Current transformers (CTs) are extensively used in electrical switchyards and substations for metering and protection purposes [1] and are expected to operate properly for at least 30 years [2]. Normally, aging of CTs under service conditions is relatively slow, but they also may fail prematurely due to various reasons, such as design faults, inadequate quality during manufacture, lightning strikes, operation beyond rated conditions and inadequate maintenance [3]. Compared with other high voltage apparatus, failure of a CT can be violent or even catastrophic, causing damages to the CT itself as well as to nearby located assets and humans [4–9]. Build-up of internal pressure during a failure of a CT results in an instant fire due to burning of oil and explosion of porcelain housing, where porcelain pieces can spread to a distance up to 100 m [4], [6].

中文翻译：

---

斯里兰卡132/220 kV油纸电流互感器状态评估

电流互感器 (CT) 广泛用于电气开关站和变电站，用于计量和保护目的 [1]，预计至少可以正常运行 30 年 [2]。通常情况下，CT 在使用条件下的老化速度相对较慢，但也可能由于设计故障、制造过程中质量不足、雷击、超出额定条件运行和维护不足等各种原因而过早失效[3]。与其他高压设备相比，CT 的故障可能是剧烈的甚至是灾难性的，会对 CT 本身以及附近的资产和人员造成损害 [4-9]。CT 发生故障时内部压力积聚，会因油燃烧和瓷壳爆炸而引起瞬间火灾，瓷片可扩散到 100 m 的距离[4]，