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J. C. Gómez, D. H. Tourn - gPV fuse: special characteristics for photo voltaic cells protection

J. C. Gómez, D. H. Tourn

IPSEP, Rio Cuarto National University, Argentine, jcgomez@ing.unrc.edu.ar

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Abstract:


During the last 50 years, the application of Photovoltaic cells (PV cells) has increased at a high speed. Also the number of cells forming strings and arrays raises, for which the terminal rated voltage, is reaching today values of the order of the thousand volts and the faults currents are slowly increasing its magnitude. PV cells have special characteristics that require protective devices specifically designed for this application, among which the fuse presents optimum features. The main PV cells characteristics are: dc power generation, low short-circuit current magnitudes and X/R ratios (< 25 ms), behavior highly influenced by temperature, etc. Besides the use in the system of storage batteries and reversible inverters, could generate inverse currents due to cells shade, unbalances, and faults. The most used gPV fuse specification is the new IEC 60269-6, that gives some rough guidelines such as: g breaking range, 10 kAdc as minimum breaking capacity, cyclic condition to determine rated current, not applicability of “gates”, fuse selection steps, etc. In order to meet the PF cells characteristics and IEC specifications, several brands of fuses have appeared in the market, showing the actual trend for that application. Also fuse manufacturers give “application rules” that have some inconsistencies and difficult the fuse selection. A summary of the market available fuses and their characteristics is presented, also discussing the advantages and disadvantages of their parameters and characteristics, criticizing some shortcomings and over-dimensioning. The need for more coordinated work between PV cells and fuses manufacturers is stressed, indicating the areas where this work is required.

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