电压类型对柱板电极放电故障下油纸绝缘产气特性的影响

由于换流变压器内存在交直流复合电场,交流变压器所采用的色谱诊断方法是否适用于换流变压器尚未可知,因此本文建立了一套交流及交直流复合电压作用时油纸绝缘柱板放电试验平台,对比了两种电压作用下的产气特性,并分析了原因。研究结果表明:柱板电极在不同类型电压作用下油纸绝缘产气特性不同,交流产气量大,产气速率大,能够较早地发现故障;而交直流复合场产气前期变化不明显,最后阶段产气量骤增后绝缘迅速失效;另外,交流和交直流复合电压作用下油纸绝缘柱板缺陷模型DGA诊断结果相同,都为火花放电,说明已有DGA诊断标准在换流变压器中有一定的适用性。

Impact of Voltage Type on the Gas Production Characteristics of Oil-paperInsulation Under Discharge Fault of Column Plate Electrode

Because of the existence of AC-DC combined electric field in converter transformer, whether the convention DGA method can be used in converter transformer still remains unclear.So a set of platform for dissolved gas in oil analysis of column-plate discharge was built to compare the difference in DGA between AC and AC-DC combined voltages. The test results show that the dissolved gases characteristics for oil-paper insulation with different voltage types under column-plate electrode are different, which means that fault can be detected earlier when gas contents and gas-produced rate are bigger, and the change of generated gas in earlier stage under composite AC and DC voltage level is not obvious and there is no insulation effect after the sudden increasing of generated gas during final phase. In addition, the diagnosis results of DGA for oil-paper insulation fault with different voltage types under column-plate electrode are same, which means that the DGA diagnosis standard has certain applicability in converter transformer.