微电网传递过电压电磁暂态特性研究

Research on Electromagnetic Transient Characteristics of Transmission Overvoltage in Microgrid

为了研究微电网发生雷击事故下受不同因素影响产生过电压的变化规律,针对直击雷和感应雷过电压两种情况,本文利用PSCAD/EMTDC平台搭建了含典型微源的线路过电压模型,重点研究了微电网中电缆和变压器的防雷能力,对变压器传递过电压以及电缆长度和负荷类型对过电压大小影响进行了研究。仿真结果表明:电缆末端过电压随电缆长度的增加而减小,变压器加装避雷器后,能够将过电压限制在较低的水平。仿真结果可为实际系统设计提供参考依据。

In order to investigate the regularity of the overvoltage affected by different factors under the lightning strike accident in microgrid,aiming at the problem of direct lightning flash and inductive thunder overvoltage,the author established a model of line overvoltage with typical microsource on the platform of PSACD/EMTDC. The lightning protection capability of cable and transformer in microgrid is researched,and the influence of overvoltage on the transfer overvoltage of transformer and cable length and load type is analyzed. The simulation indicates that the overvoltage of cable terminal is reduced as the increase of the length of the cable. And when the transformer is equipped with lightning arrester,the overvoltage can be limited to a lower level. These results can be used as a reference for the design of the actual system.