电缆终端内绝缘带与绝缘油相容性试验研究

为解决电缆终端内绝缘带溶胀导致的渗漏油问题,以退运充油终端内以及未使用的同型号绝缘带、绝缘油为研究对象,基于运行要求设计了相容性试验,并进行了红外光谱、失重率、击穿电压等对比测试,分析了溶胀发生的原因以及防治措施。测试结果表明硫化不充分会导致橡胶材料更容易与聚异丁烯绝缘油反应,绝缘带与绝缘油加速热老化后绝缘带质量、绝缘油击穿性能均有明显降低。使用该批次橡胶绝缘带的电缆终端投运后,浸泡在绝缘油中的绝缘带溶胀甚至软化开裂,会导致密封失效发生渗漏油,同时绝缘油击穿性能下降,需尽快更换相应电缆终端。目前并无适用的电缆附件内材料相容性试验和高黏度绝缘油击穿电压测试方法标准,基于已开展的多组对比试验结果,明确了电缆终端内绝缘带与绝缘油相容性试验的关键参数和评价指标,提出适用于高黏度绝缘油的击穿电压测试方法,为同型号充油终端的检查和更换措施提供技术支持,避免了批次性故障的发生。

Compatibility Test Between Insulation Belt and Insulation Oil in Cable Terminal

In order to solve the problem of oil leakage caused by swelling of insulating tape in the cable terminal, this paper studies the same type of used and unused insulating tape and oil. On the basis of operating requirements, it designs the compatibility test, conducts comparative tests on infrared spectroscopy, weight loss rate and breakdown voltage, and analyzes the causes of swelling and preventive measures. The test results show that inadequate vulcanization will lead to easier reaction between the rubber and polyisobutylene insulating oil, and the weight of insulating tape and the breakdown performance of insulating oil are obviously reduced after accelerated thermal aging of insulating tape and oil. After the cable terminals using the batch of rubber insulated tapes are put into operation, insulating tape soaked in the insulating oil swells and even softens and cracks. Oil leakage may result in seal failure, and the breakdown performance of insulating oil decreases at the same time. It is required to replace the relevant cable terminals as soon as possible. At present, there is no applicable standard for testing material compatibility and breakdown voltage of high viscosity insulating oil in cable accessories. Based on a number of comparative experimental results that have been carried out, the paper defines the key parameters and evaluation indexes of compatibility test between insulating tape and insulating oil in the cable terminal, and proposes the breakdown voltage test method suitable for high viscosity insulating oil. This research can provide technical support for inspection and replacement of the same type of oil filling terminal, and avoid the occurrence of batch failure.