Efficiency Analysis of Grid-connected Photovoltaic Power Plants

Analysis of photovoltaic power plant(PVPP)operations is important to both investors and users and to producers of equipment,researchers and designers as well.This paper presents the analysis of the year-long operations of the group PVPPs in Serbia connected to the distribution network which was carried out through specific indicators such as electric power generation,power,capacity factors,specific yield,losses,period of cost effectiveness of the investment,etc.Special attention has been paid to the influence of the azimuth and tilt of the photovoltaic modules on the performances of PVPPs.Results obtained through the year-long extensive measurements were compared to expected yields of PVPPs on the basis of the Climate SAF PVGIS application.The results of the analysis indicate that available software applications cannot always provide a good enough forecast of expected electric power production since they cannot always assess well enough the effects of the surrounding facilities on operations of a PVPP.In addition,it has been found that the correlation between losses of annual achieved specific yield of a PVPP and the azimuth is represented by a polynomial of the second degree,whereas the correlation between losses of the annual achieved specific yield of a PVPP and the tilt is represented by an exponential function.

Study of the Impact of Grid Disconnections on the Production of a Photovoltaic Solar Power Plant: Case of Diamniadio Power Plant

Today, renewable energy projects connected to the interconnected network, with powers of the order of tens of megawatts, are more and more numerous in sub-Saharan Africa. And financing these investments requires a reliable amortization schedule. In the context of photovoltaic systems connected to the interconnected electricity grid, the quintessence of damping is the amount of energy injected into the grid. Thus it is fundamental to know the parameters of this network and their variation. This paper presents an evaluation of the impact of power grid disturbances on the performance of a solar PV plant under real conditions. The CICAD photovoltaic solar plant, connected to the Senelec distribution network, with an installed capacity of 2 MWp is the study setting. An energy audit of the plant is carried out. Then the percentage of each loss is determined: voltage drops, module degradation, inverter efficiency. The duration of each disconnection is measured and recorded daily. The corresponding quantity of lost energy is thus calculated from meteorological data (irradiation, temperature, wind speed, illumination) recorded by the measurement unit in one-minute steps. The observation period is three months. The total duration of disconnections related to the instability of the electrical network during the study period is 46.7 hours. The amount of energy lost is estimated at 22.6 MWh. This represents 2.4% of the actual calculated production.

Choice of the Best Production Prediction Model for the Zagtouli Solar Power Plant in Burkina-Faso

In this paper, we present a study on the prediction of the power produced by the 33 MWp photovoltaic power plant at Zagtouli in Burkina-Faso, as a function of climatic factors. We identified models in the literature, namely the Benchmark, input/output, Marion, Cristo-fri, Kroposki, Jones-Underwood and Hatziargyriou prediction models, which depend exclusively on environmental parameters. We then compared our linear model with these seven mathematical models in order to determine the most optimal prediction model. Our results show that the Hatziargyriou model is better in terms of accuracy for power prediction.

Seasonal Performance of Solar Power Plants in the Sahel Region: A Study in Senegal, West Africa

The main objective of this study is to evaluate the seasonal performance of 20 MW solar power plants in Senegal. The analysis revealed notable seasonal variations in the performance of all stations. The most significant yields are recorded in spring, autumn and winter, with values ranging from 5 to 7.51 kWh/kWp/day for the reference yield and 4.02 to 7.58 kWh/kWp/day for the final yield. These fluctuations are associated with intense solar activity during the dry season and clear skies, indicating peak production. Conversely, minimum values are recorded during the rainy season from June to September, with a final yield of 3.86 kWh/kW/day due to dust, clouds and high temperatures. The performance ratio analysis shows seasonal dynamics throughout the year with rates ranging from 77.40% to 95.79%, reinforcing reliability and optimal utilization of installed capacity. The results of the capacity factor vary significantly, with March, April, May, and sometimes October standing out as periods of optimal performance, with 16% for Kahone, 16% for Bokhol, 18% for Malicounda and 23% for Sakal. Total losses from solar power plants show similar seasonal trends standing out for high loss levels from June to July, reaching up to 3.35 kWh/kWp/day in June. However, using solar trackers at Sakal has increased production by up to 25%, demonstrating the operational stability of this innovative technology compared with the plants fixed panel. Finally, comparing these results with international studies confirms the outstanding efficiency of Senegalese solar power plants, other installations around the world.

Choice of Site for the Installation of Photovoltaic Solar Power Plants in Senegal: Consequences on Electricity Production

A theoretical analysis of the electricity production of a photovoltaic solar power plant of 22 MW for different sites in Senegal is presented. The study is carried out in two coastal regions (Dakar and Saint-Louis) and two continental regions (Mbacké and Linguère). This study is done using the RET Screen clean energy project management software climate data. The amount of electricity exported to the grid is calculated for each site. The results show that the climatic conditions of the coastal and continental regions are different from November to June. From July to October, which corresponds to the rainy season in Senegal, the climatic conditions of the coastal and continental regions are similar. The results also show that although the efficiency of photovoltaic modules is better on the coast, electricity production varies little from one site to another. Climate conditions in Senegal therefore have no impact on electricity production.

Design of Capacitor Bank in Parallel to Photovoltaic Power Plant

The purpose of the paper is to develop a solution for application of PV （photovoltaic） generators in MV （medium voltage） distribution system without unacceptable voltage changes due to drops of PV power output. The proposed solution includes operation of PV with predetermined leading power factor and addition of a capacitor bank in parallel to PV plant in order to compensate the reactive power absorbed by the PV inverters. The analytical expression of required power factor angle is derived. Adding a capacitor bank in parallel to PV power plant may pose a problem because of space limitations. The dimensions and cost of small MV capacitor banks depend significantly on the capacitor bank protection against internal faults. Application of the developed negative-sequence current difference method for the unbalance protection of the capacitor banks enables to achieve a compact and cost-reduced design of the banks connected in parallel to PV power plants. A real-world example of operation of the PV plant in parallel to the capacitor bank with the novel protection scheme is described.

Large-Scale Distributed Photovoltaic Power Dispatching and Operation Management Review

Distributed photovoltaic power (PV) is the main development model of distributed generation. It is necessary to research on dispatching and operation management with large-scale distributed PV connected. This paper analyzes development status, technical requirement and dispatching and operation management situation of distributed PV in Germany and China. Then introduce the preparation of distributed PV dispatching and operation management criterion. Through summarizing the experiences and lessons of large-scale distributed PV development in Germany, it gives advice to the development of distributed PV dispatching and operation management in China.

Forecast of Power Generation for Grid-Connected Photo-voltaic System Based on Grey Theory and Verification Model

Being photovoltaic power generation affected by radiation strength, wind speed, clouds cover and environment temperature, the generating in each moment is fluctuating. The operational characteristics of grid-connected PV systems are coincided with gray theory application conditions. A gray theory model has been applied in short-term forecast of grid-connected photovoltaic system. The verification model of the probability of small error will help to check the accuracy of the gray forecast results. The calculated result shows that the ?model accuracy has been greatly enhanced.

Load Management Scheme Using Air Conditioning Electric Power Consumption and Photovoltaic Power System Generation

In the last few decades, in the world and also in the European Union, considerable resources had been invested in the rapid development of renewable energy sources and distributed generation in general. At the same time, power consumption is continuously increasing, and consumers are becoming more complex, which ultimately requires new investments in the distribution network. Concept of smart grids is generally accepted as a possible solution. Smart grid is a concept with many elements, where monitoring and control of every element in the chain of production, transmission, distribution and final consumption enable much more efficient delivery and use of electricity. One of the elements of smart grid efficiency is the ability of real-time demand-supply balancing. This balancing is carried out by monitoring of consumption and redistribution of electricity among individual end users, according to their needs. The aim of this paper is creating algorithm for real-time load management using power measurements. Algorithm for real-time load management at the ETFOS （Faculty of Electrical Engineering in Osijek）, Croatia is created based on measurements of photovoltaic power plant production, the power consumption of air conditioning system and the faculty building total electricity consumption. Expected result of real-time re-dispatching of air conditioners consumption, depending on the level of electricity production in photovoltaic power plant is decreasing peak demand of the faculty.

Study on the Energy Dispatch Strategy of PV Power Plant

Now the energy efficiency of the PV power plant is low.For this case,this paper presents a PV power plant energy scheduling strategy.It includes new grid scheme and scheduling algorithm.Through the establishment of PV power station network model and the method of computer simulation of its scheduling algorithm,this paper describes its realization way,and then proves that the scheduling strat egy is correct and the effectiveness of improving energy conversion rate.At the same time,the PV power station scheduling strategy aslo re duces the environmental pollution,and alleviates the energy crisis and environmental crisis.

A composite controller for grid connected photovoltaic systems

This paper addresses a new composite controller for a boost-buck inverter to interface the photovoltaic array with the power grid. Based on dynamically tracking the maximum power point, two novel control methodologies are proposed to control the DC-bus and the output current for the inverter. First, a new linear cycle discrete control algorithm is introduced to realize linear control of the DC-bus voltage and synchronously get the reference current for the inner current loop with a little calculation. Then, to assure a good adaptability to noise and model uncertainty, an auto-disturbance rejection controller is chosen as the output current controller, which does not depend on precise mathematics model. Thus, output current of PV system to the grid is with low harmonic distortion and unity power factor. Simulations and experiments are performed, and the results show that the system is of excellent robustness and effective.

A Simulation Research on the Grid-Connected Control Technology of Single-Phase Inverters Based on MATLAB

This paper primarily discusses the main circuit of single-phase inverter circuits.It begins by introducing the research context and the significance of the subject,then discusses the topology of grid-connected single-phase inverter circuits,continues by discussing the control strategy for grid-connected single-phase inverter circuits,realizes a sinusoidal pulse width modulation(SPWM)signal generation circuit and an inverse control algorithm program,and finally ensures good output waveform and fast dynamic response.In view of the hysteresis feature of the grid voltage’s synchronous signal sampling circuit,the acquisition function in digital signal processing(DSP)control chips is applied,and the reasons for the hysteresis phenomenon are thoroughly investigated.The reliability of the SPWM control algorithm is revealed through the results.

Test Facility for Low Potential Pumped Storage Power Plants and Hydrokinetic Turbines

The electric energy which is generated by wind power plants depends on the wind speed and exceeds with strong permissible wind speed the electric energy requirements of the country. In order not to reduce this electrical energy, it must be stored. The sensible energy storage is currently the pumped storage power plants. As the mountain ranges for conventional pumped storage power plants with drop heights of H 〉 600 m are strictly limited, the development of low potential pumped storage power plants has begun. Increasing the capacity of pumped storage power plants with regard to the wind power plants is urgently needed. In this paper, it is shown using the example of an unneeded port facility, how a port facility can be used after low conversion as a test facility for low potential pumped storage power plants and at the same time for the testing of hydro-kinetic turbines. This type of pump storage power plants does not save the energy due to large drop heights, but primarily due to the large volume flow of water.

Development of a Renewable Energy Based DC Excitation System in a Micro Hydro Power Plant

MHPPs （micro hydro power plants） have become prominent in hydropower plants as a solution to provide the energy demands of the grid. In this study, a new hybrid renewable energy based DC excitation system for synchronous generator in the developed MHPP system is introduced. Proposed hybrid DC excitation system consists of solar ＆ hydrogen energy based power generating systems. Hybrid renewable energy based system is used for the excitation of the synchronous generator in the MHPP test system. The renewables are used as a secondary energy source to provide the excitation current to a synchronous generator that generates energy in MHPP. A PV （photovoltaic） array is used as the main source of excitation, and a FC （fuel cell） stack is used for DC excitation in the lack of sunshine. In the experimental setup, an electrical control card is developed, and a microcontroller is used to perform the proposed excitation system. All experimental results obtained from 5 kW rated power MHHP test system. Experimental results show that, the proposed method provides the continuous excitation current, and the operation of the synchronous generator is uninterrupted. The proposed method is also practical and easily implemented for MHPP systems.

考虑共享储能容量配置的多虚拟电厂优化运行方法

由于分布式能源具有间歇性和波动性的特点,其大规模接入电网会对系统稳定性产生一定的影响。为了减少用户侧用电成本以及提高新能源的消纳能力,在多虚拟电厂背景下提出共享储能系统促进风光消纳的规划和运行双层决策博弈模型。上层模型对共享储能电站投资运行成本进行等年值转换分析,以共享储能总成本最低且使用寿命尽可能的长为目标函数建立模型;下层模型以虚拟电厂运行成本最低及弃风弃光最小为目标函数建立运行优化模型。采用鲸鱼算法与CPLEX商业求解器结合的形式对共享储能电站的容量配置、充放电行为以及虚拟电厂运行状态进行求解,并通过设置3个场景算例对所提方案进行验证,结果表明,所提方法可以优化共享储能电站容量最优配置和充放电策略,提高可再生能源的消纳能力和虚拟电厂系统运行效率,兼顾供给侧与需求侧的利益,使电能分配更加公平合理。

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。

光伏阵列对松嫩草地土壤细菌群落组成与多样性的影响

为阐明光伏电站对松嫩草地土壤细菌组成与多样性的影响,调查并测定了吉林西部一座光伏电站的光伏板行间、光伏板下和光伏阵列周边(对照)的植物群落特征和土壤特征,采用Illumina HiSeq 2500基因测序仪进行了土壤细菌16S rDNA测序.结果表明:光伏阵列呈现提高土壤细菌Ace,Chao1和Simpson多样性指数的趋势,并显著增加拟杆菌纲、梭菌纲、酸杆菌纲、放线菌纲和γ-变形菌纲的相对丰度.影响土壤细菌群落的主要因素是土壤pH和全碳、全氮和总有机碳含量,以及植物群落地上生物量和盖度.光伏阵列对松嫩草地土壤细菌群落组成和优势纲丰度均有一定的影响,并对土壤细菌多样性的恢复发挥了积极作用.

干旱区光伏电站运营对局地生态环境的影响

光伏发电符合能源产业发展方向,我国光伏电站在西北干旱地区建设最为广泛,但西北干旱地区生态环境较为脆弱,目前,对于干旱区光伏电站运营过程中可能产生的环境影响尚不清楚。以青海省海南州共和塔拉滩光伏发电园为研究区,基于2023年3月—2024年2月光伏电站内光伏区和自然空地区生态环境指标的观测数据,并结合2000—2020年研究区域的遥感监测数据,综合分析了光伏电站的运营对局地大气、土壤、植被等生态环境要素的影响。结果表明:光伏电站的运营对局部大气起到增湿、增大温度极端值、减缓风速的作用,平均增湿3.87%、减少风速0.25m·s^(-1),温度极端值变化1.72℃;对局部土壤起到增温、减湿、降低土壤CO_(2)含量的作用,平均升温1.83℃、湿度减少4.81%,土壤CO_(2)降低156.94ppm。光伏电站运营能够促进电站所在区域植被覆盖度增加和植被生长,对生态系统固碳能力起到正向促进作用,光伏电站及其周围区域NDVI均值增速比海南州地区快0.001kgC·m^(-2)·a^(-1)。光伏电站的运营可明显改善周边生态环境,起到空气增湿、土壤增温、防风固沙、促进植被生长的作用,促使局地生态环境不断向好。

考虑不同区域气象与地理条件差异的广域光伏电站规划

目前全国各地正大力发展光伏发电,并有部分省份提出了全省光伏发电发展目标。与局部光伏电站规划相比,以全省这样的广域为规划范围会遇到气象信息难以获取、光伏出力难以估计、各地地理条件差异大等问题。为此提出了一种考虑地理与气象条件差异的广域光伏电站规划方法。针对各地气象条件差异,通过纬度、太阳位置等地理信息计算出任意地点任意时间的光照强度,再通过气象插值模型获得目标位置的其他气象信息,并构建了含注意力机制的长短期记忆网络模型,对各地单位光伏容量的光伏出力进行预测。针对各地地理条件差异,结合了预测得到的各地区单位光伏容量年发电量,计算了不同地理条件影响下单位光伏容量的占地面积和开发成本,考虑了不同位置的电网运行约束,构建了广域光伏电站规划模型。以某一典型省份为场景验证了所提方法的合理性和优越性。与只通过光照强度强弱决定光伏电站开发的方法相比,考虑地理与气象差异的规划方法所得到的发电量更高也更准确,并且为各地的光伏电站开发提供了参考。

光伏电站自备用可调的虚拟同步控制调频策略

采用自备用控制的光伏电站能够为电网提供调频能力,但现有的自备用控制难以评估最大功率,调频经济性需要量化,且无法提供虚拟惯量,光伏电站调频效果有待提高。针对此问题,提出光伏电站自备用可调的虚拟同步调频控制策略。首先,基于光伏运行P-V特性,提出光伏最大功率估算策略以及变步长电压控制策略,实现光伏自备用控制;其次,基于虚拟同步控制策略和光伏电站架构,引入频率反馈控制环,提出光伏自备用可调的虚拟同步控制策略,光伏电站在提供频率响应功率的同时,以虚拟惯量的形式支撑电网的频率稳定。此外,并联在光伏直流侧的储能,可以保证在光伏自备用率动态调整过程中直流侧母线电压的稳定。进一步分析了最大功率估算算法误差对虚拟同步调频控制策略的影响,以及虚拟同步控制参数变化对调频效果的影响。最后,通过Simulink仿真验证了所提控制策略的有效性,为光伏并网调控提供理论支撑。