基于电缆频率特性及信号脉冲宽度的电缆局部放电在线定位方法

为减小电力电缆局部放电定位过程中噪声及反射脉冲的干扰,实现局放源的在线定位,提出了基于频率特性及信号脉冲宽度的电缆局部放电定位方法。该方法通过模拟局放脉冲信号在电缆中的传播,分析了局部放电脉冲信号在电缆中的传播特性,推导出考虑频率特性的脉宽变化函数关系式,最后结合实测的脉宽与传输距离的拟合曲线,通过迭代计算获取准确的故障位置。利用PSCAD/EMTDC搭建电缆模型,在不同故障距离下的对该方法进行仿真验证,并与小波变换的定位结果进行比较,结果表明其定位误差低于0.6%,说明该方法具有较高的准确性与实用性。

On-line of Cable Partial Discharge Localization Method Based on Cable Frequency Characteristics and Signal Pulse Width

In order to reduce the interference of noise and reflected pulse during partial discharge of power cable, and realized the on-line positioning of PD, a partial discharge localization method based on frequency characteristics and signal pulse width was proposed. The method analyzes the propagation characteristics of the partial discharge pulse signal in the cable by simulating the propagation of the partial discharge pulse signal in the cable, and derived the relationship of the pulse width variation function considering the frequency characteristics. Finally, combined with the measured pulse width and transmission distance. Fitted the curve and obtain an accurate fault location by iterative calculation. Used PSCADE/MTDC to build the cable model, the method was simulated and verified under different fault distances, and compared with the positioning results of wavelet transform. The results show that the positioning error is lower than 0.6%, which indicates that the method has higher accuracy and practicality.