Microgrid : Stability Analysis and Control

Many innovative control techniques have been used for enhancing the stability of microgrid as for proper load sharing. The most common method is the use of droop characteristics for decentralized load sharing. The power sharing of distributed sources is the main focus of this dissertation. In this book, an angle droop controller is used to share power amongst converter interfaced DGs in a microgrid. An enhanced frequency droop controller is also proposed for better dynamic response and smooth transition between grid connected and islanded modes of operation. Power quality enhanced operation of a microgrid in presence of unbalanced and non linear loads is also addressed in which the DGs act as compensators. A frequency and voltage isolation technique between microgrid and utility is shown by using a back-to- back converter. For accurate load sharing, the droop gains have to be high, which has the potential of making the system unstable. To improve this situation, a supplementary droop controller is designed. Two methods are proposed for load sharing in an autonomous microgrid in rural network with high R/X ratio lines.