电力系统中性点不接地系统单相接地故障特性与暂态过程研究

Research on Single-Phase Ground Fault Characteristics and Transient Processes in Neutral-Point-Not-Earthed Power Systems

摘要

中性点接地方式直接影响电力系统的运行稳定性与故障特性。中性点不接地系统因结构简单、经济性高而广泛应用于中低压配电网，但在单相接地故障下易出现零序电压升高、暂态电流复杂及过电压持续等问题，对绝缘安全构成威胁。本文基于理论分析与暂态仿真，研究单相接地故障的电压、电流变化规律与暂态响应特征。结果表明，故障初期的电容电流、残余电压及暂态电弧是引发过电压与谐振的关键因素。通过零序网络建模与能量传递分析，揭示了不同接地电容、线路长度及故障电阻下系统的动态响应规律，为接地方式优化、故障检测与过电压防护提供理论依据。

Abstract

The grounding method of the neutral point directly impacts the operational stability and fault characteristics of power systems. Neutral-Point-Not-Earthed (NPE) systems, widely adopted in medium and low-voltage distribution networks due to their simple structure and cost-effectiveness, often exhibit zero-sequence voltage surges, complex transient currents, and sustained overvoltages during single-phase ground faults, posing insulation safety risks. Through theoretical analysis and transient simulation, this study investigates the voltage-current variation patterns and transient response characteristics of single-phase ground faults. Results demonstrate that capacitive currents, residual voltages, and transient arcs during fault initiation are critical factors triggering overvoltages and resonances. By modeling zero-sequence networks and analyzing energy transfer, the dynamic response patterns under varying grounding capacitance, line length, and fault resistance are revealed, providing theoretical foundations for optimizing grounding methods, fault detection, and overvoltage protection.

关键词

中性点不接地 / 单相接地故障 / 暂态过程

Key words

Neutral point ungrounded / Single-phase ground fault / Transient process

参考文献

[1] 侯强民. 铁路中性点不接地电力系统故障选线技术探析[J]. 电力设备管理, 2025,(22):224-226.

[2] 马超. 中性点不接地系统铁磁谐振机理及抑制措施研究[D]. 山东大学, 2014.

[3] 王青. 小电流接地系统单相接地故障的矢量融合与行波测距技术[D]. 湖南科技大学, 2010.