An electric arc furnace transformer secondary side overcurrent protection circuit

Abstract

The invention provides a secondary side overcurrent protection circuit of an electric arc furnace transformer. The circuit comprises the electric arc furnace transformer, a voltage transformer, a first current transformer, a breaker, a breaker tripping circuit, a second current transformer, a primary side microcomputer relay protection device and a secondary side microcomputer relay protection device, wherein the voltage transformer, the first current transformer, the breaker and the breaker tripping circuit are connected to the primary side of the electric arc furnace transformer, the second current transformer, the primary side microcomputer relay protection device and the secondary side microcomputer relay protection device are connected to the secondary side of the electric arc furnace transformer, the primary side microcomputer relay protection device is respectively connected with the voltage transformer, an opening triangle of the voltage transformer and the first current transformer, a tripping signal output interface of the primary side microcomputer relay protection device is connected into the breaker tripping circuit in parallel, the secondary side microcomputer relay protection device is connected with the second current transformer, and a signal output interface of the secondary side microcomputer relay protection device is connected into the breaker tripping circuit in parallel. Thus, overcurrent protection flexibility and reliability are increased, fault handling time and fault judging time are saved, and the service life of the transformer is prolonged.

Description

technical field [0001] The invention relates to a transformer protection circuit, in particular to an electric arc furnace transformer secondary side overcurrent protection circuit. Background technique [0002] At present, the overcurrent protection of the secondary side of the electric furnace transformer in the steel plant generally adopts the inverse time overcurrent relay as the protection element. This type of protection device belongs to the first generation relay protection device, which is composed of inductive overcurrent relays. It has unreliable action, unstable performance, and the adjusted setting value will change after a period of time. In addition, the environment of the steelmaking plant is relatively harsh, and the secondary overcurrent of the steelmaking transformer is frequent, especially in the period of arcing and well penetration, which is more prone to short-circuit overcurrent phenomenon, which aggravates the aging of the overcurrent relay performan...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide an overcurrent protection circuit for the secondary side of the electric arc furnace transformer in view of the problems existing in the prior art, which solves the problem that the traditional use of an inverse time overcurrent relay will cause the protection to refuse to operate, resulting in a leapfrog tripping problem

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