Abstract: To address the lack of basis for sensor configuration and the incomplete multidimensional feature system in existing acoustic-vibration monitoring, this paper derives parameterized adaptive arrangement criteria for sensor arrays based on vibration propagation wavelength constraints and the three-phase spatial distribution of windings. It establishes a five-dimensional feature diagnosis model with frequency complexity, vibration stationarity, multi-point correlation, energy similarity, and harmonic ratio as dimensions. Alarm thresholds for each dimension are determined with reference to industry standards such as GB/T 6451—2015, DL/T 1540—2016, DL/T 393—2010, statistical results from published literature, and engineering field measurement data, and the differentiated response patterns of each feature under typical fault modes are summarized. Three months of monitoring results for Donghua No. 2 main transformer show that the feature combination at edge measurement points is consistent with a slight loosening pattern of clamping force at the winding end. This judgment is listed as an item pending inspection, and outage verification is planned, providing technical support for condition-based maintenance.