Evaluation of Multi-Inverter Anti-Islanding With Grid Support and Ride-Through and Investigation of Island Detection Alternatives

The report, Evaluation of Multi-Inverter Anti-Islanding With Grid Support and Ride-Through and Investigation of Island Detection Alternatives, documents results from a set of laboratory simulations and experiments.

Technical Report

Evaluation of Multi-Inverter Anti-Islanding With Grid Support and Ride-Through and Investigation of Island Detection Alternatives (Michael Ropp et al. 2019)
This report documents results from a set of laboratory simulations and experiments to determine the impact of photovoltaic (PV) inverter grid support functions on various anti-islanding detection methods. The project team included Sandia National Laboratories and Northern Plains Power Technologies.

Topics Covered

Testbed setup for conducting the laboratory experiments (inverters tested were single-phase 3 kilowatt, and three-phase 50 kilowatt).

The grid support functions studied were volt-var (with watt priority), frequency-watt, and ride-through.

The anti-islanding methods studied were non-continuous positive feedback on frequency error with and without increasing magnitude (two of the most commonly-used methods in modern inverters) and impedance-detection methods (methods that manipulate the negative sequence current).

Observations of run-on-time and non-detection zone were made at various active and reactive power conditions, at various irradiance levels, and with various grid support functions.

The use of collaborative controls as a mitigation measure was explored in simulations.

Key Takeaways

Enabling voltage regulating functions was not observed to have an adverse effect on anti-islanding performance, and in certain cases, resulted in reduced run-on-time.

Ride-through of voltage and frequency was observed to have an adverse impact on islanding detection, however, in all cases tested, run-on-times remained within the two-second requirement in IEEE Std 1547. The use of collaborative controls was shown to mitigate the negative impacts of ride-through.