A Novel Vibration Frequency Response Analysis Method for Mechanical Condition Detection of Converter Transformer Windings

Converter transformer harmonic currents are both the main cause of winding looseness and effective information for detecting winding looseness fault. In this letter, an online vibration frequency response analysis (VFRA) method is proposed using high amplitude and wide frequency electromagnetic forces generated by harmonic currents. The vibration frequency response function is defined as the ratio of vibration acceleration to current squared. A harmonic loading system is built to simulate the actual operating situations of the converter transformer. The laboratory experimental results verify that the VFRA can effectively identify winding looseness fault and enable online monitoring of winding mechanical condition.