Working principle and advantages of current transformer

Current transformer (CT) is a device that converts high current in the power system into low current, making the measurement of high current safer and more efficient. Its working principle is based on the law of electromagnetic induction, which can convert high current into low current that can be measured and analyzed, thus playing a key role in the power system.

The basic structure of the current transformer includes an iron core, a primary winding and a secondary winding. The primary winding is usually composed of a conductor through which the current flows. It is responsible for receiving high current and generating a magnetic field in the iron core. The secondary winding is wrapped around the iron core. It obtains the magnetic field from the primary winding through electromagnetic induction, thereby generating a low current proportional to the primary current. The current of the secondary winding can be read by a measuring instrument, a protection device or a control system, and further processed and analyzed.

The main advantage of the current transformer is that it can safely measure high currents. Since the current transformer converts high currents into lower currents, it can be measured using standard instruments, avoiding the safety risks that may be caused by directly measuring high currents. In addition, current transformers can provide high-precision measurement results, making the current data in the power system more accurate. This is essential for power metering and system protection, and helps improve the operating efficiency and safety of the power system.

In the application of power systems, current transformers have several important functions. First, they are used for power metering, helping power companies to accurately measure electricity and calculate bills by converting high currents into low currents. Second, in the protection function of the power system, CTs can monitor the changes in current in real time and quickly cut off the circuit when a fault occurs, thereby protecting the safety of power equipment and systems. In addition, CTs are also widely used in equipment status monitoring and control systems, providing necessary data support to help engineers perform fault diagnosis and maintenance.

Choosing a suitable current transformer requires considering multiple factors, including rated current, ratio, load capacity, and insulation level. The rated current determines the operating range of the CT, the ratio affects the accuracy of the measurement, and the load capacity and insulation level affect the stability and reliability of the CT in different environments. Choosing a suitable CT can improve the operating efficiency of the power system, reduce the occurrence of faults, and ensure the safety of the system.