Research on the Optical Current-Transformer Applied to Flat-Shape Three-Phase Bus-Bars for Low or Middle Transmission Currents

光电流互感器（OCT）目前在实际应用中还很少。近年来，人们对OCT的实际应用和性能的提高进行了一些新的研究。这些研究的主要目的是充分利用OCT重量轻、体积小、隔离性好的优点，开发可集成到断路器等电力设备中的OCT。我们已经研究了将OCT应用于3或6千伏的低压或中压三相电力设备的可能性。在本研究中，我们提出了在母线周围有屏蔽的OCT结构，并对磁场干扰进行了分析。结果表明，采用本文提出的双屏蔽结构，可以减少三相交流磁场的相互干扰和涡流的影响，这是将OCT应用于三相母线设备时存在的问题。这种结构既可以应用于母线的并排布置，也可以应用于母线的纵向布置，而不改变屏蔽的形式。本OCT中使用的磁性材料（如磁传感器薄膜和屏蔽芯）的非线性特性引起的问题进行了实验研究，并对其进行了成像。（1997年）开展了模拟OCT结构的实验工作。结果表明：(1)无取向S-Fe层合材料具有良好的屏蔽效果。(2)本实验制备的（BigdY）_3D2(FeAl)_5O_<12>薄膜在线性上具有良好的M-H特性。(3)认为适当选择交流光学检测器可以消除轻微的波形畸变。为了减小光传输损耗，有必要进一步改进场传感器的结构。我们正在继续研究这个问题。

The optical current transformaer (OCT) was scarcely used in applications fo far. Recently some new reseaches on the OCT have been begun for its practical application and improbements of performance. The main purpose of those researches is to develop the OCTs that can be incorporated into electric power devices like the circuit-breakers, taking full advantage of the OCT that is light weight, small size and good isolation. We have studied the possibility of applying the OCT to three-phase power equipment used at a low or middle voltage of 3 or 6 kV.In this study, we proposed the OCT sturyucture that has shielding around bus-bars and made analyzes about the interference of magnetic fields.(Year : 1996) It was shown that mutual interference in three-phase ac fields and the influence of eddy currents which are problems when applying the OCT to the three-phase bus-bar equipment can be reduced by using the proposed duoble shield structure. This sturcture can be applied to both the side by side and the longitudinal arrangements of bus-bars without a change in the form of the shield. Porblems originating in non-linear characteristics of magnetic matrials, such as magnetic sensor films and shielding cores, used in this OCT were investigated experimentally and mage them clear.(Year : 1997) We deceloped experimental work on the OCT structure simulated. As a result of this experimental investigation, the following were confirmed : (1) Non-oriented S-Fe laminations exhibit the sufficient shielding effect for this application. (2) The (BigdY)_3D2(FeAl)_5O_<12> film prepared for this experiment shows excellent M-H characteristics on linearity. (3) It is considered that the slight waveform-distrotion can be removed by apporpriately selecting the ac optical detector.It is necessary to improve the structure of field sensor further for decreasing liht transimission losses. Our research is being continued to work this problem out.