Current Transformer of Personal and instrument Safety

Current Transformer of Personal and instrument Safety Points : Current Transformer of Personal and instrument Safety One of the terminals of the secondary winding is earthed so as to protect equipment and personnel in the vicinity in the event of an insulation breakdown in the current Transformer. As already explained when secondary of C.T. is open, high voltages are induced in it. This may be dangerous to a person dealing with the equipment; it may cause damage to the C.T. insulation. In addition, the core may he left permanently magnetized causing considerable ratio and phase angle errors. Such errors can be removed by demagnetizing the core by passing a large primary current (with secondary open, and gradually reducing it to zero).