DEVELOPMENT OF POLTRATION-FREE INSULATING OILS AND UTILIZATION TO ENVIRONMENT FRIENDLY POWER APPARATUS

采用阻挡放电反应器将氢氟碳化合物（HFC134a）气体组分与菜籽酯油和硅油结合，对两种绝缘油的电流体动力（EHD）泵送性能和介电强度进行了研究。本研究的结果如下：1。利用FT-IR ATR法对标准油和变性油的光谱差值进行对比，发现变性菜籽油和硅油中分别形成了C-F和C-O自由基以及C-H和C-O自由基。与标准油相比，通过少量添加离子组分，变性油的电泵能力得到了显著增强。在实验中使用的电极几何形状（准甜甜圈到平面型）中，当外加电压高达20 kV时，电流水平小于1 μA。在变性油中平行平面电极处的电位分布也表明，在电极附近存在更多的异质电荷层，表明这种强抽运是由纯导电抽运机制引起的。脉冲蠕变放电受变性油中离子组分的敏感影响。在变性油中，与标准油相比，拖缆的传播时间更长，但正拖缆的长度不超过标准变压器油的±15%。与标准油相比，变性油的交流击穿电压也降低了。而变性菜籽油的介电强度与标准变压器油相当。另一方面，设计了新型的同轴锥杆电极组合，并对其射流特性进行了实验研究。当对棒状电极施加直流正电压时，液体从安装在接地锥形电极顶部的玻璃管出口强力喷出。这种EHD抽运来自于棒状电极附近离子电荷的积累。研究还表明，在棒电极表面局部涂覆绝缘子会导致泵送压力的升高和传导电流的减小。作为一种新型的充油动力装置冷却技术，电激泵送是一种很有前景的冷却技术，但需要考虑电激泵送机理与电绝缘之间的互反关系。少

The properties of electrohydrodynamic (EHD) pumping and dielectric strength were examined for two insulating oils, rapeseed ester oil and silicone oil, which were denatured by a bonding of hydrofluorocarbon (HFC134a) gas components decomposed using a barrier discharge reactor. The results obtained from this study are as follows.1. By taking the difference between spectrums of standard oil and denatured oil using a FT-IR ATR method, it was found that C-F and C-O radicals and C-H and C-O radicals were formed respectively in the denatured rapeseed ester oil and silicone oil.2. The electrical pumping ability in denatured oils was reinforced significantly compared with standard oils by a slight addition of ionic components. In the electrode geometry (quasi-doughnut to plane type) used in the experiment, the current level was less than 1 μA for the applied voltage up to 20 kV. The potential distribution measured at parallel plane electrodes in denatured oils also showed that there existed a … More heterocharge layer near the electrodes, which suggested that the powerful pumping was attributable to the pure conduction pumping mechanism.3. Impulse creeping discharges were affected sensitively by the ionic component in denatured oils. In denatured oils, the streamer propagated longer compared to standard oils, but the lengths of positive streamer did not exceed±15% of those in standard transformer oil. The ac breakdown voltage in denatured oils also reduced compared to those of standard oils. The dielectric strength of denatured rapeseed ester oil, however, was comparable to that of standard transformer oil.On the other hand, the coaxial cone to rod electrode assembly was devised newly and the properties of the liquid jet were experimentally examined. When a positive dc voltage was applied to the rod electrode, the liquid spouted forcibly from the glass tube outlet installed in the top of grounded conical electrode. This EHD pumping comes from the accumulation of ionic charges in the vicinity of rod electrode. It is also shown that a partial insulator coating of rod electrode surface leads to a rising of the pumping pressure and a reduction of the conduction current. An EHD pumping is expected largely as a new cooling technique in the oil-filled power apparatus, but there is need to take into consideration a reciprocal relation between the EHD mechanism and the electrical insulation. Less