Feasibility Study on Real-time Measurement System of Voltage-Current Waveform in Molded Type of Voltage-Current Sensor in Power Distribution Systems

功率因数的实时观测对三相配电系统的维护和稳压至关重要。近年来，工厂和家庭中的固态电源变换器和逆变器系统可能产生的高次谐波效应已经成为一个严重的障碍，它将导致用于相位补偿的电感器等电力设备的破坏。因此，电压和电流波形的同步测量必然是配电系统中不可缺少的技术。为了实现电压和电流波形的同时观测，我们设计并提出了一种树脂模塑型电压电流传感器，其中电极的几何形状设计将在一定程度上自由，并使用有限元法（FEM）从理论上讨论了新型传感器的基本行为。在本项目中，我们首先利用后向有限差分法辅助的修正有限元分析方法研究了现有树脂型传感器中的瞬变电磁现象。因此，我们已经能够掌握传感器的动态行为，包括在我们实验室的伪配电系统下传感器电流波形中观察到的高次谐波。采用日立微处理器H8单板计算机系统设计并实现了实时观测系统，该系统具有10位A/D转换器和以太网适配器，以及无线局域网路由器。采用H8操作系统（H8 OS），支持基于HTTP协议的数据（端口号为80），当向单板计算机系统提出数据采集请求时，通过AID转换器通过无线局域网系统获取数字数据。

The real-time observation of a power factor will be essential for the maintenance and the stable voltage regulation in three-phase power distribution systems. Recently, the higher harmonics effect, that may be produced through solid state power converter and inverter systems in factories and homes, has been a serious obstacle, that will result in the destruction of the power apparatus such as an inductor for phase compensation. Therefore the concurrent measurement of both the voltage and current waveforms must be an indispensable technology in power distribution systems. To carry out the concurrent observation of both the voltage and current waveforms, we have devised and proposed a resin molded type of voltage-current sensor, where the design of the geometry of electrodes will be free to some extent, and discussed the fundamental behavior of the new sensor theoretically using the Finite Element Method (FEM).In this project, at first, we have investigated the transient electromagnetic phenomena in the present resin type sensor using the modified FEM analysis aided by the backward finite difference method. As a result, we-have been able to grasp the dynamic behavior of the sensor including the higher order harmonics, that have been observed in the current waveform of the sensor under the pseudo power distribution system at our laboratory. We have designed and implemented the real-time observation system using the Hitachi Microprocessor H8 single board computer system, that has the 10 bits A/D converter and the Ethernet adapter, and the wireless local area network router. Using the H8 operating system(H8 OS), that supports the data based on the HTTP protocol(the port number of 80), when the data acquisition request will be thrown to the single board computer system, the digital data through the AID converter will be obtained over the wireless local network system.