XLPE高压电缆本体中局部放电信号的传输特性

Propagation and Attenuation Characteristics of Partial Discharge Signal in High Voltage XLPE Power Cable

局部放电信号在电缆中的传输特性对于放电水平的确定、局部放电定位及干扰区分有着重要的意义。以珠海拱澳线路110 k V电缆为研究对象,在不同长度的电缆上进行单一频率正弦信号的现场实测。运用均匀传输线理论计算得到单一频率正弦信号在该电缆中的单频衰减系数。通过Fourier变换计算高斯函数模拟的局部放电脉冲在电缆本体中的传输衰减特性,对脉冲的幅值、宽度、面积随传播距离变化规律进行了计算,并在不同长度的电缆上对局部放电校正脉冲的传输进行了实验验证。研究结果表明:单一频率高频正弦信号在电缆中的单频衰减系数与频率成正比,高斯函数模拟的局部放电脉冲在电缆本体中的传输服从指数函数与余补误差函数成积的规律,上升时间10 ns的高斯模拟脉冲幅值衰减到10%的传播距离为490 m;脉冲面积在一定范围内为放电量Q与电缆特性阻抗Z的乘积。

The propagation characteristics of partial discharge（PD） signals in cables are very important for the discharge assessment, PD source localization, and interference distinction. Thus, the study is concentrated on the Zhuhai Gong＇ao 110 kV cable system. Experiments on propagation characteristics of single frequency sinusoidal signals were conducted on cables with different lengths. Thereby, the attenuation constant of single frequency sinusoidal signal that propagates in this cable was obtained based on the transmission line theory. Through the Fourier transform, the propagation characteris- tics of Gaussian partial discharge pulses in the cable were calculated, including amplitude, width, and area. The propagation characteristics of partial discharge signals were experimentally verified on different lengths of cable. The re- suits show that the attenuation constant of single frequency sinusoidal signal is proportional to frequency, the propagation of Gaussian PD pulses obey the discipline that is described by the product of exponential function and Gaussian error function, and the amplitude of Gaussian pulse with a 10 ns rise time will decrease to 10% after propagating for 490 m. And the area under the pulse equals to the product of charge Q and characteristic impedance Z within a certain distance.