After short-circuit impacts or transportation vibrations, field personnel usually hope to obtain comparable judgment criteria for whether transformer windings have undergone displacement or deformation without lifting the cover. The frequency response method reflects the internal structural state of the winding through the corresponding relationship between swept-frequency excitation and response amplitude, and the test results are presented as curves, making it easy to compare horizontally with historical data or equipment of the same model. WFX-5800 is designed for field O&M scenarios, focusing on simple wiring and the operability of curve comparison.
In common field configurations, the upper sweep frequency limit of some instruments remains at the level of several hundred kilohertz, with limited response resolution for subtle structural changes such as inter-turn winding variations; the sweep measurement range of WFX-5800 is set to 500Hz–2000kHz, covering the medium- and high-frequency bands of greater concern in frequency response testing. The amplitude measurement range covers -100dB to +20dB, meeting the frequency response testing needs of 6kV and above power transformers and special-purpose equipment such as reactors. Compared with devices that provide only single measurement results, this model supports on-screen comparison of multiple measurement curves, allowing O&M personnel to intuitively see shifts in peak and valley positions without relying on manual point-by-point readings.
The device adopts the swept-frequency response method, with excitation and acquisition channels working in time division, and the time required for a single complete sweep depends on the set number of frequency points. Before testing, confirm that the winding under test has been taken out of service and fully discharged; when wiring, note the tap changer position for easy re-test comparison under the same operating conditions. For handover acceptance or re-testing after major overhaul, it is recommended to retain the original data files as a baseline for subsequent judgment.
Frequency response curves are relatively sensitive to measurement wiring positions and grounding methods, and curves obtained from the same transformer under different wiring conditions should not be directly mixed. Strong electromagnetic interference in the field environment may affect readings in low-amplitude frequency bands, so testing can be scheduled during relatively stable periods according to field conditions. The instrument should be stored away from moisture and severe vibration; if unused for a long time, it is recommended to power it on for inspection before putting it into field use.
