计及分布式电源的小电阻接地系统作业安全接地防护研究

Research on Safe Grounding Protection for Small Resistance Grounding System Considering Distributed Generation

中性点经小电阻接地系统存在单相“误送电”情况下残压过大、跨步电压过高问题,会对作业人员的人身安全造成威胁,尤其是在分布式电源大量接入趋势下问题愈发严重。首先从接地措施的基础安全入手,分析接地极的接地方式及相关土壤特性,提供相应的典型土壤接地电阻计算方法;其次,基于PSCAD/EMTDC联合Anysy软件搭建含分布式电源的小电阻接地系统作业接地模型,分析残压、跨步电压过大的问题。最后,结合实际现场验证,提出有效的检修作业接地安全措施,为相关部门安全作业提供有益借鉴。

Excessive residual voltage and step voltage in the case of single-phase"false power supply"of the neutral point grounding system with small resistance may pose a threat to the personal safety of operators,especially in the trend of large-scale connection of distributed generation supplies.Firstly,the grounding mode of grounding electrode and related soil characteristics are analyzed from the safety basis of grounding measures.The corresponding typical soil grounding resistance calculation method is provided.Secondly,based on PSCAD/EMTDC and Anysy software,the operating grounding model of small resistance grounding system with distributed power supply is built to analyze the problems of residual voltage and excessive step voltage.Finally,combined with the actual field verification,the effective grounding safety measures for maintenance operation are put forward to provide useful reference for relevant departments.