基于ATP-EMTP高阻地区变电站地电位升安全限值的确定方法

Method for Determining Safety Limits of Ground Potential Rise in High Resistivity Area Substations Based on ATP-EMTP

高土壤地区通常需要通过降阻来满足工程对接地电阻及地电位升的要求,但在某些地区采取措施后仍不能达到安全要求。依托某500 kV变电站接地网设计工程,在避雷器安全性分析的基础上,研究并提出了提高变电站地电位升限值的方法。首先,通过仿真计算软件ATP-EMTP建立了500 kV变电站地电位升高引起的氧化锌避雷器反击模型,进而计算地电位升高时避雷器的能量吸收;其次使之与避雷器允许最大流通容量进行对比,得到避雷器耐受地电位升值;最后校验了二次电缆、接触电压和跨步电压的安全性能,得出了本站地电位提升可行的结论。

It is usually necessary to reduce resistance to meet the requirements of grounding resistance and ground potential rise in high soil resistivity area. But in some areas,safety requirements cannot be achieved after taking measures. The methods to improve the ground potential rise and limit of substation is studied and proposed,based on the design project of grounding grid in a 500 kV substation and the analysis of lightning arrester safety. Firstly,the model of lightning arrester counterattack caused by ground potential rise in 500 kV substation is established by simulation software ATP-EMTP,and then the energy absorption of lightning arrester is calculated when ground potential rises. Secondly,it is compared with the maximum allowable flow capacity of the arrester to get the potential appreciation of the surge arrester.Finally,the safety performance of secondary cable,contact voltage and step voltage is checked,and the feasible conclusion of ground potential lifting is obtained.