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Effective and efficient monitoring of a photovoltaic plant are indispensable to maintain the generated power at the desired specifications. In this work, a simple and effective monitoring method based on parametric models and the double exponentially smoothing scheme is designed to monitor photovoltaic systems. This method merges the simplicity and flexibility of empirical models and the sensitivity of the double exponentially smoothing strategy to uncover small deviations. Essentially, the empirical models are adopted to obtain residuals to detect and identify occurred faults. Here, a double exponentially smoothing scheme is used to sense faults by examining the generated residuals. Moreover, to extend the flexibility of the double exponentially smoothing approach, a nonparametric detection threshold has been computed via kernel density estimation. Several different scenarios of faults were considered to assess the developed method, including PV string fault, inverter disconnection, circuit breaker faults, partial shading, PV modules short-circuited, and soiling on the PV array. It is showed using real data from a 9.54 kWp photovoltaic system that the considered faults were successfully traced using the developed approach.

Because of the considerable fluctuations of the power generation and load in Photovoltaic (PV) - Battery (BAT) systems, power management strategies become indispensable since BAT is needed to maintain the generation/load balance, and to regulate the DC bus. Indeed, energy management strategies must take into account the limits of the system, i.e. the nominal PV/BAT power rating and the state of charge (SOC) of BAT. However, the actual use might be different from the intended one, forcing the system to attain its limits. This paper is mainly focused on the limits control and energy saturation management applying to a sample standalone DC micro grid. It consists to share accurately the variable power loads among sources according to their ratings, including the regenerative breaking in minimum SOC'BAT case and the full supply of power load demand in maximum SOC'BAT case. Furthermore, the DC bus voltage is regulated to its predefined level, as a design parameter. The proposed control algorithms are detailed, and the system design during overstress and nominal conditions is given. The main advantage of this algorithm is its simplicity. The efficiency of the control strategy for energy saturation management is verified and analyzed through simulation/experimental system using Matlab/Simulink and DSpace. The results obtained show that the proposed technique can intelligently manage the energy flows and thus ensure that the system operates correctly and safely in the different modes: normal mode and saturated mode.

The estimation of the electrical power output and energy yield of high concentration photovoltaic (HCPV) modules is a hard task because of the many parameters involved. In this work, we propose the usage of an Artificial Neural Networks (ANN) method to estimate the maximum power output of a FLATCON® CPV-module manufactured by Fraunhofer ISE. The advantage of the ANN is that it is a part of the Artificial Intelligence Deep Learning domain, which makes it easy to model complex systems. A detailed knowledge about the underlying module technology is not necessary. In this work, various meteorological parameters are tested as inputs of the ANN including spectral matching ratios for considering the spectral variation of the solar irradiance to evaluate the maximum power output of the HCPV module under study. Eleven scenarios considering different combinations of input parameters have been investigated. It is demonstrated that the ANN gives excellent results and allows for an accurate prediction of the HCPV module’s instantaneous power output with only a few amount of data used on training the ANN. The model has been tested using the measured data set of a FLATCON® CPV-module located on the rooftop of the Fraunhofer ISE in Freiburg, Germany. The module has been electrically characterized outdoors in the period from April 2013 to April 2014. The accuracy of the proposed ANN approach was analyzed using this measurement data in combination with error metrics. It was found that the best agreement between the measured and the predicted maximum power output was achieved when using direct normal irradiance, wind speed, ambient temperature and spectral matching ratios as input. The normalized root mean square error for the maximum power output over one year is found to be between 2.2 and 4.6%. The deviation of the modelled energy yield to the measured one is in the range of 0.2–2.2%.

According to its geographical location, Algeria holds one of the highest solar potential in the Mediterranean basin, as indicated in many studies. Unfortunately, an important lack of data of the solar global radiation is observed. With a huge area of 2 381 741 km2, it is necessary to have numerous stations performing radiation measurement in order to quantify in an objective way the solar potential. Previously, several studies have been conducted dealing with solar potential evaluation. In this study, an update of the Algerian solar atlas is presented. Thus, a solar mapping on the national territory was carried out based this time on data measured over a period of almost 37 years. In fact MEERA-2 ”The Modern-Era Retrospective Analysis for Research and Applications, Version 2, NASA”, were used in this study.Therefore, solar maps for solar radiation on different tilting planes were plotted thanks to the use of SURFER® software, through Kriging interpolation method. Furthermore, measured data for five (05) locations across the country were used in order to make comparison to those given by MERRA-2. Keywords: Solar radiation, MEERA-2 data, Solar atlas, SURFER® software, Kriging interpolation method

The demand for solar energy has rapidly increased throughout the world in recent years. However, anomalies in photovoltaic (PV) plants can reduce performances and result in serious consequences. Developing reliable statistical approaches able to detect anomalies in PV plants is vital to improving the management of these plants. Here, we present a statistical approach for detecting anomalies in the DC part of PV plants and partial shading. Firstly, we model the monitored PV plant. Then, we employ a generalized likelihood ratio test, which is a powerful anomaly detection tool, to check the residuals from the model and reveal anomalies in the supervised PV array. The proposed strategy is illustrated via actual measurements from a 9.54 PV plant.

During the on-site operation, the PV water pumping system can be faced different unexpected troubles, although the accurate sizing and the fit erection. Recently, different studies showed that the lack of enough information about the geospatial characteristics of the area, required during the sizing of a Photovoltaic Water Pumping System (PVWPS) is the main cause. In this attempt, an investigation study on geospatial characteristics has been conducted, in the Mansoura desert region; about 70 km south of Ghardaia headquarter. The main goal was to spotlight on different suitable locations for implementing PVWPS. The study has been carried out on six zones; namely: Ain Losseik, Old Mansoura, New Mansoura, Oued Ghazalat, Khanget-fedj and Zawiat Lacheikh. The evaluation consists on census and classifying the wells or boreholes according to the geographical location, the water source behavior, the soil specifics, agriculture and ranching activity, type of the crops, etc … It has been averred that the renewable aquifer levels vary between the averages of 20 and 45 m. However, the Albian borehole static levels can be reached between the averages of 3 and 8 m. The aquifer hydraulic behavior has been achieved by calculation of hydrogeology properties. Thus, the obtained data were compared and classified, whereas the suitable DC pumps were selected, accordingly. This method can be used to detect the different local geospatial effects influencing the system operation. Furthermore, it can be considered as a key point subject that could be extended, in future works.

Through the current study, a new approach combining the Hadj Arab (HA) translation’s method and an efficient solver for systems of nonlinear equations with singular Jacobian (ASSJ) has been developed, in the aim to extract the main five parameters from experimental (I–V) curves. Firstly, Hadj Arab method was used to translate the measured I–V curve at any weather conditions into a reference I–V curve at standard test conditions (STC) (25 °C, 1000 W/m2). The key points given by the I–V curve reference were then used by the one diode model to obtain the five parameters reference. Two models, namely: Model 1 with the serial resistance reference (RSref) and Model 2 with calculated serial resistance (RS) were used to simulate the behaviour of an aging Isofoton (106/12) PV module. Following, comparison and validation upon the outdoor measurements, Model 1 was selected and employed to simulate the behaviour of an aging connected PV plant with a rated power of 3.2 kWp. Thus to predict its output power under real conditions. Twenty five I–V curves references were used to get twenty five different parameters vectors for modelling the PV plant. The validation of the proposed model based on different five parameters vectors has been carried out by confronting the results, given by the model with the measured output power for two different case studies (clear day, and cloudy day). The results averred a good agreement with an error below 4%. Finally the five parameters vector has been selected for modelling the behaviour of the aging connected PV plant. The effectiveness of the developed model in simulating and predicting the behaviour of the aging connected PV plant under different weather conditions has been approved.

The assimilation of cloudy radiances remains important in improving precipitation and severe weather forecasting. In practice, Numerical Weather Prediction (NWP) Models frequently do not predict meso-scale phenomena, so the phenomenon is either predicted but not realised, or is well predicted but not where it is observed. Radiative Transfer Models such as TIROS-Television and Infrared Observation Satellite Operational Vertical Sounder (RTTOV) and libRadtran are the mathematical operators used in the simulation of satellite data. In the data assimilation process, an effective reproduction of the mesoscale convective phenomenon leads to high quality data analysis. Therefore, we are looking for an operator that reproduces the NWP model’s behaviour in a realistic way. Several cloud parameterisation schemes are available in RTTOV and libRadtran to simulate the satellite cloudy radiances. Each selected scheme may result in different simulated brightness temperature data compared to those observed by sat...

This paper describes the current situation of the renewable energies (RE) in Algeria and the structure of the national grid. In view of studying the issues of grid integration of injection of renewable energy produced by distributed systems. The main issues to be considered actually in Algeria are the lines upgrade and the protections design, to prepare the near future of large share of renewable electricity in the national energy mix. For grid integration, due to continuously decreasing cost of battery storage, the modeling and the structure of control of a photovoltaic grid connected system is given.

Electrification of rural population has been always a strategic decision for the counties with high potential in terms of solar energy. However, different renewable and sustainable energy technologies can be adopted for electrification including photovoltaic system, diesel or hybrid system (photovoltaic and diesel). However, the choice between these options is exclusively dependent on many factors including the reliability and the cost associated with these technologies. This study aims to examine the reliability of the electrification of rural areas using a standalone photovoltaic (PV) system in a Sahara environment (Algerian desert). In order to assess the electrical performance of the photovoltaic system, an experiment is set up in the village of Fadnoun, which is located in 2100 km south of Algiers (Algerian capital). The experiment is carried out for one year and the reliability of the system together with the way in which this electrification influence the energy consumption the villagers are assessed. It should be noted that this is the first experimental study of this kind that has been carried out in Algeria. In addition, a technical-economic analysis was conducted by taking into account many parameters including cont, nominal power, solar radiation, and low voltage length. The outcomes of this study can be used as a benchmark to assess the performance of renewable energy technologies in other rural areas and make an informed decision about the most appropriate technology for electrification in rural areas.

The main goal of this study is to present the effect of weather conditions on grid-connected photovoltaic (PV) system performance installed in the Saharan area of south Algeria (Adrar) for the year 2010 has been analyzed on daily base. This region is characterized by high ambient temperature in the summer, strong solar insolation potential and low humidity rate. The data measurement was carried out in the Unit of Research in Renewable energy URERMS in various daily climatic condition (clear, cloudy and Sandstorm day). The performance evaluation based on the monitoring of PV array and inverter performance during the system operation derived parameters included final yield, reference yield, performance ratio and system efficiency. The analysis shows that the lowest value was in the performance ratio and efficiency of the PV module, system and the inverter, and the maximum value was in the capture and system losses, since the values in clear day were 76.5%, 10.88%, 94.65%, 10.29%, 1.18 h/day and 0.26 h/day respectively due to high average ambient temperature 32.3 °C. The lowest value was in reference yield, array yield, final yield in sandstorm day were 2.65 kW h/kWp/day, 2.17 kW h/kWp/day and 2.12 kW h/kWp/day respectively due to low level of solar irradiation was 2.65 kW h/m2, which caused by high wind speed 6.9 m/s with sand dust particles. The experimental results show that the lowest values of the system efficiency and performance ratio (10.29% and 76.5% respectively) caused by the high module temperature equal to 41.1 °C in the clear day, and the fast-changing of the solar irradiance is caused by variation of clouds cover or dust storm affects the energy generated and stability of the PV system.

This paper proposes an approach used to optimize the energy for a stand-alone photovoltaic (PV) system in isolated regions. The intended objective is house energy comfort. The aim is to present the impact of flow energy of housing on the system reliability. The operation of stand-alone PV system is represented by a simulation program. This later describes the principle of energy equilibrium among diverse sub-systems, using different mathematical models of different parts of renewable energy system. The recommended models were implemented via Matlab-Simulink software with real input data. The reliability is achieved by reducing the loss power supply probability criteria, with improvement of the battery life cycle during the operating years of the PV system., Cet article propose une approche basée sur des modèles mathématiques validés, pour l’optimisation de l’énergie dans un système photovoltaïque (PV) autonome destiné à l’électrification d’un habitat dans une région isolée. L’objectif attendu est le confort énergétique de l’habitat. Le but du travail est de montrer à travers la modélisation mathématique l’impact du profil dynamique de la consommation énergétique sur la fiabilité du système PV. Le fonctionnement de ce dernier est représenté par un programme de simulation sous Simulink, qui décrit le principe de l'équilibre énergétique entre les sous-systèmes, en utilisant des modèles mathématiques validés avec des données d’entrées réelles. Les résultats obtenus ont montrés une bonne fiabilité des modèles utilisés, pour prévoir le fonctionnement optimal du système photovoltaïque.

A directly-coupled photovoltaic water pumping system (DC/PVPS) is generally designed by considering the worst month conditions on lowest daylight-hours, the maximum monthly daily required water volume and tank to store the excess water. In case of absence of hydraulic storage (water tank) or it is not enough dimensioned, the extra amount of pumped water is lost or is not reasonably used, when the system is operated on full daylight-hour. Beside that the extra amount of energy, which might be produced by the PV generator, is not exploited, when the system is operated only during a specified period-time needed to satisfy the demand. Beyond the accurate design that satisfying the end-user, a new approach has been developed as target to exploit maximally the PV array energy production, by maximizing the discharge rate of the system. The methodology consists of approaching maximally the demanded energy to the supplied energy on full operating day. Based on the demand/supply energy condition, the approach has been developed, upon the PV array and the pump performance models. The issued approach predicts the maximum delivery capacity of the system on monthly daily water volumes versus the monthly daily averages of solar irradiation, previously recorded. Its efficacy has been investigated and discussed according to the estimated and experimental values of its linearity coefficient, following the characterization tests of a designed system, carried out at our pumping test facility in Ghardaia (Algeria). The new theoretically and experimentally obtained flow-rates fit well, except insignificant deviations. The demand and supply energy curves are approximately approachable. Compared to the previous required water volumes, the new predicted averages show an annual excess rate between 41% and 54%. This rate is expected to be extracted by an annual surplus energy rate between 29% and 36% of the total annual provided energy rate. The proposed approach may be a tool to investigate the maximal delivery capacity and to determine the corresponding maximal PV energy production to be exploited of such system, so that to select the best management at any case.

Detecting anomalies in a photovoltaic system play a core role in keeping the desired performance and meeting requirements and specification. For this propose, a simple and efficient monitoring methodology using principal component analysis model and multivariate monitoring schemes is designed to monitor PV systems. The principal component analysis model is used to generate residuals for anomaly detection. Then, the residuals are examined by computing the monitoring schemes ( T 2 and square predicted error) for the purpose of fault detection. However, these conventional schemes are usually derived under the hypothesis of Gaussian distribution. Thus, the major aim of this paper is to bridge this gap by designing assumption-free principal component analysis-based schemes. Specifically, a nonparametric approach using kernel density estimation is proposed to set thresholds for decision statistics and compared with the parametric counterparts. Real measurements from an actual 9.54 kWp grid-connected PV system are used to illustrate the performance of the studied methods. To evaluate the fault detection capabilities of the proposed approach, six case studies are investigated, one concerning a string fault, one involving a partial shading, and one concerning the loss of energy caused by inverter disconnections. Results testify the efficient performance of the proposed method in monitoring a PV system and its greater flexibility when using nonparametric detection thresholds.

This paper presents a simple way to approximately evaluate the photovoltaic (PV) array performance degradation, the studied PV arrays are connected to the local electric grid at the Centre de Developpement des Energies Renouvelables (CDER) in Algiers, Algeria, since June 2004. The used PV module model takes in consideration the module temperature and the effective solar radiance, the electrical characteristics provided by the manufacturer data sheet and the evaluation of the performance coefficient. For the dynamic behavior we use the Linear Reoriented Coordinates Method (LRCM) to estimate the maximum power point (MPP). The performance coefficient is evaluated on the one hand under STC conditions to estimate the dc energy according to the manufacturer data. On the other hand, under real conditions using both the monitored data and the LM optimization algorithm, allowing a good degree of accuracy of estimated dc energy. The application of the developed modeling procedure to the analysis of the monitored data is expected to improve understanding and assessment of the PV performance degradation of the PV arrays after 12 years of operation.

Almost 80 % of Algerian territory is appropriate for the exploitation of solar energy. The Algerian energetic strategy provides a substantial injection of PV electricity to the national grid. Currently, about 344 MWp of PV arrays which corresponds approximately to 2,34 km2 of module surfaces, are connected on electricity grid over the national territory. The Algerian Northern regions are characterized by strong pollution and high humidity. These phenomena affect the energetic productivity of PV generator. The objective of our study is to analyze experimental grid connected PV system power in coastal locations. Hence, experiments have been conducted on three identical PV systems to determine the electrical performances. Transformer-less inverters are the most attractive for the ground-based photovoltaic (PV) system due to their efficiencies, reduced cost and weight. Besides, the absence of the galvanic isolation generates problems of capacitive leakage current on the AC side and the degradation of the insulation resistance on the DC side of the inverter. In this work, experimental study of the behavior of single-phase inverters without transformers is presented. The main objective of this work is to study the degradation of the insulation resistance at the input of the inverter, and the capacitive leakage current at the output of the inverter. This study was achieved at the CDER on a rainy day of 15/03/2017, on the first PV plant connected to the low voltage network in Algeria. This investigation can help forecasting the PV array energetic production by taking into account natural conditions.

Many studies have been conducted in recent years, dealing in general with solar energy assessment in Algeria and solar radiation evaluation in particular. In our study, an intercomparison of different sources of solar radiation we have used in previous studies was achieved. In fact, as an input, data obtained from PVGIS database, from modelling using Angstrom-Prescott relation and from RETScreen® software database were used in order to perform the comparison. Meanwhile, for the validation, measured data for five (05) locations across the country were used in order to make comparison to those given by PVGIS, RETScreen® and Angstrom model. The confrontation showed that data contained in the RETScreen® database fits the best among others. The present contribution could give an important information and feedback, for future investments in the solar sector in the country. In fact, recently, the government within the framework of the Algerian programme for renewable energy has increased its goal concerning the electricity production from renewable, which is now set to 25,000 Megawatts to be installed by 2030, with 13,575 MW of capacity for solar photovoltaic. Therefore, a reliable assessment is needed to be carried out before achieving any solar plant.

In this paper, a model of optimal sizing was recommended, to optimize the sizes of batteries capacity and photovoltaic (PV) generator for a standalone PV system without extra and with energy management of load. The recommended model was implemented in Matlab-Simulunk, takes into account the sub-models of the standalone PV system and the strategy of load management. This model uses two optimization criteria, the loss of power supply probability concept for the reliability and the energetic cost for the economic evaluation. The former is achieved by reducing the loss power supply probability and by reducing the shadings of load. The last is attained by lowering the batteries replacement during the operating years of the PV system, through the improvement of the battery life cycle. The adopted methodology is based on the real consumption profiles, real weather conditions, energy storage capacity and PV array peak power. A case study was conducted to an electrification project with the autonomous photovoltaic systems, which is intended to remote and scattered housings in Ghardaia site, Algeria.

The high potential recorded by desert of Algeria in terms of sun exposure offers scope to exploit this source of renewable energy to answer the needs for water supply and public lighting in isolated populations. Our objective is to guarantee the reliability of the photovoltaic power generation equipments located in remote and isolated areas, including photovoltaic pumping stations, expected to supply water to local people for human consumption and for livestock from drilling isolated. Thus, we are focused particularly on the reliability of these systems and their maintenance in operational mode. The introduction of the e-maintenance can reduce cost and time management of equipment, and provide easy access to relevant information for the user by freeing up geographical constraints. Our study aims to introduce the techniques proposed by the e-Maintenance, to improve the management of the maintenance process. In this project a cooperative distributed platform of e-maintenance is proposed, including data acquisition systems, control, maintenance management, diagnosis assistance, management of documentation, etc. An e-maintenance platform is a collaboration platform offering a set of software components and software services for maintenance support (integrated and/or distant) all enable maintenance actors to find each other, and the information they need, and to be able to communicate and work together to achieve maintenance process. In this platform, the process of the various modules must be designed following a process of knowledge capitalization and data processing to ensure the diagnosis and prognosis of the pumping system of the Photovoltaic system and thus ensure its reliability. This processing chain will be tested in a first time in a mini-solar station to show the feasibility of the approach.

This paper presents the results of electrical performance measurements of 90 crystalline silicon PV modules following long-term outdoor continue exposure. The modules form the PV array of the first grid-connected PV system in Algeria. This grid connected PV system was installed in Algeria (CDER) at Bouzareah site is effectively operating since June 2004. The analysis have shown that all the PV modules are still creating power but less than the rated power. A mathematical model has been used in order to perform PV module testing at different irradiance and temperature conditions. The different parameters can be computed mainly from the open-circuit voltage, the short-circuit current, the voltage and current at maximum power point. Electrical measurements have shown different degradations of current-voltage parameters. All the modules presented a decrease of the nominal power. However, this decrease is different from one module to another.

The energy strategy of Algeria is based on the acceleration of the development of solar energy. The strategic choice is motivated by the availability of a huge potential in solar energy. This energy is the major focus of the energetic program where the photovoltaic (PV) solar systems constitute an essential part. The photovoltaic energy fully meets the needs of facilities in remote desert areas where connection to the grid is too expensive. However, the southern Algerian regions are generally characterized by frequent sandstorms. This natural phenomenon causes the dust accumulation on PV modules. Consequently, this may reduce the efficiency of PV array. The objective of this research is to study the effects of the dirt accumulation on the optical transmittance of a PV array glazing in desert regions of Algeria. Firstly, we have validated our model of irradiance on tilted plane, which was the result of Hottel model improvement for Algerian sites. Secondly, the experiments have been conducted on the effect of the dust particle accumulation on the PV modules glazing. The tests were performed with the PVPM2540C in natural conditions to determine the current/voltage characteristics and see the resulting efficiency. It was found in this study, that the dust accumulation on the PV generator glazing surface tilted at 32° can significantly decrease the irradiance transmittance during the day by an average between 0% and 8% after an exposure period of several months.

This paper recommends an optimal sizing model, to optimize the capacity sizes of different components of photovoltaic water pumping system (PWPS) using water tank storage. The recommended model takes into account the submodels of the pumping system and uses two optimization criteria, the loss of power supply probability (LPSP) concept for the reliability and the life cycle cost (LCC) for the economic evaluation. With this presented model, the sizing optimization of photovoltaic pumping system can be achieved technically and economically according to the system reliability requirements. The methodology adopted proposes various procedures based on the water consumption profiles, total head, tank capacity and photovoltaic array peak power. A case study is conducted to analyze one photovoltaic pumping project, which is designed to supply drinking water in remote and scattered small villages situated in Ghardaia, Algeria (32°29′N, 3°40′E, 450 m).

The present work aims to contributing to the perspective of using lead acid batteries for the storage of energy produced by photovoltaic plants. After a review of different models tackling the performance of lead acid batteries, we opted for the electrochemical approach and based our study on the evolution of the electrolyte specific gravity during charge/discharge cycling tests of a 12 V lead acid battery. The test results revealed a drop of the specific gravity of the electrolyte during successive C/D cycling. This is reflected by the maxima (1.2463 g/cm3–1.1697 g/cm3) and the minima (1.1273 g/cm3–1.106 g/cm3) of the specific gravity values after uninterrupted tests, revealing underlying irreversible reactions. Further data collection and analysis will serve as building blocks for an operational model.

International audience; Reliability and lifetime of photovoltaic (PV) systems depend mainly on the energy performance of modules and on their different degradation modes. Accordingly, research must be focused on degradations of PV modules. This paper presents the results of investigations carried out on the degradation mechanisms of PV modules of the Melouka central in the area of Adrar in Algeria after 28 years of exposure in the Saharan environment. Main degradation modes are observed through visual inspection of PV modules: discoloration of encapsulant, broken and abrasion of glass, delamination, discoloration and hot spot of cells, oxidation of front grid fingers and thermal shocks. The current-voltage (I-V) characteristics are acquired with outdoor measurements in the site. The experimental results permit to detect both hot spots and thermal shocks which are the most detrimental total defects visually observable in the site, and to quantify the reduction of electrical performance data correlated with visual degradation data. A maximum power (Pmax) degradation rate of 1.22%/year is found which is closely related to short-circuit current (Isc) of 0.78 %/year, followed by fill factor (FF) of 0.57%/year and finally short-circuit voltage (Voc) of 0.1%/year. Akin results are reported in literature for PV modules exploited under desert climate for long duration.