Method for controlling stability when microgrid grid connection switches to island operation mode

摘要

#$%^&*AU2018102188A420201029.pdf#####Abstract The invention discloses a method for controlling stability of a transition from grid-connected operation to island mode operation of a microgrid, wherein a microgrid central controller and a rapid measurement and control unit are employed to acquire electrical quantities of the microgrid and liaison line and to receive an instruction from a superior system, thereby obtaining real-time operation state of the microgrid; in the case of planned island, the real-time load and power output of the microgrid system are calculated to determine whether source-load are balanced; otherwise, if the system satisfies the island criterion, the main power supply is switched to a V/f operation mode from a PQ operation mode, and the PCC switch is disconnected to determine whether the system operates normally, if the system is abnormal, a fault circuit is immediately tripped once detected, and the determination restarted; if the system is normal, whether source-load are balanced in the microgrid is determined, if source-load are unbalanced, calculating a power unbalance value, the storage battery output is adjusted, whether source-load are balanced is determined again, if sourceload unbalanced, low-voltage/low-frequency load shedding is carried out, and the balance is determined again. The invention can realize the effect of simple detection and renders good stability.I CPt C.I~t. .I t-Ind I .. andnd h~gdd~d.VtI s .g. a*ulanarealtniaI-ad cnmhl~bdnld a te i I y Panne nakphpnerppy ~ontoI~ao.,nad tadftlanna PO tena. Tfthethe dg~dFig.2 2/2u