How to confirm the saturation of current transformer?
In order to study the working characteristics of the current transformer and confirm whether it can saturate and affect the correctness of the maintenance operation when maintaining external faults from large currents, the test can be stopped through some test methods. These measures will be introduced below. Obviously, the direct test method is to accept a practical load on the secondary side, apply current from the primary side, and observe the secondary current to find the saturation point of the current transformer. However, regarding maintenance-grade current transformers, the saturation point may exceed 15 to 20 times the rated current. When the current transformer becomes larger, it may be difficult to stop the test in the field. In addition, the saturation point of the current transformer can be measured through the volt-ampere characteristic test.
As mentioned earlier, the saturation of the current transformer is the saturation current of the current transformer calculated due to the excessive magnetic flux density of the iron core. The test method of the volt-ampere characteristic is: the original side is disconnected, the current passes through the secondary side, and the voltage drop on the secondary side winding is measured. Since the primary side of the current transformer is open, the primary side current has no demagnetization effect, and the iron core is easily saturated under small currents. Therefore, the volt-ampere characteristic test does not need to increase the large current, which is easier to complete in the field.