Difference between the principle of voltage transformer and current transformer - Database & Sql Blog Articles

Probe current voltage pin 420*4450 head diameter 5.0 over current current and voltage pin

inductance

The main difference is that the working state is very different during normal operation, mainly as follows:
1) The current transformer can be short-circuited twice, but it must not be open; the voltage transformer can be opened twice, but not short-circuited
2) For the secondary side load, the primary internal impedance of the voltage transformer is small or even negligible. It can be considered that the voltage transformer is a voltage source; while the current transformer has a large internal resistance, so that it can It is considered to be a current source with an infinite internal resistance.

3) When the voltage transformer works normally, the magnetic flux density is close to the saturation value, and the magnetic flux density decreases when the fault occurs; the magnetic flux density is very low when the current transformer works normally, and the magnetic current becomes very large due to the primary side short-circuit current during the short circuit. The pass density is greatly increased, sometimes even far exceeding the saturation value.

4) Voltage transformer is a special transformer used to measure the high voltage of the power grid. It can convert the high voltage to a lower voltage according to the specified ratio, and then connect it to the meter for measurement. Voltage transformers, the primary voltage is no matter how many volts, and the secondary voltage is generally specified as 100 volts to supply the voltage required by the voltmeter, power meter and voltage coil of the kilowatt hour meter and relay.
An electrical device that converts a large current into a small current in a predetermined ratio, called a current transformer. The current on the secondary side of the current transformer is typically specified as 5 amps or 1 amp to supply the current coil current of the ammeter, power meter, kilowatt hour meter, and relay.