What Is a Current Transformer?

A current transformer is a commonly used power measurement equipment. It is mainly used for mutual inductance detection of current in power systems. It is usually used together with a voltage transformer to complete the measurement of current, voltage, and other parameters in power measurement. This article will introduce the structural composition, current transformer working principle, and current transformer application in order to better understand the working principles and applications of current transformers.

What are the structural components of a current transformer?

The current transformer, a common electrical measuring instrument, is used to measure high-voltage current and convert the measured current into a signal that conforms to the standard current size. Its main structure includes an iron core, winding, magnetic permeation path, and shell.

First of all, the iron core is one of the important components of the current transformer, usually made of iron material with low magnetic permeability. This part is capable of creating a magnetic flux when current flows and concentrates the effect of the measured current on the winding, thereby generating an induced electromotive force.

Secondly, the winding is another core component in the current transformer. A winding is a set of coils wound around an iron core, through which an input current through a current transformer generates a magnetic field. As the magnetic field changes, this part can generate an induced electromotive force and output a signal proportional to the input current.

In addition, the flux path is another important part of the current transformer. It connects the core and the winding together, along the permeable path, the magnetic flux can flow through the winding smoothly. This part is usually made of iron core or other high-permeability material.

Finally, the shell is the protective cover of the current transformer, which can protect the inside of the current transformer from external interference and damage. The enclosure is usually made of an enclosure material such as plastic or metal.

What is the current transformer working principle?

A current transformer is a sensor used to measure the current in the grid. The current transformer working principle is based on the law of electromagnetic induction, that is, when an electric current passes through a wire, a magnetic field is generated. The current transformer passes the wire under test through a coil, and the iron core in the coil is connected to a secondary coil. When current passes through the wire under test, it creates a magnetic field in the core, which is transmitted through the core and the secondary coil.

Electromagnetic induction in the secondary coil produces a secondary voltage proportional to the current in the wire being measured. Usually, there is a plug-in transformer ratio in the secondary coil, through which the secondary voltage can be reduced to a voltage value within a safe range, and then transmitted to the measuring device as a measurement signal.

Since the current transformer only induces a current in the secondary coil and is not directly connected to the wire under test, the current transformer can provide a non-contact method of measuring current while protecting the operator and the measuring equipment. Therefore, current transformers are widely used in power systems to measure current, monitor the status and operation of the power grid, and protect power equipment.

What is the application of current transformers?

Protection and control in power systems: Current transformers can be used to measure high currents and output low current signals suitable for protection and control systems. In this way, problems such as current overload, short circuits, and ground faults in the power system can be detected, and measures can be taken in time to avoid accidents.
Power monitoring and metering: Current transformers can be used to measure current and power in power systems for power metering and monitoring. This is very important for power companies and can help them better understand the operation of the power system, thereby improving the stability and reliability of the power system.
Industrial automation control: Current transformers are also widely used in industrial automation control, such as motor control, lighting control, etc. By measuring the current, the control and monitoring of equipment such as motors and lighting can be realized, thereby improving the efficiency and quality of industrial production.

In conclusion, you must clearly know the basic information about current transformers. If you want to know the types of current transformers, the advantages and disadvantages of current transformers, and current transformer installation, you can read our other articles.