Photovoltaic System Components Research Articles

Micro-cracks Detection of Polycrystalline Solar Cells with Transfer Learning

As the photovoltaic (PV) systems are universally utilized in power systems, the defect of solar cells, the core components of PV system requires to be detected in a low-cost and high-efficiency method, because of its wide application and direct influence on power generation efficiency and system stability. The principal aim of this study is to apply transfer learning in defect detection of polycrystalline cells with image-level labelled mono images and unlabelled poly images. The experiment was conducted with DAN models based on a MK-MMD to represent the distance between source domain and target domain and Resnet-50 backbone to learn transferable features. Three contrast methods were designed to make comparison with DAN. It has been proved that DAN model based on MK-MMD and Resnet-50 shows a promising performance on transferring from monocrystalline tasks to polycrystalline tasks.

Mitigation of transient overvoltages in microgrid including PV arrays

This study investigates the mitigation of transient overvoltages (TOVs) in a microgrid supplied by renewable distributed generation resources, which include photovoltaic (PV) generators, hydro generation unit, and wind power generators. ATP/EMTP is used in this study as electromagnetic transient software. Accurate simulation models are needed to carry out the study. Therefore, a three-phase PV system model based on the equivalent Newton–Raphson circuit is used, and the efficiency of the PV system components is studied. Then, the use of the PV generation system model for switching studies is investigated using two different electrical systems. The use of different mitigation methods for TOVs at the microgrid is investigated. Three different mitigation methods are considered. First, a device to compensate reactive power such as static var compensator (SVC) is represented as a TOVs mitigation method. Then, adding a supercapacitor as TOVs mitigation method is evaluated. After that, a combination of active and reactive power simultaneously to mitigate TOV, by the addition of SVC to a supercapacitor, is investigated. The grid-connected mode and isolated mode of the microgrid are considered. The results show that the usage of SVC with supercapacitor has the ability to mitigate the transient overvoltage and the waveforms are more regular.

A New High Gain DC-DC Converter With Model-Predictive-Control Based MPPT Technique for Photovoltaic Systems

High step-up DC/DC converter and maximum power point tracking (MPPT) control are essential components in photovoltaic (PV) systems. For the purpose of utilizing PV module in power generation, this manuscript proposes 1-new high step-up DC/DC converter 2-model predictive control based maximum power point tracking (MPC-MPPT) algorithm with optimum number of sensors. The suggested topology is able to provide a voltage gain up to 10 times of input-voltage and its measured efficiency is around 93%. MPC is a prevalent control technique with superior transient and steady-state performances in PV systems. However, in PV DC/DC converters, conventional MPC based MPPT technique typically requires two voltage-sensors and one current-sensor. For the purpose of reducing system cost, this manuscript presents MPC based MPPT technique with two-sensors. The algorithm is designed to operate with both fixed and adaptive step-size. Different scenarios and operating conditions are evaluated both in Simulink and with hardware set-up. Results obtained from the simulation and experimental work are consistent and verify the analytical analysis of the system.

Cost Optimization of a Stand-Alone Hybrid Energy System with Fuel Cell and PV

Renewable energy has become very popular in recent years. The amount of renewable generation has increased in both grid-connected and stand-alone systems. This is because it can provide clean energy in a cost-effective and environmentally friendly fashion. Among all varieties, photovoltaic (PV) is the ultimate rising star. Integration of other technologies with solar is enhancing the efficiency and reliability of the system. In this paper a fuel cell–solar photovoltaic (FC-PV)-based hybrid energy system has been proposed to meet the electrical load demand of a small community center in India. The system is developed with PV panels, fuel cell, an electrolyzer and hydrogen storage tank. Detailed mathematical modeling of this system as well as its operation algorithm have been presented. Furthermore, cost optimization has been performed to determine ratings of PV and Hydrogen system components. The objective is to minimize the levelized cost of electricity (LCOE) of this standalone system. This optimization is performed in HOMER software as well as another tool using an artificial bee colony (ABC). The results obtained by both methods have been compared in terms of cost effectiveness. It is evident from the results that for a 68 MWh/yr of electricity demand is met by the 129 kW Solar PV, 15 kW Fuel cell along with a 34 kW electrolyzer and a 20 kg hydrogen tank with a LPSP of 0.053%. The LCOE is found to be in 0.228 $/kWh. Results also show that use of more sophisticated algorithms such as ABC yields more optimized solutions than package programs, such as HOMER. Finally, operational details for FC-PV hybrid system using IEC 61850 inter-operable communication is presented. IEC 61850 information models for FC, electrolyzer, hydrogen tank were developed and relevent IEC 61850 message exchanges for energy management in FC-PV hybrid system are demonstrated.

Fault Diagnosis in Microgrids with Integration of Solar Photovoltaic Systems:A Review

Microgrids are essential components to help create the future electric grid which features a significant penetration of renewable and clean energy resources. However, a critical challenge in the protection of microgrids is the fault detection and diagnosis process, particularly in the presence of high uncertainties and varying topologies of microgrids. Faults in microgrids can cause instabilities, inefficient power generation, and other losses. Therefore, not only does it matter to understand various fault/failure modes and their root causes and effects, but it is also essential to develop real-time automated diagnosis tools to capture early signatures of fault evolution and enable proper mitigating actions. Given the significance of this issue, the present paper starts with a review of different failure modes occurring in various components of grid-connected photovoltaic systems, before offering a deeper review of the state of the art of fault diagnosis techniques specifically applied to solar photovoltaic systems in microgrids.

Identification technique of DC series arc‐fault strings in photovoltaic systems

AbstractThe DC series arc‐faults lead a risk due to an aging of photovoltaic system components enhanced by environmental factors and high DC voltages in already existing photovoltaic systems. Until recently, many research activities have focused on the detection of DC series arc‐faults by current signature analysis. However, DC arc detector has two problems. First, it is difficult to distinguish arc noise and switching noise of power conditioner by circuit current in photovoltaic system. Secondly, when a DC series arc fault occurs in the photovoltaic system, DC series arc‐fault string cannot be specified because the arc noise is propagated in the circuit. In this article, we propose two novel techniques for the DC series arc‐fault detection and identification of faulty strings. Experiments were performed by generating DC series arc in the field. The proposed technique is investigated based on the experimental results in the terms of effectiveness and applicability.

Modeling Solar Modules Performance Under Temperature and Solar Radiation of Western Iraq

<p>This paper demonstrates a mathematical representation of Photovoltaic (PV) solar cells and hence panels performance. One-diode solar cell model is implemented to simulate the cell and extract the performance indications. The tested PV modules are BP Solar (60 Watt) and Synthesis Power (50 Watts), which are operating in a PV generation system in the University of Anbar - Iraq, College of Applied Sciences. The math model demonstrates Power versus Voltage (P-V) characteristic curves to depict and study various parameters with affecting variations in the PV array performance. The parameters include ambient and cell temperature degrees and solar irradiance (G) level which are the main elements to dictate the productivity of a solar system. G is represented by sun unit (1 sun=1 kW/m<sup>2</sup>). The outcomes of the simulation model characteristics curves have been compared with curves provided by the tested modules data sheets. MATLAB software has been used to simulate the model and extract the results. This paper also investigated photovoltaic simulation with maximum power point tracking (MPPT) converter to evaluate hence predict the behaviors of the whole photovoltaic DC current generation using PSIM Power Electronics program. The model focuses on the basic components in PV systems; The panel and the DC-DC converter. The modeling outcome data will be used as a reference verifying the performance of the tested modules during the year seasons under the dominating dusty hot weather in western Iraq.</p>

Photovoltaic Power Systems Optimization Research Status: A Review of Criteria, Constrains, Models, Techniques, and Software Tools

The photovoltaic (PV) generating system has high potential, since the system is clean, environmental friendly and has secure energy sources. There are two types of PV system, which are grid connected and standalone systems. In the grid connected photovoltaic system (GCPV), PV generator supplies power to the grid, whether or not the whole or a portion of the generated energy will be used to supply load demands. Meanwhile, the standalone photovoltaic system (SAPV) is used to fulfil a load demand that close to its point of use. These days, many researchers study in term of optimization sizing of photovoltaic system, in order to select optimum number of PV modules, inverter, battery storage capacity, and tilt angle. Based on that, this review aims to give explanations on approaches done by previous researchers in order to find ultimate combinations for design parameters. Moreover, the paper discusses on modelling of PV system components, which includes PV panels’ output power estimation and battery system. Finally, simulation softwares that used as sizing tools in previous studies are reviewed and studied.

An improved numerical optimization algorithm for sizing and configuration of standalone photo-voltaic system components in Yemen

This paper presents an improved optimization method for sizing standalone photo-voltaic (PV) systems. Numerical methods for optimization and configuration of array size, charge controller, storage battery capacity, and power inverter of PVs are implemented using MATLAB and hourly meteorological data and load demand. DC voltage operation is also optimally selected. Loss of load probability analysis is conducted to set the benchmark for determining all possible PV arrays and battery capacities. Then, the optimum design is proposed based on the lowest levelized cost of energy and net present value. The case study refers to the meteorological data of Yemen and the typical load role of the domestic sector in Yemen. Results show that the net present value of 6.6024 kWh/day PV system for Yemen is 22224 USD, while the cost of energy generated by the proposed system is 0.403 USD/kWh and the loss of load probability (LLP) is equal to 0.130%.

Reliability assessment of a power system with cyber-physical interactive operation of photovoltaic systems

With an increased transition towards low carbon technologies and their interactions with information and communication technologies (ICT) in a smart grid environment, reliability performance studies should essentially be incorporated with cyber-physical systems interactions. Such an integrated operating environment is inevitably exposed to cyber-physical system threats, particularly, with the increased presence of new and smart components. In the purview of the above, this paper proposes an innovative algorithm to determine the availability and unavailability of cyber physical interactive system components for quantifying the level of risk posed by random cyber threats. This paper also provides the pathway for the power system reliability assessment of a cyber-physical integrated system operation with multiple photovoltaic (PV) system configurations by incorporating Markov-Chain transitions for PV system components. A set of case studies were performed by simulating the cyber-physical integrated operating environments and the results suggest that impacts from cyber threats on interactive PV operation are considerable and a quantitative assessment is required to determine real impacts on a specific power system.

A scalable method for estimating rooftop solar irradiation potential over large regions

An estimate of solar irradiation potential over large regions requires the knowledge of the long-term spatio-temporal distribution of the solar radiation as well as the identification of the suitable surfaces where the photovoltaic (PV) installations can be built. These main components can be modelled in different ways and are thus affected by different sources of uncertainty. Thus, when estimating the exploitable potential over large regions, it is important to measure the accuracy of the entire process. In this work, we provide a generic method to estimate the solar irradiation potential of rooftops over large regions and an estimate of the corresponding uncertainties when calculating the long-term electricity generation of PV plants. This method uses satellite based solar radiation data covering a period of 22 years, with a temporal resolution of 30 min and a spatial resolution of 3.8–5.6 km. Suitable surfaces on rooftops are identified using Digital Surface Models combined with building footprints. This allows to determine the geometry of rooftops, such as slope, and orientation with a spatial resolution of 0.5 m. Finally, we calculated the electricity generation based on models which take into account all characteristics of PV system components. In order to estimate the accuracy of the model for electricity production, we compared the monthly generation of 500 PV plants in Switzerland consisting of different PV technologies (mono-crystalline, poly-crystalline and thin film) with the estimates. The validation results show a correlation coefficient (R2) of 0.9 and a median monthly relative error between 0.28% (August) and 28.08% (December). The monthly estimates are more accurate during summer time, while spatially and technology-wise no significant differences are found.

A photovoltaic system experiment in a laboratory environment

Solar photovoltaic energy sources are rapidly gaining potential growth and popularity compared to conventional fossil fuel sources. This work presents a photovoltaic system laboratory experiment developed for engineering students to emphasize the need for enhanced renewable energy education. The experiment exposes students to photovoltaic system components, working principles, and maximum power operating point. It is designed to complement a renewable energy course. Results along with animation from the hands-on experiment are presented in this study.

Investigation on the effects of front-cavity on flame location and thermal performance of a cylindrical micro combustor

Micro combustor acts as the most important component of the micro thermo photovoltaic (TPV) system. It is crucial that the design and performance of a micro combustor are optimized for its application in a micro TPV system. A micro combustor with front-cavity is proposed in this study, and comparisons of flame stability and thermal performance of the micro combustor with and without front-cavity are made. In addition, the effects of front-cavity size and front-cavity shape on OH mass fraction, flame location and thermal performance of micro combustor are also discussed. The front-cavity in the micro combustor helps to improve the flame stability, increase outer wall temperature value and total energy conversion efficiency for the micro TPV system. It is found that the micro combustor with arc front-cavity (inner diameter ratio of front-cavity and combustion chamber is β = 0.9) is more suitable for the application in the micro TPV system.

Modeling and Simulation for an 8 kW Three-Phase Grid-Connected Photo-Voltaic Power System

Abstract Gird-connected Photo-Voltaic (PV) systems rated as 5-10 kW level have advantages of scalability and energy-saving, so they are very typical for small-scale household solar applications. In this paper, an 8 kW three-phase grid-connected PV system model is proposed and studied. In this high-fidelity model, some basic PV system components such as solar panels, DC-DC converters, DC-AC inverters and three-phase utility grids are mathematically modelled and organized as a complete simulation model. Also, an overall power controller with Maximum Power Point Control (MPPT) is proposed to achieve both high-efficiency for solar energy harvesting and grid-connection stability. Finally, simulation results demonstrate the effectiveness of the PV system model and the proposed controller, and power quality issues are discussed.

Estimation of bright roof areas for large scale solar PV applications to meet the power demand of megacity Hyderabad

Hyderabad is reeling under a severe power crisis aggravated due to the recent bifurcation of the state of Andhra Pradesh. Telangana state needs more power than residual Andhra Pradesh due to greater demand from its Industrial and Agricultural consumers. The installed capacity (established as well as under construction) of power plants under Telangana Power Generation Corporation (TSGENCO) includes 2282.5 MW of thermal coal based power, 2081.76 MW of hydro power and 1 MW solar power. As more than 50% of the power source is coal based, there exists a threat of fossil fuel depletion and enhanced Green House Gas (GHG) emissions. Solar electricity has the potential to offset these negative impacts. This paper concentrates on evaluating the roof top area required for solar power generation using Remote Sensing and GIS apart from developing an algorithm using analytical methods, to estimate the photo-voltaic system components required, for the total power requirement of Hyderabad city.

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.

Simulation of Electrical Characteristics of a Solar Panel

The fast-growing photovoltaic system market leads to the necessity of the informed choice of major energy components and optimization of operating conditions in order to improve energy efficiency. Development of mathematical models of the main components of photovoltaic systems to ensure their comprehensive study is an urgent problem of improving and practical using of the technology of electrical energy production. The paper presents a mathematical model of the solar module implemented in the popular software MATLAB/Simulink. Equivalent circuit of the solar cell with a diode parallel without derived resistance is used for modelling. The serie8s resistance of the solar module is calculated by Newton's iterative method using the data of its technical specifications. It ensures high precision of simulation. Model validity was evaluated by the well-known technical characteristics of the module Solarex MSX 60. The calculation results of the experiment showed that the obtained current-voltage and current-watt characteristics of the model are compatible with those of the manufacturer.

Trap-clearing Spectroscopy in Perylene Diimide Derivatives

Perylene diimide (PDI) derivatives are important components of organic circuits and photovoltaic systems, but the electron trapping mechanism(s) in higher-LUMO PDIs (−3 to −4 eV, where radical anions are expected to react with atmospheric water and oxygen) are not well characterized. Here, we examine the spatial distribution of traps in transistors made from PDIs with these higher LUMO levels and measure trap-clearing spectra in n-type organic materials using time- and wavelength-resolved frequency-modulated Kelvin probe force microscopy (FM-KPFM). We find that the rate of trap-clearing under visible light does not follow a LUMO-level trend, and we observe spectral evidence for different trapping mechanisms on bare versus HMDS-treated SiO2.

User learning and emerging practices in relation to innovative technologies: A case study of domestic photovoltaic systems in the UK

Due to the rapid growth of the domestic photovoltaic (PV) sector in the UK all involved are at an early learning stage in terms of implementation. Investors typically rely on national standards and guidance when developing specifications that define PV system components. However, PV technology performance is promoted and reported solely in terms of cost and energy efficiency goals, without holistic consideration of other contributing factors such occupants’ ability to effectively manage PV systems to reduce the peak demand issue linked with PV systems in the UK. This paper examines policy, design, installation, handover and use of domestic PV systems. An in-depth case study of 20 households in a new-build UK development demonstrates the challenges related to introducing PV systems in housing. Key findings identify the need for complete rather than partial design team involvement and capacity building for inexperienced residents as well as building industry actors. PV systems are perceived by policy makers and industry as requiring very limited occupant interaction with limited potential to impact on energy use practices—thus an integrated PV system learning process incorporating occupant feedback is disregarded. Poor individual occupant learning support and PV system feedback onsite makes this learning difficult.

Reliability evaluation of future photovoltaic systems with smart operation strategy

This paper investigates a new operation strategy for photovoltaic (PV) systems, which improves the overall reliability of the system as a result of the improvement in the reliability of the critical components. First, a mathematical model is proposed using the fault tree analysis (FTA) to estimate the reliability of the PV systems in order to find the suitable maintenance strategies. The implementations demonstrate that it is essential to employ smart maintenance plans and monitor the identified most critical components of PV systems. Then, an innovative analytical method based on the Markov process is presented to model smart operation plans in PV systems. The impact of smart operation strategy on the PV systems is then evaluated. The objective of this paper is to develop plans for improving the reliability of PV systems. A series of case studies have been conducted to demonstrate the importance of smart operation strategies for PV systems as well as the applicability and feasibility of the proposed method.