12kV固体绝缘开关柜中绝缘气隙缺陷的放电特征

Discharge Characteristics of Air-Gap Defects in Insulating Material of 12kV Solid Insulated Switchgear

为获取12k V固体绝缘开关柜内部绝缘材料中气隙放电特征,搭建12k V固体绝缘开关柜内部绝缘材料气隙缺陷放电试验平台,测量气隙放电在不同电压幅值、不同气隙直径以及不同谐波频率下的局部放电信号。提取并分析气隙缺陷在不同电压幅值下局部放电三维特征图谱,比较不同频率下气隙缺陷放电在正、负半周期内的局部放电差异。研究结果表明,固体绝缘开关柜内部绝缘材料在有气隙缺陷情况下,不同的电压幅值会影响放电量大小与放电次数;谐波频率越高,每周期的放电次数越多,但正、负半周的单次最大放电总量维持在一定的水平,不会出现较大的波动;绝缘介质的气隙直径越大,放电次数越少,每次放电的放电量越大,危害越严重。据此获得的不同试验条件下的n-φ-q三维图,可用于固体绝缘开关柜气隙缺陷放电的模式识别,也有助于对固体绝缘开关柜内部绝缘材料缺陷放电提供理论指导。

In order to obtain the air-gap discharge characteristics of the internal insulation material in 12 k V solid insulated switchgears, an experiment platform of internal insulating material air-gap discharge was built. The partial discharge signals were measured under different voltage amplitudes, air-gap diameters and frequencies. The three-dimensional characteristic spectrums of the partial discharge of air-gap defects under different voltage amplitudes were extracted and analyzed, and the differences of partial discharge under positive and negative half cycles at different frequencies were compared. The results show that different voltage amplitudes will affect the amount and number of discharge in case of the air-gap defects in the insulation material of solid insulated switchgear. The higher the harmonic frequency, the more the number of discharges per cycle, but the total discharges in the positive and negative half cycles are maintained at a certain level, without major fluctuations. Moreover, the larger the air gap diameter of the insulating medium, the less the number of discharges, the greater the discharge capacity of each discharge, the more serious the hazard. The three-dimensional graphs obtained under different experimental conditions can be used to identify the air-gap defect discharge of solid insulated switchgear as well as providing the theoretical guidance for the defect discharge of insulating material in solid insulated switchgear.