Overcurrent Factor

Also called a safety factor, it is the factor by which to multiply the primary nominal current of the CT to obtain the maximum current in its primary circuit up to the limit of its class of accuracy. The standard NBR 6856/92 specifies the overcurrent factor for the protection service at 20 times the nominal current.

When the load connected to a current transformer is less than the nominal load of this equipment, the overcurrent factor is changed by being inversely proportional to said load. Therefore, the natural protection that the TC offered to the device is impaired.

The magnetizing current is that which circulates in the primary current transformer winding as a result of the magnetizing flux of the core. The magnetization curve of the current transformers supplied by the manufacturers ensures that the voltage induced in the secondary and the corresponding magnetizing current are calculated, among other parameters.             gear 21644

The magnetizing curve of a current transformer for protection service, the voltage obtained at the knee of the curve is that corresponding to a flux density B equal to 1.5 tesla (T), from which the current transformer enters saturation.