基于低电压的反时限微网保护方案

摘要

针对由逆变型分布式电源组成的微网,在低电压保护的基础上,利用距离保护的一部分思想,提出了低电压反时限微网保护方案.对比传统的保护方案,在不同短路故障情况下,对保护原理和动作特性、保护之间的配合进行了研究,并研究分析含有直接接地的旋转式微源的微网,以及过渡电阻等特殊问题对于低电压反时限保护方案的影响,并提出改进建议.在MATLAB/Simulink环境下建立了含有不同控制方式的分布式电源的微网模型,并在此基础上对保护方案进行仿真验证,仿真结果表明该方案在微网并网和孤岛条件下,均有良好的动作性,而且具有较快的切除故障能力,并有一定程度的抗过渡电阻能力.%In order to deal with the micro-grid, which consists of inverter distributed generations ( DG) , on the basis of the low-voltage protection, using part of ideological thoughts of distance protection scheme, this paper proposed a low-voltage inverse-time protection scheme for micro-grids.Compared with the traditional protection, the protection principle, operating characteristics, coordination between primary protection and backup protection were investigated under different short circuit fault conditions, and analyzed the micro-gird which consisted of rotary DGs, and the tran-sition resistance and the influences of other special problems on the low-voltage inverse-time protection scheme were also investigated, and proposed improved recommendations.In MATLAB/Simulink environment, a micro-grid model which contained different control methods of distributed generation was built, and verified the protection scheme.The low-voltage inverse-time protection has good performance under different operating conditions and high resistance to fault resistor, and is able to remove fault quickly.