Laboratory verification of light component transformer
The combined transformer is a combination device of current and voltage transformers that share an insulating bushing. The two transformers are electrically independent from each other, so they can be independently verified by current transformer and voltage transformer.
Three-phase combined transformers are also known as high-voltage power metering boxes, usually two current transformers and two voltage transformers share a box or resin casting mold, the function of each is still relatively independent, can be separated from the ground one by one verification.
Three-phase voltage transformer is also a kind of combined transformer with a set of iron core, which requires three-phase voltage verification. The punctuality error of the combined transformer in the separate inspection of each station is not equal to the error in practice, because they have electromagnetic effects on each other.
However, because they have been noted in the design and manufacture of the influence quantity restricted to a certain scale, so as long as each transformer is separated and qualified, and the mutual influence quantity does not exceed the specified value, the combined transformer can be judged to be qualified.
As long as a certain influence quantity is out of tolerance in a transformer, it needs to be analyzed in combination with its practice errors. Simply put, this transformer needs to reduce the fundamental error to compensate for the additional error of other influence quantities.