中文摘要：

变电站中二次设备集中区域如主控室、保护小室内均安装有等电位接地网,等电位接地网与主接地网的连接对二次设备安全有重要意义,目前相关规范的要求在关键点上往往论述的比较含混.因此从等电位接地网的作用入手,通过数值计算,分析了在工频和雷击故障下,分布式的等电位接地网与主接地网连接方式对二次电缆电压、电流的影响,并综合考虑了二次等电位接地网的主要功能,提出了等电位接地网与主接地网的连接方式和限流措施.研究表明：每个等电位接地网采用单点与主接地网连接的方式,相比每个等电位接地网多点与主接地网连接的方式,能够有效降低二次电缆上承受的电压;增设排流线可以显著降低二次电缆承载的电压,降低电缆屏蔽层内流过的电流;采用全站等电位接地网与主接地网仅一点接地的做法虽然可以使二次接地网等电位,但会导致等电位接地网远端与主接地网之间产生较大电位差,造成设备绝缘击穿、接触电位差过大等问题.

英文摘要：

Equipotential grounding grid is installed in areas where secondary equipment is concentrated, such as main control rooms and relay rooms. The connecting between equipotential grounding grid and main grounding grid is of great importance for secondary equipment. The requirements in relevant standards and regulations are accidentally vague in key points. By numerical calculations, we analyzed how the ways of distributed equipotential grounding grid and main groun- ding grid connection affect the voltage and current in secondary cables. By comprehensively considering the functions of the equipotential grounding grid, we put forward the connecting method of secondary and primary grounding grid, and took the measures to confine fault current in secondary cables. Research shows that, single-point connection, which can reduce the potential exerted on the secondary cables greatly, has a advantage compared with multipoint connection in the connection between equipotential grounding grid and main grounding gird. Installing drain wire can not only reduce the potential exerted on the secondary cables significantly, but also reduce the current flowing through the shielding layers of the cables. Though electric potential difference between different equipotential grounding grids in a substation can be eliminated by connecting them together with drain wire, and then connected to the main grounding grid at a single point, the method can also produce great potential difference between far-end of the equipotential grounding grid and main grounding grid. This will cause the problems such as primary equipment＇s insulation breakdown and high touch potential difference etc.