抗水树XLPE电力电缆的工频击穿特性

Power Frequency Breakdown Characteristics of Water-tree Retardant XLPE Power Cable

为检验电缆材料是否具有抗水树枝能力,建立抗水树枝材料性能试验手段和评价程序,在同一制造厂分别采用5种不同电缆绝缘料,生产同一绝缘结构的电缆,并制作成90个电缆试样。在相同试验条件下,进行14d负荷循环、120d加速老化、180d加速老化、360d加速老化和480d加速老化试验,然后对老化前原始样和老化后电缆试样共6种不同老化状态的电缆试样进行工频逐级击穿,试验研究XLPE电力电缆工频击穿特性。试验结果表明:普通电缆绝缘料制造的XLPE电力电缆工频击穿特性相对抗水树电缆绝缘料制造的XLPE电力电缆工频击穿特性存在明显差异,抗水树XLPE电力电缆经过480d加速老化试验后仍保持较好的工频击穿特性,安全运行寿命较长。

Ninety pieces of power cable samples with the same insulating structure were made using 5 kinds of insulation materials, and all of the samples were produced by the factory at the same producing process. At the same test condition, all the samples were distributed into 6 groups to form 6 kinds of aging states that depend on different accelerating aging periods. The 6 kinds of aging states of samples included original state, 14 d loading cycle state, 120 d accelerated aging state, 180 d accelerated aging state, 360 d accelerated aging state, and 480 d accelerated aging state. Then, all of the samples were tested one by one to validate their AC breakdown voltage. The test results of AC breakdown voltage test of every sample show that the AC breakdown voltage of samples with common insulation is rather lower than other samples＇with water-tree retardant insulation. On the other hand, the length and shape inspection of water-tree inside the slice of 6 kinds of samples reveal the observable difference among these samples. That is, the cable with water-tree retardant insulation is safer to meet special operation requirements, and its operation life is much longer.