ISLANDING DETECTION METHOD AND APPARATUS, GRID-CONNECTED INVERTER, AND COMPUTER-READABLE STORAGE MEDIUM

An islanding detection method includes: continuously detecting a voltage frequency at a point of common coupling; calculating, according to the voltage frequency, a frequency deviation of the voltage frequency between two adjacent detections; obtaining, when the frequency deviation is less than a preset frequency threshold, a voltage phase in a preset closed-loop phase-locking manner; obtaining, when the frequency deviation is greater than or equal to the preset frequency threshold, the voltage phase in a preset open-loop phase-locking manner; determining, according to the frequency deviation, the voltage frequency, and the voltage phase, a reference current for injecting a frequency perturbation; controlling, according to the reference current, the grid-connected inverter to output a current to the point of common coupling; and determining, when the voltage frequency exceeds a preset range, that an islanding effect occurs.