Case Study of Abnormal H_2 in Insulating Oil of Fault Free Transformer

By combining typical cases, the paper analyzes abnormal H2 in insulating oil of transformer. It is believed that the single H2 abnormity does not necessarily mean that there are transformer defects, and it should be comprehensively judged by results of infrared test, iron core current test, PD test and routine outage test. The single H2 abnormity not due to faults is caused by water electrolysis, oxidizing reaction of iron and catalytic reaction of stainless steel.