XLPE电缆的差频检测技术研究

Study on the Difference Frequency Detecting Technique for XLPE Cable

研究发现在同时对含水树枝 XL PE电缆施加两个频率相近或近似呈倍数关系的正弦电压时 ,检测回路中会有超低频水树枝劣化特征电流信号产生 ,据此可对电缆绝缘的水树枝老化状态进行在线或离线诊断。模拟实验分别找出了在线和离线情况下与工频电压进行叠加的最佳叠加电压频率和叠加电压值 。

It is found that if two voltages are applied, whose frequency are close to each other or approximate to multiple relationship, to water treed XLPE Cable, an ultralow frequency current signal as the characterization of water treeing appears in detecting circuit. The deteriorating situation of water treeing in XLPE Cable insulation can be diagnosed on line or Off line by detecting this signal. The optimum superposition frequencies and voltages to power frequency voltage for On line and Off line detecting XLPE Cable are found by test on the simulating circuit. Finally the formation mechanism of superposition respones is analyzed.