Method for overcoming flashover of iron core of large-scale starting autotransformer to ground

Abstract

The invention discloses a method for overcoming flashover of an iron core of a large-scale starting autotransformer to the ground. The method comprises the steps of enabling the voltage of the iron core of the large-scale autotransformer to be distributed unevenly during starting, generating a potential between main grounding and auxiliary grounding or between the auxiliary grounding and the auxiliary grounding, and generating a loop current, and enabling the large-scale autotransformer to be in multi-point grounding, after starting, enabling the voltage of the iron core of the large-scale autotransformer to be uniformly distributed, enabling the auxiliary grounding to fail under the action of the resistor, only enabling the main grounding to work, and enabling the large-scale autotransformer to be in single-point grounding at the moment. Compared with the prior art, multi-point grounding is creatively carried out in the starting stage of the transformer, flashover caused by high voltage between iron cores at the starting moment is avoided through multi-point grounding, single-point grounding is achieved in the running stage of the transformer, and a loop current is avoided in therunning process.

Description

technical field [0001] The invention relates to a method for overcoming the flashover of a transformer during start-up. Background technique [0002] When the transformer is in normal operation, the iron core must be reliably grounded at one point. If there is no grounding, the floating voltage of the iron core to the ground will cause intermittent breakdown and discharge of the iron core to the ground. After the iron core is grounded at one point, the floating potential of the iron core will be eliminated. possible. However, when the iron core is grounded at more than two points, the uneven potential between the iron cores will form a circulation between the grounding points, and cause the multi-point grounding of the iron core to generate heat. Existing large-scale dry-type transformers (above 10000kVA) basically have a huge iron core. Due to the large energy change at startup, the instantaneous voltage distribution of the iron core is extremely uneven. When a single poin...

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Problems solved by technology

But when the iron core is grounded at more than two points, the uneven potential between the iron cores will form a circulation between the grounding points, and cause the iron core to be grounded at multiple points and generate heat.

Existing large-scale dry-type transformers (above 10000kVA) basically have a huge iron core. Due to the large energy change at startup, the instantaneous voltage distribution of the iron core is extremely uneven. When a single point is grounded, the iron core far away from the ground will generate High voltage, core-to-ground flashover occurs

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