An abnormal increase of transformer oil dielectric loss in service and its cause were introduced, and the treatment process to make the dielectric loss to reach standard was summarized, based on the experience of operation and overhaul.

• 摘要介绍了变压器油介损增高和产生这些现象的原因，并根据运行和检修经验综述了使变压器油介损达标的处理方法。