Abstract: This article discusses the phenomenon of inconsistency between the readings of the main transformer oil conservator's oil level gauge and the actual oil level in a certain substation. A comprehensive analysis of the abnormal phenomenon is conducted from aspects such as infrared detection, oil drainage during power outages, and internal inspection of the oil level gauge. It is determined that the cause is the detachment of the float ball in the oil level gauge from the interior of the oil conservator, leading to incorrect readings. This issue, if not addressed in time, may lead to misjudgment of oil level, insulation oil leakage, or even main transformer tripping. In response to the issue of inconsistency between the readings of the oil level gauge and the actual oil level, a further analysis is conducted on the effectiveness of infrared temperature measurement in various types of oil conservators, and corresponding maintenance suggestions and detection method optimization schemes are proposed, providing a reference for subsequent operation and maintenance of the main transformer oil conservator's oil level detection.