Eaton Power Xpert Solar 1500 User Manua

Troubleshooting58 Power Xpert Solar 1500/1670 kW Inverter MN141001EN—October 2014 www.eaton.comAlternatively to measuring the voltage across resistorsRG1-4, checking for milliampere-current thru this resistorcircuit will determine if PV-positive is faulted to equipment/earth ground. Due to the low amperage, an inline ammetercan be used, by carefully lifting the circuit-wire off GET (wire16GN902), and placing the ammeter between the wire16GN902 and effective GET Bus.The presence of current indicate a Positive ground-fault.Step-2: Is the Inverter damaged?Should PV positive been applied directly to the PV-negative, ifthe inverter’s PV-disconnecting means (DS1, DS2, DS3)were closed, excessive fault-current can flow through theinverter and damage the inverter stack by flowing currentthrough the IGBT bypass diodes. The DC bus capacitors willhave been reversed biased, in addition.Before proceeding, ensure the PV-array and AC-grid are fullydisconnected (isolated) from the inverter, and the inverter’sDC bus capacitance is fully discharged.Conduct an inverter (Stack) diode and capacitor check.Consult Eaton if damage is found. The inverter stacks willhave to be replaced.If a Ground-fault problem persists contact Eaton.Notes:2a A PV Array Ground Fault is defined as a short-circuit (i.e., anelectrical contact) between the grounding electrode (andequipment) of the PV system and the normally non-groundedPV array conductors. Such a fault condition, if unchecked,allows non-intended current to flow in the normal groundingconductors and equipment back to the PV energy source(i.e., solar cells). This type of Ground Fault is not to beconfused with a “direct short” (i.e., electrical contact)between the non-grounded PV conductors or circuits (e.g.,PV positive) and the grounded PV conductors or circuits(e.g., PV negative). Such a PV direct short is protected(limited) by the combiner-box fuses of the PV systemsource-combiners and the inverter re-combiner.2b A positive-grounded PV systems will look physically thesame, yet be electrically opposite in polarity by groundingthe PV positive to earth (i.e., voltage-meter will read oppositepolarity). SunPower Corporation supplied positive-groundsolar modules in the past, now moot with modules that canbe negative grounded. As noted earlier in this manual,inverter’s employing positive-grounded modules must befactory built and UL1741 End-of-Line tested as apositive-ground inverters. They cannot be field-changed andretain the factory UL1741 certification.