Patent ID: 9541598
Date: 2017-01-10
CPC Classifications: G01R,H02H,H02S,Y02E

Claim:
1. A smart junction box for series connected photovoltaic units providing bypass diodes, the smart junction box comprising: a housing providing terminals receiving electrical connections to series connected photovoltaic units at multiple electrical junctions between the series connected photo voltaic units as joined by the bypass diodes; a remote communication circuit for communicating with a central station; I/O circuitry communicating with the terminals to digitize electrical measurements of the electrical junctions; and a processor receiving the digitized electrical measurements and executing a stored program to monitor the digitized electrical measurements across at least one photovoltaic unit to detect electrical arcing in at least one of the photovoltaic units to provide a signal through the remote communication circuit to the central station wherein the detection of electrical arcing monitors a voltage across at least one photovoltaic unit to: (a) identify a dominant frequency over time; (b) subtract the dominant frequency over time from the monitored voltage to produce a corrected voltage; and (c) analyze a trend of a spectral amplitude of the corrected voltage as a function of frequency to indicate arcing when the trend meets a predetermined criterion.