The DC test, which is an effective means for the diagnostics of oil impregnated paperinsulated cable, is still used even now, but it is ineffective and harmful for the plastic insulated cable.
直流电压试验作为一种对油浸纸绝缘电缆非常有效的方法应用至今，但它对塑料绝缘电缆是无效而且有害的。
2
Detection of furfurol content in transformer oil is an effective method to judge the aging degree of insulatedpaper in the transformer.