交直流复合电场中油纸绝缘沿面放电现象及特征

油纸绝缘沿面放电是换流变压器中常见的一种故障类型,了解换流变压器内沿面放电现象及特征对实现设备故障诊断具有重要意义,不过由于换流变压器内主要为交直流复合电场,放电现象与交流单独作用时有明显区别,所以诊断判据应不同,但是目前缺少换流变压器的诊断依据,因此为了得到换流变压器沿面放电的诊断依据,搭建了一套交直流复合电压作用下油纸绝缘沿面放电检测平台,观察了交直流复合电压作用下油纸绝缘沿面放电现象,统计了局部放电和油中溶解气体特征变化规律,根据放电特征和油中溶解气体产物将放电严重程度进行分级,为换流变压器诊断提供判据。结合交直流复合电压作用时沿面局部放电及产气特征可以为换流变压器故障严重程度提供判定依据。

The Phenomena and Characteristics of Oil-Paper Insulation Surface Discharge Under AC and DC Voltage

Surface discharge in oil-paper insulation is a common defect in converter transformer. Because of the complex operation conditions in converter transformer, the occurrence likelihood of surface discharge increases. It is important to understand the phenomena and characteristics of surface discharge in oil-paper insulation for fault diagnosis of converter transformer. But the electric field in converter transformer is AC-DC combined electric field, which is quite different from AC voltage. So this article built an oil-paper insulation surface partial discharge detection platform under AC-DC combined voltage, and then analyzed the trend of partial discharge characteristics, at last divided the severity classification according to the characteristics of discharge and dissolved gas analysis (DGA). The diagnosis method under AC voltage has certain applicability under AC-DC combined voltage.These characteristics on partial discharge and DGA could be the foundations of fault diagnosis for converter transformer.