Wiring structure for low voltage signal double winding transformer partial discharge test

Abstract

The invention discloses a wiring structure for a low voltage signal double winding transformer partial discharge test. The middle of the first terminal and the second terminal of a partial discharge-free excitation transformer is grounded. The first terminal and the second terminal are connected with a compensation reactor combination respectively. One terminal of the phase winding of a first low voltage winding is connected with the first terminal of the partial discharge-free excitation transformer, and the other two terminals of the phase winding of the first low voltage winding are interconnected. The neutral point terminal of the first low voltage winding is connected with one terminal of the phase winding of a second low voltage winding. The two terminals of the phase winding of the second low voltage winding are interconnected. The neutral point terminal of the second low voltage winding is connected with the second terminal of the partial discharge-free excitation transformer. The bushing end screen terminal of the tested phase at the high voltage side of the tested low voltage side double winding transformer is grounded via a detection impeder, and the detection impeder is connected with the partial discharge detector.

Description

technical field [0001] The invention relates to a wiring structure for a partial discharge test of a low-voltage side double-winding transformer. Background technique [0002] In recent years, in order to save investment costs, large power plants generally design only one start-up backup transformer. This type of transformer has a special structure and has the characteristics of large capacity, large transformation ratio, and double windings on the low-voltage side. During the partial discharge test, since the capacitive current of the high-voltage winding is coupled to the pressurized side through the transformation ratio, and the test voltage of the pressurized side is generally low due to the reason of the wiring group, this makes the reactive current of the transformer pressurized side It is too large to exceed the capacity of the test equipment, and the conventional equipment configuration of the debugging unit is difficult to meet the test requirements. [0003] Duri...

AI Technical Summary

Problems solved by technology

During the partial discharge test, since the capacitive current of the high-voltage winding is coupled to the pressurized side through the transformation ratio, and the test voltage of the pressurized side is generally relatively low due to the reason of the wiring group, this makes the reactive current of the transformer pressurized side Too large exceeds the capacity of the test equipment, and the conventional equipment configuration of the debugging unit is difficult to meet the test requirements

[0003] During the long-term operation of the transformer, some weak parts of its internal insulation will undergo partial discharge under the action of high field strength, which will lead to a decrease in insulation performance. Under the long-term action of severe partial discharge, it will even cause the breakdown of the transformer. Therefore, Affect the safe and reliable operation of transformers, especially ultra-high voltage transformers, under long-term working voltage

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