Features of Miniature Current Transformer operation

Miniature Current Transformer has no resistance on the primary side. The ordinary Miniature Current Transformer is a transformer with parallel resistance on the secondary side, and the output is current. The miniature current transformer in the Miniature Current Transformer is a resistor in parallel on the secondary side, and the output is a voltage. Miniature Current Transformer is divided into two ways of use: multi-turn winding type and through-core type.

The Miniature Current Transformer site generally uses oil-free drying, but more manufacturers also believe that it should be heated by electricity when the product is full of oil. This is also convenient. We observe the temperature rise of the product itself. This is particularly important for Miniature Current Transformers of 220kv and above.

Since the insulation of the Miniature Current Transformer is relatively thick, if it is in an oil-free state, the conduction effect is poor, even if the temperature is relatively low from the outside, and the internal insulation may be aging or even scorched due to overheating. In view of this, it should be energized to heat the product with oil, wait until the temperature rises and stabilizes, and then drain the oil inside the product for oil-free drying.

Therefore, the current through the primary winding on the Miniature Current Transformer cannot be higher than 70% of the rated current. Note that the metal expander must be removed, and a temporary cover plate with joints or valves for vacuuming, oiling, and measurement must be installed; the primary winding must be connected in series, and it must be connected with a copper wire of equal cross section. Make a reliable short circuit.

It is necessary to use an insulation resistance meter to measure the insulation resistance of the primary and secondary windings to the ground, and pay attention to recording the corresponding temperature; during the vacuum drying operation of the Miniature Current Transformer short-circuit method, when the primary winding is short-circuited, take care to measure the volt-ampere The characteristics of itself.