Module-level health monitoring of solar PV plants using LoRa wireless sensor networks

Shuda, Eduan Joseph (2019-04)

Thesis (MEng)--Stellenbosch University, 2019.

Thesis

ENGLISH ABSTRACT: The monitoring of PV plants is a crucial aspect in ensuring smooth operation and optimum e ciency. Early detection of faults or ine ciencies can greatly reduce downtime and increase overall plant e ciency. Faults include temporary and permanent soiling, shadowing, anomalous ageing and critical electrical or mechanical faults. Many solar installations are located at remote locations; faults often go unnoticed and unattended to for long periods. A remote module-level monitoring system can detect ine ciencies and faults when and where they occur. A wireless module-level monitoring system that measures electrical and environmental quantities related to PV module performance is proposed in this work. Although various wireless module-level sensor approaches exist, the sheer size of a typical solar PV plant presents challenges for the wireless technologies presented in these approaches. Di erent wireless technologies such as Bluetooth, Zigbee, Wi-Fi, GSM, Sigfox and LoRa were evaluated for the proposed monitoring system. LoRa was chosen as the wireless technology due to its long range and low power consumption. A number of sensor nodes and a gateway was designed, built and tested. Each sensor node is capable of measuring voltage, current, irradiance, ambient temperature, module temperature, orientation and tampering detection. Initial eld tests that were carried out indicate that the sensor nodes measure with adequate accuracy to evaluate PV module performance in detail. The developed monitoring system consisting of fteen sensor nodes, a gateway and a remote GUI application was tested on a operational PV plant. Shading and soiling eld scenarios, as well as a shading experiment proved that the module-level monitoring system is capable of detecting faults and ine ciencies within a PV plant. Results that were obtained indicate the following: sensor nodes are modular, self-powered and low maintenance. The wireless technology used to transmit measurement data from the sensor nodes to a central gateway is capable of operating on a small, medium or large PV plant. The monitoring system is also capable of remote detection and reporting via the GUI application.

AFRIKAANSE OPSOMMING: Die monitering van FV (Fotovoltaïese)-eenhede of modules is noodsaaklik vir die instandhouding en optimale funksie daarvan, veral waar daar verskeie modules in 'n afgeleë aanleg gekoppel is. Vroeë opsporing van foute en probleme dra by tot die optimale funksionering van 'n FV aanleg, en is belangrik om aftyd te beperk. Probleemareas sluit in: tydelike en permanente besoedeling van die oppervlakte van die module, ongewensde skadu blootstelling, abnormale veroudering van panele, sowel as kritieke elektriese of meganiese foute. Daar is deesdae meer en meer van hierdie aanlêe wat in afgeleë gebiede opgerig word, 'n toedrag van sake wat beteken dat foute en probleme dikwels vir lang periodes van tyd onopgemerk en verwaarloos bly. 'n Afstandsmoniteringsmodule (AMM) sal in sulke gevalle wenslik wees om probleme en foute op te spoor en tyd-effektiewe instandhouding toe te laat. Hierdie studie en tesis stel 'n draadlose (radio-afhanklike), veeldoelige moniteringsisteem wat elektriese en omgewingsfaktore ontleed, voor. Die doel hiervan is om die optimale funksie van sulke panele en groeperings van panele te verseker. Alhoewel daar reeds sulke moniteringsisteme bestaan, is daar bepaalde uitdagings en praktiese probleemareas vir radioafhanklike monitering betrokke - veral by groter aanlêe. In hierdie studie is verskillende radio-afhanklike tegnologieë ondersoek en evalueer vir die AMM: oa Bluetooth, Zigbee, Wi-Fi,GSM, Sigfox, en LoRa. LoRa was uiteindelik gekies as gevolg van die effektiwiteit oor langer afstande, asook die lae kragverbruik. Verskeie sensor-modules asook 'n toegangspoort (portaal) is ontwerp, gebou en getoets. Die sensors was almal in staat om die volgende te meet: potensiaalverskil (volt), stroom, straling (sonskerpte), omgewingstemperatuur, module-temperatuur, oriëntasie en versteuring agv meganiese of kriminele faktore. Gedurende die beginfase was praktiese toetsing daarop gerig om vas te stel dat die modules voldoende akkurate data genereer, om sodoende die funksie van FV-eenhede deeglik en in detail te ontleed. Uiteindelik is 'n AMM ontwerp, gebou en getoets wat uit 15 sensor nodes, 'n toegangspoort en 'n afgeleë Grafiese Gebrui- kerskoppelvlak bestaan het. Die modules is in 'n bestaande, werkende FV-aanleg ontplooi. Hier is ongewensde skaduwee-gevalle asook besoedeling van die FV-eenhede ondersoek, terwyl verdere skaduwee-situasies eksperimenteel toegepas is. Die inligting uit hierdie scenario's verkry, het bewys dat die AMM effektief en akkuraat probleemareas en foute uitwys. Resultate uit hierdie studie bewys die volgende: die ontwerpte en geboude sensor nodes is nie net modulêr nie, maar vereis min instandhouding en gebruik ook min krag. Die radiotegnologie wat gebruik was om data van die sensor-modules na die toegangspoort te stuur, is geskik om diens te doen in klein-, medium- en groot FV-aanlêe. Die moniteringsisteem is dus effektief om afstandsmonitering te doen en hierdie data via 'n toegangsportaal na 'n Grafiese Koppelvlak te stuur, vanwaar die nodige instandhouding dan geïnisieer kan word.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/106206
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