The direct test method is to bring the actual load on the secondary side, pass current from the primary side, and observe the secondary current to find the saturation point of the current transformer. However, for protection-level current transformers, the saturation point may exceed 15-20 times the rated current. When the current transformer becomes larger, it will be difficult to conduct the test on site.
In addition, the saturation point of the current transformer can also be measured through the volt-ampere characteristic test. As mentioned earlier, the saturation of the current transformer is caused by the calculation of the saturation current of the current transformer due to the excessive magnetic flux density of the core. The test method of volt-ampere characteristics is: the primary side is open, current is passed through the secondary side, and the voltage drop on the secondary side winding is measured. Since the original side of the current transformer is open, there is no demagnetization effect of the original side current, and the iron core is easily saturated under the action of a small current. Therefore, the volt-ampere characteristic test does not need to add a large current, which is easier to implement on site.https://www.ctsensorducer.com/