高预测精度.针对多元线性回归算法、马尔科夫链预测、神经网络算法、支持向量机和组合预测等光伏系统输出功率的直接预测方...     

基于PVsyst的山地光伏系统设计与优化

针对山地光伏电站建设的技术难点进行分析,在提高山地光伏电站的效率、降低成本、保证系统运行安全的情况下,对徐州鼓楼区九里山南山坡太阳能光伏电站的系统进行设计与建设,对组件的排布方式、阵列间距、组件的支架与基础设计、系统设备的选型、方阵阴影分析、电站发电量与节能减排进行优化设计与计算。     

Small scale photovoltaic desalination for rural water supply - demonstration plant in Gran Canaria

A small reverse osmoisis (RO) plant supplied by a photovoltaic (PV) power supply has been installed at the island of Gran Canaria. On behalf of this system the feasibility of small PV-RO systems (1 m³/d) is investigated. The RO-plant is described in detail concerning its technical specifications, its operation constraints and its energy demand. Furthermore the photovoltaic power supply is described in detail. With simulations it is shown how the system is designed to guarantee a reliability of more than 96% in the water supply. A brief economic analysis shows that the water production costs are still high (about 16 $/m³) but can be lowered in future.     

太阳能光伏冰箱技术的应用分析

文章结合太阳能制冷技术的特点,指出了太阳能光伏冰箱研发的重要性,并对太阳能光伏冰箱系统的基本组成及工作原理进行了介绍;进而,分别从光伏转换效率和优化设计两个方面,对太阳能光伏冰箱系统的实际应用中存在的关键问题进行了分析。最后,结合太阳能光伏冰箱技术的研究现状和当前太阳能电池的生产成本变化,指出了太阳能光伏冰箱技术应用的市场前景广阔。     

光伏发电并网逆变器建模及电能质量评估

鉴于光伏发电并网逆变器的建模对于光伏大规模接入、保障系统稳定运行具有重要意义,提出了系统仿真方案,利用Hammerstein-Wiener(HW)非线性模型对光伏并网逆变器的运行进行仿真。通过试验获得直流逆变器电压电流波形、交流逆变器电压电流波形、电压公共耦合点、电网和负荷电流;利用编程确定各种模拟波形并搜索与实际波形相比最准确的模型,同时将该方法运用到电能质量分析中,进而完成对系统的分析和建模。模拟结果表明,该模型效果较好,可以为系统规划、防止系统故障和改善电能质量等方面提供理论依据。     

光储联合电站建模与仿真

为解决光伏电站发电的波动性与不稳定性,介绍了光伏电站与全钒液流电池储能电站联合运行的系统结构,基于PSCAD/EMTDC仿真平台,建立了光伏电池、光伏控制系统、全钒液流电池及其控制系统的电气模型,对并网及故障模式下光储联合电站系统的运行情况进行了仿真研究。结果表明,光储联合电站运行时储能系统能很好地平抑光伏电站的输出功率波动,故障模式下能维持光伏电站的稳定运行。全钒液流电池储能电站可提高光伏电站运行的经济性与可靠性,同时增强了光伏电站输出的可预测性。     

The function of a ground sensor for photovoltaic system reliability

Several measures to evaluate and assess the performance of photovoltaic installations have been conducted by BPP Teknologi. However, analysis on the installation, safety and reliability related to electrical failures on the photovoltaic power source is almost never discussed. As the number of large photovoltaic installations in Indonesia is growing and some significant failure modes on the existing systems are observed, therefore a reliability study should be taken. In this paper, one of the safety subsystem components and the grounding path recommended for photovoltaic systems is discussed. Furthermore, an analysis on the installed system failure modes and their possible causes is described. Some conclusions and recommendations for further photovoltaic installations in Indonesia based on the previous discussion and analysis are also presented.     

分布式光伏发电系统最大功率点跟踪技术比较研究

基于当前光伏阵列最大功率点跟踪技术的研究现状,介绍了适用于分布式光伏发电系统最大功率点跟踪的各种常用控制方法,阐述了每一种控制方法的技术原理,分析和比较了这些常用控制方法的特点,总结了各自的优点和缺点,最后对分布式光伏发电系统最大功率点跟踪方法的选择问题进行了探讨,并指出了具体选择方法时应综合考虑的各种因素。     

Evaluation of technical improvements of photovoltaic systems through life cycle assessment methodology

Since solar energy systems feed on a ‘clean’ energy source, they do not produce polluting emissions during their operation. However, they carry the environmental weight of other phases in their life cycle. In order to analyze the energy and environmental profile of these systems, it is necessary to expand the system boundaries, taking into account also the ‘hidden impacts’ related to production, transportation and system disposal at the end of its technical life. Here, the life cycle assessment methodology is applied to derive a complete and extended energy and environmental profile of photovoltaic systems. As reference case, a conventional multi-crystalline building integrated system is selected, retrofitted on a tilted roof, located in Rome (Italy) and connected to the national electricity grid. Then improved configurations of the reference system are assessed, focusing on building integration issues and the operational phase (considering an experimental hybrid photovoltaic system with heat recovery). Environmental ‘pay back times’ of the assessed systems are then calculated for CO₂ equivalent emissions and embodied energy. All the analyzed configurations are characterized by environmental pay back times one order of magnitude lower than their expected life time (3–4 years vs. 15–30 years). Thanks to a wider exploitation of photovoltaic potential during its ‘zero emission operation’, these results are further lowered by photovoltaic hybrid systems (environmental pay back times, depending on heat recovery configuration, go down to 40–50% of the values calculated for the reference case).     

Design scheme for fast charging station for electric vehicles with distributed photovoltaic power generation

The demand for fast charging is increasing owing to the rapid expansion of the market for electric vehicles. In addition, the power generation technology for distributed photovoltaic has matured. This paper presents a design scheme for a fast charging station for electric vehicles equipped with distributed photovoltaic power generation system taking the area with certain conditions in Beijing as an example construction site. The technical indexes and equipment lectotype covering the general framework and subsystems of the charging station are determined by analyzing the charging service demand of fast charging stations. In this study, the layout of the station is developed and the operation benefits of the station is analyzed. The design scheme realizes the design objective of “rationalization, modularization and intelligentization” of the fast charging station and can be used as reference for the construction of a fast charging network in urban area.     

新能源系统中双储能耦合燃煤机组的应用策略研究

  目的  随着新能源电力消费比例不断提高,燃煤机组耦合双储能技术的能源系统发展受到广泛关注。  方法  文章基于能源系统组成、储能技术特性、项目示范情况以及技术瓶颈等方面的分析,针对风电、光伏嵌入下双储能技术耦合燃煤机组参与电力系统调峰应用开展了运行控制策略研究。  结果  双储能技术耦合燃煤机组可通过不同的结构组成、运行策略优化有效解决新能源系统运行稳定性、能源高效利用以及技术经济性等问题,但目前尚未到实现大规模商业化应用阶段。  结论  双储能耦合燃煤机组在新能源系统中的推广应用,需要对双储能技术的策略优化及储能技术本身的发展突破方面不断开展工作。     

The Vulcano Project

The chief aim of the Vulcano Project is to evaluate the technical and financial feasibility of supplying electric power to small, remote village out of reach of utility grids by using a photovoltaic solar energy system.

The experiment consists of the design, construction, and operation on the Island of Vulcano ( Sicily), of a plant for the production of electric power by means of a stand-alone photovoltaic system.

Alternatively, the plant can supply energy in parallel to the existing diesel power station, as a “ fuel-saver” in order to investigate the economics of this type of operation.     

Analytical model for predicting the performance of photovoltaic array coupled with a wind turbine in a stand-alone renewable energy system based on hydrogen

We present the results of an analysis of the performance of a photovoltaic array that complement the power output of a wind turbine generator in a stand-alone renewable energy system based on hydrogen production for long-term energy storage. The procedure for estimating hourly solar radiation, for a clear sunny day, from the daily average solar insolation is also given. The photovoltaic array power output and its effective contribution to the load as well as to the energy storage have been determined by using the solar radiation usability concept. The excess and deficit of electrical energy produced from the renewable energy sources, with respect to the load, govern the effective energy management of the system and dictate the operation of an electrolyser and a fuel cell generator. This performance analysis is necessary to determine the effective contribution from the photovoltaic array and the wind turbine generator and their contribution to the load as well as for energy storage.     

Sizing procedure for photovoltaic refrigerating systems using a simple approach of the LLP calculation

We present a sizing procedure for photovoltaic refrigerating systems. By simulating the system operation, loss of load probability (LLP) calculation is performed and allows one to optimise the sizes of the photovoltaic generator and the refrigerated enclosure. The system components are characterised by energy models which are joined in the simulation procedure to describe the system behaviour. This procedure has been validated and shows a good agreement with experimental results.     

MODEL FOR A SOLAR-ASSISTED CLIMATIZATION SYSTEM

We propose an extended model for the climatization of an ecological building. Solar radiation is the main energy source. The theoretical approach includes models for: (i) generating meteorological data; (ii) generating solar radiation data; (iii) optimum operation of a photovoltaic array; (iv) thermal interactions between building and ambient; (v) operation of the climatization system; and (vi) operation of the refrigeration system. Preliminary results show that the photovoltaic array provides all of the energy required to drive the climatization system in midsummer on clear days. The Romanian standard STAS 6648/1-82 overestimates the thermal load of the climatization system. The development of more sophisticated computing procedures is desirable. We show the influence of the type of day (with clear or covered sky) and of solar-cell quality on both the thermal load and the power delivered by the photovoltaic array.     

Enhancing the electrical performance of a solid oxide fuel cell using multiobjective genetic algorithms

Several technologies are being used in distributed generation applications with variable degree of success. Among those are: wind turbines, small-scale hydropower plants, biomass, microturbines, photovoltaic arrays, and fuel cells. A fuel cell is a device that converts the chemical energy of fuel to electric energy. New improvements in the fuel cell technology significantly meliorated the technical characteristics of this technology. Environmental friendliness, practically noise free operation, and very high efficiency make fuel cells a challenger on the future electricity markets.The connection between the fuel cell and the load is through an inverter using Pulse Width Modulation. Subsequently, the fuel cell produces a significant amount of harmonics. This paper describes the use of multiobjective genetic algorithms in the design of a fuzzy logic control system for a solid oxide fuel cell.