电发光检测聚合物绝缘起始劣化的方法

Electroluminescence-a technique to detect the initiation of degradation in polymeric insulation

电缆聚合物绝缘的劣化 (电树枝 )有两个阶段 :第 1是诱导期或起始期 ;第 2是扩展期。文中论述了劣化初始期聚合物内电场强度增强点会有发光 ( EL )现象 ,它不同于局部放电( PD)引起的发光现象 ,至少比 PD检测灵敏度高两个数量级。文中详细介绍了 EL现象发生的机理 ,以及进行实验和检测 ,最终认为 :EL是一种可在电树枝起始之前检测聚合物劣化的有效方法 ,并成功地用于 50 0 k V XL

The degradation of polymeric insulation (electric treeing) has two distinct time periods. The first is the incubation period or the initiation phase, when hardly anything appears to happen in the insulation, and the second is the propagation period during which partial discharges occur and the tree grows. The initiation period of electric treeing is not well understood, but it has been established that prior to electric tree inception light is emitted at points of electric stress enhancement in the polymer. This light is not due to partial discharge (PD) but to the phenomenon of electroluminescence (EL). The intensity of EL is at least two orders lower and the spectra of EL. which is different from the light of PD. EL is also emitted prior to the conversion of a water tree to an electric tree. EL is a powerful technique to detect polymeric degradation prior to electric tree inception and was successfully used in the investigation of 500 kV XLPE power cables.