Detailed description of the current transformer has what function

A current transformer is a current conversion device. It transforms high voltage and low voltage currents into lower voltage currents to supply appearance and maintenance equipment and to isolate appearance and maintenance equipment from high voltage circuits. The current transformer's secondary current is 5A, which makes it safe and convenient to measure the appearance and relay maintenance equipment, and also enables it to be standardised in production.

The structure of the current transformer is composed of iron core, primary winding, secondary winding, terminal and insulation support. The primary winding of the current transformer turns less, connected in series in the demand for measuring current in the line, the flow of large measured current, the secondary winding turns more, connected in series in the measurement of the appearance or relay maintenance circuit.

　　The secondary circuit of the current transformer is not allowed to open circuit. Current transformer in operation, its secondary circuit has always been closed, but because of the measurement of the appearance and maintenance equipment series winding impedance is very small, the current transformer operation is close to the short-circuit situation, the primary current magnetising force is greatly offset by the secondary current, the total flux density is not large, the secondary winding potential is not large. When the current transformer open circuit, the secondary circuit impedance is infinite, the current is equal to zero, the primary current has completely become the excitation current, in the secondary winding seizure of a very high potential, hostage to personal safety, constitute the appearance of the maintenance equipment, transformer secondary insulation damage.

　　The secondary circuit of the current transformer must be grounded to avoid a breakdown of insulation, the secondary string of high pressure, hostage to personal safety, damage to equipment.