基于FBG的电缆XLPE绝缘局部放电检测研究

光纤布拉格光栅(fiber bragg grating, FBG)的波长编码特性适用于电力电缆中间接头局部放电的准分布式检测。但是电缆主绝缘材料交联聚乙烯(XLPE)的弹性模量很低,利用FBG检测其局部放电声信号还存在可行性及灵敏度等问题。以XLPE为研究对象,对比了XLPE中尖刺-气隙放电和油中针-板放电所产生的声信号强度,分析了FBG传感器检测XLPE中尖刺-气隙放电声信号的灵敏度及衰减特性。实验表明:XLPE中尖刺-气隙放电产生的声信号强度远小于油中针-板放电;FBG传感器可测得最小300 pC的放电信号;XLPE中声信号衰减严重,FBG传感器测得的局部放电声信号幅值符合一阶指数衰减规律,衰减系数为0.07 Np/mm。

Research on partial discharge detection of cable insulation based on FBG

The wavelength coding characteristic of fiber bragg grating (FBG) is very suitable for the quasi-distributed detection of partial discharges(PDs) on cable joints. However, the elastic modulus of cable main insulation-XLPE is very low. There are still some problems such as feasibility and sensitivity in the detection of XLPE PD by FBG. Taking XLPE as the research object,the intensity of acoustic signal generated by XLPE spike-air gap discharge model and needle-plate discharge model in oil was compared, and studies the feasibility and attenuation characteristics of FBG sensor detecting acoustic signal of XLPE spike-air gap discharge model were studied. Experiments show that the intensity of acoustic signal generated by XLPE spike-air gap discharge model is far less than that of needle-plate discharge model in oil, and the FBG sensor can detect a PD with the minimum 300 pC. The amplitude attenuation of PD measured by the FBG sensor is serious, and conforms to the first-order exponential attenuation, and the attenuation coefficient is 0.07 Np/mm.