基于阻性相位检测技术实现配电网单相接地故障就地隔离方法

Implementation of on-site isolation method for single-phase grounding faults in distribution networks based on resistive phase detection technology

在配电网小电流接地系统中,单相接地故障隔离技术方案主要包括工频参数法、高频参数法、外加信号法等,但都存在可检测性差、干扰因素多、容错率低等问题。文中分析了系统发生接地故障时的电流分布和零序导纳相位角特征,研究了系统中性点不同阻值电阻对故障电流幅值的放大效果、零序导纳相位角的移相效果。提出了基于阻性相位检测技术实现单相接地故障就地隔离的方法,该方法使故障特征量具有高可检测性和故障路径具有可标识性。真型实验表明,阻性相位保护不受接地点故障介质特性、消弧线圈、潮流方向、安装方向等干扰因素影响,且保护耐过渡电阻高达3 kΩ。该保护技术成熟、成本低、易实现,参数整定简单,可广泛推广。

In the small current grounding system of distribution network,the single-phase grounding fault isolation technology mainly includes power frequency parameter method,high frequency parameter method and external signal method,but there are problems such as poor detectability,many interference factors and low fault tolerance rate.The current distribution and zero sequence admittance phase Angle characteristics of the system are analyzed.The amplification effect of the different resistance values of the system neutral point on the fault current amplitude and the phase shift effect of the zero sequence admittance phase Angle are studied.In this paper,a method based on the resistive phase detection technique is proposed to realize the isolation of single-phase grounding fault in situ,which makes the fault characteristic measure have high detectability and the fault path have identifiability.The true type experiments show that the resistive phase protection is not affected by the interference factors such as the fault medium characteristic of the ground point,arc suppression coil,power flow direction and installation direction,and the protection resistance is as high as 3kΩ.The protection technology is mature,low cost,easy to realize,simple parameter setting,and can be widely popularized.