330 kV变电站35 kV侧经小电阻接地改造技术可行性分析

Feasibility analysis on transformation technology of small resistance grounding on 35 kV side of 330 kV substation

330 kV变电站35 kV高压设备及电缆单相接地故障,因短路电流无法达到保护动作条件而导致事故进一步扩大。为了提高330 kV变电站35 kV系统运行可靠性,提出了35 kV侧经接地变压器和小电阻接地的方式。提出了小电阻接入方案,并通过仿真系统建立了基于实际变电站的建模,分析了小电阻接地前后短路电流变化情况,论证了接地电阻、电容器投退对短路零序电流的影响,从而证实了小电阻接地的可行性。

Single-phase grounding faults of 35 kV high-voltage equipment and cables in 330 kV substation expanded as short-circuit current failed to reach the standard of protection action.In order to improve the operation reliability of 35 kV system in 330 kV substation,transformer grounding and small resistance grounding on 35 kV side were proposed.Besides,a scheme of the small resistance integration was presented.Modeling of substation through a simulation system was implemented to analyze the short-circuit current changes before and after small resistance grounding,and the impact of switching of grounding resistance and capacitors on zero-sequence current was demonstrated to verify feasibility of small resistance grounding.