交直流复合电压下变压器油中金属微粒聚集特性和局部放电特性研究

Aggregation Behaviors and Partial Discharge Characteristics of Metal Particles in Transformer Oil Under AC/DC Composite Voltage

通过开展不同比例交直流复合电压下油中金属微粒在半球电极间的聚集试验,同步采集不同时刻的局部放电(PD)信号,对放电频率及平均放电量进行统计,最后对金属微粒的聚集行为与PD特性的关联性进行了分析。结果表明:金属微粒在直流电压下的聚集区域最大,在交、直流分量比为3∶1的复合电压下的聚集最为紧密;放电频率随时间呈下降趋势,且随着交直流复合电压中交流分量的增加,放电频率逐渐增加;金属微粒与电极间的碰撞频率及金属微粒聚集的紧密程度是影响局部放电频率及平均放电量的主要因素。

The accumulation test of metal particles in oil between spherical electrodes under different ratios of AC/DC composite voltage was carried out,the partial discharge(PD)signals at different moments were collected simultaneously.And then the discharge frequency and average discharge quantity were counted,and the correlation between the aggregation behavior of metal particles and PD characteristics was analyzed.The results show that the accumulation area of metal particles under DC voltage is the largest,and the metal particles aggregated the most closely under 3:1 AC/DC composite voltage.The discharge frequency decreases with time,while gradually increases with the increase of AC component in AC/DC composite voltage.It is considered that the collision frequency between metal particles and electrodes and the closeness of particle accumulation are the main factors affecting the frequency of partial discharge and the average discharge quantity.