Optical measurement of partial discharges in silicone gel under repetitive pulse voltage
Optical measurement of partial discharges in silicone gel under repetitive pulse voltage
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重复脉冲电压下硅凝胶局部放电的光学测量
DOI：
10.1109/iseim.2005.193562
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
O. Lesaint
中科院分区：
文献类型：
--
作者：
M. T. Do;J. Augé;O. Lesaint
硅凝胶用于功率半导体组件，以密封系统免受水分和大气污染物的影响，也可以消除高压（最近绝缘栅双极晶体管- igbt -模块高达6.5 kV）下空气中可能发生的局部放电。这里考虑的电极几何结构是由用于模块的陶瓷衬底构成的。PD可以在铜轨的尖锐边缘开始。利用凝胶的透明性，在交流和重复脉冲下进行了PD的光学测量。结果表明，光学测量导致非常高的PD检测灵敏度（<1pC）。所得结果可以区分电压阈值，当电压升高时，电致发光、局部放电和不可逆凝胶降解相继发生。研究了外加电压形状和频率的影响。这些测量清楚地表明空间电荷对局部放电开始的影响，这取决于峰值到峰值电压，而不是瞬时施加电压。由此得出结论，在交流电压下的经典PD测量不能充分代表凝胶在重复脉冲作用下的实际性能。
Silicone gels are used in power semi-conductor assemblies to seal the system against moisture and atmospheric contaminants, and also to eliminate partial discharges that may occur in air at high voltage (up to 6.5 kV in recent insulated gate bipolar transistor -IGBT- modules). The electrode geometry considered here is constituted by a ceramic substrate used in modules. PD's can be initiated at the sharp edges of copper tracks. Taking advantage of the transparency of gels, optical measurements of PD's are carried out in this work both under AC and repetitive pulses. It is shown that optical measurements lead to a very high PD detection sensitivity (<1pC). Results obtained allow to distinguish voltage thresholds at which electroluminescence, partial discharges, and irreversible gel degradation successively occur when the voltage is increased. The influence of the shape of the applied voltage and frequency are investigated. These measurements clearly show the influence of space charges on partial discharge inception, that depends on the peak to peak voltage rather than on the instantaneous applied voltage. It is concluded that classical PD measurements under AC voltage do not adequately represent the actual performance of gels subjected to repetitive pulses.