主从控制微电网孤岛切换暂态振荡分析与抑制

Analysis and Damping of Transient Oscillation in Islanding Switching-Over Process for Microgrid Under Master-Slave Control

针对微电网孤岛切换暂态稳定性问题,提出暂态振荡因素分析方法及其抑制策略。通过分解孤岛切换暂态过程,分析诱发主逆变器不稳定性的因素,构建了由系统级控制层与逆变器控制层组成的双层控制系统。最后,根据主动与被动孤岛切换的特点,分别提出了相应的孤岛切换策略,提升切换过程中暂态稳定性及其恢复速度,实现抑制孤岛切换暂态振荡的目的。仿真结果表明,即使微电网中主逆变器容量比例较低,所提控制策略仍可较好地实现孤岛平滑切换,提高了微电网供电的稳定性与可靠性。

In order to improve transient stability during microlvid islanding switching-over process, a factor analytical method is proposed and a damping strategy is designed for transient oscillation. By dividing the process into periods, factors causing master inverter instability are analyzed, and a double-layer control system, consisting of system control layer and inverter control layer, is built. Finally, a control strategy for microgrid islanding switching-over is proposed, according to different characteristics of initiative and passive islanding switching-over, to promote transient stability and its recovery rate. Simulation results indicate that the proposed control strategy can help the microgfid seamlessly switched over from grid-connected mode to islanded mode. The control strategy enhances microgrid＇s power supply stability and reliability, even in case of low power capacity of master inverter.