Micro current transformer site will generally use oil-free drying, but some manufacturers believe that we should pay attention to the product is full of oil, electrified heating, so that we can observe the temperature rise of the product.
This is particularly important for micro current transformers of 220kv and above, because the insulation of these products is thicker, in the oil-free State, the conduction effect is poor, even if the temperature from the outside appears to be low, and the internal insulation may be aging due to overheating and even 忐 Coke. It is also because of this, micro-current transformer in the use of, to pay attention to the best in the oil state of the product electrified heating, until the temperature rise and stabilize and then release the oil inside the product for oil-free drying.
When it is in an oil-free vacuum, the current passing through the primary winding must not be higher than 70% of the rated current.
For vacuum drying operation of micro current transformer short circuit method: First of all, it is also necessary to pay attention to remove the metal expander, installed with vacuum, oil injection and measurement of the joints or valves of the temporary cover; after that, the winding series wiring, with equal section of copper wire to make it reliable short connection; Open two wiring boxes, remove the outer wiring,
At this time, the two-arm bridge should be used to measure its two winding DC resistance, recording the corresponding temperature, using this data as the drying process to calculate the average temperature of two windings of the benchmark value.
Micro current transformer short-circuit method of vacuum drying operation, after the need to pay attention to the use of insulation resistance meter to measure the first winding insulation resistance, and then the corresponding temperature should be recorded. The vacuum drying operation of the micro-current transformer short circuit method refers to the measurement of voltammetry under the short-circuit state of a single winding. At this time, it is also necessary to pay attention to the protection winding all parallel wells to apply AC voltage to the measurement of two winding < or primary winding) Ammeter to reach the rated current of micro-current transformer.and record the applied AC voltage value.