中文摘要：

微网（MG）作为智能电网重要组成部分,目前在控制方面还存在一些问题,特别是微网的解列和并网控制。针对并网过程对微网和主电网电能质量的影响,通过研究电网中的频率和功率特性关系,对微网并网过程中的功率流动进行了详细的分析。最后使用电力系统仿真软件PSCAD/EMTDC对并网过程进行了仿真,通过比较最佳并网时刻前后的不同并网过程,分析了其频率和功率变化的不同。研究结果表明,微网和主电网电压相对相位的不同对并网过程的电能质量有很大的影响。

英文摘要：

Some control problems about the base component of the smart grid-mirgord（MG） are still unsolved excellently,especially the control of transfer between grid connected and islanded modes.Aiming at the effect on power quality during the process of grid connected,the power flower of connection was analyzed based on the characteristic of frequency and active power.The time when the voltage between the two sides of switch became nearly zero was chosen as the best chance to connect to the grid.By the simulation tool PSCAD/EMTDC,the different grid connected processes before and after the best chance were compared.The frequency and active power fluctuations were analyzed.The results indicate that the relative phase angle between the voltage of the grid and the voltage of microgrid has a great effect on the power quality during the process of grid connected.