Describe in detail what the current transformer does -

A current transformer is a current switching device. It converts high-voltage and low-voltage large currents into low-voltage low-current supply meters and relay protection devices and isolates the meters and protection devices from high-voltage circuits. The secondary side current of the current transformer is 5 amps, which makes the use of measuring instruments and relay protection equipment safe and convenient, and also makes it possible to standardize its manufacture. The structure of a current transformer is composed of an iron core, a primary winding, a secondary winding, terminals and insulating supports. The number of turns of the primary winding of the current transformer is small, and it is connected in series in the line that needs to measure the current, and a large measured current flows through it. inside. The secondary circuit of the current transformer is not allowed to open. When the current transformer is working, its secondary circuit is always closed, but because the impedance of the series winding of the measuring instrument and the maintenance equipment is very small, the working environment of the current transformer is close to the short circuit state, and the magnetizing force generated by the primary current is greatly increased. All are compensated by the secondary current, the total magnetic flux density is not large, and the potential of the secondary winding is not large. When the current transformer is open, the impedance of the secondary circuit is infinite, the current is equal to zero, and the primary current completely becomes the excitation current, which generates a high potential in the secondary winding, threatening personal safety, and forming secondary insulation of the appearance, protective equipment, and transformer. damage. The secondary circuit of the current transformer must be grounded to avoid primary insulation breakdown and secondary high voltage in series, jeopardizing personal safety and damaging equipment.