330 kV变电站35 kV侧经小电阻接地改造技术可行性分析

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。

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

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