island loop detection method and apparatus for network loop converters

摘要

method and apparatus for detecting islanding for grid-loop converters methods and apparatus are presented for unintentional islanding detection for grid-side converters in which phase angle disturbance is introduced by modifying switching signals of grid side converter and a reactive power mismatch between generation and grid load is formed from the occurrence of unintended islanding, where the applied phase disturbance is determined according to two predefined curves to form an equivalent positive feedback at different frequencies to prevent the converter from forming an island on a new stable frequency after the grid is turned off.