Detection system for monitoring bridge arm conducting state in commutating device

Abstract

The invention relates to a detection system for monitoring conducting state of bridge arms in a rectifying device, which comprises six bridge arms, and is characterized by also comprising bridge arm current monitoring and displaying units, an oscillating source, a reset button, a current presence detecting unit and a fault indicating and memory retaining unit. The total number of the bridge arm current monitoring and displaying units is six, and each circuit has the same structure; one bridge arm current monitoring and displaying unit consists of a bridge arm mutual inductor, a rectifying electric bridge, an amplifying comparator, a multi-frequency oscillator and a light emitting diode, which are connected; one end of the reset button M is earthed, and the other end of the reset button M is connected with reset pins of six multi-frequency oscillators of the bridge arm current monitoring and displaying units; and the oscillating source is connected to input pins of the six multi-frequency oscillators of the bridge arm current monitoring and displaying units. The detection system adopts a digital chip with higher integration level, a digital arithmetic circuit and the light emittingdiode so as to quickly, duly and accurately reflect conducting conditions of each bridge arm, and uses the light emitting diode to display conducting signals of the bridge arms.

Description

technical field [0001] The invention belongs to the technical field of electric transmission, in particular to a detection system for monitoring the conduction state of a bridge arm in a rectification device. Background technique [0002] At present, in my country's metallurgy, steel rolling, mining and other fields, all-digital high-power AC and DC drive systems are widely used. For example, AC-AC frequency conversion main drive for plate hot rolling, mine winch main drive, cold rolling mill DC drive, and high-power electrolysis power supply and other electrical drive systems. Among them, the thyristor rectifier is a very important power component in the above transmission system. The device is composed of six thyristor components (thyristor plus radiator), which are connected through busbars to form a three-phase bridge fully controlled rectifier circuit, which is placed in the cabinet. The six groups of thyristors can be regarded as six bridge arms, and the controller s...

AI Technical Summary

Problems solved by technology

However, if a trigger failure occurs, such as the thyristor cannot be triggered, or the trigger signal fails, the fast fuse cannot be fused, and the bridge arm is still disconnected.

At this time, it is impossible to detect which bridge arm is faulty

Therefore, this scheme can only protect the thyristor, but cannot completely reliably detect the conduction of the bridge arm

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