After an outlet short circuit of a transformer, the windings may undergo axial or radial deformation, but this is difficult to detect by visual inspection. When selecting a winding deformation tester, procurement personnel need to focus on whether the instrument can stably capture these small changes. The following summarizes the key selection points from five aspects.
The effectiveness of the frequency response analysis method depends on the sweep range. It is recommended to choose an instrument with a sweep range covering 0.5 kHz to 2 MHz, so as to include the low-frequency, mid-frequency, and high-frequency response characteristics of the windings. The sweep excitation method should be continuously adjustable to avoid missing key resonance peaks due to fixed-point measurement. The BRF-6200 has an output frequency range of 1 Hz to 2 MHz, which can meet routine diagnostic needs.
During on-site testing, electromagnetic interference at the substation may mask weak signals. The dynamic range of the instrument is recommended to be no less than 80 dB, and it should have filtering and averaging functions. During procurement, attention can be paid to whether the instrument uses digital phase locking or correlation detection technology to improve the signal-to-noise ratio.
Dual test modes (such as single-phase excitation/dual-phase excitation) can adapt to different wiring scenarios. Procurement personnel should confirm whether the instrument supports quick-connect terminals and whether it provides wiring error prompts, so as to reduce repeated on-site operations.
The software should be able to automatically calculate correlation coefficients, plot amplitude-frequency curves, and support comparison of historical data. During selection, it is necessary to confirm whether the software provides clear deformation criteria and whether it supports report export.
The instrument should be able to store multiple sets of test data and support retrieval by transformer number. The report format should preferably comply with the requirements of preventive test regulations, facilitating archiving and horizontal comparison.
