Method and device for quickly eliminating ferroresonance of voltage transformer

Abstract

The present invention discloses a method for quickly eliminating ferroresonance of a voltage transformer. The method is that a three-phase voltage and an open-delta voltage of the voltage transformerare first sampled, and then flux linkage corresponding to a zero sequence voltage is calculated by an integration algorithm. When the ferroresonance of the transformer is detected, it is further detected whether an absolute value of the flux linkage corresponding to the zero sequence voltage or the open-delta voltage falls within a set range, and if so, a secondary harmonic elimination circuit starts for harmonic elimination. The invention also discloses the corresponding device for quickly eliminating the ferroresonance of the voltage transformer. With the method and the device, harmonic elimination trigger time is accurately analyzed and controlled on the basis of the conventional secondary harmonic elimination principle; the influence of iron core saturation of the voltage transformer on the harmonic elimination process is effectively eliminated; and the success probability of single harmonic elimination is greatly improved.

Description

technical field [0001] The invention relates to fault elimination of voltage transformers in electric power systems, in particular to a resonance elimination control method and device when ferromagnetic resonance occurs in neutral point indirect grounding system voltage transformers. Background technique [0002] In the neutral point indirect grounding system, some voltage transformers used to measure the voltage to the ground, the neutral point of the primary winding is directly grounded, when the no-load bus closes, the single-phase ground fault disappears or the system load When changing, the excitation inductance of the voltage transformer will have a nonlinear change, which may form a parameter match with the system’s capacitance to the ground, which will cause ferromagnetic resonance, cause system overvoltage and voltage transformer overcurrent, and then cause insulation damage and grounding. Or phase-to-phase faults, as well as voltage transformer fuses blown, burned ...

AI Technical Summary

Problems solved by technology

[0004] At present, most of the existing microcomputer resonance elimination devices are put into the resonance elimination circuit after a short delay or no delay when the resonance is detected. This method has a large difference in the effect of resonance elimination in field applications, and often fails to eliminate the resonance. In extreme cases, there may even be new resonance or more serious resonance after the resonance elimination circuit is put into use. Therefore, more accurate control of the resonance elimination process is required to make it more effective and more Quickly eliminate resonance

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