接有冲击性负荷的微电网电能质量分析

Power Quality Analysis of Microgrid with Impact Load

微电网通过连接分布式电源与大电网,可有效降低分布式发电对电网的冲击,提高供电可靠性.但由于微电网网架相对脆弱,随着冲击性负荷的大量接入,电网谐波、电压不平衡等因素对微网电能质量影响越来越明显.建立了风光储交流微电网并网系统,并以炼钢电弧炉作为典型冲击性负荷模型,重点分析了弧长变化较大的熔化期对微电网造成的三相不平衡、电压波动、谐波等电能质量问题.结果表明,冲击性负荷接入对并网方式下的微电网系统电能质量有很大影响.

The microgrid can effectively reduce the impact of distributed power generation on the power grid and improve the reliability of power supply by connecting the distributed power source and the large power grid. However,because of the relatively fragile grid and the massive access of the impact load,the factors such as voltage imbalance and the grid harmonics have become more and more obvious for the impact of the microgrid power quality. The grid-connected system of AC microgrid with wind-light storage is established,and the steel-making electric arc furnace is used as the typical impact load model. The three-phase unbalance,voltage fluctuation and harmonic caused by the melting period of the arc length change are analyzed mainly in the paper. The results show that the impact load access has a great impact on the power quality of the microgrid system under the grid connection mode.