基于零序电流投影分量比值的小电阻接地系统故障保护

Fault Protection Based on the Ratio of Zero-sequence Current Projection Components for Low-resistance Grounding System

通过分析单相接地故障时小电阻接地系统的电气量特征,提出了一种基于零序电流投影分量比值的小电阻接地系统故障保护方案,先根据零序电流投影法进行初次选线,再利用相位差值进行二次判断。通过Matlab/Simulink对所提保护方案进行了仿真验证,证明了该方案能够在高阻接地时可靠动作,切实提升了中性点经小电阻接地配电网络保护的灵敏性。

The electrical characteristics of a single-phase grounding fault in a low-resistance grounding system was aualyzed,and a fault protection scheme was proposed for low-resistance grounding systems according to the ratio of the zero-sequence current projection components.The primary line selection was performed according to the zero-sequence current projection method and then the phase difference value was used for the secondary judgment.The proposed protection scheme was verified by Matlab/Simulink.The simulation results show that the scheme has a certain ability to withstand transition resistance,which effectively improves the sensitivity of the ground fault protection.