Thyristor-assisted arc-extinguishing hybrid on-load tap-changer

Abstract

A thyristor-assisted arc-extinguishing hybrid on-load tap switch. The switch comprises a main current loop and a thyristor module connected to the main current loop in parallel. The main current loop comprises a first contact switch, a main loop switch and a second contact switch connected sequentially. The main loop switch comprises two static-state flow guiding contacts separated from each other, and a movable switch moveably connected to the two static-state flow guiding contacts. A thyristor module establishes a trigger condition of a thyristor by means of a potential difference in a mechanical switch contract enabling process so as to make the triggering of the thyristor module more safe and reliable. When a continuous current of the thyristor in the thyristor module lasts for less than 12 milliseconds, arcing does not occur in a triggering process, switch transition is stable, and no arc shock and heat is generated.

Description

technical field [0001] The invention relates to an on-load tap-changer, in particular to a hybrid on-load tap-changer which utilizes a thyristor to assist arc extinguishing. Background technique [0002] The on-load tap changer is an important component of power voltage regulating transformers and industrial voltage regulating transformers. Through it, the tap position of the transformer can be adjusted without interrupting the load current, and then the fine-tuning of the transformation ratio can be realized to change the voltage of the transformer. Output voltage or output capacity; however, traditional on-load tap-changers will generate arcs when switching, and the generation of arcs will inevitably lead to energy loss and pollution of transformer oil. [0003] Thyristor on-load tap-changers can completely avoid arcing during gear switching. With the continuous development of power electronic devices, performance parameters and reliability indicators continue to improve. ...

AI Technical Summary

Problems solved by technology

[0004] In order to improve the safety of the thyristor switch, Zhao Gang from the School of Electrical Engineering of Xi'an Jiaotong University studied a thyristor-based arc-free on-load tap-changer, whose structure is as follows figure 1 As shown, in the low-voltage simulation test of this tap changer model, it is found that the arc extinguishing switch cannot always effectively extinguish the arc, and its arc extinguishing characteristics are related to the direction of the arc current and the status of the switch. The test also found that it is used for the bypass switch current The trigger conduction status of the forward and reverse thyristors when the switch is closed is closely related to the sequence of closing nodes 4 and 5 and the direction of the arc current when they are closed. This problem has not been solved in its open literature. Not commercially available

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