When an on-load tap changer operates abnormally, it typically manifests as output voltage fluctuations, abnormal switching sounds, or excessive transition processes. If field O&M personnel rely solely on experience, it is often difficult to determine whether the problem lies in transition resistance, transition time, or three-phase simultaneity. At this point, a tester capable of simultaneously recording transition waveforms and calculating relevant parameters can help O&M personnel quickly obtain a basis for judgment.
The instrument can continuously acquire the transition waveform during the switching process and automatically calculate the transition time. By observing the waveform shape, O&M personnel can distinguish situations such as transition resistance being inserted too early or too late, or abnormal bridging time. The measurement results are presented simultaneously as waveforms and numerical values, facilitating comparison with historical data.
For conventional on-load tap changer transition resistance measurement scenarios, the instrument can measure the transition resistance value of each phase. At the same time, through three-phase synchronous acquisition, it calculates the time difference of the three-phase switching actions, namely three-phase simultaneity. This parameter helps identify phase-to-phase asynchrony problems caused by mechanical transmission or contact wear. The test wiring method matches common field switch types, reducing repeated wiring and disconnection.
• Routine substation maintenance: record the operating characteristics of the on-load tap changer and establish an initial archive.
• Troubleshooting abnormal switching: when voltage drops or abnormal noise occurs during voltage regulation, locate the faulty phase through waveforms.
• After switch overhaul: verify whether transition resistance, transition time, and simultaneity have returned to normal ranges.
• Long-term operation tracking: compare multiple test waveforms to observe whether the transition process deteriorates over time.
Note: The above information and technical parameters are sourced from Yangzhou Darui Electric Co., Ltd. and published after compilation.
