The function of current transformer:

The variable flow and electrical isolation in power system, power system measuring instrument, relay protection equipment to obtain a two electrical circuit current information, in order to ensure the safety and economical operation of power system, the running condition of the power equipment must be monitored and measured. But the direct access measurement and protection device is not in general a high voltage equipment, and need a large current system into small current scaling, supply measuring and protection device.

When measuring the large current of alternating current, in order to facilitate the two meter measurement, we need to transform it into a relatively uniform current (the two rated 5A of current transformer in China), and the voltage on the line is relatively high, such as direct measurement is very dangerous. 1A The current transformer plays the role of variable flow and electrical isolation. It is the sensor in power system measuring instrument, relay protection, two devices to obtain information of a circuit of electrical current, current transformer high current into low current proportion, a current transformer is connected in a system, the two side connected measuring instrument, relay protection etc..

Classification of current transformers:

The current transformer will be divided into the measurement current transformer and the protective current transformer.

The function of measuring the current transformer is used to measure (billing) and measure the current of operating equipment.

The protective current transformer is mainly matched with the relay device. When the circuit is short circuit and overload, it will provide signal to cut off the fault circuit to relay the relay, so as to protect the safety of the power supply system.