The present application belongs to the technical field of
distributed power grid, and particularly relates to a grid-
connection control method and
system of an active distributed intelligent
microgrid. The method comprises: when the active distributed intelligent
microgrid meets the starting grid-connection condition, the
microgrid is controlled to grid-connection as follows: 1) adjusting the
voltage amplitude and frequency of the microgrid to the range allowed for grid-connection, and adjusting the
phase difference between the microgrid waveform and the
power grid waveform to a decreasing trend, and then performing step 2); 2) calculating the
time difference between the
current time and the time of the next synchronous forward zero-crossing point, the synchronous forward zero-crossing point being the synchronous forward zero-crossing point of the microgrid waveform and the
power grid waveform; and judging whether the
time difference is within the
time range allowed for grid-connection, if yes, then grid-connection is performed; otherwise, when the
time difference is greater than the upper limit of the
time range allowed for grid-connection, waiting until the time difference is within the
time range allowed for grid-connection, and when the time difference is less than the
lower limit of the time range allowed for grid-connection, performing step 1).