Demagnetization of load core of current transformer

For current transformer demagnetization, the primary winding is open, and the secondary winding is energized with power frequency current. It can be judged by the current transformer as the current value gradually increases from zero to a certain value. If the current suddenly increases suddenly, it means that the iron core has entered Magnetic saturation stage). Then slowly reduce the current to zero, and repeat this 2-3 times. Before disconnecting the power supply, the primary winding should be short-circuited before disconnecting the power supply. The core demagnetization is completed. This method is called the open-circuit demagnetization method. For some current transformers, the number of turns of the secondary winding is relatively large. If the open circuit demagnetization method is used, the open winding may generate high voltage. Therefore, a larger resistance can be connected to the secondary winding. The primary winding is energized with current, which gradually changes from zero to the maximum allowable current of the primary winding of the transformer, and then to zero, and repeats 2-3 times. The iron core may not be completely demagnetized due to the load. Since the maximum current of the primary winding is limited, it may burn the primary winding if it is too large. If the voltage generated by the secondary winding connected to the load is not too high, the load resistance of the secondary winding can be increased. This can improve the demagnetization effect.