分布式电源接入对小电阻接地系统零序电流保护影响的机理分析

摘要

从本质上研究了分布式电源接入对小电阻接地系统零序电流保护的影响，并结合数值仿真进行验证。此外，在满足继电保护可靠动作的前提下，分析了配电网允许分布式电源侧的接入最大短路容量与并网位置、并网变压器中性点接地阻抗的关系。结果表明：分布式电源接入可能导致保护动作失去选择性、误动或拒动；在不同并网位置情况下，合理的设置并网变压器中性点接地阻抗值，可以减小分布式电源接入对配电网保护带来的影响，从而可增加允许分布式电源侧的接入最大短路容量。%This paper focuses on the influence of distributed generation on zero sequence current protection in low resistance grounding system, verifying with mathematical simulation. The relationship between the maximum allowable short-circuit capability of distributed generation and the grid-connected location or the impedance of grid-connected transformer’s neutral ground. The result shows that distributed generation may lead to the lose of selectivity or missing operation. Reasonable values of impedance of grid-connected transformer’s neutral ground can decrease the influence of distributed generation on the distribution network protection, increasing the maximum of short-circuit capability of distributed generation. This work is supported by Science and Technology Projects of China Southern Power Grid (Project number: 0301XX2406).