The transformer is divided into voltage transformer and current transformer. Its main functions are: to accurately transfer the voltage and current information of primary system to the relevant equipment of secondary side; to transform the high voltage and current of primary system into the low voltage (standard value) and small current (standard value) of secondary side, so as to standardize and miniaturize the measurement, metering instrument, relay and other devices The insulation requirements of the secondary equipment are reduced; the secondary side equipment and the secondary system are well isolated from the high-voltage equipment of the primary system in electrical aspects, so as to ensure the safety of the secondary equipment and personnel.
Both are special transformers! Commonly used in instrument signal acquisition,
Voltage transformer (PT) is used for voltage conversion. Generally, it is high voltage (such as 110KV, 10kV) that can be converted into normal voltage that can be used by ordinary instrument, 380V, 220V, so that the instrument can display. The secondary circuit of voltage transformer can be opened, but it shall not be short circuited
Current transformer (CT) converts the large current signal (several hundred amperes, several thousand amperes) into the small current which is easy to use for the current instrument.
The secondary current transformer can be short circuited, but shall not be open circuited.https://www.ctsensorducer.com/