Basic introduction and application of Current Transformer

Current Transformer (CT) is a device used to measure and monitor current in power systems. Its main function is to convert high current into lower current so that it can be safely measured and monitored, while providing signals to protection devices, metering instruments and control systems. CT is widely used in the protection, metering and control of power systems and is an indispensable and important part of power systems.

Current transformers are usually composed of iron cores, windings and insulating materials. Its basic principle is to convert the current on the primary side (high current) into the current on the secondary side (low current) by electromagnetic induction. The primary winding is directly connected in series in the circuit, while the secondary winding is connected to the measuring instrument or protection device. Since the secondary current of the current transformer is a reduced proportion of the primary current, it can be measured and analyzed within a safe current range.

In power systems, CTs are widely used. First, they are used for power metering, which converts large currents into small currents so that the metering instrument can accurately measure the current, thereby measuring electric energy. This is essential for bill calculation and load management of power companies. Secondly, CTs also play an important role in protection systems. By converting high current into low current, the protection device can more easily monitor abnormal changes in current, so as to cut off the circuit in time when faults such as short circuit or overload occur, protecting equipment and personal safety. In addition, CT is also used in the equipment's condition monitoring and control system, providing real-time data and feedback to help engineers perform equipment maintenance and fault diagnosis.

When selecting a current transformer, several key parameters need to be considered. The first is the rated current, which determines the operating range and accuracy of the CT. The second is the transformation ratio, which is the ratio of the primary current to the secondary current, which directly affects the measurement accuracy. In addition, the load capacity and insulation level of the CT need to be considered to ensure its stability and reliability under various environmental conditions. Selecting the right CT can improve the operating efficiency and safety of the power system.