Diagnostic method for photovoltaic systems based on light I-V measurements

Sergiu Spataru, Dezso Sera, Tamas Kerekes, Remus Teodorescu

Research output: Contribution to journalJournal articleResearchpeer-review

95 Citations (Scopus)

Abstract

Improving PV system reliability and reducing maintenance and operating costs have become important factors in increasing the competitiveness of PV. Addressing these issues requires diagnostic methods that can detect and identify the occurrence and cause of power loss in the PV system, be it external, such as shading or soiling, or degradation or failure of the PV modules and balance-of-system components. This allows for performing preventive and/or reparative maintenance, thus minimizing further losses and costs.
This article proposes a complete diagnostic method for detecting shading, increased series-resistance losses, and potential-induced degradation of the PV generator by analysing changes its current-voltage characteristic curve. The diagnostic method is based on parameters that can be easily calculated from the shape of the current-voltage curve, making it machine-analysis friendly and suitable for implementation in the power electronic converter. Moreover, the dimensionless formulation of the diagnostic parameters and the application of fuzzy logic in evaluating the diagnostic rules, make this method applicable to a wide range of standard crystalline silicon based PV systems.
The design and analysis of the diagnostic parameters and logic was performed based on module level tests on standard crystalline silicon PV modules, and were optimized to detect even small partial shading and increase series-resistance losses. To demonstrate the practical application and operation of this method, the diagnostic parameters and rules were applied “as is” to a field test setup consisting of a crystalline silicon based PV string and a commercial string inverter capable of measuring the I-V curve of the PV string, yielding a similar high-detection rate.
Original languageEnglish
JournalSolar Energy
Volume119
Pages (from-to)29-44
ISSN0038-092X
DOIs
Publication statusPublished - Sept 2015

Keywords

  • Diagnostic method
  • Current-voltage characteristic
  • Fault detection
  • Increased series resistance,
  • Partial shading
  • Photovoltaic systems
  • Potential-induced degradation
  • Crystalline silicon

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