油浸纸套管电容芯子浸渍不良缺陷的放电过程及其特征

Discharge Process and Characteristics of the Poor Impregnated Defect of Capacitor Core in Oil-Immigrated Paper Bushing

为了研究油浸纸套管浸渍不良缺陷的劣化机理,研制了透明的套管模型,利用良好套管模型漏油后补油不抽真空的方法,模拟浸渍不良缺陷;利用阶梯升压法,研究浸渍不良套管缺陷模型的局部放电参数、介质损耗正切值和电容量的变化情况,同时观测了放电过程中的产气部位和产气现象,并结合试验后解剖,分析油浸纸电树枝碳化通道。研究结果表明,对于油浸纸套管浸渍不良缺陷劣化过程,局部放电检测比较灵敏、特征显著,而介质损耗正切值、电容量检测不灵敏。放电位于芯子末屏极板边缘,沿极板边缘纸层表面发生电树枝沿面爬电并产生连续的气泡。放电相位呈现明显的对称分布,放电相位与放电量的φ-q散点图呈现"翼状"分布特点,可作为诊断和识别油浸纸套管电容芯浸渍不良缺陷放电严重程度的特征谱图。

In order to study the degradation mechanism of the poor impregnated defect in oil-impregnated paper bushing（ OIP）,an OIP model is made by transparent sheath. A poor impregnated defect is designed by the non-vacuum oil injection after its linking oil. The parameter of changes of partial discharge,tan δ and capacitance are measured by the step by step raising voltage method,while the discharge phenomenon are observed. And also observing the position of bio-gas, gas-producing phenomenon, combined with trial anatomy, analysis of carbonization oil impregnated paper electrical tree channel. The result shows that PD detection is more sensitive for poor impregnated defect than tan δ and capacitance. The partial position is located at the edge of coil and electrical tree creepage would produce along the surface of oil-impregnated paper and produce continuous bubbles. The diffusion of Phase-resolved partial discharge is symmetrical about the 180° phase of applied votage.The φ-q spectrogram of partial discharge has a typical characteristic of the wing shape which may be used to diagnose the discharge type and severity of poor-impregnated defect in OIP.