After the on-load tap changer has been dismantled and serviced, field O&M personnel often encounter the following situation: the switch operates normally, but when the transition resistance is re-measured, the values fluctuate, and the transition time and simultaneity data lack comparability. Such phenomena are mostly related to the degree of match of the test solution rather than defects in the switch itself. Clarifying the test requirements at the selection stage can reduce the repetitive workload of subsequent re-testing.
Transition Resistance Measurement: Difference Between Single-Point Acquisition and Full-Process Recording
Conventional solutions mostly use single-point sampling or simple bridge methods to read the transition resistance. Due to the transient nature of the switching process, details in the transition waveform are easily missed. The DRD-9300 on-load tap changer tester records the switching process by full-process recording, incorporating the transition resistance, transition time, and simultaneity into the same operation record, making it convenient for O&M personnel to judge the recovery condition by comparing waveform changes before and after maintenance. For verification scenarios after dismantling and servicing, full-process recording reflects the completeness of the transition process better than single-point readings.
Simultaneity Judgment: Phase-Separated Recording and Manual Comparison
The simultaneity test focuses on the time consistency of the switching operations of each phase. Some conventional practices rely on manual comparison of time values after separate measurements; affected by the operating rhythm and recording method, the source of deviation is not easy to distinguish. The DRD-9300 synchronously records the switching timing of each phase in a single operation, reducing the variables introduced by separate measurements and making the simultaneity data closer to the actual operating state of the switch. During field use, O&M personnel can judge whether the mechanism needs adjustment or re-testing based on the recorded results.
Selection Focus: Covering Common Requirements of Maintenance Verification
From the perspective of field O&M, when selecting equipment, priority should be given to confirming whether the device can simultaneously cover the three parameters of transition resistance, transition time, and simultaneity in a single operation, avoiding the wiring and recording burden brought by coordinating multiple instruments. The parameter configuration of the DRD-9300 is oriented toward the switching characteristic test requirements of common on-load tap changers, and during post-maintenance re-testing, trend judgment can be made directly against historical records. Before testing, confirm that the wiring method matches the switch type, and save the waveform records promptly after testing for subsequent re-test comparison.
