Method and device for inhibiting transformer no-load switch-on surge

Abstract

The invention relates to a device and a method for inhibiting inrush current upon switching on an idling transformer. The device includes more than one thyristor set linked between an AC power switch and the transformer, each phrase of the AC current is linked to at least one thyristor set; a side contactor parallely linked to the thyristor sets; a resistance-capacitance circuit parallely linked to two ends of a thyristor power module which forms the thyristor set. A front end voltage transformer in the system tests the power voltage; a current transformer tests the phase current of the transformer; a back end voltage transformer tests transformer voltage whose signal output terminals are respectively linked to the corresponding input terminals of a control unit. The control unit firstly calculates the size and phase of the pre-magnetizing flux linkage in the transformer, and calculates the link time for the premier winding sets to determine the connecting time for the thyristor set, as well as the link time for other winding sets, finally short-circuits the thyristor through the side switch sets. The invention can inhibit the excitation inrush current upon switching on the idling transformer to a great extent.

Description

technical field [0001] The invention relates to a device for suppressing transformer excitation inrush current generated when a transformer is put into operation without load in a power supply and distribution system, in particular to a device and method for suppressing transformer no-load closing inrush current. Background technique [0002] The excessive excitation inrush current generated when the transformer in the power supply and distribution system is turned on without load often causes problems such as the malfunction of the microcomputer protection device, the increase of the mechanical stress of the winding, and the deterioration of the power quality. At present, for this situation, the second harmonic braking coefficient is basically changed in the front-end microcomputer protection device to avoid the no-load closing surge, thereby preventing the protection device from malfunctioning. However, when the transformer is closed with no load, due to the uncertainty of...

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Problems solved by technology

[0003] In view of the fact that the currently widely used methods cannot efficiently solve the problems of microcomputer protection malfunctions caused by transformer no-load closing inrush current, the patent of the present invention focuses on eliminating and suppressing transformer no-load closing inrush current, and provides a method for suppressing transformer no-load closing inrush current. A device and method for gate inrush current, thereby effectively solving problems such as microcomputer protection malfunctions caused by excessive excitation inrush current in power supply and distribution systems

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