基于真空永磁的变压器干式有载分接开关研究

Research on Transformer Dry On-load Tap-changer Based on Vacuum Permanent Magnet

变压器的输出电压由分接开关来控制,通过改变变压器绕组抽头与分接开关的连接来改变绕组的匝数比,实现对变压器输出电压的控制。在直流输电中,有载调压开关尺寸大、价格相对昂贵的特点限制了有载调压方式的应用。针对传统有载分接开关体积大、操作复杂的不足,采用永磁直动型真空有载开关能更好地减小体积并降低成本,且由于直流输电电压电流没有零点,所以相较于交流输电会产生更大的弧光反应。因此文章研制了一种干式真空永磁有载分接开关,实现了负载电流和级间环流全部在真空灭弧室内切换,有效避免了机构失调运行引起的分接间弧光短路事故,实现了对直流系统电压的分级调整与优化处理,减少了换流变压器侧电压变化对整个直流系统造成的不利影响,提高了直流输电系统的运行稳定性及经济效益。

The output voltage of the transformer is controlled by the tap-changer,and the turn ratio of the winding is changed by changing the connection between the transformer winding tap and the tap-changer,and the output voltage of the transformer is controlled in this way.In HVDC transmission,the large size and relatively expensive price of on-load regulator limit the application of on-load regulator.In view of the disadvantages of large volume and complex operation of traditional on-load tap-changer,the permanent magnet direct-acting vacuum on-load switch can reduce the volume and cost better.In addition,since the voltage and current of the DC transmission have no zero point,larger arc reaction will be generated compared with that of the AC transmission.Therefore,a dry vacuum permanent magnet on-load tap-changer is developed in this paper to realize the switch of the load current and interstage circulation in the vacuum arc extinguishing chamber,effectively avoiding the arc short circuit accident between the tap and tap caused by the misoperation of the mechanism.It realizes the hierarchical adjustment and optimization of DC system voltage,reduces the adverse influence of transformer side voltage change on the whole DC system,and improves the operation stability and economic benefit of the DC transmission system.