The current transformer TZLU-250x450 is a zero-sequence device. Structurally, it is a frame through which a three-phase cable passes. When a current passes through its cores, a zero magnetic field is formed, since all induced fields are compensated due to the same angle.
A protective relay, automation, alarm and control equipment is connected to the transformer. If a contact and a short circuit occurs between the cable cores, the balance of angles is immediately disturbed and the force that compensates for the magnetic field disappears. It is formed under the influence of currents and leads to a voltage in the transformer, which is immediately transmitted to the protective circuit, in which the relay is triggered. This prevents an emergency situation, which is alerted by an alarm device.