电缆高压侧极化-去极化电流检测装置研究

Research on cable polarization-depolarization current detection device on high voltage side of cable

为解决工业现场的电缆绝缘状态诊断问题,设计了一种电缆高压侧极化-去极化电流(PDC)检测装置。通过分析工业现场环境中影响PDC测试的因素,表明了高压侧测试方式更适合工业现场的电缆绝缘状态诊断。由于电缆的极化去极化电流变化范围大(pA~mA),且现场存在各种电磁干扰,装置中的微电流检测电路采用了自动换挡和低通滤波的设计,满足了装置对快速变化的电流的测量以及抗干扰能力的要求,装置的电流测试范围为±1 pA~±2 mA,分辨率为1 pA。该装置采用与上位机之间采用了无线通信的数据传输方式,使得该装置在现场放置时灵活性强,能够适应复杂的测试环境。经现场应用表明,该装置能够对电缆的绝缘状态进行准确评估。

In order to solve the problem of diagnosing cable insulation state in industrial field,it designed a set of polarization and depolarization current(PDC)detection device on high voltage side of cable.By analyzing the influencing factors on PDC test in industrial field environment,this paper shows that the test method at the high voltage side is more suitable than traditional method at low voltage side for diagnosing cable insulation state.Due to the large variation range of polarization and depolarization current of the cable(pA~mA)and various electromagnetic interferences on site,the microcurrent detection circuit in the device adopts the design of automatic shift and low-pass filter,which meets the measurement ability and anti-interference ability.The current test range of the device is±1 pA~±2 mA,and the resolution is 1 pA.The data transmission mode of wireless communication is adopted between the device and the host computer,so that the device has strong flexibility when placed on site and can adapt to the complex test environment.The field application shows that the device can accurately evaluate the insulation state of the cable.