Transformer online-PD briefs own tank and bushing sensing on oil plant. This page is the other common industrial HV package: SF₆ GIS and the unconventional PD methods used because conventional IEC 60270 coupling is awkward on sealed bays in the field.
Partial discharge in GIS launches fast electromagnetic pulses that UHF sensors (roughly the hundreds-of-MHz to GHz class in practice) can pick up through windows, built-in antennas, or external ports. Acoustic sensors help locate sources compartment by compartment, but SF₆ and flange reflections attenuate sound sharply—so many programs use UHF for detection and trend, acoustic for localization during outages or commissioning. Free metallic particles, insulator surface contamination, and floating shields each leave patterns; continuous monitors need interference rejection and a defined response path, not a dashboard nobody owns.
Specify sensor coverage per bay and duct, not one antenna “for the hall.” Commission with known pulse injection or sensitivity checks so a quiet channel is not a dead channel. Trend PRPD or equivalent fingerprints after switching and after gas work; a new cluster after a compartment open is a finding, not weather. Pair PD alarms with gas-quality and interlock status—SF₆ density still matters—but do not wait for a density alarm to discover a particle that has been discharging for weeks.
A sealed bay without PD ears is a sealed ignorance. Listen in UHF, confirm location when the pattern demands it, and open the compartment on evidence—not on hope.