ABSTRACT
Insulating oils, fl uids, and gases are used as dielectrics in the electrical equipment and apparatus. The liquids used in the transformers are mineral oil and synthetic fl uids, such as askarel, silicone, RTemp, Wecosal, Alpha 1, and GE R113. (The synthetic fl uids such as askarel, silicone, RTemp, etc. have a fi re point of not less than 300°C and are classifi ed as less fl ammable insulating fl uids by the National Electric Code, NEC.) Mineral oil is also used as a dielectric in circuit breakers, reclosers, interrupters, and the like. The most common insulating gas used in circuit breakers and completely enclosed substations is sulfur hexafl uoride (SF6). This chapter covers electrical, chemical, and visual tests which are normally conducted for the maintenance of transformer oils and fl uids. Also, this chapter includes a discussion on the inspection, handling, and reconditioning of insulating oil, fl uids, and gases used in electrical equipment.
