DEVICE THAT ABSORBS ZERO-SEQUENCE HARMONICS IN LOW-VOLTAGE ELECTRICITY DISTRIBUTION NETWORKS

摘要

The invention relates to a device, autotransformer and system for eliminating zero-sequence harmonics for unbalanced three-phase systems with non-linear loads, which comprises a siliceous steel core reinforced with plates for reducing losses caused by eddy currents; terminals in terminal blocks suitable for each value of current and a metal cabinet with forced ventilation and an air louvre suitable for the heat to be evacuated, the siliceous steel core comprising three C-shaped legs disposed one in front of the other one at 120° intervals, forming a three-pointed star; three windings of copper insulated according to the power or current circulating through the windings, with taps for making the phase connections or crossings. According to the invention, the distribution of fluxes being distributed in the three legs of the siliceous steel core in a proportion of 50% in the first leg, 25% in the second leg and 25% in the third leg, for each phase, the polarity of the second and third legs being reversed, causing the fluxes in the second and third legs to be summed with a sign opposite to that of the flux of the first leg, giving a result of zero. The current through the neutral is thereby absorbed and the residual current is re-injected into the phases in a balanced manner