基于小波暂态能量的自适应故障选线新方法

针对当前小电流接地系统在相电压过零时发生故障选线准确率不高的问题，分析了小电流接地系统发生单相接地故障后零序电流的频率特征。提出了一种基于小波暂态能量的故障初始角自适应故障选线新方法，该方法利用快速傅里叶变换获取电压相位估算故障初始角，并根据能量最大值原理进行故障选线。通过理论分析，数字仿真实验，证明了所提出的方法基本不受过渡电阻、故障初始角、电弧故障和故障距离的影响，能够准确快速地选出故障线路。

A New Method of Adaptive Fault Line Selection Based on Wavelet Transient Energy

In order to solve the problem that the fault line selection accuracy is not high when the phase-voltage is close to zero-crossing point,the frequency characteristics of the zero-sequence current after a single-phase to ground fault occurs in non-solidly-grounded system are analyzed.At the same time,a new adaptive fault line selection method based on wavelet transient energy fault initial angle is proposed.The method uses fast Fourier transform to obtain voltage phase to estimate the initial angle of the fault,and selects the fault line according to the principle of energy maximum.Through theoretical analysis and numerical simulation,it is proved that the proposed method is not affected by transition resistance,initial angle of fault,arc fault and fault distance,and the fault line can be selected accurately and quickly.