Island protection method based on low-voltage distributed photovoltaic access management and control system

The invention provides an islanding protection method based on a low-voltage distributed photovoltaic access management and control system, and the method comprises the steps: taking a voltage frequency swing range delta f and a voltage amplitude swing range delta U within a set time T as the determination of an islanding protection mode, and if the absolute value of the voltage frequency swing range is greater than or equal to 0.2 Hz or the absolute value of the voltage amplitude swing range is greater than or equal to 20V, starting the islanding protection mode; if yes, the passive island detection criterion is established, the low-voltage intelligent circuit breaker judges that the island effect occurs, and the grid-connected point is cut off immediately and reported to the intelligent gateway; if the absolute value of the voltage frequency swing range is smaller than 0.2 Hz, active island detection is started, and disturbance is injected to the output current of the inverter. On the premise of considering