基于双电容串联模型的TEV传感器在电缆终端局部放电检测中的研究

Research on Partial Discharge Detection of Cable Termination with TEV Sensor Based on Two Capacitors in Series Model

为研究不同暂态对地电压(TEV)传感器对电缆终端局部放电(PD)检测结果的影响,对基于不同模型的两种TEV传感器下的终端PD特征进行对比分析,并在此基础上提出了一种终端PD检测的新方法。通过电缆终端电热老化平台模拟终端实际运行条件,利用传感器提取PD数据,对比分析了终端局部放电特征以及传感器信噪比(SNR)。结果表明:不同传感器下电缆终端的局部放电特征及传感器SNR存在明显差异。基于单电容模型的TEV传感器在单次放电波形上升时间、持续时间及SNR低于双电容串联模型的TEV传感器;尽管PD信号的幅值差异较小,但基于双电容串联模型的TEV传感器在检测终端PD信号及抑制干扰上更具优势。此外,基于新方法提取的终端PD信号分布于触发信号的二、四象限,这些特征可为终端PD检测时放电信号的相位判定提供理论依据。

In order to investigate the effect of different TEV sensors on the partial discharge（PD） test results of cable terminations, the PD characteristics of terminations under two sensors were analyzed, and a new method for PD detection of terminations was proposed. An electrical-thermal ageing platform was used to simulate the actual operating condition of terminations, and the PD data were extracted using the TEV sensors, and then the PD characteristics of the terminations and the signal-to-noise ratio （SNR） of the sensors were analyzed. The results show that the PD charactersfics of the terminations and the SNR of the sensors are different under the two sensors. The rise time and duration time of the single discharge waveform and the SNR of the sensor based on single capacitor model are lower than that of the sensor based on two capacitors in series model. Despite the amplitude of the PD signals is almost the same, the TEV sensor based on two capacitors in series model has more advantages in PD detection of terminations and restrain interference. In addition, the PD signals detected by the new method are distributed in the second and fourth quadrant of the trigger voltage signal. These characteristics can provide theoretical basis to judge the phase of discharge signals in PD detection of terminations.