Automated inverter tests match load bank results in UL comparison
Illustrative image: Unsplash contributor on Pexels
UL Solutions has found comparable results from conventional and automated islanding tests on the same photovoltaic inverter. Both methods met the IEEE 1547 clearing time requirement across five representative Category B cases.
The conventional setup used a manually adjusted resistor, inductor and capacitor load bank. Keysight’s alternative combined its SL1200 Series grid emulator with SL1221A software, using power hardware in the loop (PHIL) simulation and automatic RLC tuning. The comparison covered different operating modes and power levels, with load conditions between 95% and 105%.
Much of the work in an islanding test comes before the grid is disconnected. The local load has to be tuned close to the inverter’s output, creating the difficult condition in which generation and consumption are closely balanced. Repeating that adjustment across the test programme adds substantial manual work. Keysight’s software automates the tuning and sequence under IEEE 1547.1 Clause 5.10, along with the reporting.
Keysight’s summary reports that automated test execution took less than a day, against weeks for the conventional approach.
