US Patent 9366714 Abnormality detection architecture and methods for photovoltaic systems

One aspect of the inventive technology disclosed herein, in certain embodiments, may involve the determination of at least one measured, instantaneous intra-string current difference for each of the power generating string, and the use of such determinations to assess the existence of leakage current, a frequent ground fault predecessor, thereby enabling preclusion of a ground fault that would otherwise result. Certain methods and detection architecture may enable precise abnormality location, e.g., enabling the identification of which solar module assembly in particular is faulty. Another aspect relates generally, in certain embodiments, to detection circuit architecture operable to sequentially impress a leakage current inducing voltage upon each rail of a photovoltaic system. Another relates generally, in certain embodiments, to the use of at least one current interrupter at each end of a string to preclude flow therethrough in the event of e.g., unintended field reversal.