适用于振荡波电缆局放测试的π型检测阻抗设计

Design of π-type Detection Impedance for Oscillatory Wave Cable Partial Discharge Test

振荡波电缆局放测试是一种新兴的电缆缺陷检测手段,而采集到的局放信号质量与检测阻抗密切相关。传统RC型检测阻抗无法兼顾检测到局放脉冲的能量以及对低频试验电压的抑制效果。为改善检测阻抗的性能,设计了一种适用于振荡波电缆局放检测的π型检测阻抗。理论分析与试验结果表明:该检测阻抗能够在保证输出脉冲能量较高的同时对低频试验电压有更强的抑制作用,且输入输出具有良好的线性关系;在振荡波电缆局放定位中,应用该检测阻抗能有效检测局放信号及其多次反射波,并能准确定位电缆缺陷。因此,π型检测阻抗在高压长电缆局放测试方面有广阔的应用前景。

Oscillatory wave cable partial discharge(PD)test is a new method for cable defects detecting.The quality of the PD signal collected is closely related to the impedance detection.The traditional RC-type detection impedance cannot take into account the energy of PD pulse detected and its attenuation effect on low frequency test voltage.In order to improve the performance of the detection impedance,a kind ofπ-type detection impedance for oscillatory wave cable PD test is presented.Theoretical analysis and experimental results show that theπ-type detection impedance has a better attenuation effect on low frequency test voltage while keeping a high output pulse energy.In addition,there is a good linear relationship between the input and output signals.In the application of cable PD location under oscillating wave,this detection impedance can be used to detect the PD signal and its reflected waves effectively,and to locate the cable fault accurately.Therefore,theπ-type detection impedance has broad application prospects in the PD test for high-voltage and long-distance cables.