Evaluation of Photovoltaic Inverters Under Balanced and Unbalanced Voltage Phase Angle Jump Conditions

In 2016, 1.2 GW of photovoltaic (PV) power tripped off in California during the “Blue Cut Fire” when PV inverters miscalculated the grid frequency during a line-to-line fault. In response, the 2018 edition of the IEEE 1547 interconnection standard was updated to mandate distributed energy resource (DER) devices “ride-through” voltage phase angle changes that appear during faults. This new requirement is designed to ensure bulk-system stability is not impacted by emergent DER misbehaviors triggered by local fault events. Transitory DER behaviors under phase changes may still significantly impact grid operations, so it is necessary to quantify the DER response to both balanced and unbalanced voltage phase angle shifts. To achieve this, two PV inverters were subjected to balanced and unbalanced phase jump changes defined in the IEEE 1547.1-2020 test protocol to validate compliance to IEEE 1547. Experimental results show that one DER inverter was compliant to IEEE 1547 and its “momentary cessation” behavior produced stable power system response. However, the other PV inverter failed the IEEE 1547.1 compliance test and tripped off during some of the phase jump experiments.