Abstract: An apparatus for identifying a fault in the windings of a distribution transformer, a transformer, and an associated method, said device comprising: a first Rogowski current sensor at a high-voltage incoming current terminal, and a second Rogowski current sensor in tandem at a low-voltage outgoing current terminal and at a low-voltage incoming current terminal; a first conductor of the low-voltage outgoing current terminal, passed through in one direction through the second sensor, and a second conductor of the low-voltage incoming current terminal, passed through in the opposite direction through the second sensor; the first and second sensors generate output signals indicating the primary current and the secondary current; both signals are integrated, generating output signals proportional to the primary current and the secondary current, obtaining a transformation ratio, which is compared with a threshold, and sending a fault signal if said threshold is exceeded.

Abstract: The present invention is related to the development of a new formulation of electrical grade porcelain having improved mechanical and dielectric characteristics, and whose primary application is in electrical components, such as electric insulators. This invention has as its main object to provide a new alternative to increase the final properties of an electrical grade porcelain, which is related to the incorporation of suitable concentrations of nanosized ceramic oxides, as part of the initial composition of porcelain paste. This new nanotechnology alternative favors an increase in the final properties of electrical grade porcelain, such as flexural strength or cold rupture modulus, as well as dielectric strength, which is due to the incorporation of ceramic oxides such as alumina (?-Al2O3) and zirconia (ZrO2), in micrometer scale (i.e., less than 100 nanometers), favorably modify the microstructure of the base porcelain.

Abstract: A porcelain bushing for transformers withstanding impulse voltages rated at 45 kV and 1.2/50 &mgr;s without external flashover, having a creepage to arcing distance ratio of 1.05 to 1.24. The bushing includes a body constituted by a flange fitted with a gasket seat groove, a neck having a curvature radius ranging from 5 to 7 mm, and a mouth equipped with a two-level stepped gasket seat and a semicircular groove. A threaded shank for the attachment of the porcelain bushing to the mounting surface and a groove rail extending along the shank's thread is also provided. In a preferred embodiment, the body is coated with glassy enamel in order to protect the porcelain material against contamination by external agents as well as against the adoption of water.