ENSAIO DE RIGIDEZ DIELÉTRICA EM ÓLEO MINERAL ISOLANTE SOB VARIAÇÃO DE TEMPERATURA

Abstract

Currently the known way to regulate capacitance and voltage levels of a medium voltage capacitor is the switching method, which is nothing more than the removal or commissioning of a capacitor bank, and such drives can be performed. in several ways including manual or automatic. The operation of this equipment has a high cost, it is costly because the device responsible for the opening or closing maneuver (on or off) is complex. However, by thoroughly investigating the variables that contribute to the specific capacitance value of a system that presents characteristics of a capacitor, it is clear the possibility of manipulating such variables and arriving at a satisfactory result, not taking into account in the first instance. your degree of difficulty. Capacitance depends on three basic variables which are: the area of ​​their armatures, the distance between these armatures and the type of dielectric material used (dielectric constant), this for simple systems, not considering special and singular systems that may exist. A conventional capacitor commercialized has as insulating material the mineral insulating oil that guarantees certain characteristics and parameters that are adequate to the operating voltage level. However, if it is possible to change the physical properties of this material through temperature variation, it is expected that its dielectric constant value will change (atomic disorder level), a function of this imposed situation; and consequently change its nominal capacitance value, guaranteeing to the equipment characteristics of becoming variable due to the variation of the physical properties. Insulating mineral oil presents considerable values, under the action of the different temperature gradients imposed in the test, it can be constructed a equipment that works all the time connected to the system, avoiding the use of switching devices. The capacitance level regulation will be in charge of the fluid working temperature, which will be controlled according to the need of the SEP (Electric Power System).