石化企业10 kV配电系统小电阻接地的应用

Application of Low Resistance Grounding in 10 kV Distribution System in Petrochemical Enterprises

某大型石化项目的10 kV配电系统的电容电流大于10 A,且出线回路均为铠装电缆沿桥架敷设。结合各类接地方式的特点及适用情况,该项目确定采用小电阻接地方式,即接地电阻与接地变组合接地。计算接地电阻阻值、接地变容量,并配置零序保护,实现在10 kV系统发生单相接地故障时能够迅速切断电源,确保人身安全。

In a large petrochemical project,the capacitive current of the 10 kV distribution system is greater than 10 A,and the outgoing circuit is laid along the bridge with sheathed cables.According to the characteristics and application of various grounding modes,the project determines to use low resistance grounding mode,that is,grounding resistance combined with grounding transformer grounding.By calculating the grounding resistance value,grounding variable capacity and configuring zero-sequence protection,the power supply can be cut off quickly when single-phase grounding failure occurs in 10 kV system,thus ensuring personal safety.