Transformer excitation inrush current suppression device and suppression method based on residual magnetism estimation

Abstract

The invention relates to the technical field of transformer excitation inrush current suppression in power systems, in particular to a transformer excitation inrush current suppression device and suppression method based on residual magnetism estimation. Based on the estimation of residual magnetism of a transformer, no-load switching is carried out on the transformer by controlling the closing time of a circuit breaker, and thus, excitation inrush current is suppressed. Excitation inrush current suppression is realized by the transformer excitation inrush current suppression device as well asthe original voltage and current transformers and transformer outlet circuit breaker of a power system. The transformer excitation inrush current suppression device includes a CPU processing module board, an AT board (namely, TA / TV module), an MOSFET module board, a power module board and a bus board. The residual magnetism in the iron core can be estimated accurately. The optimal closing time can be calculated. A closing signal can be sent to the circuit breaker according to the mechanical characteristics of the circuit breaker. The excitation inrush current at the no-load closing time of the transformer can be reduced. The impact of the excitation inrush current to the transformer can be reduced. The transformer differential protection action can be avoided. Harmonics caused by no-loadclosing can be reduced. The influence of the power transmission of surrounding DC converter stations can be avoided.

Description

technical field [0001] The invention relates to the technical field of transformer excitation inrush suppression in power systems, in particular to a transformer excitation inrush suppression device and suppression method based on residual magnetism estimation. It is based on the estimation of the residual magnetism of the transformer and realizes the suppression of the excitation inrush current by controlling the moment when the circuit breaker is switched on and switching the transformer without load. Background technique [0002] As an important equipment for the development of modern industry, power transformers, the iron core components made of ferromagnetic materials are the most critical parts that directly affect the electrical performance of transformers. A device with a closed ferromagnetic material core structure, in the process of being continuously put into operation and then cut out of operation, due to the hysteresis characteristics of ferromagnetic materials,...

AI Technical Summary

Problems solved by technology

The high current of the inrush current will generate a large mechanical force in the winding to deform the winding, thereby reducing the short-circuit resistance and service life of the transformer

The high-order harmonics in the excitation inrush current will increase the electromagnetic loss, cause the backflow of the transformer, and easily cause damage to the sensitive equipment of the power system

At the same time, the excitation inrush current will also cause periodic distortion of the bus voltage, resulting in the failure of DC commutation in the converter station. The prediction function frequently adjusts the trigger angle of the inverter side, causing DC power fluctuations

In the process of connecting the transformer to the grid, in addition to causing great damage to the transformer itself, the inrush current will also deteriorate the power supply quality of the power system. Not only cannot the energy be effectively integrated into the grid, but it will also cause a great drag on the grid itself

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