非侵入式双芯线电流传感器的研制

Development of nonintrusive current sensor for two-wire power cords

采用需求响应电力监控系统管理终端用电量,可提高智能电网运行效率。电流传感器是监控系统的关键组成之一,但传统的单芯线电流传感器不适用于终端设备双芯线电流的非侵入式检测。该文提出一种非侵入式双芯线电流传感器,采用环电线的开气隙磁芯控制电流产生的磁场分布,通过4个磁阻传感器分别测量4处气隙磁场,共同求解双芯线电流以及双芯线绕中轴旋转角度。使用时传感器扣合在被监测双芯线外包层,无需任何对准过程,可实现任意轮廓双芯线电流的非侵入式检测。实验表明:该传感器在0~20 A量程内的非线性度为±1.5%,电流测量误差不超过±1.8%。

Deployment of demand response electricity monitoring systems to manage end-use of electric power is an effective way to improve operating efficiency of the smart grid. Current sensor is one of the key components in the system. However, current sensors for single-wire power cords can＇t detect current nonintrusively in two-wire power cords connected to end-use appliances. This paper presented a nonintrusive current sensor for two-wire power cords, which used a gapped magnetic core surrounding the power cord to constrain the distribution of the magnetic field generated by the current. The magnetic fields in four air gaps were respectively measured by four magnetoresistive（MR） sensors. The current in the power cord and the rotation angle of the power cord around its central axis were calculated together by four MR sensors. The sensor embraced the monitored power cord in operation without any alignment process, and can detect current nonintrusively in two-wire power cords of any profile type. The experimental results show that the nonlinearity of the sensor is ±1.5% for the current range from 0 to 20 A with the maximum error limited to ±1.8%.