电力系统低碳转型，构建安全高效和灵活可靠的配电网为基础的新型电力系统将对我国“碳达峰、碳中和”目标的实现起到关键作用。文中以低压直流（low voltage direct current，LVDC）配网系统为研究对象，针对配电网低压侧的接地故障问题，提出了一种采用IGBT构造投切旁路的人体保护方法。文中建立接地故障等效模型并进行理论分析，通过故障阈值识别判据产生保护人体的投切旁路信号，并对不同类型的接地故障进行区分，考虑多支路故障情况对旁路投切保护判据的影响，将故障值范围进行划分，进一步提出了旁路投切的分级保护方案，搭建实物模型对保护方法进行验证。实验结果表明所提保护方法能保护人体安全，具有灵敏性好，安全可控的优点，能显著提高配网系统的运行稳定性。
英文摘要:
The low-carbon transformation and the construction of novel power system based on a safe, efficient, flexible and reliable distribution network will play a pivotal role in the realization of "carbon peaking and carbon neutrality" goals. This paper takes the low voltage direct current (LVDC) distribution network system as the research object, a human body protection method using insulated gate bipolar transistor (IGBT) is proposed to construct a switching bypass for the grounding fault problem on the low voltage side of the distribution network. The grounding fault equivalent model is established for theoretical analysis, the switching bypass signal protecting human body is generated through the fault threshold identification criterion, and different types of grounding faults are distinguished. Considering the influence of multi-branch fault conditions on the protection criterion of bypass switching, the fault value range is divided, and the hierarchical protection scheme of bypass switching is further proposed. A physical model is built to verify the protection method. The experimental results show that the proposed protection method can protect human safety with the advantages of good sensitivity, safety and controllability, also can significantly improve the operation stability of the distribution network system.