Distributed bus voltage regulation and economic dispatch for multi-bus AC microgrids

Abstract

Considering the power generation cost and bus voltage quality, a distributed economic optimization control strategy and a novel bus voltage estimation method is proposed for the multi-bus low-voltage AC microgrid (MG). Based on the distributed consistency protocol, a novel distributed bus voltage estimator (DBVE), which uses the currents, voltages and the line impendence angle information of local and neighbor DGs, is presented to recover each bus voltage of the system precisely. Meanwhile, a modified distributed incremental cost rate (ICR) consistency protocol is proposed to obtain the global optimal dynamic economic dispatch (ED) of system under the capacity constraints by switching seamlessly the control strategy of each dispatchable DG (DDG) between constant power control and distributed ED strategy. Moreover, the active power is dispatched to minimize the total power generation cost considering the capacity limitation of each DG and balance between supply and demand, and the apparent power is shared among DGs according to the maximum active power rate of all DGs. To this end, a small-signal stability analysis is given to obtain the feasible regions for the control parameters. Finally, several simulation cases are conducted under various working conditions to verified the effectiveness and feasibility of the proposed method.

Keywords

• Bus voltage estimation
• Distributed control
• Economic dispatch
• Bus voltage regulation