Ship transformer excitation surge current restraining device

Abstract

The invention relates to a ship transformer excitation surge current restraining device which is connected between a power supply bus and a ship transformer. The restraining device comprises a miniature transformer, a rectifier, a voltage stabilization capacitor, an inverter and an output inductor, wherein the miniature transformer, the rectifier, the voltage stabilization capacitor, the inverter and the output inductor are sequentially connected. The primary side of the miniature transformer is connected with the power supply bus and the output end of the output inductor is connected with the ship transformer. The miniature transformer is used for increasing the voltage at the secondary side and achieving the function of isolation protection. Alternating current is changed into direct current through the rectifier. A charging capacitor is used for supporting the voltage at the direct current side and flat waves at the same time. The output inductor is used for filtering out high-frequency glitches. Compared with the prior art, the ship transformer excitation surge current restraining device has the advantages that the structure is simple, excitation surge current can be effectively restrained, the responding speed is high, and the restraining effect is good.

Description

technical field [0001] The invention relates to the technical field of a ship power system, in particular to a ship transformer excitation inrush suppression device. Background technique [0002] The transformer in the large-scale ship power system has a large capacity and occupies a considerable proportion of the total ship load. It is one of the important equipment in the ship power system. When the ship is in normal operation, the excitation current of the transformer is very small, generally 1% to 2% of the rated current. When the transformer is switched on without load and put into power grid operation, due to the saturation and nonlinear characteristics of the transformer core flux, a large instantaneous current will be generated, and its amplitude may reach extremely high values. At this time, the current waveform will be severely distorted, forming an exciting inrush current. Exciting inrush current may cause malfunction of transformer relay protection, and high-or...

AI Technical Summary

Problems solved by technology

Exciting inrush current may cause malfunction of transformer relay protection, and high-order harmonics may also cause electromagnetic interference, affecting the normal operation of surrounding electronic equipment

In addition, the excitation inrush current will also cause a large transient voltage drop at the busbar, which will affect the normal operation of the ship's power system

[0003] According to the literature search, Zhang Qibing and others published "Analysis and Research on Pre-magnetization of Ship Transformer" in "Power System Protection and Control" in 2010. This paper proposes: According to the actual situation, in order to suppress the excitation generated when the transformer is closed with no load Inrush current, the usual method is to place a resistor in series in the closing circuit to limit the amplitude and transient process of the inrush current, but this method is easily affected by system parameters and transformer remanence

With the development of switch technology, phase-selection and phase-separation closing technology has appeared. Due to the difficulty in measuring transformer residual magnetism and the influence of uncontrollable factors such as the dispersion of circuit breaker action and contact pre-breakdown, there are still some difficulties in practical application.

There is also a method to suppress the excitation inrush current by changing the distribution of the primary and secondary windings, that is, to achieve the purpose of suppressing the excitation inrush current of the transformer by increasing the self-inductance of the transformer during the closing process, but this method changes the internal structure of the transformer, which may cause Unexpected impact on the steady-state operation of the transformer

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