Testing Low Voltage Ride Through capabilities of solar inverters

The increase in the rated power of PV inverters has brought with it new requirements, such as Low Voltage Ride Through and reactive power compensation. Field tests in PV plants are too expensive in terms of production losses, and therefore laboratory tests have become a simple, flexible and inexpensive alternative. In this paper, a 500 kW test bench for testing solar inverters has been developed. The test bench is based on two inverters connected back-to-back. One of them acts as a controlled voltage source while the other is the inverter under test. The DC link is fed by a diode rectifier which only compensates for the power losses of all the elements in the test bench. With this test bench, Low Voltage Ride Through performance of a 500 kW solar inverter can be completely tested at full load. The results presented meet the requirements of the German BDEW standard.

► A test bench for testing Low Voltage Ride Through of PV inverters was developed.
► A 500 kW back to back topology has been used, allowing rated power tests.
► Simple laboratory tests under controlled conditions replace high cost field tests.
► Results for the German BDEW standard on a commercial inverter are presented.