非接触式中继装置用于长电缆局部放电定位研究

Research on Partial Discharge Positioning of Long Cable Based on Non-contact Relay Device

时域反射法(time domain reflectometry,TDR)被广泛应用于电力电缆局部放电(partial discharge,PD)定位,而长电缆中局部放电存在严重的衰减,难以有效识别反射波到来时刻,导致定位精度较低。为此,分析了高频局放信号的传播特征,提出了一种局部放电信号中继放大的思想。基于电缆的传递函数设计了符合注入脉冲有效频带的高频电流传感器(high frequency current transformer,HFCT),并研制了一种非接触式行波放大装置,进而利用标准校准脉冲模拟单次局部放电信号在电缆的中继放大效果,最后通过实测局部放电信号的验证了方法的可行性。实验结果表明:信号中继放大装置能够有效增加电缆中反射信号的幅值,延长局部放电在电缆中的传输距离,并有望发展成为一种能够实现超长电缆中局部放电精确定位的新方法。

Time domain reflectometry(TDR)is widely used for power cable partial discharge(PD)positioning.However,the partial discharge in long cable has relatively serious attenuation,and it is difficult to effectively recognize the arrival time of reflected wave,resulting in low positioning accuracy.For this reason,the propagation characteristics of high-frequency partial discharge signal were simulated and analyzed,and an idea of partial discharge signal relay amplification was proposed.A high frequency current transformer(HFCT)conforming to the effective frequency band of injected pulses was designed based on the transfer function of the cable,and a non-contact traveling wave amplification device was developed.In turn,standard calibration pulse was used to simulate the relay amplification effect of single partial discharge signal on the cable.Finally,feasibility of the method was verified by measuring the partial discharge signal.Experimental results show that the signal relay amplifying device can effectively increase the amplitude of the reflected signal in the cable and prolong the transmission distance of the partial discharge in the cable,and is expected to be developed into a new method capable of accurately positioning the partial discharge in ultra-long cable.