变频谐振下10 kV电缆缺陷局部放电检测研究

Research on Partial Discharge Detection of 10 kV Cable Defects under Frequency Conversion Resonance

采用目前方法检测电缆缺陷局部放电时,因变频谐振PD信号的影响而导致其整体有效性较差。提出变频谐振下10 kV电缆缺陷局部放电检测方法。在二阶包络线的基础上提取局部放电信号脉冲,并通过阈值策略消除局部放电信号中存在的噪声,避免其对检测过程造成干扰;提高局部放电脉冲信号的时域波形、频域波形特征量,将其输入BP网络中,在变频谐振下完成10 kV电缆缺陷局部放电检测。实验结果表明,所提方法的识别率高,其检测结果的相对误差低。

When the current method is used to detect the partial discharge of cable defects,its overall effectiveness is poor due to the influence of frequency conversion resonance PD signal.In this paper a detection method of partial discharge of 10kV cable defects under frequency conversion resonance is proposed.Based on the second-order envelope,the partial discharge signal pulse is extracted,and the noise in the partial discharge signal is eliminated through the threshold strategy to avoid the interference of noise to the detection process.The time domain waveform characteristic and frequency domain waveform characteristic quantities of the partial discharge pulse signal are improved,which are input into the BP network to complete the partial discharge detection of 10kV cable defects under frequency conversion resonance.The experimental results show that the proposed method has high recognition rate and low relative error of detection results.