In live detection of equipment such as switchgear, transformer bushings, and cable terminations, O&M personnel often encounter the problem that partial discharge signals are drowned out by on-site electromagnetic interference, and phase jitter makes the spectra difficult to interpret. Especially in distribution rooms where multiple devices are densely arranged, observing pulse amplitude with an oscilloscope alone often cannot distinguish true discharge from interference.
For the above scenarios, partial discharge detectors need to support on-site judgment from two aspects. First, detection sensitivity and calibration reliability. The built-in calibration pulse generator provides 11 levels of correction square waves from 10mV to 4V, with a pulse leading edge of no more than 60ns, making it convenient to perform amplitude calibration on the detection circuit before testing and to confirm whether the detection capability at the 0.015pC level covers the requirements of the current test object. Second, synchronization mode and phase accuracy. The device supports internal synchronization, external synchronization, and wired/wireless synchronization, with a phase accuracy of ≤0.1°. In live detection, discharge pulses and periodic interference can be distinguished based on phase distribution, reducing misjudgment.
For large factory tests or laboratory-level high-precision diagnostics, multi-channel synchronized measurement is a common requirement. The spacing between fiber-optic synchronization channels of the partial discharge detector can reach 2km, which is suitable for maintaining phase consistency between distributed test objects and detection units and avoiding spectrum shifts caused by synchronization errors. On-site O&M personnel should first confirm the compatibility between the synchronization mode and the test object layout, and then set the detection threshold based on the calibration results.
In terms of maintenance, regularly check whether the output amplitude and leading edge of the calibration pulse are within the nominal range, and keep the touchscreen and interfaces clean, which can reduce data deviation caused by calibration drift. During operation, pay attention to the shielding and grounding of synchronization cables to avoid introducing additional interference.
