Test method of main transformer CT (Current Transformer)

Abstract

The invention discloses a test method of a main transformer CT (Current Transformer). The test method comprises the steps of: in the case that the current transformers have all secondary loop current, leads are used for respectively connecting the high-voltage side, the middle-voltage side and the low-voltage side of the main transformer, and stride over the transformer; an isolation switch at one side and a breaker and an earthing isolation switch at the other two sides are closed; three-phase current is applied to the current transformer side of the side with the unclosed breaker and earthing isolation switch, so that the current flows through the current transformers at three sides of the transformer so as to simulate load current states at the three sides when the transformer operates normally; the current value, phase and differential current of each side are detected at the differential protection device for the main transformer, if the differential current is equal to 0, the ratio of transformation, the polarity and the wiring of the differential loop of each current transformer are correct. According to the test method of the main transformer CT, the correctness of the current value, phase and differential current of each main transformer CT can be simultaneously tested, so that the work efficiency and test quality are improved, and the electrical device is ensured to operate reliably.

Description

technical field [0001] The invention relates to a test method for a main transformer current transformer. Background technique [0002] The substation is an important hub of the high-voltage power grid, and the current transformer is an essential primary equipment in the substation. The conventional current transformer converts the primary current with a large value into a secondary current with a small value through the principle of electromagnetic induction, which is used to control Primary equipment for protection, measurement, metering, etc. In the process of operation, for the safety of the equipment, it is necessary to prevent the secondary open circuit of the current transformer, and the transformation ratio, 10% error, and polarity of the current transformer play an important role in the correct realization of functions such as protection, protection, measurement, and metering. The primary current inspection of the main transformer current transformer is mainly to c...

AI Technical Summary

Problems solved by technology

[0003] The present invention is to provide a test method for the current transformer of the main transformer, which solves the problem that the load phase test cannot be carried out due to the too small secondary current of the light-load equipment after power transmission, so that it cannot be put into operation in time

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