Partial discharge Partial discharge In electrical engineering, partial discharge (PD) is a localized dielectric breakdown (DB) of a small portion of a solid or fluid electrical insulation (EI) system under high voltage (HV) stress, which does not bridge the space between two conductors. While a corona discharge (CD) is usually revealed by a relatively steady glow or brush discharge (BD) in air, partial discharges within solid insulation system are not visible. PD can occur in a gaseous, liquid or solid insulating medium. It often starts within gas voids, such as voids in solid epoxy insulation or bubbles in transformer oil. Protracted partial
Halo (religious iconography) obsolete "nimbated", like the commoner "nimbate", means "furnished with a nimbus". It is sometimes preferred by art-historians, as sounding more technical than halo. "Aureole", from the Latin for "golden", has been used in English as a term for a gold crown, especially that traditionally considered the reward of martyrs, since the Middle Ages (OED 1220). But the first use recorded as a term for a halo is in 1848, very shortly after which matters were greatly complicated by the publication in 1851 of the English translation of Adolphe Napoléon Didron's important "Christian Iconography: Or, The History of Christian Art in