Converter and converting device for reducing effect of zero-sequence current on transformer

Abstract

The invention discloses a converter and a converting device for reducing the effect of a zero-sequence current on a transformer. The converter comprises three primary windings and three secondary windings. The number of turns of winding of the primary windings is equal to the number of turns of winding of the secondary windings. The input ends of the three primary windings are connected with N-phase wires of the output side of a low-voltage distribution transformer, and the output ends of the primary windings are connected with the input ends of the secondary windings in a cross mode. The converting device comprises a first breaker, the converter, a second breaker, a protection control circuit, a surge protector, an open-phase safeguard, an air switch used for protecting the open-phase safeguard, a current transformer used for collecting current values of N-phase wires of the input end of a zero-sequence current converter, an ampere meter used for displaying current values collected by the current transformer, and a time relay. The proportion of the zero-sequence current flowing back to the distribution transformer is reduced, wherein the zero-sequence current is produced by an unbalance three-phase load in a low-voltage distribution network, the unbalance degree of the three-phase current can be effectively reduced, and the damage to the transformer from the zero-sequence current is reduced.

Description

technical field [0001] The invention relates to the solution to the harm caused by the zero-sequence current generated by the unbalanced three-phase load phenomenon in the low-voltage distribution network to the transformer. Background technique [0002] In the traditional three-phase four-wire distribution transformer wiring system in our country, due to various reasons such as the low-voltage single-phase load cannot be fully divided manually, and the actual operating rate of the distributed load is different, it will inevitably cause three-phase load imbalance. Phenomenon. The transformer under the unbalanced operation of the three-phase load will inevitably generate zero-sequence current, and the existence of zero-sequence current inside the transformer will generate zero-sequence magnetic flux in the iron core, and these zero-sequence magnetic flux will be on the wall of the oil tank of the transformer Or other metal components to form a loop. However, when the distri...

AI Technical Summary

Problems solved by technology

Some people may switch loads to adjust the zero-sequence current, but the uncertainty of residential electricity consumption, no matter how to adjust the load will generate zero-sequence current

Therefore, the problem that the zero-sequence current caused by the unbalanced three-phase load in the low-voltage distribution network will cause harm to the transformer needs to be solved urgently.

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