ADAPTIVE MAGNETIZING INRUSH CURRENT RESTRAINING DEVICE AND METHOD

摘要

A magnetizing inrush current restraining method and device. According to the method, the state of a transformer before no-load closing is considered comprehensively, and different control strategies are adopted according to different states; during local manual opening or distant remote-control opening, an angle identical to an opening phase angle is selected for closing; during tripping caused by short-circuit faults, magnetizing inrush currents at the moments of different closing phase angles in the range of 0-360 degrees are estimated according to three-phase voltage information at the moment of opening to obtain a closing phase angle corresponding to the minimum magnetizing inrush current; and during man-made demagnetization after opening, the angle of any of three phases is selected as 90 degrees for closing. The method and the device have the capability of automatically recognizing the state of the transformer before no-load closing and executing the corresponding control strategy and the capability of automatically learning the time needed by switch closing and automatically adjusting closing exit triggering moments; the device also has a complete set of functions for protecting electric quantity of the transformer.