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
Ghosts in English-speaking cultures of Latin "spiritus" also in the meaning of "breath, blast" from the earliest attestations (9th century). It could also denote any good or evil spirit, i.e. angels and demons; the Anglo-Saxon gospel refers to the demonic possession of Matthew 12:43 as "se unclæna gast". Also from the Old English period, the word could denote the spirit of God, viz. the "Holy Ghost." The now prevailing sense of "the soul of a deceased person, spoken of as appearing in a visible form" only emerges in Middle English (14th century). The modern noun does, however, retain a wider field of application, extending