基于超高频法的GIS自由金属微粒局部放电检测与特性研究

Partial discharge detection and characteristics probe of free metal particles in GIS based on UHF method

为了研究自由金属微粒对三相共筒式GIS设备运行的影响,提高局部放电检测水平,试验设计了3种不同形状、尺寸的自由金属微粒模型。采用逐步升压法对其进行试验,用超高频法测量了不同模型试品的局放起始电压,局放信号波形,对不同类型的自由金属微粒放电过程做了分析,建立了局部放电变化灰度图和脉冲分布图,获得了相应的图谱特征。试验结果表明,自由金属微粒尺寸较大,形状较规则,其局部放电正负半周差异性较小,放电幅值也相对较小;当微粒较小且形状越不规则,其局部放电越剧烈,放电量越大。另外试验结果还表明,在试验电压范围内,对于三相共筒式GIS,并没有发现自由金属微粒跳动情况。

In order to study the influence that free medal particles have on the three- phase GIS and raise the level of partial discharge detection,the experiment design three kinds of free medal particles models which have different shapes and different sizes lying in the inside of GIS. After improving voltage step by step in the experiment,measuring PD inception voltage and PD signal waveform in the trend diagram of the different test models,analyzing different types of free medal particles discharge process,we can establish the trend chart of particle discharge,gray degree diagram and waveform diagram and obtain the corresponding map features at last. The experimental results show that the larger the free medal particles＇ size and the more rules the free medal particles own,the less the otherness of the positive and negative half cycle is and the smaller the discharge amplitude is. On the other hand,when the smaller and more rules,the more dramatic for partial discharge and the greater amount of discharge. Otherwise,we haven＇t founcl free metal particle＇s beating in the range of the experiment voltage on the three- phase GIS.