How much power is lost in a hot-spot? A case study quantifying the effect of thermal anomalies in two utility scale PV power plants

Skomedal, Åsmund; Aarseth, Bjørn Lupton; Haug, Halvard; Selj, Josefine; Marstein, Erik Stensrud

doi:10.1016/j.solener.2020.10.065

Cited by 24 publications

(10 citation statements)

References 23 publications

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“…However, the measured data of the authors confirm the thesis of temperature impact on efficiency of photovoltaic cells assumed in other publications. The higher temperature of PV cells causes a decrease in the voltage generated by the cell, which in turn causes a decrease in generated power and thus photovoltaic conversion [9][10][11][24][25][26]. As a result of tests, it was also confirmed that maintaining the cleanliness of the panels is an important factor affecting the efficiency of a photovoltaic installation [14][15][16].…”

Section: Results In Relation To International Literaturementioning

confidence: 96%

“…If one of the PV panels is damaged during operation, the efficiency of the installation will be reduced in relation to the project assumptions [9], and the owner will face a significantly extended payback period. It is not always possible to quickly detect cell damage in PV panels caused by a "hot-spot", i.e., thermal damage to the cell, which can be caused, e.g., by its partial shading.…”

Section: Monitoring Of Pv Installationsmentioning

confidence: 99%

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In Situ Tests of the Monitoring and Diagnostic System for Individual Photovoltaic Panels

et al. 2021

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The dynamic development of photovoltaic systems in the world and in Poland is mainly related to the drop in prices of installation components. Currently, electricity from photovoltaics is one of the cheapest renewable energy sources. The basis for effective energy generation is, first of all, failure-free operation of the photovoltaic system over a long period of operation, up to 30 years. The paper presents the results of a study of a low-cost distributed system for monitoring and diagnosis of photovoltaic installations (SmartPV), capable of assessing the operating parameters of individual photovoltaic panels. The devices were tested by connecting them to an existing photovoltaic installation, allowing the measurement of operational parameters of individual photovoltaic panels as well as operating conditions such as illuminance and panel surface temperature. The data were recorded on a server using wireless Wi-Fi transmission. Interesting data were collected during the tests, confirming the usefulness of the suggested device for monitoring the photovoltaic installations. Differences in performance of the photovoltaic panel depending on solar radiation and surface temperature were recorded. The temperature coefficient of power was determined, allowing for increased accuracy in the prediction of generated power. The correct recording in different situation, i.e., shading, sensor damage or weather anomalies, was verified. Based on the collected data, rules will be defined for an expert application which, in combination with SmartPV devices, will ensure a quick response to any malfunctions of the photovoltaic system, both related to failures and those resulting from natural degradation during operation.

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Section: Results In Relation To International Literaturementioning

confidence: 96%

Section: Monitoring Of Pv Installationsmentioning

confidence: 99%

In Situ Tests of the Monitoring and Diagnostic System for Individual Photovoltaic Panels

et al. 2021

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“…One of these factors is shading. The PV cells must be identical and benefit from the same operating conditions, however, if any of these cells is shaded, the current through the cell will be very high and voltage across its terminals will be inverted causing a high thermal dissipation on its surface called hotspot (Skomedal et al, 2020;Zhang et al, 2021). Niazi et al, 2019) Partial shading mostly caused by obstacle shadows arising at specific times, and by clouds that move temporarily (Lee et al, 2021), it can be one of the main causes of mismatch losses which are *Corresponding author.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the impact of partial shading on the performance of photovoltaic panels

Fatima¹,

Mohamed²,

Mamadou³

et al. 2022

J. Eng. Technol. Res.

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This experimental work presents an investigation on the impact of partial shading of a photovoltaic (PV) solar cell on the performance of different types of PV solar panels. A mono-crystalline panel and a polycrystalline panel were used for the experiments as well as three types of covering materials with different transmittance levels (white leaf, tree leaf and transparent paper). The shaded cell area varies by 20, 50 and 100% and the electrical parameters of the modules were measured in each case. The transmittance level of each material used was characterized. The study shows that the performance degradation depends principally on the type of material used and the shading rate applied. The performance degradation also depends on the type of panel used. The position of the shaded cell has no impact on the results obtained.

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“…There is little research on how to estimate energy losses based on thermal images, making it difficult to make mitigation actions that are proportional to the severity of the faults. In a recently published paper, we try to mitigate this lack of knowledge by combining aerial thermographic imaging with power loss analysis on string level [2].…”

Section: Introductionmentioning

confidence: 99%

Robust and Fast Detection of Small Power Losses in Large-Scale PV Systems

Skomedal

Øgaard

Haug

et al. 2021

IEEE J. Photovoltaics

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Due to the fast growth in global installed photovoltaic (PV) capacity, performance monitoring for large-scale PV systems is an increasingly relevant and important topic. A large volume of research exists in this field, but there is a need for comparison of different methods and their performance toward relevant metrics, a broad discussion of the different choices involved, and subsequent consolidation. In this article, we focus on the detection of small power losses on string-level. We discuss the different choices involved in building a robust string performance monitoring scheme. We suggest the following approach: 1) identify bad data quality and do data-filtering; 2) calculate the daily specific yield on string level; 3) calculate the relative difference in specific yield between the strings (relative yield); 4) identify historical faults; 5) correct for seasonal variations; and 6) apply control charts to detect performance losses in new data and issue alarms/report to the system operators. Based on data from a utility scale PV power plant we compare different control charts in terms of detection time and sensitivity. We show that the cumulative sum (CUSUM) median and the Tukey-CUSUM charts are the most promising fault detection methods of the ones we have tested. We can robustly detect faults causing a performance loss of about 1% within 35 days of the drop in performance.

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How much power is lost in a hot-spot? A case study quantifying the effect of thermal anomalies in two utility scale PV power plants

Cited by 24 publications

References 23 publications

In Situ Tests of the Monitoring and Diagnostic System for Individual Photovoltaic Panels

In Situ Tests of the Monitoring and Diagnostic System for Individual Photovoltaic Panels

Evaluation of the impact of partial shading on the performance of photovoltaic panels

Robust and Fast Detection of Small Power Losses in Large-Scale PV Systems

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