Arc-less on-load tap-changer for transformer

Abstract

The invention discloses an arc-less on-load tap-changer for a transformer, which comprises at least two fixed contacts, a moving contact, a first two-way switch and a second two-way switch, wherein the fixed contacts are connected with a transformer winding, and the moving contact is connected with a winging terminal and is dragged by a motor under the driving action of a selector switch; one end of each fixed contact is respectively connected with the different taps of a transformer winding; the moving contact comprises the first two-way switch, a through contact and a second two-way switch, wherein one end of the first two-way switch, one end of the through contact and one end of the second two-way switch are fixedly connected with the winding terminal; and the other ends of the first two-way switch, the through contact and the second two-way switch of the moving contact are successively connected with the fixed contacts in the moving process. The arc-less on-load tap-changer for the transformer can realize the arc-less switch of the tap of the transformer winding, and has the advantages of low cost and reliable operation.

Description

technical field [0001] The invention relates to the field of transformers, in particular to a transformer arcless on-load tap changer. Background technique [0002] In the prior art, due to changes in the primary side voltage (grid voltage), load size and nature of the distribution transformer in operation, the secondary side voltage may have a large change. Distribution transformers in my country cover voltage levels below 35kV. In order to maintain the load voltage within the specified range (±5% UN) and ensure the normal needs of electrical equipment, the distribution transformer must be adjusted. [0003] The basic principle of transformer on-load voltage regulation is to draw several taps from the coil on one side of the transformer (usually the high-voltage side), and switch from one tap to Another tap is used to change the effective number of turns to adjust the voltage. The on-load tap changer is composed of two parts, one part is the transformer body, which is dif...

AI Technical Summary

Problems solved by technology

[0008] The existing problems are: the mechanical tap changer generates arc during the tap switching process, causing contact ablation; when the vacuum tap changer adopts a fixed structure, the off-state vacuum switch is always under voltage, and it needs to be designed according to the system voltage. Due to the slow opening and closing time of the vacuum switch in the type structure, the moving speed of the moving contact needs to be coordinated with it, which is difficult to control

In this scheme, since the thyristor is a semi-controlled device, it is difficult to realize the timing coordination of the thyristor on and off when the moving contact moves.

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