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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoPlainText><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'>Wrenchsters,<o:p></o:p></span></p><p class=MsoPlainText><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'><o:p> </o:p></span></p><p class=MsoPlainText><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'>I have an Enphase 7.5kW system on a residence with utility Smart Metering, both the PV Production Meter as well as the utility billing meter being “read” every hour. This system has experienced many “AC Frequency Out Of Range” events since the system was installed. Below is copied the Enphase Event message. This particular event was for 5 minutes. Most of the events (all events are AC Frequency Out Of Range) last 5 to 10 minutes but occasionally they have lasted from 45 minutes to 64 minutes.<o:p></o:p></span></p><p class=MsoPlainText><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'><o:p> </o:p></span></p><p class=MsoPlainText><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'>My question is: Could the use of the smart metering increase the likely hood that AC Frequency events happen? Or is this just a coincidence and that we are dealing with fluctuating utility power AC Frequency issues?<o:p></o:p></span></p><p class=MsoPlainText><u><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'><o:p><span style='text-decoration:none'> </span></o:p></span></u></p><p class=MsoPlainText><b><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'><<<o:p> </o:p></span></b></p><p class=MsoPlainText><b><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'><o:p> </o:p></span></b></p><p class=MsoPlainText><b><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'>Started on: Mon February 04, 2013 12:49 PM EST<o:p></o:p></span></b></p><p class=MsoPlainText><b><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'> Cleared on: Mon February 04, 2013 12:54 PM EST <o:p></o:p></span></b></p><p class=MsoPlainText><b><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'><o:p> </o:p></span></b></p><p class=MsoPlainText><b><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'>Recommended action<o:p></o:p></span></b></p><p class=MsoPlainText><b><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'><o:p> </o:p></span></b></p><p class=MsoPlainText><b><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'>This condition should correct itself. No action is required.<o:p></o:p></span></b></p><p class=MsoPlainText><b><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'> <o:p></o:p></span></b></p><p class=MsoPlainText><b><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'>Details<o:p></o:p></span></b></p><p class=MsoPlainText><b><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'><o:p> </o:p></span></b></p><p class=MsoPlainText><b><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'>The microinverter reports that the frequency coming from the utility is either too low or too high as specified by applicable regional standards.<o:p></o:p></span></b></p><p class=MsoPlainText><b><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'><o:p> </o:p></span></b></p><p class=MsoPlainText><b><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'> AC frequency is the frequency at which voltage varies on the utility grid. Frequency Out of Range events are usually transient and self-correcting by the utility.<o:p></o:p></span></b></p><p class=MsoPlainText><b><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'><o:p> </o:p></span></b></p><p class=MsoPlainText><b><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'> When the microinverter detects an out of frequency condition, it must remain offline until the utility has been within acceptable limits continuously for a short period of time (seconds to minutes, varies by region). If during that time the utility again exceeds or falls short of acceptable limits, the five-minute timer must restart and the microinverter may not begin producing power for an additional short period following the last out-of-bounds condition. >><o:p></o:p></span></b></p><p class=MsoPlainText><b><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'><o:p> </o:p></span></b></p><p class=MsoPlainText><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'>Best,<o:p></o:p></span></p><p class=MsoPlainText><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'>Dave<o:p></o:p></span></p><p class=MsoPlainText><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'><o:p> </o:p></span></p><p class=MsoPlainText><span style='font-size:14.0pt;font-family:"Times New Roman","serif"'><o:p> </o:p></span></p><p class=MsoNormal>David Palumbo<o:p></o:p></p><p class=MsoNormal>Independent Power LLC <o:p></o:p></p><p class=MsoNormal>462 Solar Way Drive<o:p></o:p></p><p class=MsoNormal>Hyde Park, VT 05655<b><o:p></o:p></b></p><p class=MsoNormal><b><i>www.independentpowerllc.com <o:p></o:p></i></b></p><p class=MsoNormal>Vermont Solar Partner<o:p></o:p></p><p class=MsoNormal>25 Years Experience, (802) 888-7194 <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>