Experimental Evaluation of Load Rejection Over-Voltage from Grid-Tied Solar Inverters: NREL (National Renewable Energy Laboratory)

Austin Nelson, Anderson Hoke, Justin Chebahtah, Trudie Wang, Brian Zimmerly, Michael Ropp, Sudipta Chakraborty

Research output: NRELPresentation


This paper investigates the impact of load rejection over-voltage (LRO) from commercially available grid-tied photovoltaic (PV) solar inverters. LRO can occur when a local feeder or breaker opens and the power output from a distributed energy resource exceeds the load power. Simplified models of current controlled inverters can over-predict over-voltage magnitudes, thus it is useful to quantify testing. The load rejection event was replicated using a hardware testbed at the National Renewable Energy Laboratory (NREL), and a set of commercially available PV inverters was tested to quantify the impact of LRO for a range of generation-to-load ratios. The magnitude and duration of the over-voltage events are reported in this paper along with a discussion of characteristic inverter output behavior. The results for the inverters under test showed that maximum over-voltage magnitudes were less than 200 percent of nominal voltage, and much lower in many test cases. These research results are important because utilities that interconnect inverter-based DER need to understand their characteristics under abnormal grid conditions.
Original languageAmerican English
Number of pages17
StatePublished - 2015

Publication series

NamePresented at the 42nd IEEE Photovoltaic Specialists Conference (PVSC-42), 14-19 June 2015, New Orleans, Louisiana

NREL Publication Number

  • NREL/PR-5D00-64511


  • distributed energy
  • electric power systems
  • inverter
  • load rejection over-voltage
  • photovoltaic
  • solar


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