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

光学电流互感器(OCT)到目前为止还很少应用。近年来，由于OCT的实际应用和性能的提高，已经开始了一些新的研究。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，开发出可集成到断路器等电力设备中的OCT。本文研究了将OCT应用于中低电压为3~6KV的三相电力设备的可能性，提出了母线周围屏蔽的OCT结构，并对磁场干扰进行了分析(1996年)，结果表明，采用该双屏蔽结构可以减少三相交流电场中的相互干扰和涡流的影响。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。对OCT中使用的磁性材料(如磁敏感膜和屏蔽铁心)的非线性特性问题进行了实验研究，并对这些问题进行了处理。实验研究的结果证实：(1)无取向S-铁层压板具有足够的屏蔽效果。(2)本实验制备的(BigdY)3D2(FeAl)5O；12&gt；薄膜具有良好的M-H线性度特性。(3)认为通过选择合适的交流光学探测器，可以消除轻微的波形失真，为了降低LiHT传输损耗，有必要进一步改进场传感器的结构。我们的研究正在继续解决这个问题。

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.