Performance of grid-connected PV system in Southern Norway
This paper presents performance results from one of the first grid-connected photovoltaic (PV) systems in Norway. The 45 kWp system is mounted on top of a flat roof at the headquarters of a local utility company, Agder Energi, in the coastal town of Kristiansand. The system consists mainly of multi-crystalline silicon modules, with one thin film array. The system has been in operation since May 2011 and is instrumented for research and monitoring purposes. Data recorded include global and diffuse horizontal irradiation, tilted irradiation and other weather parameters, PV module temperatures, DC and AC current and voltage for three arrays, in addition to inverter power data and voltage quali…
Uniqueness verification of blue fraction as a parameter of spectral irradiance quantification
The spectral distribution of global irradiance is measured in the optimal tilt (45° south) plane of array for the calender year 2020 in Grimstad, Norway. In this work the spectral distribution is quantified in terms of the Blue Fraction (BF). The uniqueness of BF has been tested and reported using the same methodology used for uniqueness verification of average photon energy (APE). The results show that the coefficient of correlation between the APE and BF was 0.98, meaning a possible bijective relation between these two parameters whereby both indicate a similar spectrum. The percentage contribution of integrated irradiance (Rc) was calculated for 25 nm wavelength bins for the BF region 35…
Investigation of temperature coefficients of PV modules through field measured data
Abstract Varying broadband irradiance and temperature are generally known as the major factors influencing the performance of PV modules, but studies have also shown the substantial impact of spectral variations. In this work, a simple and efficient method to calculate the temperature coefficient using long term data is demonstrated. Temperature coefficients of PV modules are estimated from long term performance data following IEC 60891 standard with additional spectral correction, and are compared against the datasheet values. Significant improvement of correlation coefficient from −0.89 to −0.97 is observed during the regression for maximum power temperature coefficient of two poly-crysta…
Impact of increasing penetration of photovoltaic (PV) systems on distribution feeders
This paper investigates impact of increasing photovoltaic (PV) penetration on distribution feeders. The main focus of this work is on ‘how PV systems penetration can influence operation of the protective devices in the distribution feeder?’. PV systems' impact, in a distribution feeder, for 3Φ fault has been analyzed. It considers fault location and protective devices (PDs) settings (e.g. time of PDs operation before a fault gets cleared by it). This paper is also emphasizing on ‘how the penetration of PV can affect voltage quality / unbalance in the distribution feeder’. The considered distribution feeders are supplying residential network and therefore loading on different phases are goin…
Performance of zero energy homes in smart village skarpnes
In Smart Village Skarpnes in southern Norway, five detached houses are designed as zero energy homes. This work reports on the photovoltaic (PV) power production and energy consumption behavior of these homes and discusses whether an annual zero energy budget may be achieved. Results so far indicate that the extremely low annual energy consumption assumed for these types of homes may be difficult to achieve, and also point at a need for better matching between production and consumption power profiles. Performance results are based on monitoring data combined with estimated performances from PVsyst simulations. The work is part of a larger research project that investigates how the introduc…
Performance assessment of field deployed multi-crystalline PV modules in Nordic conditions
This paper presents an investigation of data monitoring quality and evaluation of performance degradation of four different multi-crystalline silicon (mc-Si) photovoltaic (PV) modules installed in the higher latitude conditions in southern Norway. Degradation of each module has been investigated in terms of degradation of short-circuit current (I SC ), open-circuit voltage (V OC ), fill factor (FF) and maximum power (P MPP ). The analysis for the period of monitoring data from 2014 to 2018 show no considerable module degradation compared to the standard degradation rate of all parameters. The statistical analysis of I SC shows an average degradation of 0.17% for all modules. Spectral correc…
Moisture ingress in photovoltaic modules: A review
Abstract Moisture ingress in photovoltaic (PV) modules is the core of most degradation mechanisms that lead to PV module power degradation. Moisture in EVA encapsulant can lead to metal grids corrosion, delamination and discolouration of encapsulants, potential induced degradation, optical and adhesion losses. The present work is a review of literature on the causes, effects, detection, and mitigation techniques of moisture ingress in PV modules. Literature highlights on determining the diffusivity, solubility, and permeability of polymeric components of PV modules via water vapour transmission rate tests, gravimetric, and immersion methods, have been presented. Electroluminescence, photolu…
Development of a test station for accurate in situ I-V curve measurements of photovoltaic modules in Southern Norway
The development of an outdoor test station for accurate in situ I-V curve measurements of photovoltaic (PV) modules is described. The modules are installed in an open-rack configuration at the University of Agder in Southern Norway. Seven new and three aged PV modules of different type and make are being tested, including mono-and multicrystalline silicon from differing manufacturing routes, triple-junction amorphous silicon, and CIS. Data acquisition is controlled with a multichannel electronic load system and LabVIEW software, recording high-resolution I-V curves at one-minute intervals. Between I-V curve sweeps, each module is operated at the maximum power point. Characteristic electrica…
Energy measurements at Skarpnes zero energy homes in Southern Norway: Do the loads match up with the on-site energy production?
Five houses are designed as zero-energy homes in Skarpnes, Norway. The energy goal is to achieve net zero-energy balance on an annual basis. The houses have heat pumps and solar cells (PV). Energy use and delivered energy have been monitored from June 2015. Variations between calculations and measurements are explained by technical and non-technical reasons. For the first year, higher than expected energy loads result in a solar energy cover factor of 65–87% of delivered electricity. The PV generation performs satisfactorily, hence, it may be possible to achieve energy goals during later years provided technical adjustments or behavioral changes. Acknowledgements. This report has been writt…
On-grid residential development with photovoltaic systems in Southern Norway
The application of residential photovoltaic (PV) systems is increasing rapidly worldwide. In Southern Norway, a group of on-grid smart houses with embedded PV systems, solar thermal collectors, and geothermal heat pumps are under development at Skarpnes. In this paper, performance analysis based on simulations of an on-grid residential house with PV system located at Skarpnes is presented. This project is expected to demonstrate zero energy and zero emission housing in Norway. This paper discusses a theoretical study of home energy consumption with electricity production for a single house from a PV system, including simulations of irradiation conditions and tilt angles, and of the PV syste…
Temperature profiles of field-aged multicrystalline silicon photovoltaic modules affected by microcracks
In this work, the temperature sensitivities of field-aged multicrystalline silicon PV modules affected by microcracks are investigated. It is found that the temperature coefficient of efficiency of all modules has increased more than 10 times over the 20 years period, mainly due to a degradation in the temperature coefficients of fill factor. Temperature coefficient of efficiency of PV modules affected by microcracks changed from -0.44 %/ °C to -1.51 %/°C under solar irradiance conditions at 1010 - 1030 W/m2. Inconsistent values for the Evans–Floschuetz efficiency ratio versus temperature plots for the microcrack affected modules were also observed.
Review on photovoltaic based active generator
An active generator has the capacity to support frequency control and instantaneous power balance. The grid operator adjusts the power dispatch of generators according to power demand fluctuations. Photovoltaic (PV) based active generators can be used as load following generators in the same manner as other power dispatch generators. This new type of distribution system, based on active generator(s), needs new innovative management and operation strategies for increasing the penetration of intermittent renewable energy systems. The considered PV based active generator has three units, i.e., PV array, battery storage and super capacitor. In this review paper, the management and operation app…
Analysis of spectral irradiance distribution for PV applications at high latitude
The spectral distribution of global tilted irradiance measured in Grimstad, Norway, is analyzed in terms of the average photon energy ( $APE$ ) blue fraction ( $BF$ ) and useful fraction ( $UF$ ). The results based on eight months of recorded data show a general shift of the $APE,\ BF$ , and $UF$ values to higher values than reference AM1.5G spectrum, with 1.63 eV, 0.45, and 0.88 being the average indices, respectively. The statistical coefficient of variation ( $CV$ ) is used to determine the variation of indices. The $CV$ for $APE,\ BF$ , and $UF$ are calculated to be 20.1%, 26.1%, and 25.7%, respectively confirming the earlier findings on $APE$ being a more accurate index for the quantif…
Development of a big data bank for PV monitoring data, analysis and simulation in COST Action 'PEARL PV'
COST Action entitled PEARL PV aims at analyzing data of monitored PV systems installed all over Europe to quantitatively evaluate the long-term performance and reliability of these PV systems. For this purpose, a data bank is being implemented that can contain vast amounts of data, which will enable systematic performance analyses in combination with simulations. This paper presents the development process of this data bank.
Contributions to the knowledge base on PV performance: Evaluation of the operation of PV systems using different technologies installed in southern Norway
To assist in establishing an accepted knowledge base on PV-modules and systems performance using a representative range of technologies, devices have to be installed at diverse locations, covering a broad range of environmental conditions. For the example of a high latitude location, modules and systems are installed and under investigation in southern Norway (Kristiansand region) by the University of Agder in cooperation with industrial partners. This paper presents first results of the analysis of module performance. The operational behavior of the modules is used to derive a modeling scheme applicable for performance prediction. This use is demonstrated by giving the expected annual perf…
A Deep Learning Approach for Automated Fault Detection on Solar Modules Using Image Composites
Aerial inspection of solar modules is becoming increasingly popular in automatizing operations and maintenance in large-scale photovoltaic power plants. Current practices are typically time-consuming as they make use of manual acquisitions and analysis of thousands of images to scan for faults and anomalies in the modules. In this paper, we explore and evaluate the use of computer vision and deep learning methods for automating the analysis of fault detection and classification in large scale photovoltaic module installations. We use convolutional neural networks to analyze thermal and visible color images acquired by cameras mounted on unmanned aerial vehicles. We generate composite images…
A qualitative examination of performance and energy yield of photovoltaic modules in southern Norway
Three different, commercially available photovoltaic modules have been monitored outdoors in the town of Grimstad, Norway. The present paper describes the experimental setup that was implemented, in particular details of the low-cost electronic loads. Results compare measured performance with manufacturer's data, and temperature measurements enable a comparison with performance at standard test condition temperature. Overall, the monocrystalline module performed best both regarding maximum efficiency and overall energy production, whereas the module based on triple junction amorphous silicon technology had the worst performance considering these criteria. The gross numbers of energy yield c…