Experimental Study on Voltage-Current Sensor embedded in Insulator

电力企业在维护、控制和稳定电压调节方面迫切需要对用户端电能进行准确的估计。根据电压和电流的实际波形观察功率因数有几种方法。然而，传统上每个传感器都是独立安装在配电线路上的。为了实现对功率因数的波形观测，设计并提出了一种绝缘子内置式电压电流传感器。本课题通过对单相配电系统、水平和垂直三相配电系统的有限元分析，从理论上分析了电压、电流传感器在单相配电系统、水平配电系统和垂直三相配电系统中的相移原因。为了补偿电流传感器中的相移，我们引入了新型电流传感器线圈，它们以相反的极性连接在一起，使得安装在每条相配电线路上的传感器只测量其相线上的磁链，而消除由于其他相电流而产生的磁链。最后，在理论设计的基础上，在绝缘子公司制作了嵌入上述两个线圈的电压-电流传感器的样机，并在模拟的三相配电系统中得到了对电流传感器相移的补偿效果。

The precise estimation of the electric power at the consumer end-side is eagerly demanded for the maintenance, control and the stable voltage regulation by electric power companies. There are several approaches to the observation of the power factor based on the practical waveform of both the voltage and the current. However, conventionally each sensor has been installed on power distribution lines independently. The measurement systems will be large and complicated to result in no maintenance free systems.To carry out the waveform observation for power factor, we have devised and proposed an insulator built-in type of voltage-current sensor. According to our previous investigations on the sensor, it was found out theoretically that a serious phase shift in the measured waveforms of the voltage and the current might occur owing to the electromagnetic interference of each phase.In this project, we have investigated the cause of phase shift in the voltage and current sensors through the finite element analyses on the single phase power distribution system, the horizontal and vertical three-phase power distribution systems. To compensate the phase shift in the current sensor, we have introduced the new current sensor coils, that are connected with opposite polarity to each other so that the sensor installed on each phase distribution line will measure only the flux linkage across its phase line and cancel the flux linkage due to other phase currents.Finally, based on the theoretical design, the prototype of the voltage-current sensor embedded in an insulator with above two coils has been fabricated in the insulator company and it has been found out experimentally that the effect of compensation on the phase shift in the current sensor could be obtainable in the simulated three-phase power distribution system.