Low-Cost I–V Tracer for PV Modules under Real Operating Conditions

Abstract

Solar photovoltaic technologies have undergone significant scientific development. To ensure the transfer of knowledge through the training of qualified personnel, didactic tools that can be acquired or built at a reasonable price are needed. Most training and research centres have restrictions on acquiring specific equipment due to its high cost. With this in mind, this article presents the development and transfer of a low-cost I–V curve tracer acquisition system. The device is made up of embedded systems with all the necessary hardware and software for its operation. The hardware and software presented are open source and have a low cost, i.e., the estimated material cost of the system is less than 200 euros. For its development, four institutions from three different countries participated in the project. Three photovoltaic technologies were used to measure the uncertainties related to the equipment developed. In addition, the system can be transferred for use as an academic or research tool, as long as the measurement does not need to be certified. Two accredited laboratories have certified the low uncertainties in the measurement of the proposed system.

Field I-V Curve Measurements Methodology at String Level to Monitor Failures and the Degradation Process: A Case Study of a 1.42 MWp PV Power Plant

“…One of the helpful tools used in the commissioning process is to carry out on-site I-V curve measurements of photovoltaic strings or generators to assess the PV generator's effective peak power. It also has other advantages such as: testing a vast sample of PV modules right where they are installed, revealing weak PV modules (i.e., hotspots), detecting faulty connections (preventing fire, shocks, and injury), identify shadowing, reverse polarization, and, if done regularly; it may also reveal degradation issues as described by [1,2,7,[10][11][12].…”

“…The demand for investors for the determination of on-site PV power is increasing [2,[10][11][12]. Brief testing time, low uncertainty, and repeatability of results are critical aspects of the general quality guarantee procedures required to fulfill this demand, as noted in [4,5,13].…”

“…Brief testing time, low uncertainty, and repeatability of results are critical aspects of the general quality guarantee procedures required to fulfill this demand, as noted in [4,5,13]. The market and research laboratories offer various kinds of field I-V curve measurement devices and methods [1,2,7,10,11,14,15] that promise to fulfill these requirements.…”

“…According to [1,2,10], reliable on-site I-V curve measurements require an operator with good knowledge about the main parameters that influence the measurements. Therefore, an experienced operator is vital because the measurements do not depend only on the I-V curve plotter and the implemented correction procedure (i.e., extrapolation to standard test conditions (STC) or photovoltaics for helpfulness scale applications test conditions (PTC)) [11,14,15]. Significantly, the integrator is aware of the specific uncertainties of his/her PV system, and the correct procedure is applied [1,2,10,11,16].…”

“…Measurement of PV generators on-site is a well-established and well-used commissioning procedure [1,2,[10][11][12][13][16][17][18][19][20]. Therefore, the methodology used in this work consists of successive measurements of the I-V curves on PV strings (device under test (DUT)) installed in different segments of the PV power plant.…”